Lithium-sulfur (Li-S) batteries are recognized as one of the most promising energy storage systems due to the high energy density and cost effectiveness. However, their practical implementation has still been handicapped due to notorious lithium polysulfide (LiPS) shuttle and depressed sulfur redox kinetics. It is therefore desirable to exploit key mediators synergizing electrical conductivity and electrocatalytic activity for the cathode. Herein, we report the employment of atmospheric pressure chemical vapor deposition to harness the efficient and controllable synthesis of metallic VTe2 over particulated MgO substrates, which has scarcely been demonstrated by conventional wet chemical synthetic routes thus far. The thus-derived VTe2@MgO heterostructure as an efficient promotor enables effective regulation of LiPSs with respect to polysulfide capture/conversion and Li2S decomposition. As a result, a S/VTe2@MgO cathode with a sulfur loading of 1.6 mg cm-2 harvests long-term cyclability with a negligible capacity decay of 0.055% per cycle over 1000 cycles at 1.0 C. Even at a sulfur loading of 6.9 mg cm-2, the cathode still delivers electrochemical performances that can rival the state-of-the-art high-loading counterparts. Our work might offer a feasible solution for developing heterostructured promotors with multifunctionality and electrocatalytic activity for high-performance Li-S batteries.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was financially supported by the National Natural Science Foundation of China (51702225), National Key Research and Development Program (2016YFA0200103), Natural Science Foundation of Jiangsu Province (BK20170336), and Beijing Municipal Science and Technology Commission (Z161100002116020). M.L.W., Y.Z.S., Z.T.S., C.H.W., Z.X., Z.N.T., J.Y.S., and Z.F.L. acknowledge the support from Suzhou Key Laboratory for Advanced Carbon Materials and Wearable Energy Technologies, Suzhou, China.