Metal-doped mesoporous silica as sulfur hosts in lithium-sulfur battery with enhanced conductivity and polysulfide adsorption ability

Heterogeneous element doping is conducted on mesoporous SiO2 to make utilize of the low-cost material as the sulfur host in lithium-sulfur battery. Its conductivity is distinctly improved by introducing metal element into mesoporous SiO2. The synthesized M-doped mesoporous SiO2 (M is elemental Ti, Sn or Al), show enhanced adsorption ability due to the higher electron delocalization by the metal grafting. As a result, the S fused M-SiO2 cathodes deliver the considerable capacities and cycle performances. With the high sulfur loading of 88%, the initial capacities of 814.2, 1027.5 and 1000.3 mAh g(-1) are obtained for the S/Al-SiO2, S/Sn-SiO2 and S/Ti-SiO2 cathodes at 0.2C. The capacity decays over 1000 cycles are only 0.003%, 0.065% and 0.054%, respectively. Over 200 cycles, the capacity retentions are 50.4%, 57.9% and 57.8% for the Ti-Si02 cathode at higher current rate of 1C, 2C and 5C.