Carbon-sulfur composite material, preparation method thereof and lithium-sulfur battery

Abstract

The invention provides a carbon-sulfur composite material which comprises a high-porosity porous carbon matrix loaded with a small amount of one or more than two metals and / or metal compounds of Co, Fe, Ni, Cr, Mn and Zn in situ, and sulfur particles, a three-dimensional interconnected electron conduction path with a rich interface and a rapid ion diffusion channel are constructed through high-porosity graded porous carbon, pores of a porous carbon matrix are partially filled with sulfur particles, the surfaces of nano carbon particles are partially coated with sulfur particles, electrons and lithium ions are in full contact with active sulfur at the interface, and the active sulfur and the lithium ions are in full contact. The carbon-sulfur composite material has the advantages that the utilization rate of sulfur is increased, the mechanical stability of an electrode is improved, a small amount of metal and / or compounds are uniformly dispersed among the nano carbon particles, effective chemical adsorption is performed on polysulfide, meanwhile, electrochemical conversion of lithium polysulfide to Li2S2 / Li2S is promoted, and the electrochemical performance of the carbon-sulfur composite material is improved.

Description

technical field [0001] The invention belongs to the field of lithium-sulfur batteries, and in particular relates to a sulfur-carbon composite material supporting an in-situ catalyst, a preparation method thereof, and a lithium-sulfur battery. Background technique [0002] In lithium-sulfur batteries, elemental sulfur is used as the positive electrode material, with a theoretical specific capacity of 1675mAh / g. Using metal lithium as the negative electrode, the theoretical specific energy density reaches 2600Wh / kg, which is the energy density that can be achieved by current commercial lithium-ion batteries (LIBs). In addition, it has the advantages of low cost and no pollution, and is regarded as a new generation of high energy density energy storage system with great potential. However, elemental sulfur and its discharge product Li still exist in lithium-sulfur batteries. 2 The problems of poor S conductivity, severe volume expansion and contraction during charging and disc...

AI Technical Summary

Problems solved by technology

However, when the existing carbon-sulfur composite materials use these two methods to reduce the proportion of inactive components in the sulfur cathode, the electrical performance of the cathode material is not good when used in batteries.

Images