Battery anode material and preparation method thereof and lithium battery

Abstract

The invention provides a battery anode material and a preparation method thereof and a lithium battery. The preparation method of the battery anode material comprises the following steps: epitaxiallygrowing a high-quality gallium nitride thin film on a conductive crystal substrate to obtain an epitaxial structure; and modifying the epitaxial structure through electrochemical corrosion, forming holes in the surface of the high-quality gallium nitride thin film and making the holes run through the epitaxial structure and forming a crystal gallium nitride material serving as the battery anode material. The crystal gallium nitride material is first used as the battery anode material and is directly used as an electrode in the lithium battery; the preparation method overcomes the technical challenge that the preparation technique of the crystal gallium nitride material is not compatible with the traditional electrode technique; and through adoption of the high-conductivity homogeneous substrate, epitaxial growth of the gallium nitride materials with different properties and structures and modification of the material through the electrochemical corrosion process, the high-quality gallium nitride electrode material is obtained, wherein the material has good cycle stability and high capacity, and has a good application prospect.

Description

technical field [0001] The disclosure belongs to the technical field of new energy, and relates to a battery negative electrode material, a preparation method thereof, and a lithium battery. Background technique [0002] With the rapid development of science and technology, new devices and intelligent systems have put forward higher requirements for energy storage and conversion. Lithium-ion battery is a reversible battery that converts electrical energy and chemical energy through lithium-ion as a medium. It has the characteristics of high energy density, good cycle stability and environmental protection, and has attracted widespread attention from all walks of life. [0003] New anode materials are the key to improving the capacity and cycle stability of lithium-ion batteries. The performance of lithium-ion batteries is closely related to its positive and negative electrode materials. Commercial positive electrode materials are mainly layered lithium cobaltate, lithium ma...

AI Technical Summary

Problems solved by technology

The performance of lithium-ion batteries is closely related to its positive and negative electrode materials. Commercial positive electrode materials are mainly layered lithium cobaltate, lithium manganese oxide, and lithium iron phosphate. The theoretical capacity and actual capacity are close to 300mAh / g, and it is difficult to greatly improve space

The negative electrode materials mainly include four categories: the first category is commercial graphite-like carbon materials, which are close to their theoretical capacity (372mAh / g) after a lot of modification research, but still cannot meet the needs of high-performance lithium-ion batteries with high energy density and cycle stability. Good performance requirements; the second type is transition metal oxides, whose theoretical capacity (500mAh / g-1000mAh / g) is higher than that of graphite-based carbon materials, but highly active particles produced by oxidation / reduction during charge and discharge tend to Because of reaching low energy state through agglomeration, the electrochemical stability of the material is damaged

The third type is Si-based materials, which have a very high theoretical capacity (4200mAh / g), but the volume expansion is as high as 300% after fully intercalating lithium; the fourth type is lithium titanate materials, which have a stable structure (desorption The unit cell parameter a=0.836nm~0.837nm before and after lithium intercalation) and high lithium intercalation potential (1.55V), however, the low conductivity causes serious capacity attenuation during high current charge and discharge

Aiming at the electrochemical properties of the above materials, various optimization studies have been carried out, such as nanostructure, doping and coating, etc., but it is difficult to obtain anode materials with high capacity and stable structure.

[0004] To sum up, it is difficult for the current anode materials to achieve both. Graphite-based carbon materials have good stability, but low theoretical capacity; Si-based materials have the highest theoretical capacity, but poor cycle stability.

Despite adopting a variety of modification methods, including: doping, nanostructure and coating, etc., they have not fundamentally overcome the contradiction between stability and capacity.

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