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Positive electrode material and preparation method thereof, and secondary battery

A positive electrode material and positive electrode technology, applied in the overcharge-proof positive electrode material and its preparation, and in the field of secondary batteries, can solve the problems of limited improvement in battery overcharge safety, deterioration of battery electrochemical performance, and additive content limitations, etc., to achieve Reduce overcharge safety hazards, improve the first discharge capacity and capacity retention rate, and the effect of uniform delithiation degree

Inactive Publication Date: 2021-02-26
SHENZHEN POLYTECHNIC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The technical solution of adding an overcharged film-forming additive to the electrolyte can block the current path through the polymerization reaction of the additive, but the cost of the additive itself is relatively high, and on the other hand, such additives generally deteriorate the electrochemical performance of the battery. , due to the negative effect on the electrochemical performance, the content of this additive in the electrolyte is strictly limited, and its effect on improving the battery overcharge safety is relatively limited.

Method used

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  • Positive electrode material and preparation method thereof, and secondary battery
  • Positive electrode material and preparation method thereof, and secondary battery

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preparation example Construction

[0026] The present invention also provides a preparation method of positive electrode material, comprising:

[0027] (1) Preparation of lithium nickel manganese oxide

[0028] A lithium nickel manganese oxide powder material with a spinel structure with a D50 of 30-100 nm was prepared by a liquid phase sol-gel method;

[0029] (2) Coating of lithium nickel manganese oxide

[0030] A dry coating method is used to coat the lithium nickel manganese oxide on the core material with a layered structure.

[0031] Wherein, the preparation of lithium nickel manganese oxide includes: according to the chemical formula LiNi 0.5 mn (1.5-x) m x o 4, where M is Al or Ti, 0≤x≤0.08, weigh the Li source, Ni source, Mn source and M source in the formula, mix them uniformly and dissolve them in water to obtain a mixed solution, heat and stir the mixed solution and slowly add the precipitate Control the pH value to be neutral, then slowly add ammonia water and continue to stir, heat up and k...

Embodiment 1

[0035] A cathode material including LiCoO 2 Core material and LiNi with spinel structure cladding the core material 0.5 mn 1.5 o 4 , LiNi 0.5 mn 1.5 o 4 The D50 is 58nm, and the specific surface area BET is 24m 2 / g, the discharge voltage platform is 4.95V, and occupies LiCoO 2 8% of the mass of the core material.

[0036] Its preparation method is:

[0037] (1) Preparation of lithium nickel manganese oxide

[0038] Li(CH 3 COO).2H 2 O, Ni(CH 3 COO) 2 .4H 2 O and Mn(CH 3 COO) 2 .4H 2 O, weigh and mix according to the formula amount and dissolve in a certain quality of water to prepare a 1mol / L solution. After mixing, stir at 50°C and gradually drop in citric acid, control the pH value to be neutral and drop slowly Add ammonia water and keep stirring continuously for 4 hours, then increase the solution temperature to 85°C, and keep stirring until a gel state with high viscosity is formed, then dry at 85°C for 24 hours, and use a sand mill to grind the dried pre...

Embodiment 2

[0042] A cathode material including LiCoO 2 Core material and LiNi with spinel structure cladding the core material 0.5 mn 1.49 Ti 0.01 o 4 , LiNi 0.5 mn 1.49 Ti 0.01 o 4 The D50 is 55nm, the specific surface area BET is 30m 2 / g, the voltage platform is 5V, and occupies LiCoO 2 10% of the mass of the core material.

[0043] Its preparation method is:

[0044] (1) Preparation of lithium nickel manganese oxide

[0045] Li(CH 3 COO).2H 2 O, Ni(CH 3 COO) 2 .4H 2 O, Mn(CH 3 COO) 2 .4H 2 O and Ti(CH 3 COO) 2 .4H 2 O is weighed and mixed according to the formula amount and dissolved in a certain quality of water to prepare a 1mol / L solution. After mixing, stir at 50°C and gradually drop in citric acid, control the pH value to be neutral and slowly drop in At the same time, keep stirring the ammonia water continuously for 4 hours, then increase the temperature of the solution to 90°C, and keep stirring until a gel state with high viscosity is formed, and then dr...

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Abstract

The invention provides a positive electrode material and a preparation method therefor, and a secondary battery.The positive electrode material comprises a core material having a layered structure andlithium nickel manganese oxide having a spinel structure and coating the core material, D50 of the lithium nickel manganese oxide is 30-100 nm and a specific surface area BET is 20-100 m<2> / g. According to the positive electrode material, the overcharge potential safety hazard of the secondary battery can be reduced from a chemical system, and meanwhile, a first discharge capacity and a capacityretention ratio of the secondary battery can be improved so that the cycle performance of the secondary battery is improved. The preparation method of the positive electrode material comprises the following steps: (1) preparing lithium nickel manganese oxide, namely preparing a lithium nickel manganese oxide powder material with a spinel structure and a D50 of 30-100nm by adopting a liquid-phase sol-gel method; and (2) coating the lithium nickel manganese oxide: coating the core material with the layered structure of the lithium nickel manganese oxide by using a dry coating method. The lithiumnickel manganese oxide powder shell material is prepared by adopting a liquid-phase sol-gel method, and the coating layer is prepared by adopting a dry method so that the prepared material is betterin coating performance, and better overcharge secondary battery safety can be obtained.

Description

technical field [0001] The invention relates to the field of positive electrode materials, more specifically, the invention relates to an overcharge-proof positive electrode material, a preparation method thereof, and a secondary battery. Background technique [0002] As a new type of green energy, lithium-ion batteries have the advantages of high specific energy, small self-discharge, high open circuit voltage, no memory effect, long cycle life, and no environmental pollution, so they are widely used in mobile phones, notebook computers, digital cameras, etc. At the same time, lithium-ion batteries are also the power supply of electric vehicles and the energy storage power supply of solar renewable energy. It is the most widely used secondary battery at present. [0003] During the charging process of the lithium-ion battery, due to improper operation or failure of the battery management module, when the voltage exceeds the charging cut-off voltage, the lithium-ion battery ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/505H01M4/525H01M10/0525
CPCH01M4/366H01M4/505H01M4/525H01M10/0525H01M2004/028Y02E60/10
Inventor 李鲲罗大为林峰
Owner SHENZHEN POLYTECHNIC
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