Carbon nanotubes assembled on porous TiO2 matrix doped with Co3O4 as sulfur host for lithium-sulfur batteries

摘要

Advanced design and fabrication of high performance sulfur cathodes with improved conductivity and chemical adsorption towards lithium polysulfides (LiPS) are crucial for further development of Li-S batteries. Hence, we designed a TiO2/Co3O4-CNTs composite derived from Ti-MOF (MIL-125) as the host matrix for sulfur cathode. The polar nature of metal oxides (TiO2, Co3O4) creates the adsorptive sites in the composite and leads to an efficient chemical capture of LiPS. The CNTs ensure the contact between S/Li2S and the host material with high conductivity, enhanced charge transfer and fast electrochemical kinetics. At the same time, the CNTs strengthen the stability of the electrode material. Consequently, the as-prepared TiO2/Co3O4-CNTs composite showed excellent electrochemical performance. The cell with S-TiO2/Co3O4-CNTs delivers an initial specific capacity of 1270 mAh g(-1) at 0.2 C and high rate performance with a capacity of 603 mAh g(-1) at 3 C.