Synthesis of carbon-bound lithium-ion conductor-carbon composite anode materials with carbon fiber structure

Abstract

The invention relates to a carbon-bound lithium ion conductor-carbon composite negative electrode material with a carbon fiber structure and a preparation method thereof. The material particles prepared by the method are made of small crystals of lithium ion conductors and small particles of carbon negative electrode active materials bound by carbon fibers. The fixed formation improves the charge and discharge current density of the material. Carbon fiber has high tensile strength and fiber softness, which to a certain extent buffers the volume change, pulverization and agglomeration of the material during charging and discharging, and effectively prevents the bound small carbon particles from charging and discharging in a long-term cycle. Under the condition of exfoliation into multi-layer graphite, the cycle stability of the electrode is improved, the rate performance of the material is improved, and it has a larger capacity. The production process of this material is short and the cost is low. When the mixed particles are subjected to high temperature treatment, the polymer material is carbonized into a three-dimensional carbon fiber network with a carbon fiber structure, and the lithium ion conductor and small carbon particles are bound in the same particle. Realize one-step completion of material production.

Description

technical field [0001] The invention relates to a preparation method of a carbon-bound lithium ion conductor-carbon composite negative electrode material with a carbon fiber structure, and uses the material as the negative electrode material of a lithium ion battery. Background technique [0002] With the increasing application of lithium-ion battery technology in the electric vehicle industry, aviation industry, electronic equipment, etc., people have put forward higher requirements for the performance of lithium-ion batteries, and electrode materials are the key factors to improve the performance of lithium-ion batteries . In terms of negative electrode materials, most of the current commercial lithium-ion battery negative electrode materials are graphite. The theoretical lithium intercalation capacity of graphite is 372mAh / g. Its crystals are complete and have high orientation. It produces about 10% volume expansion and contraction, and its layered structure is easily de...

AI Technical Summary

Problems solved by technology

In terms of negative electrode materials, most of the current commercial lithium-ion battery negative electrode materials are graphite. The theoretical lithium intercalation capacity of graphite is 372mAh / g. Its crystals are complete and have high orientation. Produce volume expansion and contraction of about 10%, and its layered structure is easily destroyed during cycling

In addition, in the cycle process, it is inevitable that the electrolyte solvent will be co-embedded between the graphite layers, which will generate gas and volume expansion, causing the graphite flakes to peel off, resulting in irreversible loss of active materials and continuous destruction and regeneration of the solid electrolyte interface film (SEI film). , consume lithium ions, resulting in shortened battery cycle life

Metal ion compounds have good performance of conducting lithium ions, but have the disadvantage of poor conductivity, and there is a large volume change with the intercalation and extraction of lithium ions, so its electrochemical performance, cycle stability, rate capability not ideal

Images