Molecular ‘capturing’ and ‘seizing’ MoS2/TiN interlayers suppress polysulfide shuttling and self-discharge of Li–S batteries

With high energy density and low cost, lithium sulfur (Li–S) batteries own the potential to be next-generation electrochemical storage/conversion devices. However, their cyclic stability and life span are considerably impaired by polysulfide shuttling and self-discharge. Here, we design a microfiber glass filter-molybdenum disulfide/carbon-titanium nitride (μFGF-MoS2/C–TiN) interlayer for suppressing the shuttle of polysulfides and self-discharge of Li–S batteries. TiN in the interlayer molecularly captures high-order polysulfide Li2S8 with an adsorption energy up to −6.48 ​eV, the largest high-order polysulfide absorption value ever reported. The μFGF-MoS2 layer mechanically seizes polysulfides with interconnected torturous mesopores by functioning as a molecular sieve. With a sulfur loading of 4.5 ​mg ​cm−2, the Li–S batteries based on μFGF-MoS2/C–TiN exhibit remarkable over-1000-cycle stability with an only 0.05% capacity decay per cycle and deliver an initial discharge capacity of 1000 mAh g−1 at 1C. The self-discharge is alleviated with an insignificant 10.3% capacity loss after a 30-day rest.