Method for producing hard carbon lithium metal composite negative pole material for lithium ion battery

Abstract

The present invention relates to lithium ionization cell used hard carbon - lithium metal compounding cathode material preparation method, belonging to chemical engineering and new material technology field, in particular relating to lithium secondary cell cathode material preparative technique field. One method is to make hard carbon material with lithium powder mixing upon inert gas atmosphere, to obtain hard carbon - lithium metal compounding cathode material. Another method is to prepare hard carbon material powder into electrode piece, then under inert gas atmosphere pressing lithium foil on hard carbon electrode piece surface to obtain hard carbon - lithium metal compounding cathode material. The mass ratio relation of lithium with hard carbon material in above-mentioned two methods satisfies that the lithic first excess loading capacity can compensate hard carbon first non-reversible capacity. Said invention provided method can prepare cathode material with more than first Coulomb 100 per cent, high electrochemical activity, large reversible capacity, fine cycle performance, low material cost, and simple technological process etc advantages.

Description

technical field [0001] The preparation method of a hard carbon-lithium metal composite negative electrode material for lithium ion batteries belongs to the technical field of chemical engineering and new materials, and particularly relates to the technical field of preparation of lithium secondary battery negative electrode materials. Background technique [0002] Lithium-ion battery is a new type of high-energy secondary battery that began to be put into practical use in the 1990s. It has outstanding advantages such as high voltage, high energy density, good cycle performance, small self-discharge, and no memory effect. It has been widely used in mobile phones and notebooks. Computers, digital products, electric tools and other portable equipment fields. As the power source of electric vehicles and hybrid vehicles, lithium-ion batteries have shown good application prospects and great application potential in many fields such as military equipment and aerospace. [0003] Si...

AI Technical Summary

Problems solved by technology

[0004] The main problems of graphite negative electrode materials are: (1) Artificial graphite needs to be prepared by high-temperature graphitization at 1900°C to 2800°C, and the temperature is too high; (2) The theoretical specific capacity is 372mAh / g, which is relatively low; (3) Fragile structure leads to very limited stability and is also highly sensitive to electrolyte

However, in actual use, during the charging and discharging process of lithium metal in liquid electrolyte, dendritic dendrites will be generated on the surface of lithium metal, which will reduce the charging and discharging efficiency, and even break through the diaphragm, causing serious problems of battery short circuit and burning.