Core-shell structured MoS2@S spherical cathode with improved electrochemical performance for lithium-sulfur batteries

Abstract

To suppress shuttling effect and improve electrochemical performance of the sulfur cathode for lithium-sulfur batteries, core-shell structured MoS2@S spherical cathode has been synthesized through a chemical route using MnCO3 as template. The MoS2 shells consist of MoS2 nanosheets. For comparison, MoS2/S cathode has also been synthesized through melting and diffusion of sulfur to commercial MoS2 powders. The electrochemical performance of the MoS2@S and MoS2/S cathodes have been evaluated using cyclic voltammetry, discharge/charge cycling, electrochemical impedance spectroscopy coupled with impedance fitting. The electrochemical performance of the MoS2@S spherical cathode has been much improved compared with that of MoS2/S. The capacity of the MoS2@S spheres can reach 1185.7mAhg−1 at 0.2C and 955.1mAhg−1 at 1C with initial-cycle coulombic efficiency of 90%. The capacity fading of each cycle is 0.1% during 200 lithiation/delithiation cycles. The MoS2@S spherical cathode with high cyclic capacity and stability is promising cathode candidate for lithium-sulfur batteries.