Lanthanum-doped high-rate zinc-manganese battery positive electrode material and preparation method thereof
阅读说明：本技术 一种镧掺杂高倍率锌锰电池正极材料及其制备方法 (Lanthanum-doped high-rate zinc-manganese battery positive electrode material and preparation method thereof ) 是由 卢锡洪 张昊喆 何锦俊 郑惠民 于明浩 于 2019-08-28 设计创作，主要内容包括：本发明提供一种镧掺杂高倍率锌锰电池正极材料及其制备方法,其中,电池的正极材料为La<Sup>3+</Sup>掺杂MnO<Sub>2</Sub>纳米球,负极为锌基材料,电解液为硫酸锌与硫酸锰混合液,La<Sup>3+</Sup>掺杂MnO<Sub>2</Sub>纳米球采用水热法制备得到,然后通过涂膜法将其负载在导电基底上。本发明的锌离子电池以La<Sup>3+</Sup>掺杂MnO<Sub>2</Sub>纳米球为正极材料,在MnO<Sub>2</Sub>材料中掺杂La<Sup>3+</Sup>,得到La<Sup>3+</Sup>掺杂MnO<Sub>2</Sub>材料,通过La<Sup>3+</Sup>的掺杂,增强了MnO<Sub>2</Sub>的稳定性和导电性,使其组装的锌离子电池的电池容量和充放电倍率得到大幅的提升,La<Sup>3+</Sup>的掺杂改变了MnO<Sub>2</Sub>材料的结构,扩大了二氧化锰的层间距,使材料的结构在充放电过程具有更好的可逆性,提升了其循环稳定性。(The invention provides a lanthanum-doped high-rate zinc-manganese battery anode material and a preparation method thereof, wherein the anode material of the battery is La 3+ Doped MnO 2 Nanospheres, a negative electrode is a zinc-based material, an electrolyte is a mixed solution of zinc sulfate and manganese sulfate, and La 3+ Doping MnO 2 The nanospheres are prepared by a hydrothermal method and then loaded on a conductive substrate by a coating method. The zinc ion battery of the invention uses La 3+ Doped MnO 2 The nanosphere is a positive electrode material in MnO 2 Doping La in the material 3+ To obtain La 3+ DopingMnO 2 Material through La 3+ By doping of MnO 2 The stability and the conductivity of the zinc ion battery are greatly improved, the battery capacity and the charge-discharge rate of the zinc ion battery assembled by the zinc ion battery are greatly improved, and La 3+ Doping of changes MnO 2 The structure of the material enlarges the interlayer spacing of manganese dioxide, so that the structure of the material has better reversibility in the charge-discharge process, and the cycle stability of the material is improved.)
1. A lanthanum-doped high-rate zinc-manganese battery positive electrode material is characterized in that: the battery anode material is La 3+ Doping MnO 2 The negative electrode of the battery is a zinc-based material, and the electrolyte is 2mol L -1 Zinc sulfate and 0.4mol L -1 Manganese sulfate mixed liquor;
the La 3+ Doped MnO 2 The diameter of the nanosphere is 200-600 nm.
2. The lanthanum-doped high-rate zinc-manganese battery cathode material according to claim 1, characterized in that: the La 3+ Doped MnO 2 La in nanosphere 3+ The doping proportion is 0.001-50%.
3. The lanthanum-doped high-rate zinc-manganese battery positive electrode material according to claim 2, characterized in that: the La 3+ Doping MnO 2 The nanospheres are prepared by a hydrothermal method and then loaded on a conductive substrate by a coating method.
4. The lanthanum-doped high-rate zinc-manganese battery cathode material according to claim 3, characterized in that: the La 3+ Doping MnO 2 The nanosphere is prepared by mixing 0.01-100 mmol L -1 MnSO 4 ，0.001～100mmol L -1 La(NO 3 ) 2 ，0.01～100mmol L -1 KMnO 4 The mixed aqueous solution is used as a precursor solution and prepared by a stirring method or a hydrothermal method, and then the synthesized La is synthesized by a coating method 3+ Doping MnO 2 The nanosphere powdery solid material is coated on the conductive substrate, and the coating thickness is 1-10 μm.
5. The lanthanum-doped high-rate zinc-manganese battery positive electrode material according to claim 4, characterized in that: the stirring temperature is 0-80 ℃, and the stirring time is 0.1-72 hours; the hydrothermal reaction temperature is 60-220 ℃, and the hydrothermal time is 0.1-72 h.
6. The lanthanum-doped high-rate zinc-manganese battery positive electrode material according to claim 5, characterized in that: the hydrothermal reaction temperature is 70-150 ℃, and the reaction time is 60-720min.
7. The lanthanum-doped high-rate zinc-manganese battery positive electrode material according to claim 1, characterized in that: the electrolyte can also be a mixed solution of zinc chloride, zinc sulfate and zinc trifluoromethanesulfonate.
8. The lanthanum-doped high-rate zinc-manganese battery cathode material according to claim 4, characterized in that: the conductive substrate is carbon cloth, carbon paper, aluminum foil, copper foil, foamed nickel, foamed copper and the like.
9. A preparation method of a lanthanum-doped high-rate zinc-manganese battery positive electrode material comprises the following steps:
s1) adding 0.01 to 100mmol L -1 MnSO4，0.001～100mmol L -1 La(NO 3 ) 2 ，0.01～100mmol L - 1 KMnO 4 The mixed aqueous solution is a precursor solution and is prepared by a stirring method or a hydrothermal method, wherein the stirring temperature is 0-80 ℃, and the stirring time is 0.1-72 hours; the hydrothermal temperature is 60-220 ℃, and the hydrothermal time is 0.1-72 h;
s2) after the reaction is finished, carrying out centrifugal separation and precipitation on the solution, washing the solution for 3-5 times by using deionized water, and drying the solution to obtain La 3+ Doping MnO 2 A nanomaterial;
s3) synthesizing La by using a coating method 3+ Doping MnO 2 And nano coating the conductive base material to the coating thickness of 1-10 μm to obtain the battery anode material.
10. The lanthanum-doped high-rate zinc-manganese battery positive electrode material according to claim 9, characterized in that: in the step S3), the conductive base material is one of carbon cloth, carbon paper, aluminum foil, copper foil, foamed nickel and foamed copper.
Technical Field
The invention relates to the technical field of energy storage batteries, in particular to a lanthanum-doped high-rate zinc-manganese battery positive electrode material and a preparation method thereof.
Background
With the increasing energy demand and environmental protection, the concentration of toxic gases such as nitrogen oxides and sulfur oxides in the atmosphere, which are associated with global warming, has been increasing with the increasing consumption of fossil fuels. The demand for electric energy in modern economic society and industrial culture is increasing day by day, and the demand for electric energy in the world is expected to double by 2050. The pursuit and use of inexpensive and reliable renewable and clean energy sources for power generation is our ultimate goal, and the storage of electrical energy is a critical part of achieving this goal. As renewable energy sources, including wind, solar, tidal and geothermal, are intermittent in nature, are widely dispersed, and are not always available. In order to utilize these free and unlimited energy sources, it is necessary to store these energy sources when there is energy source, and the battery system plays an important role in storing electric energy, and at present, the power battery market includes lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries and lithium ion batteries, but these battery systems have some problems, which restrict the further development of these batteries.
Since their introduction by sony corporation in 1991, lithium Ion Batteries (LIBs) have become the leading battery Energy Storage System (ESS) in the market as compared to other rechargeable batteries. Zinc ion batteries have superior electrochemical performance compared to other types of batteries. Overall, the main expression is three points: (1) The zinc ion battery has not only high energy density but also high power density. According to the constant current charging and discharging result, the energy density and the power density calculation formula, the power density can be calculated to be 12kW/kg at most and is far higher than that of a common battery on the market, and the energy density of the zinc ion battery can be 320 W.h/kg at most and is about 15 times that of a super capacitor. And (2) the zinc ion battery has low cost. The zinc ion battery has simple manufacturing process and can be assembled in the air, thereby greatly reducing the manufacturing cost. Meanwhile, the metal zinc is rich in resources and is the metal with the lowest price except iron. In the current market, both hydrogen fuel cells and lithium ion cells have high electrode material and production and manufacturing costs, which limits the application range. The low cost of zinc ion batteries will contribute to their widespread use in the battery market. And (3) the environment is friendly, and the safety is high. The electrolyte of the zinc ion battery adopts nearly neutral zinc sulfate and zinc acetate aqueous solution (the pH value is between 5 and 7). The zinc and its inorganic salt are nontoxic, and there is no pollutant generated in the production and application process of the battery. Therefore, the zinc ion battery belongs to a green environment-friendly battery.
LIBs are commonly used in small electronic products such as notebook computers, digital cameras, and cellular phones due to their light weight, large capacity, and high energy density. However, when large-scale applications are involved, such as in stationary grid energy storage or electric vehicles, the high cost and safety issues associated with LIBs become very significant contributors. Several accidents involving explosion and fire of lithium batteries, such as tesla cars and samsung smartphones, have recently occurred because lithium batteries use flammable organic electrolytes. In terms of economic cost, lithium resources are not very abundant, and even considered gold in the next century by some people, there is a risk of long-term shortage.
Theoretical capacity of zinc (Zn) metal (820 mAh g) -1 ) Large size, low cost, low toxicity and the like, and is widely concerned. As a grid-connected energy storage system, a rechargeable water-based zinc ion battery is becoming a novel energy storage device with a wide application prospect due to the advantages of the rechargeable water-based zinc ion battery in the aspects of rate capability, safety, cost and the like.
Common zinc ion batteryManganese dioxide, vanadium pentoxide, metal ferricyanide and the like are used as positive electrode active materials, metal zinc is used as a negative electrode active material, and a water solvent containing zinc salt is used as an electrolyte. In the water-soluble electrolyte, the potentials of different areas of the zinc electrode with uneven surface are different, so that an infinite number of corrosion micro-batteries with combined action are formed. Corrosion causes self-discharge of the cell, reducing the zinc utilization and cell capacity. In the sealed environment of the battery, hydrogen generated in the corrosion process causes the internal pressure of the battery to increase and accumulate to a certain degree, and can cause the leakage of electrolyte and even explosion. In addition, the discharge process of the water system zinc ion battery directly generates insoluble ZnO or Zn (OH) 2 When the anode product covers the surface of the electrode, the normal dissolution of zinc is influenced, the reaction surface area of the zinc electrode is reduced, and the electrode loses activity and becomes passive. The specific surface area of the electrode is reduced, and relatively speaking, the electrode density is increased, so that the polarization of the battery is caused, and the cycle performance of the battery is reduced. In addition, due to the uneven deposition of zinc ions, dendrites are generated during the charge and discharge processes, resulting in a large potential safety hazard of the battery. In addition, the anode materials of the zinc ion batteries reported at present are very limited, the cycle performance is poor, and the preparation process is complex. And due to the high potential window of the manganese material, manganese dioxide in the zinc-manganese battery is easily reduced into divalent manganese ions during charging and discharging and is dissolved in water, so that the battery is damaged.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a lanthanum-doped high-rate zinc-manganese battery positive electrode material and a preparation method thereof. According to the invention, the lanthanum ion is doped, so that the interlayer spacing of manganese dioxide is enlarged, and the damage of zinc ions to the manganese dioxide material in the processes of charge and discharge embedding and removing is weakened, thereby improving the cycle stability of the manganese dioxide material; on the other hand, by doping lanthanum ions, active sites of the material are increased, and the capacity, the multiplying power and the electrochemical performance of the material are improved.
The technical scheme of the invention is as follows: a lanthanum-doped high-rate zinc-manganese battery anode material is La 3+ Doping MnO 2 Nanospheres;
the negative electrode of the battery is a zinc-based material, and the electrolyte is 2mol L -1 Zinc sulfate and 0.4mol L -1 And (4) manganese sulfate mixed liquor.
Preferably, the La 3+ Doped MnO 2 La in nanospheres 3+ The doping proportion is 0.001-50%.
Preferably, said La 3+ Doping MnO 2 The diameter of the nanosphere is 200-600 nm.
Preferably, said La 3+ Doping MnO 2 The nanospheres are prepared by adopting a stirring method or a hydrothermal method, and then are loaded on a conductive substrate through a coating method.
Preferably, said La 3+ Doping MnO 2 The nanosphere is prepared by mixing 0.01-100 mmol L -1 MnSO 4 ，0.001～100mmol L -1 La(NO 3 ) 2 ，0.01～100mM KMnO 4 The mixed aqueous solution is used as a precursor solution and prepared by a stirring method or a hydrothermal method, and then the synthesized La is synthesized by a coating method 3+ Doping MnO 2 The nanosphere powdery solid material is coated on the conductive substrate, and the coating thickness is 1-10 μm.
Preferably, the stirring temperature is 0-80 ℃, and the stirring time is 0.1-72 hours; the hydrothermal reaction temperature is 60-220 ℃, and the hydrothermal time is 0.1-72 h;
preferably, the hydrothermal reaction temperature is 70-150 ℃, and the reaction time is 60-720min.
Preferably, the electrolyte can also be a mixed solution of zinc chloride, zinc sulfate and zinc trifluoromethanesulfonate.
Preferably, the conductive substrate is carbon cloth, carbon paper, aluminum foil, copper foil, foamed nickel, foamed copper and the like.
The invention also provides a preparation method of the lanthanum-doped high-rate zinc-manganese battery anode material, which comprises the following steps of:
s1) adding 0.01-100 mmol L -1 MnSO 4 ，0.001～100mmol L -1 La(NO 3 ) 2 ，0.01～100mmol L - 1 KMnO 4 The mixed aqueous solution is a precursor solution and is prepared by a stirring method or a hydrothermal method, wherein the stirring temperature is 0-80 ℃, and the stirring time is 0.1-72 hours; the hydrothermal temperature is 60-220 ℃, and the hydrothermal time is 0.1-72 h;
s2) after the reaction is finished, carrying out centrifugal separation and precipitation on the solution, washing the solution for 3-5 times by using deionized water, and drying the solution to obtain La 3+ Doped MnO 2 A nanomaterial;
s3) synthesizing La by using a coating method 3+ Doping MnO 2 And nano coating the conductive base material to the coating thickness of 1-10 μm to obtain the battery anode material.
Preferably, in step S3), the conductive substrate is one of carbon cloth, carbon paper, aluminum foil, copper foil, nickel foam and copper foam.
The invention has the beneficial effects that:
1. the invention is realized by MnO 2 La is doped in the nano material 3+ The interlayer spacing is enlarged, the active sites are increased, and the conductivity is enhanced, so that MnO is effectively increased 2 Electrochemical performance and cycling stability of the nanomaterial;
2. the invention adds MnSO into the electrolyte 4 MnO is suppressed 2 The dissolution of the material effectively enhances the cycle stability of the material;
3. the zinc ion battery of the invention uses La 3+ Doping MnO 2 The nanosphere is a positive electrode material in MnO 2 Doping La in the material 3 + To obtain La 3+ Doping MnO 2 Material through La 3+ By doping of MnO 2 The battery capacity and the charge-discharge multiplying power of the assembled zinc ion battery are greatly improved, and the La 3+ Doping of (A) changes MnO 2 The structure of the material enlarges the interlayer spacing of manganese dioxide, so that the structure of the material has better reversibility in the charge and discharge process, and the cycle stability of the material is improved.
Drawings
FIG. 1 shows MnO prepared in example 2 of the present invention 2 Scanning Electron Microscope (SEM) image, wherein (a) is MnO 2 Scanning Electron Microscopy (SEM) of-0.2 La nanospherical materials, showing MnO we prepared 2 Is a nano spherical material; (b-e) is La-doped 3+ The Scanning Electron Microscope (SEM) of (a), shows that there is no significant change in the morphology of the doped material; (f-g) is MnO 2 Transmission electron microscopy of 0.2La nanospherical material, it can be seen that the material has a very distinct layered structure;
fig. 2 is an alternating current impedance diagram (EIS) of a zinc-ion battery in example 2 of the present invention; the charge transfer process and the diffusion process of the doped material are optimized;
FIG. 3 is a drawing showing preparation of La according to example 2 of the present invention 3+ Doped MnO 2 The charge-discharge curve and the rate performance of the electrode;
fig. 4 is a graph showing the cycle stability test of the zinc-ion battery in example 2 of the present invention.
Detailed Description
The following further describes embodiments of the present invention in conjunction with the attached figures:
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