XO (X = Ti, Mn) decorated hollow multi-channel carbon sub-micro fiber networks as freestanding cathode for Li[sbnd]S batteries

Abstract

Lithium-sulfur (LiS) batteries are considered as one of the most promising high-energy storage devices due to the high theoretical capacity (1675 mA·h·g−1) and large energy density (2600 W·h·kg−1). However, the poor conductivity of sulfur and “shuttle effect” of soluble polysulfide intermediates limit practical applications of LiS batteries. Herein, four kinds of carbon sub-micro fibers with different structures were designed and prepared, the effect of structure on LiS battery was studied. On this basis, the XO (X = Ti, Mn) decorated hollow multi-channel carbon sub-micro carbon fibers (HMCMFs) were prepared by electrospinning and carbonization. The HMCMFs can not only supply nanopores for relieving the expansion of sulfur but also served as high conductivity freestanding substrate for sulfur loading, meanwhile the decorated XO (X = Ti, Mn) can provide powerful chemical adsorption to polysulfide intermediates and limit “shuttle effect” Therefore, the TiO-HMCMFs/S composite shows high specific capacity of 900 mA·h·g−1 and maintain stable specific capacities up to ∼600 mA·h·g−1 over 300 cycles at 0.1 A·g−1. This work offers a facile method to build efficient sulfur cathode to acquire LiS batteries with high performance.