Nanometer lignin carbon-zinc oxidecomposite material as well as preparation method and application thereof

Abstract

The invention discloses a nanometer lignin carbon-zinc oxidecomposite material as well as a preparation method and application thereof. The method comprises the following steps: (1) dissolving ligninin an alkaline solution, carrying out hydrothermal pretreatment, conducting cooling, and adjusting a pH value to 3-5 to obtain an acid-soluble lignin solution; (2) adding a mixed solution of soluble zinc salt and soluble carbonate into the acid-soluble lignin solution, conducting a hydrothermal reaction, then adding aldehydes, and continuing the hydrothermal reaction to obtain a ploycondensed lignin / zinc oxide compound; and (3) carbonizing the polycondensed lignin / zinc oxide compound to obtain the nanometer lignin carbon-zinc oxidecomposite material. In the obtained nanometer lignin carbon-zinc oxidecomposite material, lignin carbon uniformly coats the surfaces of zinc oxide particles to form a uniform carbon layer with a continuous structure, so the problems of serious volume expansion and poor conductivity of zinc oxide serving as a lithium ion negative electrode material are solved, and the specific capacity, the initial coulombic efficiency and the rate capability of a lithium ionbattery are improved.

Description

technical field [0001] The invention belongs to the technical field of negative electrode materials for lithium ion batteries, and in particular relates to a nanometer lignin carbon oxide zinc composite material, a preparation method thereof and an application in lithium ion battery negative electrode materials. Background technique [0002] Graphite, as a traditional lithium-ion battery (LIB) anode material, has a low theoretical specific capacity (372mAh g -1 ), the low ion diffusion coefficient caused by too narrow layer spacing, and the easy formation of lithium dendrites during high-rate charge and discharge, causing safety hazards and other issues. This forces us to develop a new lithium battery anode material with high energy density, high rate performance and high safety. [0003] In recent years, transition metal oxides have been extensively studied as anode materials for lithium batteries. Zinc oxide (ZnO) has a high theoretical lithium storage capacity (978mAh g...

AI Technical Summary

Problems solved by technology

However, there are two key problems that limit the application of ZnO in lithium battery negative electrodes: (1) During the charge and discharge process, the large volume change (about 228%) leads to easy agglomeration, pulverization and rapid capacity decay of the material; (2) The electronic conductivity of ZnO itself Low, poor rate performance

These patents and papers use sodium lignosulfonate as a structure-directing agent or surfactant, and react with zinc salt in aqueous solution to prepare nano-zinc oxide. However, these materials are not suitable for lithium battery negative electrodes, mainly because lignosulfonate The water solubility of sodium bicarbonate is too strong, the load after the reaction is very small, it is easy to wash off in the process of water washing, and the prepared zinc oxide particles are too large, which cannot solve the problem of volume expansion

[0012] In summary, the lignin carbon ZnO composite material prepared by the current existing technology or process is not suitable for direct application in the negative electrode material of lithium ion battery, the main reason is that the described process is mainly based on physical compounding or its purpose is mainly for Disperse and stabilize zinc oxide particles. Most of the prepared lignin-carbon ZnO composites are still at the micron level, and the agglomeration phenomenon is still serious, which cannot solve the problems of volume expansion and low conductivity of ZnO.

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