Preparation And Research Of High Surface Area And Hierarchical Porous Carbon-sulfur Cathod Composite Material For Lithium-sulfur Battery

Nowadays, energy crisis and environmental pollution are two main issues for humansociety. Renewable cleaning energy is considered to be a promising candidate to solve thoseproblems. Lithium-sulfur battery has gotten more and more attention because of low cost,environmental friendly and high energy density. However, the applications of Li-S batteryhave been hindered by technological challenges such as poor conductivity and solubility inelectrolyte of intermediate products, which lead to low utilization of active material, shortcycle life and low coulombic efficiency.In our report, hierarchical porous active carbon (HAC) with high surface area is chosenas the cathode matrix to improve the low dispersity and utilization of sulfur. This material hasthe surface area of2200m2g-1with micropores and mesopore. Particle size，surface area andpore volume, synthesizig method are considered to synthesize sulfur-carbon composites.Results shows that the optimal conditions are small particle size, large surface area, porevolume and vapor-melting method. The prepared Sv-m-E/HACPcomposites under the optimalconditions delivers920mA h g-1while capacity retention is90%after100cycles andcoulombic efficiency remains90%.Carbon fiber paper is chosen as cathode current collector in our work. Carbon fibers withweaved structure and dispersed active carbon particles form a3D conductive network.Li-(S/HAC-CPF) cells with3D conductive network and Sv-m-E/HACPcomposites delivers aninitial discharge capacity of1692mA h g-1. It exhibite diacharge capacities of1088mA hg-1、1013mAh g-1、895mAh g-1、829mAh g-1and660mAh g-1at0.5C、1C、2C、3Cand6C, which are higher15%、41%、45%、48%and50%than Li-(S/HAC-Al) cells,respectively.