title: Enhanced Electrochemical Kinetics on Conductive Polar Mediators for Lithium-Sulfur Batteries.
abstract: Lithium-sulfur (Li-S) batteries have been recognized as promising substitutes for current energy-storage technologies owing to their exceptional advantage in energy density. The main challenge in developing highly efficient and long-life Li-S batteries is simultaneously suppressing the shuttle effect and improving the redox kinetics. Polar host materials have desirable chemisorptive properties to localize the mobile polysulfide intermediates; however, the role of their electrical conductivity in the redox kinetics of subsequent electrochemical reactions is not fully understood. Conductive polar titanium carbides (TiC) are shown to increase the intrinsic activity towards liquid-liquid polysulfide interconversion and liquid-solid precipitation of lithium sulfides more than non-polar carbon and semiconducting titanium dioxides. The enhanced electrochemical kinetics on a polar conductor guided the design of novel hybrid host materials of TiC nanoparticles grown within a porous graphene framework (TiC@G). With a high sulfur loading of 3.5 mg cm-2, the TiC@G/sulfur composite cathode exhibited a substantially enhanced electrochemical performance.
authors: Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, P.R. China.
authors: Hong-Jie
authors: HJ
authors: Peng
authors: Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, P.R. China.
authors: Ge
authors: G
authors: Zhang
authors: Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, P.R. China.
authors: Xiang
authors: X
authors: Chen
authors: Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, P.R. China.
authors: Ze-Wen
authors: ZW
authors: Zhang
authors: Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, P.R. China.
authors: Wen-Tao
authors: WT
authors: Xu
authors: Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, P.R. China.
authors: Jia-Qi
authors: JQ
authors: Huang
authors: Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, P.R. China. zhang-qiang@mails.tsinghua.edu.cn.
authors: Qiang
authors: Q
authors: Zhang
keywords: lithium-sulfur batteries; polysulfides; porous graphene frameworks; shuttle effect; titanium carbide