A carbon mixed selenium sulfide separator coating for lithium‐sulfur battery life enhancement

Lithium-sulfur batteries are one of the most promising energy storage devices in the future due to their high specific capacity and abundant natural reserves. However, the shuttle effect of soluble intermediate polysulfide products can lead to rapid decay of battery capacity, short cycle life and serious self-discharge effect, which hinders the development of lithium-sulfur batteries. Here, we coated the separator with a mixed SeS2/KB coating, which can effectively stop the polysulfide shuttle and improve the performance of lithium-sulfur batteries through the physical barrier of KB and the strong adsorption of SeS2 in synergy with each other. Theoretical calculations and experiments show that SeS2 has a strong adsorption effect on polysulfides. The lithium-sulfur battery equipped with SeS2/KB separator has excellent electrochemical performance, maintaining a capacity of 482 mAh g(S) (-1)after 1000 cycles at 1 C current density, with a decay rate of only 0.047 % per cycle.