An integrated hybrid interlayer for polysulfides/selenides regulation toward advanced Li–SeS2 batteries

Abstract

Selenium disulfide (SeS2) is one of the promising cathode materials for high energy density batteries, since it has a competitive theoretical specific capacity (1345 mAh g−1) and much better electrical conductivity over sulfur (S). Similar to S cathode, however, the practical application of SeS2 cathode is also impeded by poor cycling performance caused by the shuttling phenomenon of soluble lithium polysulfides/selenides. In this work, a graphene sponge/titanium nitride (TiN) nanowires composite is prepared as the well-designed multi-functional hybrid interlayer to be applied in Li–SeS2 batteries for the first time. The three-dimensional porous conductive framework constructed by graphene nanoscrolls/nanosheets coexited sponge and TiN nanowires provides efficient transfer channels for electrons and ions. Moreover, TiN not only has strong chemical adsorption to trap the soluble polysulfides/selenides, but also possesses electrocatalytic effects to promote the electrochemical reaction of the cathodic solid-liquid/liquid-solid and the anodic solid-liquid conversions. By virtue of the multi-functional capabilities, the as-assembled cells equipped with the hybrid interlayer exhibit an outstanding electrochemical performance with a long cycling life, a low capacity decay (0.08% per cycle), and superior rate capability (493 mAh g−1 at 5 A g−1). This work offers a new and efficient strategy to propell the development of high-performance Li–SeS2 batteries.