Positive electrode material modification method

A positive electrode material and modification technology, applied in the direction of positive electrodes, battery electrodes, active material electrodes, etc., can solve the problems of high cost, complicated process, time-consuming, etc., and achieve the effects of low cost, reduced erosion, and easy operation

Active Publication Date: 2020-09-01
LANZHOU UNIVERSITY OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method is aimed at the doping-coating double modification of the positive electrode material, which requires two steps to be realized, that is, the material is doped first, and then the material is coated. This method is complex, time-consuming and costly.

Method used

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  • Positive electrode material modification method
  • Positive electrode material modification method
  • Positive electrode material modification method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] (1) Weigh a certain amount of Al(BOB) 3 , prepare 0.3 mol L -1 Al(BOB) 3 - EC / DEC electrolyte;

[0027] (2) Use the prepared electrolyte and LiNi 0.5 co 0.2 mn 0.3 o 2 Positive electrode sheet assembled button half battery;

[0028] (3) Adjust the constant current charge and discharge current density to 0.02 mA cm -2 , control the charge cut-off voltage to 4.3 V, discharge cut-off voltage to 3.5 V, that is, the charge and discharge voltage range is 3.5-4.3 V;

[0029] (4) Under the conditions of step (3), perform three electrochemical pre-cycle activations;

[0030] (5) After the cycle is over, take out the positive electrode and wash it with EC to obtain the modified LiNi 0.5 co 0.2 mn 0.3 o 2 Cathode material.

[0031] The modified positive electrode material was subjected to a phase characterization test, and a button half battery was assembled to test the cycle performance.

[0032] figure 1 XRD patterns of the material before and after modification...

Embodiment 2

[0037] (1) Weigh a certain amount of Mg(BOB) 2 , prepare 0.5 mol L -1 Mg(BOB) 2 - EC / DEC electrolyte;

[0038] (2) Use the electrolyte prepared in step (2) and the LiNi to be modified 0.5 co 0.2 mn 0.3 o 2 Positive electrode sheet assembled button half battery;

[0039] (3) Adjust the constant current charge and discharge current density to 0.05mA cm -2 , control charge cut-off voltage 4.4 V, discharge cut-off voltage 3.6 V, charge and discharge voltage range 3.6 - 4.4 V;

[0040] (4) Under the conditions of step (3), perform 5 electrochemical pre-cycles;

[0041] (5) After the cycle is over, take out the positive electrode and wash the positive electrode with EC to obtain the modified LiNi 0.5 co 0.2 mn 0.3 o 2 Cathode material.

[0042] The modified positive electrode material was assembled into a button half battery, and the cycle performance test was carried out.

[0043] Figure 5 The cycle performance diagram of the material before and after modification...

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Abstract

The invention discloses a positive electrode material modification method which comprises the following steps of (1) preparing a bis (oxalato) borate-ethylene carbonate / diethyl carbonate modified electrolyte; (2) assembling a battery by using the prepared modified electrolyte and a to-be-modified positive electrode material; (3) controlling the constant-current charge-discharge current density ofthe assembled battery within a certain charge-discharge voltage range, and carrying out electrochemical circulation; and (5) after the circulation is finished, taking out the positive electrode, and cleaning the positive electrode with EC to obtain the modified positive electrode material. The positive electrode material modification method provided by the invention can realize the synchronous doping-coating dual modification of the positive electrode material, not only can improve the lithium layer environment of the material, but also can improve the interface stability and improve the cycling stability of the positive electrode material.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to positive electrode materials of lithium ion batteries. Background technique [0002] As an important part of lithium-ion batteries, the performance of cathode materials largely determines the energy density and power density of lithium-ion batteries. With the continuous improvement of the performance requirements of lithium-ion batteries, the development of high-performance lithium-ion battery cathode materials has become particularly important. [0003] In the long cycle process, the cathode material is poor in electrode / electrolyte interface stability and the crystal structure is easy to change, so the cycle performance of the cathode material deteriorates. In order to solve the problem of poor cycle stability of layered ternary materials, a series of modification measures such as doping and coating are usually applied to improve the long-term cycle performance of material...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/1391H01M4/36H01M4/505H01M4/525H01M4/62H01M10/0525
CPCH01M4/1391H01M4/366H01M4/505H01M4/525H01M4/628H01M10/0525H01M2004/028Y02E60/10
Inventor 崔孝玲王圣贤李昭娟李世友宋如东红脱宽有王超李文博王博梁文彪
Owner LANZHOU UNIVERSITY OF TECHNOLOGY
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