Preparation method of multi-core type phosphate compound positive electrode material with core-shell structure for lithium ion battery

A composite positive electrode material and lithium-ion battery technology, applied in battery electrodes, positive electrodes, secondary batteries, etc., can solve the problems of slow ion transmission and low electronic conductivity

Active Publication Date: 2014-06-25
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, among these polyanionic phosphate-based positive electrode materials, including LiFePO, which has been commercialized or may be commercialized 4 , LiMnPO 4 , LiVPO 4 F, Li 3 V 2 (PO 4 ) 3 etc. are limited by kinetic factors such as low electronic conductivity and slow ion transport in practical applications.

Method used

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  • Preparation method of multi-core type phosphate compound positive electrode material with core-shell structure for lithium ion battery
  • Preparation method of multi-core type phosphate compound positive electrode material with core-shell structure for lithium ion battery
  • Preparation method of multi-core type phosphate compound positive electrode material with core-shell structure for lithium ion battery

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Experimental program
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Effect test

Embodiment 1

[0022] With lithium carbonate, vanadium pentoxide, diammonium hydrogen phosphate, and lithium fluoride as raw materials, LiVPO in the obtained composite positive electrode material 4 F. Li 3 V 2 (PO 4 ) 3 with LiVOPO 4 The molar ratio is 0.1:0.4:0.5, and mix evenly; then add the reducing agent oxalic acid to the mixed material, according to the molar ratio of oxalic acid and vanadium source is 3:1, add and mix, mechanical ball mill for 8 hours, and then turn it to vacuum drying The powder was dried in an oven, fully ground the powder in an agate mortar, pressed into tablets, heat-treated at 750°C for 6 hours in an argon atmosphere, then naturally cooled to 350°C and sintered in an air atmosphere for 1 hour, and finally cooled naturally to room temperature to obtain 0.1 LiVPO 4 F 0.4Li 3 V 2 (PO 4 ) 3 0.5LiVOPO 4 of composite materials. The resulting product was formed into a button battery to measure its charge-discharge specific capacity and cycle performance. The ...

Embodiment 2

[0024] With lithium carbonate, vanadium pentoxide, diammonium hydrogen phosphate, and lithium fluoride as raw materials, LiVPO in the obtained composite positive electrode material 4 F. Li 3 V 2 (PO 4 ) 3 with LiVOPO 4 The molar ratio is 0.2:0.4:0.4, and mix evenly; then add the reducing agent oxalic acid to the mixed material, according to the molar ratio of oxalic acid and vanadium source is 3:1, add and mix, mechanical ball mill for 8 hours, and then turn it to vacuum drying The powder was dried in an oven, fully ground the powder in an agate mortar, pressed into tablets, heat-treated at 750°C for 4 hours in an argon atmosphere, then naturally cooled to 350°C and sintered in an air atmosphere for 2 hours, and finally cooled naturally to room temperature to obtain 0.2 LiVPO 4 F 0.4Li 3 V 2 (PO 4 ) 3 0.4LiVOPO 4 of composite materials. The resulting product was formed into a button battery to measure its charge-discharge specific capacity and cycle performance. The...

Embodiment 3

[0026] With lithium carbonate, vanadium pentoxide, diammonium hydrogen phosphate, and lithium fluoride as raw materials, LiVPO in the obtained composite positive electrode material 4 F. Li 3 V 2 (PO 4 ) 3 with LiVOPO 4 The molar ratio is 0.4:0.4:0.2, and mix evenly; then add reducing agent oxalic acid to the mixed material, according to the molar ratio of oxalic acid and vanadium source is 3:1, add and mix, mechanical ball mill for 8 hours, and then turn it to vacuum drying The powder was dried in an oven, fully ground the powder in an agate mortar, pressed into tablets, heat-treated at 750°C for 2 hours in an argon atmosphere, then naturally cooled to 350°C and sintered in an air atmosphere for 4 hours, and finally cooled naturally to room temperature to obtain 0.4 LiVPO 4 F 0.4Li 3 V 2 (PO 4 ) 3 0.2LiVOPO4 of composite materials. The resulting product was formed into a button battery to measure its charge-discharge specific capacity and cycle performance. The first...

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Abstract

The invention discloses a preparation method of a multi-core type phosphate compound positive electrode material with a core-shell structure for a lithium ion battery, and belongs to the technical field of lithium ion batteries. The preparation method is characterized in that the compound positive electrode material xLiVPO4F yLi3V2(PO4)3 (1-x-y)LiVOPO4 of the lithium ion battery is prepared by adopting a chemical reduction-solid phase sintering technology. The preparation method comprises the following steps: (1), blending raw materials; (2), adding a carbon source as a reducing agent, mechanically activating and then drying in a vacuum drying oven to obtain a compound precursor; (3), calcining the compound precursor obtained in the step (2) in a sintering furnace under a non-oxidation atmosphere at a temperature of 600-800 DEG C for 1-24 hours, naturally cooling to 300-700 DEG C, and sintering for 1-10 hours to obtain the multi-core type compound positive electrode material xLiVPO4F yLi3V2(PO4)3 (1-x-y)LiVOPO4 with the core-shell structure. According to the compound positive electrode material prepared by adopting the preparation method, components of cores, formed by a selfoxidation-reduction reaction, sequentially comprise LiVPO4F, Li3V2(PO4)3 and LiVOPO4 from inside to outside, and an outermost layer is of a carbon-coated microstructure. The multi-core type phosphate compound positive electrode material is special in structure components, excellent in electrochemical performance, multiple in charging and discharging platforms, easily controllable in charge state, and suitable for a power battery.

Description

technical field [0001] The invention relates to a preparation method of a lithium-ion battery positive electrode material, in particular to a method for preparing a lithium-ion battery multi-nuclear core-shell structure phosphate-based composite positive electrode material using a "chemical reduction-solid phase sintering" technology. It belongs to the technical field of lithium ion batteries. Background technique [0002] With the advent of the electronic information age, in order to meet the increasing energy demand of various mobile devices, the development of high-performance secondary lithium-ion batteries with long life, high specific power, low cost, and no pollution has become the current research trend. Lithium-ion battery cathode materials are the key components of lithium-ion batteries, and the development of cheap, high-cycle performance, and high-safety cathode materials is currently a global research hotspot. Phosphate-based cathode materials have become the f...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58
CPCH01M4/364H01M4/5825H01M10/0525H01M2004/028Y02E60/10
Inventor 郑俊超张宝韩亚东张佳峰
Owner CENT SOUTH UNIV
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