Noble metal simple substance @ nitrogen-doped carbon hollow sphere material, lithium metal negative electrode active material, lithium metal negative electrode and preparation and application thereof
阅读说明：本技术 贵金属单质@掺氮碳空心球材料、锂金属负极活性材料、锂金属负极及其制备和应用 (Noble metal simple substance @ nitrogen-doped carbon hollow sphere material, lithium metal negative electrode active material, lithium metal negative electrode and preparation and application thereof ) 是由 赖延清 洪波 姜怀 张伟 张治安 张凯 方静 于 2019-08-31 设计创作，主要内容包括：本发明属于锂金属电池负极材料领域。具体公开了一种贵金属单质@掺氮碳空心球材料,包括内嵌均匀银纳米粒子的掺氮碳空心球。本发明还提供了双亲锂性负极活性材料、负极及其制备方法。本发明提供的材料具有巨大的比表面、良好的亲锂性和电子传导性能,能够有效地缓解体积变化,降低局部电流密度和锂沉积的形核过电位,实现该3D锂金属负极在大电流密度高锂载量下持续、稳定、均匀地沉积/溶解,有效抑制锂枝晶的生长,显著提升锂金属电池的库伦效率和循环寿命。(The invention belongs to the field of lithium metal battery cathode materials. In particular discloses a noble metal simple substance @ nitrogen-doped carbon hollow sphere material which comprises a nitrogen-doped carbon hollow sphere embedded with uniform silver nano particles. The invention also provides an amphiphilic lithium negative active material, a negative electrode and a preparation method thereof. The material provided by the invention has a huge specific surface, good lithium affinity and electron conductivity, can effectively relieve volume change, reduce local current density and nucleation overpotential of lithium deposition, realize continuous, stable and uniform deposition/dissolution of the 3D lithium metal cathode under high current density and high lithium loading capacity, effectively inhibit the growth of lithium dendrites, and remarkably improve the coulombic efficiency and cycle life of a lithium metal battery.)
1. A noble metal simple substance @ nitrogen-doped carbon hollow sphere material is characterized in that: comprises a carbon hollow sphere and lithium-philic noble metal nano particles compounded on the inner wall of the carbon hollow sphere; the shell material of the carbon hollow sphere is a nitrogen-doped carbon material.
2. The dual lithium-philic 3D lithium metal negative active material of claim 1, wherein: the carbon hollow ball is at least one of spherical, rugby-ball, disc-shaped, persimmon-shaped and red blood cell-shaped, and is preferably spherical;
preferably, the thickness of the shell of the carbon hollow ball is 15-150 nm;
preferably, the carbon hollow sphere is at least one of nitrogen-doped graphitized carbon and amorphous carbon;
preferably, the shell material of the carbon hollow sphere contains 5-10.5 at% of nitrogen.
3. The noble metal element @ nitrogen-doped carbon hollow sphere material of claim 1, wherein: the noble metal nano particles are nano simple substances of at least one of silver, platinum, ruthenium, rhodium, palladium, osmium and iridium, and preferably are nano silver simple substances;
preferably, the particle size of the noble metal nanoparticles is 0.1-100 nm;
preferably, the content of the noble metal nanoparticles in the noble metal simple substance @ nitrogen-doped carbon hollow sphere material is 3 at.% to 10 at.%.
4. The preparation method of the noble metal simple substance @ nitrogen-doped carbon hollow sphere material as claimed in any one of claims 1 to 3, is characterized in that: providing a template capable of being etched and removed; forming the noble metal nano particles on the surface of the template by using a chemical plating method, then carrying out carbon coating and roasting treatment, and finally removing the template to obtain the nano-metal template.
5. The preparation method of the noble metal element @ nitrogen-doped carbon hollow sphere material as claimed in claim 4, wherein: the preparation method of the nano silver particle material with the noble metal nano particles comprises the following steps:
step (1): template activation:
mixing SiO2Placing the template in a solution of a surfactant for surface activity, and separating to obtain surface-activated SiO2A template;
the surface active agent is sodium hydroxide, stannous chloride and PbCl2At least one of mercaptopropyltrimethoxysilane;
the concentration of the surface active agent in the solution of the surface active agent is 0.01-0.2 mol/L;
step (2): chemical plating and silver plating:
surface-activated SiO2Template and AgNO3The solution is deposited with even silver nano particles under the action of a reducing agent to obtain SiO2@ Ag; the AgNO3The concentration of the solution is 0.002-0.1 mol/L;
and (3): coating with nitrogen-doped carbon:
mixing SiO2The @ Ag template is put into the solution of nitrogen-containing carbon monomer for in-situ polymerization, and SiO2The precursor is coated with carbon and then roasted to obtain SiO2@[email protected]；
The nitrogen-containing carbon monomer is at least one of dopamine, resorcinol, glucose, vinylpyrrolidone and tannic acid, preferably dopamine; in the in-situ polymerization starting solution, the concentration of the nitrogen-containing carbon monomer is 0.1-10 g/L;
and (4): demoulding plate:
mixing SiO2@ Ag @ C is placed in an etchant solution and is treated by a stripper plate;
and the concentration of the etchant is 2-8 mol/L NaOH solution.
6. The preparation method of the noble metal element @ nitrogen-doped carbon hollow sphere material as claimed in claim 5, wherein: the SiO2The average diameter of the template is 200-1000 nm, and the more preferable diameter is 300-500 nm;
preferably, the reducing agent is at least one of formaldehyde, acetaldehyde, propionaldehyde and glucose, preferably glucose;
in the step (3), the polymerization temperature is 20-50 ℃; the polymerization time is 10-48 h;
the roasting temperature is 700-950 ℃; the roasting time is 2-8 h.
7. The preparation method of the noble metal element @ nitrogen-doped carbon hollow sphere material as claimed in claim 5, wherein:
the temperature of the plate etching and stripping process is 30-80 ℃;
the time of the plate etching and stripping process is 6-24 hours.
8. The double lithium-philic composite lithium metal cathode active material is characterized by comprising a carbon hollow ball with a closed filling cavity, a lithium-philic layer compounded on the inner wall of the carbon hollow ball, and a lithium metal simple substance filled in the filling cavity of the carbon hollow ball material; the lithium-philic layer is the noble metal-lithium alloy;
preferably, the material is obtained by filling lithium into the noble metal simple substance @ nitrogen-doped carbon hollow sphere material according to any one of claims 1 to 3 or the noble metal simple substance @ nitrogen-doped carbon hollow sphere material prepared by the preparation method according to any one of claims 4 to 7 by using a melting or electrodeposition method, and performing a lithiation reaction.
9. A double lithium-philic composite lithium metal negative electrode, which comprises a current collector, conductive carbon and an active material layer compounded on the surface of the current collector, wherein the active material layer comprises the double lithium-philic composite lithium metal negative electrode active material as claimed in claim 8 and a binder;
the preparation method of the double lithium-philic composite lithium metal negative electrode comprises the following steps:
(1): slurrying the double lithium-philic composite lithium metal negative electrode active material, conductive carbon and a binder, coating the slurried materials on a current collector, and drying to obtain the lithium-philic composite lithium metal negative electrode active material;
or (2): the noble metal element @ nitrogen-doped carbon hollow sphere material as defined in any one of claims 1 to 3 or the noble metal element @ nitrogen-doped carbon hollow sphere material prepared by the preparation method as defined in any one of claims 4 to 7 is slurried with a solvent and then coated on a current collector; and (4) obtaining a negative electrode precursor, and filling lithium metal into the negative electrode precursor to obtain the lithium-ion battery.
10. The application of the double lithium-philic composite lithium metal negative electrode is characterized in that the double lithium-philic composite lithium metal negative electrode is used as a negative electrode of a lithium metal battery;
preferably, the lithium metal battery is a lithium sulfur battery, a lithium iodine battery, a lithium selenium battery, a lithium tellurium battery, a lithium air battery or a lithium transition metal oxide battery.
Technical Field
The invention belongs to the technical field of electrode materials of lithium metal batteries, and particularly relates to a negative electrode of a lithium metal battery.
Background
The negative electrode of the metal lithium battery is usually a simple substance of metal lithium, the action mechanism in the battery is the deposition and dissolution of the metal lithium, and the charge and discharge mechanism is as follows: charging of Li++ e ═ Li; discharge Li-e ═ Li+(ii) a What occurs with the negative electrode unlike conventional lithium ion batteries is the intercalation and deintercalation of lithium ions in the graphite negative electrode. Lithium metal batteries and lithium ion batteries are brand-new battery systems with different mechanisms.
The theoretical specific capacity of lithium metal is 3860mAh g-1The lowest electrochemical potential, 3.04V (relative to a standard hydrogen electrode), has been considered to be the most potential negative electrode material for next generation lithium battery systems. However, lithium metal has strong activity and has serious side reaction with electrolyte, so that a huge volume effect is generated in the repeated deposition/dissolution process of the lithium metal, and the circulation stability is reduced; on the other hand, an SEI film formed on the interface of lithium metal and electrolyte is uneven and unstable, and uncontrollable lithium dendrites are easily generated in the repeated charging and discharging process, so that huge potential safety hazards are caused, and the popularization and the use of the lithium metal negative electrode are influenced.
At present, the volume effect in the lithium metal circulation process is mainly eliminated by constructing a 3D porous skeleton structure, and the carbon material becomes an important host material for inhibiting the volume change of the lithium metal due to the advantages of light weight, good conductivity, strong toughness and the like, for example, the multi-walled carbon nanotubes are used for compacting into interlayers with different thicknesses by the lucite et al [ ding Y, Lu H, Cao Y, et al. The multi-walled carbon nanotube interlayer can form an ideal conductive network, so that rapid electron conduction is ensured; compared with pure lithium metal, the high specific surface area can effectively reduce local current density; however, under high current density, lithium metal is easy to be preferentially deposited at a place where electrons are easily available, so that lithium deposition is uneven, uncontrollable lithium dendrites are caused, coulombic efficiency is reduced, and cycle life is shortened.
Aiming at the defects of a 3D Carbon skeleton, such as Fan H, Dong Q, Gao C, et al, encapsulating Metallic Lithium inter Carbon Nanocages Enable Low Volume Effect and Dendrite-Free Lithium Metal Anode [ J ], ACS applied materials & interfaces,2019 ] the Lithium is deposited in a Carbon nano cage by utilizing the abundant spatial structure and huge specific surface area of the commercialized Carbon nano cage, and the thin-wall Carbon shell plays a good role of an artificial SEI film, so that the interface reaction is reduced, and the Lithium cathode with a Low Volume Effect is obtained. Flood wave and the like [ Hong B, Fan H, Cheng X B, et al, coating uniformity deposition of lithium metal in 3D Janus hosts [ J ] Energy Storage Materials,2019,16:259-266 ] improve the lithium affinity of the 3D carbon fiber structure by carrying out gold spraying treatment on carbon paper far away from a diaphragm surface, guide lithium to be uniformly deposited in a three-dimensional structure, and effectively improve the coulombic efficiency and the cycling stability. Although much progress has been made in the current research, the maintenance of uniform deposition of lithium at high current densities, low volume effects and interfacial side reactions have yet to be further investigated.
The invention content is as follows:
aiming at the problems of uneven deposition and poor electrical performance, particularly poor cycle performance, of the existing lithium metal cathode material in the cycle process, the invention provides a noble metal simple substance @ nitrogen-doped carbon hollow sphere material (the material can also be a double lithium-philic hollow carbon sphere or a double lithium-philic hollow carbon skeleton for short), aiming at selectively inducing the uniform deposition of lithium, improving the uniformity of lithium deposition under high current, reducing the volume effect and the interface side reaction and improving the cycle performance of the lithium metal cathode.
The second purpose of the invention is to provide a preparation method of the noble metal simple substance @ nitrogen-doped carbon hollow sphere material.
The third purpose of the invention is to provide a lithium metal negative active material (also referred to as a lithium active material) comprising the noble metal simple substance @ nitrogen-doped carbon hollow sphere material.
The fourth purpose of the invention is to provide a preparation method of the lithium metal negative electrode active material.
A fifth object of the present invention is to provide a lithium metal negative electrode comprising the lithium metal negative electrode active material.
A sixth object of the present invention is to provide a method for producing a lithium metal negative electrode (also referred to as a lithium negative electrode in the present invention).
A seventh object of the present invention is to provide a lithium metal battery comprising the lithium metal negative electrode.
A noble metal simple substance @ nitrogen-doped carbon hollow sphere material comprises a carbon hollow sphere with a closed filling cavity and lithium-philic noble metal nano particles compounded on the inner wall of the carbon hollow sphere; the shell material of the carbon hollow sphere is a nitrogen-doped carbon material.
The invention provides a 3D hollow carbon skeleton structure with double lithium affinity, wherein the inner wall of nitrogen-doped carbon is uniformly compounded with special substances of noble metal nano particles and the morphological characteristics of the special substances.
The research of the invention finds that the carbon wall material characteristics of the noble metal simple substance @ nitrogen-doped carbon hollow sphere material and the morphological characteristics of the noble metal nano particles compounded on the inner wall are the key points for realizing the synergistic action of the two. Further research finds that the nitrogen doping amount, morphology and thickness of the carbon hollow sphere are accurately controlled, the cooperativity of the carbon hollow sphere and the noble metal nanoparticles can be further improved by further matching with the control of the particle size and content of the noble metal nanoparticles, the uniform deposition of the induced lithium metal in the circulation process can be further improved, the problem of lithium dendrite can be fundamentally solved, and the circulation stability under a larger current density is remarkably improved.
The carbon skeleton material with large specific surface area, rich space structure and excellent lithium affinity is designed, and is applied to the lithium metal cathode, so that the huge volume effect of lithium metal in the deposition/dissolution process can be eliminated, lithium can be uniformly deposited in the inner cavity of the hollow carbon sphere, the interface side reaction is reduced, the growth of lithium dendrites is effectively inhibited, and the finally obtained lithium metal composite electrode has high coulombic efficiency and long cycle life under a relatively high current density.
Preferably, the carbon hollow sphere is of a hollow structure with an independent inner chamber sealed by a carbon shell, and is at least one of a sphere shape, a rugby shape, a disc shape, a persimmon shape and a red blood cell shape, and is preferably a sphere shape.
Preferably, the thickness of the shell of the carbon hollow ball is 15-150 nm; further preferably 15 to 80 nm; more preferably 15 to 50 nm.
Preferably, the specific surface of the carbon hollow sphere is 50-1000 m2(ii)/g; more preferably 103 to 401m2/g。
The carbon hollow sphere is made of a nitrogen-containing carbon material, preferably, the carbon hollow sphere is at least one of nitrogen-doped graphitized carbon and amorphous carbon, and more preferably, the carbon hollow sphere is made of amorphous carbon.
The nitrogen doping mode is in-situ doping or artificial doping, and in-situ doping is preferred.
In the carbon hollow sphere, the nitrogen content is 5-10.5 at.%; further preferably 7 to 10.5 at.%. Research shows that under the control of the content of the noble metal nanoparticles in the range, the synergistic effect of the noble metal nanoparticles and the noble metal nanoparticles on the inner wall is excellent, and the initial capacity and the cycle performance can be obviously improved.
According to the noble metal simple substance @ nitrogen-doped carbon hollow sphere material, a carbon shell of a hollow carbon sphere is a lithium-philic framework, and nano lithium-philic noble metal particles are uniformly compounded on the surface of an inner cavity. The inventor innovatively finds that the material shell and the inner wall material with the special structure have cooperativity, can cooperatively promote the uniform distribution of lithium and guide the lithium to be deposited in the cavity, thereby cooperatively improving the performance of the material in the lithium metal battery, effectively improving the volume effect and the interface side reaction of the lithium metal and obviously improving the cycle stability of the lithium battery.
The invention discovers that the special morphological characteristic that the lithium-philic noble metal nano particle is positioned on the inner wall of the carbon shell is the key for ensuring the synergy of the lithium-philic noble metal nano particle and the carbon shell material. Further research finds that the particle size, distribution amount and species of the nano metal ions are controlled, which is beneficial to further improving the cooperativity and further improving the long-term cycling stability of the lithium metal battery.
Preferably, the lithium-philic noble metal nanoparticles on the inner cavity of the carbon hollow sphere are at least one of silver, platinum, ruthenium, rhodium, palladium, osmium and iridium, and preferably are silver.
Preferably, in the noble metal simple substance @ nitrogen-doped carbon hollow sphere material, the content of the noble metal nanoparticles is 3 at.% to 10 at.%; further preferably 4 at.% to 10 at.%. The preferred nanoparticles and the preferred N-doped shell have superior synergistic properties that help to further increase the initial and cycling capacity of the material in a lithium metal battery.
Preferably, the particle size of the noble metal nanoparticles is 0.1-100 nm, preferably 0.5-60 nm, and more preferably 0.8-30 nm.
Preferably, the noble metal nanoparticle composite mode is at least one of electrodeposition or chemical plating, and further preferably chemical plating.
In order to obtain the special double lithium-philic hollow carbon skeleton material and obtain a material with excellent electrochemical performance in the field of lithium metal batteries, the invention also innovatively provides a four-step preparation process, namely a noble metal simple substance @ nitrogen-doped carbon hollow sphere material prepared by template preparation, carbon source polymerization, roasting and template etching; the method comprises the following steps: providing a template capable of being etched and removed; forming the noble metal nano particles on the surface of the template by using a chemical plating method, then carrying out carbon coating and roasting treatment, and finally removing the template to obtain the nano-metal template.
The inventor researches and discovers that a chemical silver plating method is innovatively introduced in the preparation of the template, so that the required morphology can be successfully obtained, and the noble metal simple substance @ nitrogen-doped carbon hollow sphere material with excellent electrical property can be obtained.
The research of the invention finds that the preparation difficulty lies in how to construct the nano metal particles uniformly in the closed cavity and how to control the appearance and the particle size of the nano metal particles. In order to overcome the technical difficulty and successfully prepare the material with excellent cycle performance, the invention innovatively researches and discovers that the material with the appearance and the excellent electrical performance can be successfully prepared by carrying out surface activation on the template in advance, then initiatively utilizing chemical plating and matching with in-situ carbon polymerization and etching processes and further matching with the cooperative control of the type and the concentration of an activating agent, the chemical plating conditions, the in-situ carbon polymerization conditions and the etching process conditions on the basis of the process.
In the preferred scheme, the preparation of the material with the noble metal nanoparticles as the nano silver particles comprises the following steps:
step (1): template activation:
mixing SiO2Placing the template in a solution of a surfactant for surface activity, and separating to obtain surface-activated SiO2A template;
the surface active agent is sodium hydroxide, stannous chloride and PbCl2At least one of mercaptopropyltrimethoxysilane and stannous chloride is preferred;
the concentration of the surface active agent in the solution of the surface active agent is 0.01-0.2 mol/L; further preferably 0.03-0.1 mol/L;
step (2): chemical plating and silver plating:
surface-activated SiO2Template and AgNO3The solution is deposited with even silver nano particles under the action of a reducing agent to obtain SiO2@ Ag; the AgNO3The concentration of the solution is 0.002-0.1 mol/L, more preferably 0.005-0.05 mol/L, and still more preferably 0.005-0.025 mol/L;
and (3): coating with nitrogen-doped carbon:
mixing SiO2The @ Ag template is put into the solution of nitrogen-containing carbon monomer for in-situ polymerization, and S isiO2The precursor is coated with carbon and then roasted to obtain SiO2@[email protected]；
The nitrogen-containing carbon monomer is at least one of dopamine, resorcinol, glucose, vinylpyrrolidone and tannic acid, preferably dopamine; in the in-situ polymerization starting solution, the concentration of the nitrogen-containing carbon monomer is 0.1-10 g/L, more preferably 1-10 g/L, and still more preferably 5-10 g/L;
and (4): demoulding plate:
mixing SiO2@ Ag @ C is placed in an etchant solution and is treated by a stripper plate;
the concentration of the etchant is 2-8 mol/L NaOH solution; the more preferable concentration is 3-5 mol/L.
The invention initiatively utilizes the chemical silver plating-in-situ poly-carbon-etching process to successfully prepare the material with the shape, and further discovers that the shape of the carbon hollow sphere and the uniformity, granularity and content of the metal particles can be further regulated and controlled on the basis of successfully obtaining the shape by accurately controlling the parameters such as the type and concentration of a surfactant, the concentration of Ag in the chemical silver plating process, the concentration of a carbon monomer polymerized in situ, the type and concentration of an etchant, and the like, thereby being beneficial to improving the performance of the prepared material in a lithium metal battery.
In the invention, the chemical silver plating method firstly uses SiO2Template (SiO)2Ball) is subjected to surface activation and then is mixed with AgNO3The solution is deposited with even silver nano particles under the action of a reducing agent to obtain SiO2@ Ag template;
the silica spheres are purchased commercially or manufactured by self, and the average diameter of the silica spheres is 200-1000 nm, and the average diameter of the silica spheres is preferably 300-500 nm.
Preferably, SiO is in the electroless plating initial solution in the step (2)2The concentration of the template is 0.1-20 g/L, preferably 1-10 g/L, and more preferably 5-10 g/L.
Preferably, the SiO2The spherical surface active agent is stannous chloride.
Preferably, a surfactant, SiO2The mass ratio of the balls is 2: 1-3: 1.
Preferably, the concentration of the surface active agent in the solution of the surface active agent is 0.03-0.1 mol/L.
Preferably, AgNO3、SiO2The mass ratio of the balls is 17: 25-4: 5.
The AgNO3The concentration of the solution is 0.005-0.025 mol/L.
Preferably, the reducing agent is at least one of formaldehyde, acetaldehyde, propionaldehyde and glucose, and glucose is preferred. The reducing agent is not less than AgNO3Theoretical molar amount of complete reaction.
Preferably, the concentration of the reducing agent in the chemical plating initial solution is 0.001-0.1 mol/L; more preferably 0.005 to 0.05mol/L, and still more preferably 0.005 to 0.02 mol/L.
In the invention, the carbon source polymerization stage can innovatively obtain the optimal carbon layer thickness and control the morphology of the material through the precise control of the carbon source concentration, the polymerization temperature and the polymerization time, thereby improving the electrochemical performance of the carbon source in the lithium metal battery.
Preferably, the nitrogen-containing carbon monomer is dopamine. The formed carbon-coated precursor is polydopamine.
Nitrogen-containing carbon monomer, SiO2The mass ratio of the balls is 1: 1-1.2: 1.
Preferably, the concentration of the nitrogen-containing carbon monomer in the in-situ polymerization starting solution is 5-10 g/L.
Preferably, the in situ polymerization process allows for the addition of a polymerization aid, such as trishydroxyaminomethane.
Preferably, the polymerization temperature is 20-50 ℃, and more preferably 20-30 ℃;
preferably, the polymerization time is 10-48 h, more preferably 20-40 h, and even more preferably 20-30 h;
preferably, the pH of the polymerization is 7 to 10, and more preferably 8 to 9.
In the invention, the optimal composite structure and morphology of the carbon shell and the lithium-philic metal nano particles can be obtained by controlling the roasting temperature and the roasting time in the high-temperature roasting stage, so that the deposition behavior of lithium in the composite carbon skeleton is improved.
The atmosphere of the high-temperature roasting is high-purity argon.
The roasting temperature is 700-950 ℃, and the roasting temperature is more preferably 700-850 ℃.
The high-temperature roasting time is 2-8 hours, and the preferable time is 3-5 hours.
And (4): mixing SiO2@ Ag @ C was placed in an etchant solution and treated with a stripper plate.
In the invention, the double lithium-philic hollow carbon skeleton is obtained by selecting an etchant, and strictly controlling the concentration of the etchant, the etching temperature and the etching time in the template etching stage.
The inventor researches and discovers that the etchant needs to adopt NaOH, and the concentration of the etchant needs to be controlled. Other etching means are adopted, so that the appearance construction is not facilitated, and the electrical performance is seriously influenced.
Preferably, the concentration of the sodium hydroxide is 3 to 5 mol/L.
The SiO2The etching temperature of the template etchant is 30-80 ℃, and the preferred temperature is 50-70 ℃;
the SiO2The etching time of the template etchant is 6-24 hours, and the preferable time is 6-12 hours.
The invention also provides a double lithium-philic composite lithium metal cathode active material, which comprises a carbon hollow ball with a closed filling cavity, a lithium-philic layer compounded on the inner wall of the carbon hollow ball, and a lithium metal simple substance filled in the filling cavity of the carbon hollow ball material; the lithium-philic layer is the noble metal-lithium alloy. The noble metal is at least one of silver, platinum, ruthenium, rhodium, palladium, osmium and iridium, and is preferably silver.
The invention also discloses a preparation method of the double lithium-philic composite lithium metal cathode active material, which is obtained by filling lithium into the noble metal simple substance @ nitrogen-doped carbon hollow ball material by a melting or electrodeposition method and carrying out lithiation reaction.
According to the preparation method, metal lithium is fused or electrodeposited in the double lithium-philic composite lithium metal negative electrode active material, so that a lithium simple substance and a lithium-philic framework are subjected to lithiation reaction, then lithium-philic metal nano particles are alloyed with the lithium simple substance, and the lithium simple substance is finally deposited on the surface of a lithium-philic layer, so that the long-cycle 3D lithium metal negative electrode is obtained.
Preferably, the method for filling metallic lithium is melting lithium filling or electrodeposition lithium filling, and more preferably electrodeposition lithium filling.
The lithium carrying amount of the negative electrode active material can be adjusted according to needs, and the preferable lithium carrying amount is 1-10 mA/cm2。
The double lithium-philic composite lithium metal negative electrode comprises a current collector and an active material layer compounded on the surface of the current collector, wherein the active material layer comprises the double lithium-philic composite lithium metal negative electrode active material, conductive carbon and a binder.
The current collector may be any current collector known in the art, such as a planar metal current collector, a copper foil, or the like.
The binder may be a binding polymer well known in the industry, such as PVDF.
In the active material layer, other components allowed to be added in the field of lithium metal batteries, such as conductive carbon, for example, acetylene black, are allowed to be added. The amounts of the binder and other components added may be adjusted as necessary.
The invention also provides a preparation method of the double lithium-philic composite lithium metal negative electrode, which comprises the following steps:
(1): slurrying the double lithium-philic composite lithium metal negative active material, conductive carbon and a binder, coating the slurried materials on a current collector, and drying to obtain the double lithium-philic composite lithium metal negative active material;
or (2): slurrying the noble metal simple substance @ nitrogen-doped carbon hollow sphere material with a solvent, and then coating the slurried noble metal simple substance @ nitrogen-doped carbon hollow sphere material on a current collector; and (4) obtaining a negative electrode precursor, and filling lithium metal into the negative electrode precursor to obtain the lithium-ion battery.
The invention also provides an application of the double lithium-philic composite lithium metal negative electrode, which is used as a negative electrode of a lithium metal battery;
preferably, the lithium metal battery is a lithium sulfur battery, a lithium iodine battery, a lithium selenium battery, a lithium tellurium battery, a lithium air battery or a lithium transition metal oxide battery.
The invention also provides a lithium metal battery loaded with the double lithium-philic composite lithium metal negative electrode.
Has the advantages that:
1. the noble metal simple substance @ nitrogen-doped carbon hollow sphere material is stable in structure and good in lithium affinity, can effectively reduce lithium nucleation overpotential, and realizes uniform deposition of lithium metal in a cavity inside a carbon sphere. In addition, the carbon hollow sphere can greatly increase the specific surface area and reduce the apparent current density; abundant lithium-philic metal nanoparticles in the inner cavity provide lithium-philic sites which can preferentially induce nucleation of lithium metal, so that uniform deposition of the lithium metal in the cavity of the hollow carbon skeleton is realized, and the volume effect is slowed down.
2. The research of the invention innovatively discovers that the noble metal elementary substance @ nitrogen-doped carbon hollow sphere material can play a role in packaging metal lithium, the shell layer is equivalent to an artificial SEI film, the elementary substance lithium is greatly reduced to be contacted with electrolyte, the occurrence of cross-section side reaction is avoided, and the electrochemical performance, particularly the cycling stability, of the lithium metal battery is remarkably improved.
3. The cathode provided by the invention can realize high coulombic efficiency and long cycle life under high current density. The noble metal simple substance @ nitrogen-doped carbon hollow sphere material has excellent conductivity, rich specific surface can well relieve uneven lithium deposition under high current density, and good electrochemical conditions are created for realizing stable deposition/dissolution of lithium metal.
4. The invention also provides a preparation process of preparing the template by chemical plating, in-situ polymerization of the carbon source, roasting and template etching, and innovatively discovers that the stable structure and morphology of the material can be obtained by strictly controlling the chemical silver plating conditions, the carbon source polymerization concentration, the carbon source polymerization time, the roasting process parameters and the etching conditions, and the material has excellent electrochemical performance in a lithium metal battery.
Drawings
FIG. 1 shows 0.025mol/LAgNO in example 23Solution prepared SiO2@ Ag template (A), and SiO2The appearance (B) of the double lithium-philic hollow carbon skeleton after the template is etched;
fig. 2 is an experimentally prepared long cycle 3D lithium metal negative electrode.
Detailed Description
The following is a detailed description of the preferred embodiments of the invention and is not intended to limit the invention in any way, i.e., the invention is not intended to be limited to the embodiments described below, and modifications and alternative compounds that are conventional in the art are intended to be included within the scope of the invention as defined in the claims.
Example 1
SiO with an average diameter of 500nm2The ball is prepared into 10g/L sol, stannous chloride solution with the concentration of 0.03 and 0.1mol/L, SiO2The volume ratio of the sol to the stannous chloride solution is 1:2, normal temperature activation treatment is carried out for 3 hours, suction filtration is carried out, deionized water is dispersed in 100ml of deionized water after being washed, and 100ml of 0.01mol/LAgNO is added3Dropwise adding ammonia water solution to obtain silver ammonia solution, dropwise adding 50ml0.01mol/L glucose solution, stirring at 50 deg.C in water bath for 2 hr to obtain SiO2@ Ag template. SiO 22Cleaning a @ Ag template, putting 0.5g of the template into 50ml of water, adding 0.25g of dopamine and 0.25g of trihydroxyaminomethane, stirring at normal temperature for 24 hours to obtain the precursor of the double lithium-philic hollow carbon skeleton, wherein the pH value of the precursor is 8.5. Then heating to 400 ℃ at the speed of 5 ℃/min under high-purity argon, heating to 800 ℃ at the speed of 1 ℃/min, and roasting for 3 h. And finally stirring the mixture in a 5mol/L NaOH solution in a water bath at 70 ℃ for 12 hours, filtering, washing and drying to obtain the nano silver simple substance @ nitrogen-doped carbon hollow sphere material. As can be seen from the experimental results, the SiO treated with stannous chloride solution with concentration of 0.03 and 0.1mol/L2Ball-produced SiO2Uniformly compounding silver particles with the average particle size of 15nm on the @ Ag template, and finally, uniformly compounding silver particles with the average particle size of 15nm on the inner cavity surface of the synthesized nano silver simple substance @ nitrogen-doped carbon hollow sphere material, wherein the Ag loading amounts are 7.6 at.% (0.03mol/L) and 7.9 at.% (0.1mol/L) respectively; n loading was 10.2 at.% (0.03mol/L), 10.3 at.% (0.1mol/L), respectively; the carbon layer thickness was 30 nm.
Comparative examples 1 to 1
Compared with the example 1, the difference is that the concentration of the stannous chloride solution is 0.001mol/L, specifically:
average diameter ofSiO of 500nm2The ball is prepared into 10g/L sol, stannous chloride solution with the concentration of 0.001mol/L and SiO2The volume ratio of the sol to stannous chloride solution is 1:2, normal temperature activation treatment is carried out for 3 hours, suction filtration is carried out, deionized water is dispersed in 100ml of deionized water after being washed, 100ml of 0.01mol/LAgNO is added3Dropwise adding ammonia water solution to obtain silver ammonia solution, dropwise adding 50ml0.01mol/L glucose solution, stirring at 50 deg.C in water bath for 2 hr to obtain SiO2@ Ag template. SiO 22Cleaning a @ Ag template, putting 0.5g of the template into 50ml of water, adding 0.25g of dopamine and 0.25g of trihydroxyaminomethane, stirring at normal temperature for 24 hours, and obtaining a precursor of the nano silver simple substance @ nitrogen-doped carbon hollow sphere. Then heating to 400 ℃ at the speed of 5 ℃/min under high-purity argon, heating to 800 ℃ at the speed of 1 ℃/min, and roasting for 3 h. And finally stirring the mixture for 12 hours in 5mol/L NaOH solution in water bath at 70 ℃, filtering, washing and drying to obtain a material A. As can be seen from the experimental results, SiO2The @ Ag template is only provided with a small amount of nano silver particles or even no silver nano particles, the surface of the inner cavity of the synthetic material A is almost free of silver particles, the Ag loading amount is 0.6 at.%, the N loading amount is 10.1 at.%, and the thickness of the carbon layer is 30 nm.
Comparative examples 1 to 2
Compared with the example 1, the difference is that the concentration of the stannous chloride solution is 0.5mol/L, specifically:
SiO with an average diameter of 500nm2The ball is prepared into 10g/L sol, stannous chloride solution with the concentration of 0.5mol/L and SiO2The volume ratio of the sol to stannous chloride solution is 1:2, normal temperature activation treatment is carried out for 3 hours, suction filtration is carried out, deionized water is dispersed in 100ml of deionized water after being washed, 100ml of 0.01mol/LAgNO is added3Dropwise adding ammonia water solution to obtain silver ammonia solution, dropwise adding 50ml0.01mol/L glucose solution, stirring at 50 deg.C in water bath for 2 hr to obtain SiO2@ Ag template. SiO 22Cleaning a @ Ag template, putting 0.5g of the template into 50ml of water, adding 0.25g of dopamine and 0.25g of trihydroxyaminomethane, stirring at normal temperature for 24 hours, and obtaining a precursor of the nano silver simple substance @ nitrogen-doped carbon hollow sphere. Then heating to 400 ℃ at the speed of 5 ℃/min under high-purity argon, heating to 800 ℃ at the speed of 1 ℃/min, and roasting for 3 h. Finally N at 5mol/LStirring in an aOH solution for 12 hours in a water bath at 70 ℃, filtering, washing and drying to obtain a material B. As can be seen from the experimental results, SiO2The @ Ag template is compounded with silver particles with the average particle size of 25nm, but the silver particles are not uniform and are accumulated on the surface, and finally the inner cavity surface of the synthetic material B is compounded with non-uniform silver particles, and the phenomenon that the silver particles are separated from the carbon layer even occurs.
Example 2
SiO with an average diameter of 500nm2The ball is prepared into 10g/L sol, stannous chloride solution with the concentration of 0.05mol/L and SiO are used2The volume ratio of the sol to the stannous chloride solution is 1:2, the activation treatment is carried out for 3 hours at normal temperature, the filtration is carried out, the deionized water is dispersed in 100ml of deionized water after being washed, 100ml of 0.005mol/L and 0.025mol/LAgNO are respectively added3Adding ammonia water solution dropwise to obtain silver ammonia solution, adding 125ml 0.01mol/L glucose solution dropwise at 50 deg.C, stirring for 2 hr to obtain SiO2@ Ag template. SiO 22Cleaning a @ Ag template, putting 0.5g of the template into 50ml of water, adding 0.25g of dopamine and 0.25g of trihydroxyaminomethane, stirring at normal temperature for 24 hours, and obtaining a precursor of the nano silver simple substance @ nitrogen-doped carbon hollow sphere. Then heating to 400 ℃ at the speed of 5 ℃/min under high-purity argon, heating to 800 ℃ at the speed of 1 ℃/min, and roasting for 3 h. And finally stirring the mixture in a 5mol/L NaOH solution in a water bath at 70 ℃ for 12 hours, filtering, washing and drying to obtain the nano silver simple substance @ nitrogen-doped carbon hollow sphere material. As can be seen from the experimental results, 0.005mol/L and 0.025mol/LAgNO3Solution prepared SiO2The Ag templates (shown in figure 1 (A)) can be uniformly compounded with silver particles with average particle sizes of 5nm and 25nm respectively, and finally the silver particles with average particle sizes of 5nm and 25nm are uniformly compounded on the inner cavity surface of the synthesized nano silver simple substance @ nitrogen-doped carbon hollow sphere material (shown in figure 1 (B)), and the Ag loading amounts of the prepared material under 0.005mol/L and 0.025mol/L are respectively 4.6 at.% and 10 at.%; n loading was 10.1 at.%, 10.4 at.%, respectively; the carbon layer thickness was 30 nm.
Comparative example 2-1
Compared with example 2, the difference is only AgNO3The concentration of the solution is 0.001mol/L, and specifically comprises the following steps:
SiO with an average diameter of 500nm2The ball is prepared into 10g/L sol, stannous chloride solution with the concentration of 0.05mol/L and SiO are used2The volume ratio of the sol to the stannous chloride solution is 1:2, normal temperature activation treatment is carried out for 3 hours, suction filtration is carried out, deionized water is dispersed in 100ml of deionized water after being washed, 100ml of 0.001mol/L AgNO is added3Dropwise adding ammonia water solution to obtain silver ammonia solution, dropwise adding 10ml 0.01mol/L glucose solution, stirring at 50 deg.C in water bath for 2 hr to obtain SiO2@ Ag template. SiO 22Cleaning a @ Ag template, putting 0.5g of the template into 50ml of water, adding 0.25g of dopamine and 0.25g of trihydroxyaminomethane, stirring at normal temperature for 24 hours, and obtaining a precursor of the nano silver simple substance @ nitrogen-doped carbon hollow sphere. Then heating to 400 ℃ at the speed of 5 ℃/min under high-purity argon, heating to 800 ℃ at the speed of 1 ℃/min, and roasting for 3 h. And finally stirring the mixture for 12 hours in 5mol/L NaOH solution in water bath at 70 ℃, filtering, washing and drying to obtain a material C. As can be seen from the experimental results, 0.001mol/LAgNO3Solution prepared SiO2The Ag particles cannot be uniformly compounded on the @ Ag template, a small amount of even no silver particles are distributed on the surface, the silver particles are difficult to find on the surface of the inner cavity of the synthetic material C, the Ag loading amount is 0.3 at.%, the N loading amount is 10.4 at.%, and the thickness of the carbon layer is 30 nm.
Comparative examples 2 to 2
Compared with example 2, the difference is only AgNO3The concentration of the solution is 0.5mol/L, and specifically comprises the following steps:
SiO with an average diameter of 500nm2The ball is prepared into 10g/L sol, stannous chloride solution with the concentration of 0.05mol/L and SiO are used2The volume ratio of the sol to the stannous chloride solution is 1:2, normal temperature activation treatment is carried out for 3 hours, suction filtration is carried out, deionized water is dispersed in 100ml of deionized water after being washed, 100ml of 0.5mol/LAgNO is added3Dropwise adding ammonia water solution into the solution to prepare silver ammonia solution, and dropwise adding 250ml of 0.1mol/L glucose solution into the silver ammonia solution, stirring the mixture for 2 hours in water bath at 50 ℃ to prepare SiO2@ Ag template. SiO 22Cleaning a @ Ag template, putting 0.5g of the template into 50ml of water, adding 0.25g of dopamine and 0.25g of trihydroxyaminomethane, stirring at normal temperature for 24 hours, and obtaining a precursor of the nano silver simple substance @ nitrogen-doped carbon hollow sphere. Then heating to 400 ℃ at a speed of 5 ℃/min under high-purity argon, and heating at a speed of 1 ℃/minRoasting for 3h at 800 ℃. And finally stirring the mixture for 12 hours in 5mol/L NaOH solution in water bath at 70 ℃, filtering, washing and drying to obtain a material D. As can be seen from the experimental results, 0.5mol/L AgNO3Solution prepared SiO2The Ag particles cannot be uniformly compounded on the @ Ag template, the silver layer is densely distributed on the surface of the template, the surface of the inner cavity of the synthetic material D is obviously stacked with the silver layer, the Ag loading amount is 15.6 at.%, the N loading amount is 9.8 at.%, and the carbon layer is 30nm thick.
Example 3
SiO with an average diameter of 500nm2The ball is prepared into 10g/L sol, stannous chloride solution with the concentration of 0.05mol/L and SiO are used2The volume ratio of the sol to stannous chloride solution is 1:2, normal temperature activation treatment is carried out for 3 hours, suction filtration is carried out, deionized water is dispersed in 100ml of deionized water after being washed, 100ml of 0.01mol/LAgNO is added3Dropwise adding ammonia water solution to obtain silver ammonia solution, dropwise adding 50ml0.01mol/L glucose solution, stirring at 50 deg.C in water bath for 2 hr to obtain SiO2@ Ag template. SiO 22Cleaning a @ Ag template, putting 0.5g of the template into 50ml of water, respectively adding 0.25g of dopamine and 0.5g of dopamine to prepare 5g/L and 10g/L solutions, respectively adding 0.25g of trihydroxyaminomethane and 0.5g of trihydroxyaminomethane to obtain a pH value of 8.5, and stirring at normal temperature for 24 hours to obtain a precursor of the nano silver simple substance @ nitrogen-doped carbon hollow sphere. Then heating to 400 ℃ at the speed of 5 ℃/min under high-purity argon, heating to 800 ℃ at the speed of 1 ℃/min, and roasting for 3 h. And finally stirring the mixture in a 5mol/L NaOH solution in a water bath at 70 ℃ for 12 hours, filtering, washing and drying to obtain the nano silver simple substance @ nitrogen-doped carbon hollow sphere material. From experimental results, the thicknesses of carbon layers of the precursor of the nano silver simple substance @ nitrogen-doped carbon hollow sphere prepared from 5g/L and 10g/L dopamine solutions are respectively 30nm and 50nm, the N loading amounts are respectively 9.2 at.% and 10.1 at.%, the inner cavity is compounded with uniform silver particles with the average particle size of 15nm, and the Ag loading amounts are respectively 7.5 at.% and 7.8 at.%.
Comparative example 3-1
Compared with example 3, the difference is only that the concentration of the dopamine solution is 1g/L, specifically:
SiO with an average diameter of 500nm2The ball is prepared into 10g/L sol, stannous chloride solution with the concentration of 0.05mol/L and SiO are used2The volume ratio of the sol to stannous chloride solution is 1:2, normal temperature activation treatment is carried out for 3 hours, suction filtration is carried out, deionized water is dispersed in 100ml of deionized water after being washed, 100ml of 0.01mol/LAgNO is added3Dropwise adding ammonia water solution to obtain silver ammonia solution, dropwise adding 50ml0.01mol/L glucose solution, stirring at 50 deg.C in water bath for 2 hr to obtain SiO2@ Ag template. SiO 22Cleaning a @ Ag template, putting 0.5g of template into 50ml of water, respectively adding 0.05g of dopamine to prepare 1g/L solution, respectively adding 0.05g of trihydroxyaminomethane to obtain a pH value of 8.5, and stirring at normal temperature for 24 hours to obtain a precursor of the nano silver elementary substance @ nitrogen-doped carbon hollow sphere. Then heating to 400 ℃ at the speed of 5 ℃/min under high-purity argon, heating to 800 ℃ at the speed of 1 ℃/min, and roasting for 3 h. And finally stirring the mixture for 12 hours in a 5mol/L NaOH solution in a water bath at the temperature of 70 ℃, filtering, washing and drying to obtain the nano silver simple substance @ nitrogen-doped carbon hollow sphere material (material E). According to experimental results, the thickness of a precursor carbon layer of the nano silver elementary substance @ nitrogen-doped carbon hollow sphere prepared from 1g/L of dopamine solution is 10nm, even a part of the precursor carbon layer can not form a closed spherical cavity, silver particles with the average particle size of 15nm are compounded in an inner cavity, the Ag loading amount is 7.7 at.%, and the N loading amount is 2.1 at.%.
Comparative examples 3 to 2
Compared with example 3, the difference is only that the concentration of the dopamine solution is 50g/L, specifically:
SiO with an average diameter of 500nm2The ball is prepared into 10g/L sol, stannous chloride solution with the concentration of 0.05mol/L and SiO are used2The volume ratio of the sol to stannous chloride solution is 1:2, normal temperature activation treatment is carried out for 3 hours, suction filtration is carried out, deionized water is dispersed in 100ml of deionized water after being washed, 100ml of 0.01mol/LAgNO is added3Dropwise adding ammonia water solution to obtain silver ammonia solution, dropwise adding 50ml0.01mol/L glucose solution, stirring at 50 deg.C in water bath for 2 hr to obtain SiO2@ Ag template. SiO 22Cleaning a @ Ag template, putting 0.5g of template into 50ml of water, respectively adding 2.5g of dopamine to prepare 50g/L solution, respectively adding 2.5g of trihydroxyaminomethane with the pH value of 8.5, and stirring at normal temperature for 24 hours to obtain a precursor of the nano silver elementary substance @ nitrogen-doped carbon hollow sphere. Then heating to 400 ℃ at a speed of 5 ℃/min under high-purity argon, and heating at a speed of 1 ℃/minRoasting for 3h at 800 ℃. And finally stirring the mixture for 12 hours in a 5mol/L NaOH solution in a water bath at the temperature of 70 ℃, filtering, washing and drying to obtain the nano silver simple substance @ nitrogen-doped carbon hollow sphere material (material F). According to experimental results, the thickness of a precursor carbon layer of the nano silver simple substance @ nitrogen-doped carbon hollow sphere prepared from 50g/L of dopamine solution is 200nm, even a part of spherical cavities with uneven thickness are formed, silver particles with the average particle size of 15nm are compounded in an inner cavity, and the Ag loading amount is 7.8 at.%.
Example 4
SiO with an average diameter of 500nm2The ball is prepared into 10g/L sol, stannous chloride solution with the concentration of 0.05mol/L and SiO are used2The volume ratio of the sol to stannous chloride solution is 1:2, normal temperature activation treatment is carried out for 3 hours, suction filtration is carried out, deionized water is dispersed in 100ml of deionized water after being washed, 100ml of 0.01mol/LAgNO is added3Dropwise adding ammonia water solution to obtain silver ammonia solution, dropwise adding 50ml0.01mol/L glucose solution, stirring at 50 deg.C in water bath for 2 hr to obtain SiO2@ Ag template. SiO 22Cleaning a @ Ag template, putting 0.5g of template into 50ml of water, respectively adding 0.5g of dopamine to prepare 10g/L solution, respectively adding 0.5g of trihydroxyaminomethane to obtain a pH value of 8.5, and stirring at normal temperature for 24 hours to obtain a precursor of the nano silver elementary substance @ nitrogen-doped carbon hollow sphere. Then heating to 400 ℃ at the speed of 5 ℃/min under high-purity argon, heating to 800 ℃ at the speed of 1 ℃/min, and roasting for 3 h. And finally stirring the mixture in 3mol/L and 5mol/L NaOH solutions in a water bath for 12 hours at the temperature of 70 ℃, filtering, washing and drying to obtain the nano silver simple substance @ nitrogen-doped carbon hollow sphere material. From the experimental results, the thicknesses of the carbon layers of the precursor of the nano silver simple substance @ nitrogen-doped carbon hollow sphere, which are prepared by etching the silicon sphere with 3mol/L and 5mol/L NaOH solutions, are respectively 30nm, the N contents are respectively 10.2 at.% and 10.3 at.%, the inner cavity is compounded with silver particles with the uniform average particle size of 15nm, and the Ag loading amounts are respectively 7.6 at.% and 7.7 at.%.
Comparative example 4-1
Compared with the example 4, the difference is only that the concentration of the NaOH solution is 1mol/L, and specifically:
SiO with an average diameter of 500nm2The ball is prepared into 10g/L sol, stannous chloride solution with the concentration of 0.05mol/L and SiO are used2The volume ratio of the sol to stannous chloride solution is 1:2, normal temperature activation treatment is carried out for 3 hours, suction filtration is carried out, deionized water is dispersed in 100ml of deionized water after being washed, 100ml of 0.01mol/LAgNO is added3Dropwise adding ammonia water solution to obtain silver ammonia solution, dropwise adding 50ml0.01mol/L glucose solution, stirring at 50 deg.C in water bath for 2 hr to obtain SiO2@ Ag template. SiO 22Cleaning a @ Ag template, putting 0.5g of template into 50ml of water, respectively adding 0.5g of dopamine to prepare 10g/L solution, respectively adding 0.5g of trihydroxyaminomethane to obtain a pH value of 8.5, and stirring at normal temperature for 24 hours to obtain a precursor of the nano silver elementary substance @ nitrogen-doped carbon hollow sphere. Then heating to 400 ℃ at the speed of 5 ℃/min under high-purity argon, heating to 800 ℃ at the speed of 1 ℃/min, and roasting for 3 h. And finally stirring the mixture in a 1mol/LNaOH solution in a water bath at 70 ℃ for 12 hours, filtering, washing and drying to obtain the nano silver simple substance @ nitrogen-doped carbon hollow sphere material (material G). According to the experimental result, the nano silver simple substance @ nitrogen-doped carbon hollow sphere material prepared by etching the silicon spheres by 1mol/LNaOH solution has obvious silicon spheres.
Comparative example 4-1
Compared with example 4, the difference is only that the concentration of the etchant is changed to 40 wt.% of HF solution, specifically:
SiO with an average diameter of 500nm2The ball is prepared into 10g/L sol, stannous chloride solution with the concentration of 0.05mol/L and SiO are used2The volume ratio of the sol to stannous chloride solution is 1:2, normal temperature activation treatment is carried out for 3 hours, suction filtration is carried out, deionized water is dispersed in 100ml of deionized water after being washed, 100ml of 0.01mol/LAgNO is added3Dropwise adding ammonia water solution to obtain silver ammonia solution, dropwise adding 50ml0.01mol/L glucose solution, stirring at 50 deg.C in water bath for 2 hr to obtain SiO2@ Ag template. SiO 22Cleaning a @ Ag template, putting 0.5g of template into 50ml of water, respectively adding 0.5g of dopamine to prepare 10g/L solution, respectively adding 0.5g of trihydroxyaminomethane to obtain a pH value of 8.5, and stirring at normal temperature for 24 hours to obtain a precursor of the nano silver elementary substance @ nitrogen-doped carbon hollow sphere. Then heating to 400 ℃ at the speed of 5 ℃/min under high-purity argon, heating to 800 ℃ at the speed of 1 ℃/min, and roasting for 3 h. And finally stirring in 40 wt.% HF solution in a water bath at 70 ℃ for 12H, filtering, washing and drying to obtain a material H. From the results of the experimentsIt can be seen that the silicon spheres in the nano silver simple substance @ nitrogen-doped carbon hollow sphere material prepared by etching the silicon spheres with the 40 wt.% HF solution are completely etched, in addition, the average particle size of the silver nanoparticles is obviously reduced, even the silver nanoparticles are completely etched and dissolved away, the loading amount of Ag is 0.3 at.%, and the loading amount of N is 9.7 at.%.
Example 5
The nano silver simple substance @ nitrogen-doped carbon hollow sphere material in example 1 and comparative examples 1-1 and 1-2 thereof, A, B, namely the nano silver simple substance @ nitrogen-doped carbon hollow sphere material, are mixed with PVDF and acetylene black serving as binders according to the mass ratio of 8:1:1, NMP is added for slurrying, then the mixture is uniformly coated on a copper foil, the mixture is dried to serve as a working electrode, a metal lithium sheet serves as a counter electrode, and 1M LiTFSI/DOL: DME (volume ratio of 1:1) contains 1 wt% of LiNO3Button half cell assembly, lithium deposition testing and charge-discharge cycling testing were performed for the electrolyte. At 1mA/cm2The current density and the electric quantity of (1 mAh/cm)2The charge and discharge cycle test was performed, and the test results are shown in table 1 below:
TABLE 1
The results showed that SnCl was present at a concentration of 0.03mol/L and 0.1mol/L2Solution activated SiO2Ball-produced SiO2The @ Ag template is beneficial to preparing the nano silver simple substance @ nitrogen-doped carbon hollow sphere material, and the electrochemical performance of the electrode of the nano silver simple substance @ nitrogen-doped carbon hollow sphere material is optimal.
Example 6
The nano silver simple substance @ nitrogen-doped carbon hollow sphere material obtained in example 2 and comparative examples 2-1 and 2-1 thereof, namely the material C and the material D, are mixed with binder PVDF and acetylene black according to the mass ratio of 8:1:1, NMP is added for slurrying, then the mixture is uniformly coated on copper foil, the mixture is dried to be used as a working electrode, a metal lithium sheet is used as a counter electrode, and 1M LiTFSI/DOL: DME (volume ratio of 1:1) contains 1 wt% of LiNO3Button half cell assembly, lithium deposition testing and charge-discharge cycling testing were performed for the electrolyte. At 2mA/cm2The current density and the electric quantity of (1 mAh/cm)2To carry outThe charge-discharge cycle test results are shown in table 2 below:
TABLE 2
The results showed 0.005mol/L and 0.025mol/LAgNO3Solution prepared SiO2The electrochemical performance of the nano silver elementary substance @ nitrogen-doped carbon hollow sphere material electrode synthesized on the @ Ag template is optimal.
Example 7
The nano silver simple substance @ nitrogen-doped carbon hollow sphere material prepared in example 3 and four nano silver simple substance @ nitrogen-doped carbon hollow sphere materials prepared from comparative examples 3-1 and 3-2 materials E/F are mixed with binders PVDF and acetylene black according to the mass ratio of 8:1:1, NMP is added for slurrying and then uniformly coated on copper foil, the copper foil is dried to be used as a working electrode, a metal lithium sheet is used as a counter electrode, and 1M LiTFSI/DOL: DME (volume ratio of 1:1) contains 1 wt% of LiNO3Button half cell assembly, lithium deposition testing and charge-discharge cycling testing were performed for the electrolyte. At 1mA/cm2The current density and the electric quantity of (1 mAh/cm)2The charge-discharge cycle test was performed, and the test results are shown in table 3 below:
TABLE 3
The result shows that the electrochemical performance of the electrode is optimal when the dopamine solution is 5g/L and 10g/L to synthesize the nano silver simple substance @ nitrogen-doped carbon hollow sphere material. In contrast, 1g/L of dopamine easily causes incomplete synthesized carbon spheres, can not completely encapsulate lithium metal, and easily causes subsequent interfacial side reactions. The carbon layer synthesized by 50g/L of dopamine has larger thickness and is not beneficial to the shuttling and deposition of lithium ions.
Example 8
The nano silver simple substance @ nitrogen-doped carbon hollow sphere material prepared in example 4 and the material G/H nano silver simple substance @ nitrogen-doped carbon hollow sphere material prepared in comparative examples 4-1 and 4-2, a binder PVDF and acetylene blackMixing at a weight ratio of 8:1:1, adding NMP, slurrying, uniformly coating on a copper foil, drying to obtain a working electrode, using a metal lithium sheet as a counter electrode, and using 1M LiTFSI/DOL: DME (volume ratio of 1:1) containing 1 wt% LiNO3Button half cell assembly, lithium deposition testing and charge-discharge cycling testing were performed for the electrolyte. At 1mA/cm2The current density and the electric quantity of (1 mAh/cm)2The charge-discharge cycle test was performed, and the test results are shown in table 4 below:
TABLE 4
Example 9 full cell case
The nano silver simple substance @ nitrogen-doped carbon hollow sphere material obtained in example 2 and comparative examples 2-1 and 2-1, the material C and the material D, the nano silver simple substance @ nitrogen-doped carbon hollow sphere material, PVDF and acetylene black serving as binders are mixed according to the mass ratio of 8:1:1, NMP is added to the mixture to be slurried, the mixture is uniformly coated on a copper foil, the mixture is dried to serve as a working electrode, and 1M LiTFSI/DOL: DME (volume ratio of 1:1) contains 1 wt.% LiNO3Is 0.5mA/cm of electrolyte2Bottom deposition of 5mAh/cm2The double lithium-philic composite lithium metal negative electrode is prepared as shown in figure 2. Then the composite electrode and a mesoporous carbon anode rich in S simple substance form a lithium sulfur full battery, and the lithium sulfur full battery contains 1 wt% of LiNO in a volume ratio of 1M LiTFSI/DOL to DME (1: 1)3In the electrolyte of (1), a charge-discharge cycle test was performed at 1C.
Comparative example 9-1
Mixing commercial carbon nanocages (Shanghai Shangmu Technology Co, Ltd.) without N doping and noble metal simple substance with adhesives PVDF and acetylene black according to the mass ratio of 8:1:1, adding NMP for slurrying, uniformly coating the mixture on a copper foil, drying the copper foil to be used as a working electrode, and adding 1M LiTFSI/DOL: DME (volume ratio is 1:1) containing 1 wt.% LiNO3Is 0.5mA/cm of electrolyte2Bottom deposition of 5mAh/cm2And (4) preparing the double lithium-philic composite lithium metal cathode. Then the composite electrode and a mesoporous carbon anode rich in S simple substance form a lithium sulfur full battery, and the lithium sulfur full battery contains 1 wt% of LiNO in a volume ratio of 1M LiTFSI/DOL to DME (1: 1)3In the electrolyte solution (a) of (b),charge and discharge cycle tests were performed at 1C.
The relevant results of the experimental tests are shown in the attached table 5
TABLE 5
The results showed 0.005mol/L and 0.025mol/LAgNO3The electrochemical performance of the composite metal lithium negative electrode lithium-sulfur full cell formed by further depositing lithium by using the prepared nano silver simple substance @ nitrogen-doped carbon hollow sphere material is optimal, and the positive influence on the electrochemical performance caused by the regulation of the skeleton structure and the distribution and the appearance of the nano particles is illustrated.