TiO_(2)-carbon porous nanostructures for immobilization and conversion of polysulfides

摘要

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,TiO_(2)-carbon nanocomposites embedded hierarchical porous carbon(T-hPC)interlayers are fabricated via Ti_(3)C_(2)MXene assisted phase separation and annealing method.The T-hPC processes micro-to macro-scale multipores along with highly adsorptive and catalytic carbon supported TiO_(2) 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 m Ah/g and a stable capacity of 893.8 m Ah/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.