TiO₂ microboxes as effective polysufide reservoirs for lithium sulfur batteries

Mesoporous hollow TiO₂ microboxes synthesized by a two-step solvothermal method via CaTiO₃ intermediate were applied as host materials for sulfur cathodes of lithium-sulfur batteries. 3TiO₂/7S composite containing 70 wt% sulfur exhibited the best electrochemical performance among all composites. A high discharge capacity of 924.8 mAh g⁻¹ was achieved for the 1st cycle and 67.4% of it could be retained after 200 cycles at 0.2 C. Even at a higher C-rate of 1 C, more than 600 mAh g⁻¹ of discharge capacity could be delivered after 500 cycles. The efficient polysulfide adsorption of TiO₂ microboxes demonstrated by visualized adsorption test and UV–vis measurement as well as the mesoporous hollow feature was responsible for the large discharge capacity, excellent capacity retention and decent rate capability.