Highly-dispersed vanadium nitride supported on porous nitrogen-doped carbon material as a high-performance cathode for lithium-sulfur batteries

Abstract

Transition metals and their compounds supported on carbon materials are widely used as cathodes for lithium-sulfur batteries. Vanadium nitride is considered to be a promising cathode because of its good adsorption capacity for lithium polysulfides and high catalytic activity, but in practice it usually shows insufficient electrical conductivity and low electrocatalytic activity due to particles agglomeration. In this study, highly dispersed vanadium nitride supported on porous nitrogen-doped carbon was prepared via one-pot pyrolysis in a molten salt medium. Physical characterization revealed VN particles with a uniform size distribution of ca. 10 nm well dispersed on the carbon surface. When used as a cathode for Li−S battery, the material delivered a specific discharge capacity of 1050 mAh g−1 at 0.2 C and good rate performance. During the stability test over 500 continuous cycles, the average decay rate was 0.059 % per cycle. The study demonstrates prospective application of the newly developed electrocatalytic material as a cathode in lithium-sulfur batteries.