Hierarchically porous carbon/titanium dioxide composites as efficient sulfur host for high performance Li-S batteries

The high energy density made lithium-sulfur batteries as the most promising energy storage devices. However, the poor cycle stability, which results from the severe polysulfide migration during the electrochemical cycles, inhibited the wide application of lithium-sulfur batteries. It has been proved that inhibiting the polysulfide shuttle effect and accelerating the polysulfide conversion could enhance the electrochemical performance of sulfur cathodes. Herein, hierarchically porous carbon/titanium dioxide (HPC/TD) composites are designed as sulfur host to adsorb the polysulfide and accelerate the redox conversion during cycling. Therefore, the polysulfide migration is effectively inhibited. The developed HPC/TD@S cathodes exhibit initial high capacity of 1256 mAh/g at 0.1 C. These results confirm that the accelerated redox conversion of polysulfide is beneficial for improving the electrochemical performance of Li-S batteries.