TiO2-carbon porous nanostructures for immobilization and conversion of polysulfides

Lithium-sulfur batteries (LSBs) are among the most promising series of next-generation high density energy storage systems. However, the problem of “shuttle effect” caused by dissolution and migration of polysulfide intermediates has severely inhibited their practical applications. Herein, TiO2-carbon nanocomposites embedded hierarchical porous carbon (T-hPC) interlayers are fabricated via Ti3C2 MXene assisted phase separation and annealing method. The T-hPC processes micro- to macro-scale multi-pores along with highly adsorptive and catalytic carbon supported TiO2 nanoparticles, which significantly enhances the polysulfides immobilization and improves the redox reaction kinetics when applied as lithium-sulfur battery interlayers. An initial discharge specific capacity of 1551.1 mAh/g and a stable capacity of 893.8 mAh/g after 200 cycles at 0.5 C are obtained, corresponding to a capacity decay rate of only 0.04% per cycle. The investigations in this paper can provide a simple and effective strategy to enhance the electrochemical properties for lithium-sulfur batteries.