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Electrode pole piece of perovskite vanadate blended active material

A technology of active material and electrode sheet, applied in the direction of active material electrode, negative electrode, battery electrode, etc., can solve the problems of cycle stability decline, easy to produce lithium dendrite, and limit the application of high-performance secondary battery.

Active Publication Date: 2021-11-23
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] At present, the theoretical capacity (372mAh / g) and actual capacity (350mAh / g) of commercial graphite anode cannot meet the energy density requirement of 400Wh / kg for lithium batteries in the future, and its extremely low working voltage platform is 0.05~0.1V vs Li / Li + Lithium dendrites are easily generated when operating under extreme conditions (such as low temperature, high current fast charge, overcharge, etc.), and the safety performance and rate performance are severely limited.
Although the currently developed silicon anode material has a very high specific capacity (theoretical lithium storage capacity is 4200mAh / g), its conductivity is poor, requiring the use of special high-conductivity materials
At the same time, there is a serious volume effect in the process of delithiation and lithium intercalation, and the volume expansion is close to 300-400%. When the powder is broken and separated from the current collector, the transmission of electrons and ions will be blocked, and the cycle stability is within several cycles. Significant decline will occur, which cannot meet the needs of automobiles for thousands of cycle stability
The above defects of graphite and silicon-based materials limit the application of developing high-performance secondary batteries in the future
[0004] In existing reports using mixed materials as active substances, such as the Ag used in US 3981748 2 CrO 4 and Ag 3 PO 4 Mixed positive electrodes, lithium cobalt oxide and manganese spinel blend electrodes used in US 7811707, etc., through the synergistic effect of certain specific capacities between different active materials, and by optimizing the composition, electrodes with better performance can be obtained; but currently There is no relevant report on the compound use of perovskite structure alkaline earth vanadate and other materials in the negative electrode forming materials of batteries

Method used

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  • Electrode pole piece of perovskite vanadate blended active material
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  • Electrode pole piece of perovskite vanadate blended active material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Using perovskite alkaline earth strontium vanadate SrVO 3 (x=1) The electrode material blended with graphite according to the ratio of 99:1, wherein the perovskite alkaline earth strontium vanadate SrVO 3 like figure 1 As shown, its XRD pattern shows that it is a single phase without other impurities. The results of thermogravimetry showed no O vacancies. and it looks like figure 2 As shown, it is flaky and composed of nanoparticles; the morphology of the graphite is as follows image 3 As shown, it exhibits a morphology of stacked sheets.

[0017] The preparation steps of the negative electrode diaphragm are as follows: S1 weighs 9.9g of strontium vanadate SrVO 3 and 0.1g of graphite to form a mixed active material; S2 adds the mixed active material to 50ml of N-methylpyrrolidone organic solution as an organic solvent, and then adds 0.101g of PVDF as a binder without adding a conductive agent. Material: conductive additive: binder = 99:0:1, use a ball mill to mi...

Embodiment 2

[0022] Using perovskite alkaline earth strontium vanadate SrVO 3 With the electrode material blended with graphite according to the ratio of 50:50, the preparation of its negative electrode membrane comprises the following steps: S1 weighs 4.5g of strontium vanadate SrVO 3 and 4.5g of graphite to form a mixed active material; S2 adds the mixed active material to 50ml of N-methylpyrrolidone organic solution as an organic solvent, then adds 0.5g of PVDF as a binder, and adds 0.5g of a conductive agent , active material: conductive additive: binder = 90:5:5, using a ball mill to mix at a rate of 300r / min for 5h to obtain a mixed slurry; the rest of the steps are the same as in Example 1. The obtained negative electrode membrane is 2.40mg / cm according to the surface load 2 Cut it into a disc with a diameter of 12 mm, and then carry out the electrochemical performance test of the electrode sheet as in Example 1.

[0023] Such as Figure 7 As shown, in the absence of conductive a...

Embodiment 3

[0025] Using perovskite alkaline earth strontium vanadate SrVO 3 The electrode material blended with graphite according to the ratio of 1:99, the preparation of its negative electrode membrane includes the following steps: S1 weighs 0.1 strontium vanadate SrVO 3 and 9.9g of graphite to form a mixed active material; S2 adds the mixed active material to 50ml of N-methylpyrrolidone organic solution as an organic solvent, and then adds 0.101g of PVDF as a binder without adding a conductive agent. Material: conductive additive: binder = 99:0:1; other steps are the same as in Example 1. The obtained negative electrode membrane is 2.49mg / cm according to the surface load 2 Cut it into a disc with a diameter of 12 mm, and then carry out the electrochemical performance test of the electrode sheet as in Example 1.

[0026] Such as Figure 8 As shown, in the absence of conductive additives, graphite and perovskite strontium vanadate SrVO 3 The blended electrode material has a specific...

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Abstract

The invention discloses an electrode pole piece of a perovskite vanadate blended active material. The electrode pole piece comprises a metal current collector and a negative electrode diaphragm coating the metal current collector, the negative electrode diaphragm comprises an active material formed by blending a perovskite structure alkaline earth vanadate active substance AxVO3-delta and a negative electrode material, the negative electrode material is a carbon-based material and / or a silicon-based material, and A is any one of Ca, Sr and Ba. The perovskite structure vanadate AxVO3-delta with high conductivity and high specific capacity is mixed with the carbon-based material and / or the silicon-based material to serve as an active substance, the electrochemical performance is excellent after blending, and for example, when the active substrance is mixed with graphite, the specific capacity, the rate and the safety of working voltage can be improved; when the active substrance is mixed with a silicon-based material, an electronic network framework can be constructed, the use of conductive carbon black is reduced, meanwhile, high capacity and rate capability are kept, and the composite material has great commercial potential.

Description

technical field [0001] The invention relates to the technical field of secondary batteries, in particular to an electrode pole piece of a perovskite vanadate blended active material. Background technique [0002] In recent years, electric vehicles have developed rapidly, and the requirements for lithium-ion secondary batteries have become higher and higher. High-performance lithium-ion battery negative electrodes have high specific capacity, fast charging and high power, wide operating temperature range, and long life. The requirements for longer cycle life and service life, and outstanding safety and reliability are becoming increasingly urgent. [0003] At present, the theoretical capacity (372mAh / g) and actual capacity (350mAh / g) of commercial graphite anode cannot meet the energy density requirement of 400Wh / kg for lithium batteries in the future, and its extremely low working voltage platform is 0.05~0.1V vs Li / Li + Lithium dendrites are easily generated when operating...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/131H01M4/36H01M4/38H01M4/485H01M4/58H01M4/587H01M10/0525
CPCH01M4/131H01M4/364H01M4/485H01M4/386H01M4/5825H01M4/587H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 刘颖李小磊杨晓娇林紫锋欧阳林峰
Owner SICHUAN UNIV