A Comparative Study of Cobalt Chalcogenides as the Electrode Materials on Lithium-Sulfur Battery Performance.

Lithium-sulfur batteries, as viable options for energy storage, have gained popularity because of their high energy density. However, the poor conductivity of sulfur and Li 2 S, as well as the shuttling effect of lithium polysulfides, seriously limits their commercialization. Herein, cobalt chalcogenides (Co 3 O 4 , CoS, and Co 3 Se 4 ) supported by reduced graphene oxide are synthesized as the electrode materials, which feature high conductivity, rapid kinetic conversion, and catalytic effect. Based on complementary experimental outputs and advanced computation, it is revealed that the change in anion results in distinctive performance. Among them, the cathode material based on Co 3 Se 4 /reduced graphene oxide is the best. The reasons can be ascribed to the conductive and catalytic improvement. This comparative study provides guidelines in the design of lithium-sulfur batteries via the meticulous regulation of the anions.