阅读说明：本技术 一种3d亲锂多孔金属集流体、负极及其制备和应用 (3D lithium-philic porous metal current collector, negative electrode, preparation and application thereof ) 是由 赖延清 范海林 洪波 董庆元 高春晖 张治安 张凯 于 2018-08-14 设计创作，主要内容包括：本发明属于锂电电极材料领域。具体公开了一种3D亲锂多孔金属集流体，包括3D多孔金属集流体以及复合在3D多孔金属集流体骨架上的金、银、铂中的至少一种金属。本发明还公开了所述的金属集流体的制备和应用，以及尤其制得的3D亲锂多孔锂离子负极，本发明所述的集流体，在多孔金属骨架上的金、银、铂中的至少一种金属降低了锂金属成核和沉积过程中的过电位，实现了锂金属持续循环过程中均匀的沉积和溶解，有效避免枝晶的生长，大幅度提高锂金属电池的循环寿命。(The invention belongs to the field of lithium battery electrode materials. The 3D lithium-philic porous metal current collector comprises a 3D porous metal current collector and at least one metal of gold, silver and platinum compounded on a framework of the 3D porous metal current collector. The invention also discloses the preparation and application of the metal current collector, and particularly the prepared 3D lithium-philic porous lithium ion negative electrode.)

1. A3D lithium-philic porous metal current collector is characterized in that: the composite material comprises a 3D porous metal current collector and at least one metal of gold, silver and platinum compounded on the framework of the 3D porous metal current collector.

2. The 3D lithium philic porous metal current collector of claim 1, wherein: the material of the 3D porous metal current collector is at least one of titanium, copper, nickel, iron, cobalt and manganese; preferably porous copper;

preferably, the thickness of the 3D porous current collector is 5-800 μm; more preferably 10 to 300 μm;

preferably, the porosity of the 3D porous current collector is 10-90%; further preferably 30-70%;

preferably, the pore spacing of the 3D porous current collector is 0.2-400 μm; more preferably 1 to 300 μm.

3. The 3D lithium-philic porous metal current collector of claim 1 or 2, wherein: the metal compounded on the framework is granular; the preferable granularity is 50-2000 nm; preferably 100 to 800 nm.

4. A method of preparing a 3D lithium-philic porous metal current collector as claimed in any one of claims 1 to 3, wherein:

electroplating in M plating solution by taking a 3D porous metal current collector as a working electrode and M metal as a counter electrode, and depositing metal M on a framework of the 3D porous metal current collector to prepare the 3D lithium-philic porous metal current collector;

m is at least one metal element of gold, silver and platinum;

the M plating solution is an aqueous solution containing M metal salt and a surfactant;

the content of the M metal salt is 5-50 g/L; preferably 15-45 g/L;

the content of the surfactant is 0.02-1 g/L; preferably 0.05-0.3 g/L;

preferably, the M plating solution further comprises a complexing agent, and the content of the complexing agent is preferably not higher than 300 g/L;

the current density in the electroplating process is 0.25-1.5 mA/cm²(ii) a Preferably 1 to 1.5mA/cm²；

The electroplating time is 10-60 s; preferably 10 to 30 seconds.

5. The application of the 3D lithium-philic porous lithium ion negative electrode as claimed in any one of claims 1 to 3 or the 3D lithium-philic porous lithium ion negative electrode prepared by the preparation method as claimed in claim 4 is characterized in that: and filling lithium metal into the 3D lithium-philic porous lithium ion negative electrode to prepare the negative electrode of the lithium ion battery.

6. A3D lithium-philic porous lithium ion negative electrode is characterized in that: the lithium battery comprises a 3D porous metal current collector, an alloy substrate layer compounded on a framework of the 3D porous metal current collector and a lithium metal layer compounded on the alloy substrate layer;

the alloy basal layer is an alloy formed by lithium and at least one metal element of gold, silver and platinum; preferably a lithium-silver alloy.

7. The 3D lithium-philic porous lithium ion anode of claim 6, wherein: the thickness of the alloy substrate layer is 50-2000 nm;

preferably, the thickness of the lithium metal layer is 5 to 50 μm.

8. The 3D lithium-philic porous lithium ion anode of claim 6 or 7, wherein: the material of the 3D porous metal current collector is at least one of titanium, copper, nickel, iron, cobalt and manganese; preferably porous copper;

preferably, the thickness of the 3D porous current collector is 5-800 μm; more preferably 10 to 300 μm;

preferably, the porosity of the 3D porous current collector is 10-90%; further preferably 30-70%;

preferably, the pore spacing of the 3D porous current collector is 0.2-400 μm; more preferably 1 to 300 μm.

9. A preparation method of the 3D lithium-philic porous lithium ion negative electrode as claimed in any one of claims 6 to 8, characterized in that: melting or electrodepositing and filling a lithium simple substance in the 3D lithium-philic porous metal current collector as claimed in any one of claims 1 to 3 or the 3D lithium-philic porous metal current collector prepared by the preparation method as claimed in claim 4, so that the lithium simple substance and at least one metal of gold particles, silver particles and platinum particles on the 3D lithium-philic porous metal current collector are subjected to an alloying reaction, and lithium is deposited on the formed alloy substrate layer; and preparing the 3D lithium-philic porous lithium ion negative electrode.

10. The application of the 3D lithium-philic porous lithium ion negative electrode as defined in any one of claims 6 to 8 or the 3D lithium-philic porous lithium ion negative electrode prepared by the preparation method as defined in any one of claims 9 is characterized in that: the lithium ion battery is used as a negative electrode of the lithium ion battery;

preferably, it is used to prepare a negative electrode of 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 field of energy storage devices, and particularly relates to a lithium-philic 3D current collector and a cathode prepared by adopting the current collector.

Background

Lithium sulfur batteries are the most promising next generation energy storage devices due to their ultra-high energy density 2600 Wh/kg. However, the growth and large volume effect of lithium dendrites limits its industrial application. To counter the risk of dendrites and to mitigate volume effects. The most common strategy at present is to load metallic lithium in a porous current collector. For example, Shu-Hong Yu et al [ l.l.lu, j.ge, j.n.yang, s.m.chen, h.b.yao, f.zhou, s.h.yu, Free-standing coppernon wire network current collector for improving lithium anode performance, Nano Letters 16(2016)4431-4437 ] prepared porous copper composed of copper nanofibers by a self-assembly method, but when it is used as a current collector to compose a lithium battery with a lithium sheet, metallic lithium is easily deposited preferentially on the upper surface of the porous copper, resulting in the growth of dendrites during a continuous deposition process.

The porous current collector is easy to generate dendrites because lithium metal is preferentially deposited at the tip position and the defect position due to the nonuniformity of the spatial structure of the porous current collector, so that the effective area of the porous current collector cannot be fully utilized, and finally the effective current density in the circulation process of the lithium metal battery cannot be fully reduced. In view of the problem that lithium metal is easy to grow preferentially on the upper surface, Yanqing Lai et al [ b.hong, h.fan, x. -b.cheng, x.yan, s.hong, q.dong, c.gao, z.zhang, y.lai, q.zhang, spatialuniform deposition of lithium metal in 3DJanus hosts energy Storage Materials 16 (2019)259-266 ] construct a thin metal layer on the lower surface of the 3D current collector, but the apparent battery density is not sufficiently reduced, and finally the cycle performance of the battery is difficult to improve.

In conclusion, the electrode prepared by the existing porous current collector is easy to grow dendrite, can only realize relatively stable circulation at a small current density, and can only realize the current density (2-5 mA/cm) of the practical lithium ion battery²) The cycle performance and cycle life will drop dramatically.

Disclosure of Invention

Aiming at the problems that the current density of a 3D porous current collector can not be sufficiently reduced and lithium dendrite can not be effectively inhibited, the invention aims to provide a lithium-philic 3D porous metal current collector (also called a 3D lithium-philic porous metal current collector or a lithium-philic current collector for short).

The second purpose of the invention is to provide a preparation method of the 3D lithium-philic porous metal current collector.

The third purpose of the invention is to provide an application of the 3D lithium-philic porous metal current collector.

The fourth objective of the present invention is to provide a 3D lithium-philic porous lithium ion negative electrode (also referred to as negative electrode for short) prepared from the 3D lithium-philic porous metal current collector, which aims to effectively solve the problem of lithium dendrite and improve the current density (e.g. 2 to 5 mA/cm) under high current density by controlling the structure and material²) And (4) cycle performance.

The fifth purpose of the invention is to provide a preparation method of the 3D lithium-philic porous lithium ion negative electrode.

The sixth purpose of the invention is to provide an application of the 3D lithium-philic porous lithium ion negative electrode.

A3D lithium-philic porous metal current collector comprises a 3D porous metal current collector and at least one metal of gold, silver and platinum compounded on a framework of the 3D porous metal current collector.

The proposal is that at least one metal of gold, silver and platinum is creatively compounded on a pore metal framework of a 3D lithium-philic porous metal current collector; the 3D lithium-philic porous metal current collector with the structure can effectively maintain the stability of a framework in the lithium metal deposition process; meanwhile, the metal uniformly distributed on the pore framework can induce the nucleation of the metal lithium, so that the effective specific surface area of the 3D current collector is fully utilized in the lithium deposition process, and the lithium deposition without dendrites and the long cycle life are realized.

Preferably, the material of the 3D porous metal current collector is at least one of titanium, copper, nickel, iron, cobalt, and manganese.

The 3D porous metal current collector is any one of porous titanium, porous copper, porous nickel, porous iron, porous cobalt, porous manganese and other porous single metal current collectors and binary and ternary alloy current collectors thereof.

The 3D porous binary alloy current collector is any one of porous nickel-copper, porous nickel-titanium, porous nickel-iron, porous nickel-cobalt, porous nickel-manganese, porous iron-titanium, porous iron-copper, porous iron-cobalt, porous iron-manganese, porous cobalt-titanium, porous cobalt-copper and porous cobalt-manganese alloy.

The component proportion of the 3D porous binary alloy is arbitrary.

The 3D porous ternary alloy current collector is any one of porous nickel-copper-titanium, porous nickel-copper-iron, porous nickel-copper-cobalt, porous nickel-copper-manganese and porous iron-cobalt-nickel alloy.

The component proportion of the 3D porous ternary alloy is arbitrary.

The thickness of the 3D porous current collector is 5-800 mu m.

Preferably, the thickness of the 3D porous current collector is 10-300 μm; more preferably 20 to 50 μm.

The porosity of the 3D porous current collector is 10-90%.

Preferably, the porosity of the 3D porous current collector is 30-70%; more preferably 30 to 50%.

The pore space of the 3D porous current collector is 0.2-400 mu m.

Preferably, the pore space of the 3D porous current collector is 1-300 μm; more preferably 70 to 100 μm.

Preferably, the metal particles combined with the skeleton may be one of gold, silver, and platinum, and preferably, silver.

Further preferably, a binary alloy or a ternary alloy of gold, silver, and platinum metals is compounded on the skeleton. The component proportion of the metal elements in the binary alloy and the ternary alloy is arbitrary.

The binary alloy can be gold-silver, gold-platinum or silver-platinum binary alloy. The ratio of the metal elements in the binary alloy particles may be arbitrary.

The ternary alloy particles can be ternary alloy of gold, silver and platinum; the ratio of gold, silver and platinum in the ternary alloy may be any.

Preferably, the metal incorporated in the skeleton is in the form of particles. That is, the metal compounded on the skeleton is at least one metal particle (metal particle) of gold, silver and platinum

Preferably, the granularity of the metal compounded on the framework is 50-2000 nm; preferably 100-800 nm; more preferably 200 to 750 nm.

Preferably, the metal compounded on the framework accounts for 0.1-1 Wt% of the weight of the 3D lithium-philic porous metal current collector.

The invention also provides a preparation method of the 3D lithium-philic porous metal current collector, which aims to prepare by an electrodeposition method, but has special requirements on electrodeposition preparation in the field of batteries, different from other application fields, and needs to control the uniformity of prepared electrodeposition and the granularity of deposition. In-depth research finds that the 3D lithium-philic porous metal current collector which is suitable for the field of batteries and can improve the electrical property of a subsequently prepared material can be unexpectedly prepared by controlling the concentration of a metal source in a plating solution and further controlling the current density and the electrodeposition time in the plating solution containing a surfactant in the electrodeposition process.

The preparation method of the 3D lithium-philic porous metal current collector comprises the steps of taking a 3D porous metal current collector as a working electrode and M metal as a counter electrode, electroplating in M plating solution, and depositing the metal M on a framework of the 3D porous metal current collector to prepare the 3D lithium-philic porous metal current collector.

And M is at least one metal element of gold, silver and platinum.

The M plating solution is an aqueous solution containing M metal salt and a surfactant.

In the M plating solution, the content of M metal salt is 5-50 g/L; preferably 15 to 45 g/L.

In the M plating solution, the content of the surfactant is 0.02-1 g/L; preferably 0.05 to 0.3 g/L.

The M plating solution also comprises a complexing agent; the content of the complexing agent is preferably not higher than 300 g/L.

The current density in the electroplating process is 0.25-1.5 mA/cm²(ii) a Preferably 1 to 1.5mA/cm²。

The electroplating time is 10-60 s; preferably 10 to 30 seconds.

Researches find that the composition and the composition content of the M plating solution can control the composite uniformity on the 3D porous metal current collector, and the granularity of deposited M metal can be controlled, so that the current collector which meets the use requirement of electricity and has excellent performance can be prepared.

Preferably, the 3D porous metal current collector is pretreated with an acid solution in advance.

The M plating solution disclosed by the invention can reduce the cost by controlling the concentration of the M metal on one hand, and can refine M metal nanoparticles by increasing polarization on the other hand. Moreover, the wettability of the 3D porous metal current collector can be improved, so that M metal nanoparticles are uniformly deposited on the whole 3D porous metal current collector framework; in addition, the side reaction of peracid generating hydrogen evolution and overbasing to form M hydroxide precipitate can be prevented. Therefore, the prepared 3D lithium-philic porous metal current collector has better induced lithium deposition, and the electrical property of the obtained material is further improved.

The M metal salt is water-soluble salt of at least one metal of gold, silver and platinum. If the counter electrode is an alloy, and the M metal salt contains salts of two metal elements of the counter electrode.

The surfactant is an anionic surfactant, a neutral surfactant or a cationic surfactant; preferably an anionic surfactant.

The anionic surfactant is at least one of sodium dodecyl sulfate, dodecyl phosphate, polyacrylic acid, OP-10 and OT-75.

The cationic surfactant is at least one of cetyl trimethyl ammonium bromide, cetyl trimethyl ammonium chloride, dodecyl trimethyl ammonium bromide, dodecyl trimethyl ammonium chloride and perfluoroalkyl ammonium salt.

The non-surfactant is at least one of Tween 60, Tween 65, Tween 80 and Tween 85.

The complexing agent is sodium thiosulfate and/or potassium metabisulfite. Researches show that when the counter electrode contains Ag, a certain complexing agent is added into the M plating solution, so that the electric property of the prepared material is further improved.

In the invention, the innovative M plating solution is matched with the current density and the plating time, so that the phenomenon that the deposition of M metal is too little to be beneficial to the subsequent deposition of lithium can be prevented, and the phenomenon that the deposition of lithium and M metal is too much to form continuous alloying reaction can be prevented.

The preferable preparation method of the 3D lithium-philic porous metal current collector comprises the steps of putting the porous metal current collector into a 10% hydrochloric acid solution for soaking for 20min to remove impurities and oxide films on the surface, then taking the clean and dried porous metal current collector as a working electrode, taking a silver sheet, a gold sheet or a platinum sheet or an alloy sheet thereof as a counter electrode, and preparing corresponding lithium-philic particles in a silver-based, gold-based or platinum-based or alloy plating solution thereof by controlling the time and the current.

The invention also provides application of the 3D lithium-philic porous lithium ion negative electrode, and lithium metal is filled into the 3D lithium-philic porous lithium ion negative electrode to prepare the negative electrode of the lithium ion battery.

The invention also provides a 3D lithium-philic porous lithium ion negative electrode, which comprises a 3D porous metal current collector, an alloy substrate layer compounded on the framework of the 3D porous metal current collector and a lithium metal layer compounded on the alloy substrate layer;

the alloy basal layer is an alloy formed by lithium and at least one metal element of gold, silver and platinum.

The alloy substrate layer is creatively compounded on a framework of pores of a 3D porous metal current collector on a 3D lithium-philic porous lithium ion negative electrode; depositing metal lithium on the alloy substrate layer; the structure is matched with the material components, so that the framework stability in the lithium metal deposition process can be effectively maintained; the effective specific surface area of the 3D current collector can be fully utilized, the problem of lithium dendrites is solved, and the cycle life of the negative electrode is obviously prolonged.

The alloy substrate layer has good wettability to metal lithium and is easy to form corresponding deposition layer, for example, the alloy formed by lithium and silver has AgLi and Ag₃Alloys of Li, lithium and gold include AuLi and Au₃Li、Au₅Li₄、Au₄Li₁₅Alloys of lithium and platinum with PtLi, Pt₂Li、PtLi₂、PtLi₅、Pt₄Li₁₅、Pt₇Li, and the like. The alloy substrate can induce the uniform deposition of the metal lithium on the pore framework of the porous metal current collector, so that the high specific surface area performance of the porous metal current collector can be fully utilized, the metal lithium can be uniformly deposited, and the occurrence of lithium dendrites can be effectively avoided from multiple aspects.

In the invention, the alloy substrate layer can be a binary alloy formed by lithium and one of gold, silver and platinum; for example a lithium-gold alloy, a lithium-silver alloy or a lithium-platinum alloy. Researches also find that the performance of the negative electrode is better when the alloy substrate layer is made of lithium-silver alloy, so that the formation of lithium dendrite is inhibited more favorably, and the high-voltage cycle performance of the negative electrode is further improved.

In another embodiment of the present invention, the alloy substrate layer is a ternary alloy formed by lithium and two metals of gold, silver and platinum; for example, a lithium-gold-silver alloy, a lithium-gold-platinum alloy, a lithium-silver-gold alloy, a lithium-silver-platinum alloy, or a lithium-platinum-gold alloy, a lithium-platinum-silver alloy. The ratio of the elements in the alloy may be arbitrary.

In another embodiment of the invention, the alloy substrate layer is a quaternary alloy formed by lithium and three metals of gold, silver and platinum; for example a lithium-gold-silver-platinum alloy. The ratio of the elements in the alloy may be arbitrary.

Preferably, the thickness of the alloy substrate layer is 50-2000 nm.

Preferably, the method comprises the following steps: the thickness of the lithium metal layer is 5 to 50 μm.

In the negative electrode, the material of the 3D porous metal current collector is at least one of titanium, copper, nickel, iron, cobalt and manganese; preferably porous copper;

preferably, the thickness of the 3D porous current collector is 5-800 μm; more preferably 10 to 300 μm; more preferably 20 to 50 μm.

Preferably, the porosity of the 3D porous current collector is 10-90%; further preferably 30-70%; more preferably 30 to 50%.

Preferably, the pore spacing of the 3D porous current collector is 0.2-400 μm; more preferably 1 to 300 μm; more preferably 70 to 100 μm.

The invention also discloses a preparation method of the 3D lithium-philic porous lithium ion negative electrode, the 3D lithium-philic porous metal current collector is prepared, then the 3D lithium-philic porous metal current collector is melted or electrodeposited to fill the lithium simple substance, so that the lithium simple substance and at least one metal of gold, silver and platinum on the 3D lithium-philic porous metal current collector are subjected to alloying reaction, and lithium is deposited on the formed alloy substrate layer; and preparing the 3D lithium-philic porous lithium ion negative electrode.

The 3D lithium-philic porous metal current collector is prepared by the preparation method.

Preferably, the elemental lithium is filled by an electrodeposition method. Compared with other lithium deposition methods, the obtained negative electrode has better performance by the electrodeposition method.

The method for filling the lithium in the 3D lithium-philic current collector has two methods: the first method is high-temperature lithium filling; electrodeposition of the second type. The high-temperature lithium filling firstly needs to melt the metal lithium into a flowable liquid, and the melting point of the metal lithium is 180 ℃, so the high-temperature lithium filling needs to be operated at a temperature of more than 180 ℃, which causes great operation difficulty. Meanwhile, the liquid metal lithium is more active than the solid metal lithium, so the operation environment is more severe, the oxygen content needs to be strictly controlled below 0.1ppm, and the common electrodeposition can be controlled below 100 ppm. In addition, the high-temperature lithium filling utilizes a siphonage phenomenon to adsorb metallic lithium in the porous current collector, so that the content of lithium in the porous current collector cannot be controlled, and the electrodeposition method can control the content of lithium in the porous current collector by controlling the deposition time and the deposited current.

The method of electrodepositing metallic lithium may employ an existing method, for example, electrodeposition is performed in an organic solvent containing a lithium salt using a 3D lithium-philic porous metal current collector, on which metallic lithium is to be electrodeposited, as a working electrode and a lithium sheet as a counter electrode.

The invention also provides application of the 3D lithium-philic porous lithium ion negative electrode, and the 3D lithium-philic porous lithium ion negative electrode is used as a negative electrode of a lithium ion battery.

Preferably, it is used to prepare a negative electrode of 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.

Has the advantages that:

1. the 3D lithium-philic porous metal current collector can effectively maintain the stable skeleton in the lithium metal deposition process. Meanwhile, the lithium-philic particles can be uniformly distributed to preferentially induce the nucleation of the metallic lithium, so that the effective specific surface area of the 3D current collector in the subsequent lithium deposition process is fully utilized, and finally, the lithium deposition without dendrites and the long cycle life are realized.

2. According to the 3D lithium-philic porous lithium ion negative electrode, the metal substrate layer of the material is formed on the surface of the framework of the 3D hole, and the metal lithium is more uniformly compounded on the surface of the substrate layer under the action of the metal substrate layer of the material, so that the metal lithium is bonded on the 3D metal current collector with a high specific surface area, and the high-voltage cycle performance of the obtained negative electrode can be obviously improved.

Drawings

FIG. 1 is an SEM image of the copper foam before and after depositing silver particles in example 1: (a) cu foam; (b) ag @ Cu foam

FIG. 2 is the EDS diagram and the corresponding elemental distribution diagram of silver particle modified foamy copper after lithium deposition in example 1

FIG. 3 is an SEM image of copper foam and silver particle modified copper foam of example 1 after lithium deposition: (a) cu foam; (b) ag @ Cu foam

FIG. 4 is a graph of the cycle performance of the copper foam and silver particle modified copper foam of example 1: (a)2mA/cm²；(b)5mA/cm²

FIG. 5 is an SEM image of silver particle modified copper foam of example 8: (a)10 s; (b)30 s; (c)60s

Fig. 6 is an SEM image of silver particle-modified foamy copper prepared without adding a surfactant in comparative example 5:

FIG. 7 is a graph showing the cycle performance of the silver particle-modified copper foam prepared in comparative example 5 without adding a surfactant.

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 above, 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.