Enhancing lithium-sulphur battery performance by copper oxide@graphene oxide nanocomposite-modified cathode

摘要

Nanosheet structures of copper oxide@graphene oxide (CuO@GO) composite were developed as a host material to embed sulphur nanoparticles for use as cathodes in lithium-sulphur (Li-S) batteries. The homogeneous immobilisation of sulphur in the conductive matrix of CuO@GO within a strong chemical bond between carbon and polysulphide intermediates through the Lewis acid function of CuO provides a high specific discharge capacity of the CuO@GO/S electrode in comparison with the GO/S nanocomposite. The CuO@GO/S cathode delivers a discharge capacity of 1048.95 mA h g(-1), 841.74 mA h g(-1), 736.49 mA h g-1, 695.17 mA h g(-1), 643.86 mA h g(-1), and 457.08 mA h g(-1) at different current rates of 0.1 C, 0.4 C, 0.7 C, 0.8 C, 1 C, and 2 C, respectively. The application of CuO@GO/S maintains the average coulombic efficiency of 96 % after 300 cycles at 1 C rate with a capacity retention of approximately 55.8%. The rapid ion transportation within the efficient physicochemical confinement of polysulphides confirmed the role of the CuO@GO/S nanocomposite as a promising cathode material for the next generation of high-energy density Li-S batteries. (C) 2016 Institute of Chemistry, Slovak Academy of Sciences