Optimizing the Electrodes/PEO Electrolyte Interface Reaction via Sulfiphilic and Lithiophilic C ₃ N ₄ /MoS ₂ Fillers for Solid-State Li–S Batteries

Poly(ethylene oxide) solid polymer electrolytes (PEO SPEs) for solid-state Li–S batteries (SSLSBs) offer the benefit of high energy density and high security but suffer from an inadequate lifespan arising from the polysulfide shuttling effect, lithium dendrite growth, and the sluggish Li+ transport. To resolve the issues, sulfiphilic and lithiophilic C3N4/MoS2 are composited into the PEO SPEs as fillers. Flat Li deposition is achieved owing to their strong chemical affinity for Li+ at the electrolyte/Li anode interface. Li//Li symmetrical cells with the proper content exhibit stable cycling over 4000 h at 0.1 mA cm–2. Meanwhile, the polysulfide shuttling is significantly inhibited due to the heterojunction built-in field effect, strong chemisorption capability of C3N4, and effective catalysis activity of 1T-phase MoS2 toward LiPSs. The Li/S cells exhibit an initial capacity of 800 mA h g–1 at 0.2 C and retain a reversible capacity of 420 mA h g–1 after 200 cycles at 60 °C.