N-doped carbon-embedded TiN nanowires as a multifunctional separator for Li–S batteries with enhanced rate capability and cycle stability

Lithium-sulfur (Li–S) batteries have attracted considerable attention as next-generation energy storage devices owing to their high theoretical specific capacity and safety. However, the commercialization of Li–S batteries is hindered by critical issues, including the migration of the dissolved lithium polysulfides (LiPSs) from the sulfur electrode to the lithium metal anode, resulting in poor cycling stability. Here, we report a multifunctional interlayer configured with an N-doped carbon framework and titanium nitride nanowires on a polypropylene separator (NC/TiN [email protected]) to suppress the polysulfide shuttling problem. NC/TiN [email protected] can be obtained by electrospinning and the subsequent scalable solution-based vacuum filtration. The one-dimensional structure of the TiN NWs can shorten the Li-ion diffusion distance with large electrode/electrolyte interfaces. Furthermore, the N-doped carbon framework in the NWs enables facile electron transportation and allows the suppression of the shuttle effect to improve the electrochemical reaction kinetics. The Li–S battery with a NC/TiN [email protected] separator exhibited enhanced cycling stability and rate capability, indicating that this could be a new research direction for Li–S batteries.