Influence Mechanism of Cathode Material Mixture Ratio on Lithium-sulfur Battery Performance

Abstract

To study the influence of the ratio of active material, conductive agent and binder on performance of lithium-sulfur battery, the cathode active material was prepared by ball milling sublimed sulfur and acetylene black with mass ratio of 7:3, cathode composite materials were prepared with five different proportions of active material, conductive agent and binder, then the structures and morphologies were observed and batteries were resembled and tested. Electrochemical tests show that the first discharge specific capacity of cathode material with proportion of 7:1:2 reaches 1019.0mAh/g in the current discharge rate of 0.15C, and after 100 cycles,the specific capacity reaches 547.9mAh/g with capacity retention rate of 53.7%, indicating the cathode material with this proportion is desirable, which is due to reasonable component ratio making this cathode composite material possess optimum mesoscopic electronic conductivity and macroscopic fastness. This mechanism can also be guidance for adhesion modification of other micro powders.

Keywords

• lithium-sulfur battery
• cathode material mixture ratio
• electronic conductivity
• micro powder adhesion
• modification mechanism