Liquid-phase ZnO coated Ni<2+>-Cr<3+> doped amorphous cobalt nitrate lithium battery anode material and preparation method thereof

Abstract

The invention discloses a liquid-phase ZnO coated Ni<2+>-Cr<3+> doped amorphous cobalt nitrate lithium battery anode material and a preparation method thereof. The liquid-phase ZnO coated Ni<2+>-Cr<3+> doped amorphous cobalt nitrate lithium battery anode material and the preparation method thereof are characterized by synthesizing Ni<2+>-Cr<3+> doped amorphous cobalt nitrate by adopting a solvent conversion method and coating ZnO on particles thereof to form the ZnO coated Ni<2+>-Cr<3+> doped amorphous cobalt nitrate lithium battery anode material; and then, under a high vacuum condition, removing crystallization water in a system by adopting a special heat treatment step. With the ZnO for coating, the electronic conductivity of the material can be greatly improved; owing to doped Ni<2+> and Cr<3+> ions in the system, a Co-O space structure is enabled to produce distortion, and a lithium ion diffusion-migration channel is expanded, so the electric conductivity of lithium ions is improved; the particularly beneficial effect is that the material is amorphous and is isotropic, thereby being conductive to rapid conduction of the lithium ions; and thus, the overall electrochemical performance of cobalt nitrate is greatly improved.

Description

technical field [0001] The invention relates to the technical field of a manufacturing method for a high-performance cobalt nitrate composite lithium battery negative electrode material. Background technique [0002] Lithium-ion secondary batteries have the absolute advantages of high volume, high weight-to-energy ratio, high voltage, low self-discharge rate, no memory effect, long cycle life, and high power density. Gradually grow at a rate of over 10%. Especially in recent years, with the gradual exhaustion of fossil energy, new energy sources such as solar energy, wind energy, and biomass energy have gradually become alternatives to traditional energy sources. Among them, wind energy and solar energy are intermittent, and in order to meet the needs of continuous power supply, a large number of Energy storage batteries; the urban air quality problem caused by automobile exhaust is becoming more and more serious, and the vigorous advocacy and development of electric vehicl...

AI Technical Summary

Problems solved by technology

However, it is still very difficult to take into account the rate performance and cycle capacity retention performance of the material.

The main reasons are as follows: 1. When the redox reaction occurs, the electrode material should have fast lithium ion intercalation and deintercalation and electronic conduction, that is, it should have good electronic conductivity and ion conductivity at the same time. Many negative electrode materials have high However, it is an electronic insulator, which greatly increases the polarization of the battery; 2. Many electrode materials have a large volume change during the process of lithium ion intercalation and deintercalation, resulting in electrode material particles The broken and effective electrode materials are lost during the cycle, and the large volume change also brings about the transformation of the material lattice during the charging and discharging process to produce a second phase, which seriously affects the performance of the battery.

3. Lithium battery negative electrode material with conversion reaction mechanism, the electronic insulation of the reaction product lithium compound seriously affects the reversibility of the material

Cobalt nitrate negative electrode conversion material can also provide close to or exceed 1000mAh.g -1 The specific capacity, and its rate characteristics are superior to those of metal oxides, sulfides, phosphides, carbonates, and chlorides, and the volume change of materials that lithium ions enter or exit is also small; and its main problems are: 1. Nitric acid Cobalt generally contains a lot of crystal water, and these crystal water are difficult to completely remove, which may easily cause the electrolyte to decompose, corrode the surface of the material and partially dissolve the material itself; 2. The product lithium nitrate after the conversion reaction is an electronic insulator and its lithium ions The diffusion activation energy is also high, resulting in a large electrochemical polarization; 3. The surface of cobalt nitrate is unstable and easily corroded by the electrolyte

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