Electrochimica Acta, Vol.292, 568-574, 2018
Three-dimensional hierarchical porous TiO2/graphene aerogels as promising anchoring materials for lithium-sulfur batteries
The main obstacle for broad adaption of lithium-sulfur (Li-S) batteries originates from the shuttle effect of electrolyte-soluble intermediates of lithium polysulfides (Li2Sn, 4 <= n <= 8). Rational design of multifunctional sulfur cathodes with porous conductive matrix and large polar sites is greatly desired. Herein, we report three-dimensional hierarchical porous TiO2/graphene aerogel (TiO2/GA) composites as promising anchoring materials for sulfur species. Various TiO2/GA composites with 3.5, 15.3, 54.6 and 75.2 wt% TiO2 are synthesized via a one-pot hydrothermal process. Specifically, the one containing 15.3 wt% TiO2 exhibits a superior boost in specific capacity, rate capability and cyclability. The factors contribute to the high performance attributing much to the strong interfacial chemical and physical interactions of TiO2/GA with Li2Sn. Moreover, further improved sulfur utilization is achieved by adding glucose to adjust the surface area and pore size distribution of the aerogels. At a high rate of 2 C (1 C = 1675 mA g(-1)), an initial discharge capacity up to 1011 mAh g(-1) is obtained with a decent cyclic efficiency and 100% coulombic efficiency over 500 cycles. These results bring a broad perspective for the future design on practical sulfur-based electrodes. (C) 2018 Elsevier Ltd. All rights reserved.