Modifying method by coating surface of lithium-rich positive electrode material with alumina

A lithium-rich cathode material and surface coating technology, which is applied to battery electrodes, electrochemical generators, electrical components, etc., can solve the problems of low coulombic efficiency in the first cycle, affecting the performance of cathode materials, and uneven distribution of coating layers. Achieve the effects of simple process, inhibition of metal ion dissolution, and excellent electrochemical performance

Inactive Publication Date: 2017-05-17
GUANGXI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, there are still several problems in the use of lithium-rich manganese-based ternary cathode materials: low coulombic efficiency in the first cycle; poor rate performance; high charging voltage causes electrolyte decomposition and unsatisfactory cycle performance; unsafe under high voltage
The currently commonly used surface modification method is the liquid phase coating method. By adding the corresponding coating ions and the corresponding precipitating agent to the mother liquid of the active material, the operation is often more complicated, and the coating effect is not good, resulting in the distribution of the coating layer. Inhomogeneity affects the improvement of the performance of the positive electrode material

Method used

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  • Modifying method by coating surface of lithium-rich positive electrode material with alumina
  • Modifying method by coating surface of lithium-rich positive electrode material with alumina
  • Modifying method by coating surface of lithium-rich positive electrode material with alumina

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Lithium-rich cathode material xLi 2 MnO 3 ·(1-x)LiNi 0.5 co 0.3 mn 0.2 o 2 The preparation steps are as follows:

[0040](1) Weigh 5.257 g NiSO4·H2O, 3.3732 g CoSO4·H2O, 11.4933 g MnSO4·H2O, configure into 50 mL mixed solution, stir with a glass rod until all metal salts are dissolved, weigh 2 g ammonia water (mass fraction 28%) As a complexing buffer, add the metal salt solution configured above, weigh 8 g NaOH as a precipitant, and configure it into a 50 mL solution, stir with a glass rod until the NaOH is completely dissolved;

[0041] (2) Before starting the reaction, add 100 mL of deionized water to a four-hole flask with a capacity of 500 mL, then add an appropriate amount of ammonia water with a mass fraction of 28%, and control the pH at 11.0±0.1;

[0042] (3) After the reaction started, the temperature of the reaction system was controlled at 50 °C, and the stirring intensity was 700 r / min. The metal ion solution and the precipitant were fed into the reac...

Embodiment 2

[0053] Lithium-rich cathode material xLi 2 MnO 3 ·(1-x)LiNi 0.5 co 0.3 mn 0.2 o 2 The preparation steps are as follows:

[0054] (1) Weigh 7.8855 g NiSO4·H2O, 5.0598 g CoSO4·H2O, 8.7890 g MnSO4·H2O, configure into 50 mL mixed solution, stir with a glass rod until all metal salts are dissolved, weigh 2 g ammonia water (mass fraction 28%) As a complexing buffer, add the metal salt solution configured above, weigh 8 g NaOH as a precipitant, and configure it into a 50 mL solution, stir with a glass rod until the NaOH is completely dissolved;

[0055] (2) Before starting the reaction, add 100 mL of deionized water to a four-hole flask with a capacity of 500 mL, then add an appropriate amount of ammonia water with a mass fraction of 28%, and control the pH at 11.0±0.1;

[0056] (3) After the reaction started, the temperature of the reaction system was controlled at 50 °C, and the stirring intensity was 700 r / min. The metal ion solution and the precipitant were fed into the rea...

Embodiment 3

[0067] Lithium-rich cathode material xLi 2 MnO 3 ·(1-x)LiNi 0.5 co 0.3 mn 0.2 o 2 The preparation steps are as follows:

[0068] (1) Weigh 6.5713 g NiSO4·H2O, 7.0275 g CoSO4·H2O, 10.1412 g MnSO4·H2O, configure into 50 mL mixed solution, stir with a glass rod until all metal salts are dissolved, weigh 2 g of ammonia water (mass fraction 28%) As a complexing buffer, add the metal salt solution configured above, weigh 8 g NaOH as a precipitant, and configure it into a 50 mL solution, stir with a glass rod until the NaOH is completely dissolved;

[0069] (2) Before starting the reaction, add 100 mL of deionized water to a four-hole flask with a capacity of 500 mL, then add an appropriate amount of ammonia water with a mass fraction of 28%, and control the pH at 11.0±0.1;

[0070] (3) After the reaction started, the temperature of the reaction system was controlled at 50 °C, and the stirring intensity was 700 r / min. The metal ion solution and the precipitant were fed into the...

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Abstract

The invention relates to a modifying method by coating a surface of a lithium-rich positive electrode material with alumina. The method comprises the following steps: carrying out Al2O3 surface modification on a lithium-rich positive electrode material with a sol solution, enabling a Al3+ ion coated salt to react with ammonia water, adding citric acid to form a sol solution, and then adding the lithium-rich positive electrode material to the sol solution, directly evaporating to dryness, and carrying out heat treatment to obtain a modified lithium-rich positive electrode coated with Al2O3 on the surface. The prepared lithium-rich positive electrode material has excellent electrochemical performances, the first discharge specific capacity is 289.69mAh/g and the first coulomb efficiency is 77.01% at the charge and discharge rate of 0.1C, and the capacity retention rate is still 95.45% after 50 cycles at a rate of 1C, showing a good cycle performance.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a modification method for coating aluminum oxide on the surface of a lithium-rich positive electrode material. Background technique [0002] With the increasingly prominent energy crisis and environmental pollution problems, it is imperative to develop new energy sources for sustainable development and build a low-carbon society. As a new type of high-energy green battery, lithium-ion batteries have attracted much attention and are widely used in small portable electronic devices such as mobile phones, notebook computers and digital products. [0003] Currently researched and commercialized cathode materials such as LiCoO 2 、LiNi x co y mn z o 2 、LiFePO 4 and LiMn 2 o 4 etc., the specific capacity is lower than 200mAh / g, which is difficult to meet the market application demand of high specific capacity. In recent years, lithium-rich manganese-based ternary ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/505H01M4/525H01M10/0525
CPCH01M4/366H01M4/505H01M4/525H01M10/0525Y02E60/10
Inventor 黎光旭郭进蓝志强周文政梁先庆黄海富
Owner GUANGXI UNIV
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