S@TiO2 nanospheres loaded on PPy matrix for enhanced lithium-sulfur batteries

The development of lithium-sulfur batteries has been impeded by the shuttle effect and insulation of sulfur cathodes so far. Here we report a novel cathode consisting of a sulfur@TiO2/polypyrrole (S@TiO2/PPy) composite, in which sulfur is encapsulated by TiO2 hollow spheres and then loaded on a PPy nanowire matrix together. The S@TiO2/PPy cathodes for lithium-sulfur batteries deliver an excellent electrochemical performance with a high initial specific capacity of 1385.9 mAh g(-1) at 0.2 C and a low decay rate of 0.047 % per cycle at 1 C. The enhanced property of S@TiO2/PPy composites maybe derived from a synergistic reaction on sulfur between TiO2 hollow spheres and conductive polypyrrole nanowires, which plays a vital role on inhibiting the shuttle effect and improving the conductivity of sulfur cathodes through encapsulating sulfur active materials, chemical adsorbing polysulfides and mixing the conductive component. The architectural design on S@TiO2/PPy cathodes will provide a promising route for the practical usage of lithium-sulfur batteries. (C) 2018 Elsevier B.V. All rights reserved.