Preparation method of sulfur positive electrode composite material based on high-energy density type graphene

Abstract

The invention discloses a preparation method of a sulfur positive electrode composite material based on high-energy density type graphene, which comprises the following steps: adding graphite powder, sodium nitrate and potassium permanganate into concentrated sulfuric acid, and stirring to slowly heat; after the solution is reacted and heated, adding deionized water and a reducing agent, filtering and drying to obtain graphite oxide; the preparation method comprises the following steps: performing ultrasonic treatment on graphite oxide to obtain a dispersion liquid A, heating to 80-90 DEG C, adding hydrazine hydrate, filtering, washing and drying to obtain graphene oxide; adding water into graphene oxide, and performing ultrasonic treatment to obtain dispersion liquid B; adding water into inorganic sulfide, stirring and dissolving to obtain a sulfur solution C; and mixing the dispersion liquid B and the sulfur solution C until the reaction is complete, adding dilute acid to adjust the solution to be acidic, filtering and drying to obtain the graphene/sulfur positive electrode composite material, the capacity is 1186 mAh.g <-1 > under the charging condition of 0.1 DEG C, the coulombic efficiency is 96% after 200 times of circulation, the capacity is 997 mAh.g <-1 > under the charging condition of 1 DEG C, and the capacity is 578 mAh.g <-1 > after 1000 times of circulation.

Description

technical field [0001] The invention relates to the field of lithium battery preparation, in particular to a preparation method based on a high energy density graphene-sulfur cathode composite material. Background technique [0002] Compared with traditional secondary batteries, lithium batteries have higher volume specific energy and mass specific energy, which can make batteries smaller and lighter, and are relatively energy-saving and environmentally friendly. However, the energy density of lithium batteries currently commercially used is low, generally only 150-200Wh / kg, which has become one of the bottlenecks in the application of high energy-consuming technologies. The sulfur cathode in lithium-sulfur batteries can provide a theoretical specific capacity of up to 1675mAh / g (more than five times the capacity of conventional LiCoO2 cathodes), and the lithium-sulfur electrochemical pair has an energy density of 2600Wh / kg (higher than that of conventional lithium-ion batte...

AI Technical Summary

Problems solved by technology

[0003] Graphene is an ideal candidate material for use as a high-performance composite material reinforcement. By using sulfur and graphene composite materials for the production of lithium cathodes, it can solve the problem of dissolution of