Rational design of MoNi sulfide yolk-shell heterostructure nanospheres as the efficient sulfur hosts for high-performance lithium-sulfur batteries

Although lithium-sulfur (Li-S) batteries have high theoretical capacity and energy density, their practical applications have been hampered by the rapid decay of capacity caused by the shuttle effect of polysulfides. In this paper, we synthesize the MoS2/Ni3S2 yolk-shell heterostructure nanosphere (NS) and use it for the first time as the host material for Li-S batteries. The combination of yolk-shell structure and heterostructure enables MoS2/Ni3S2 NSs to have large sulfur storage space and abundant active sites, which can effectively capture polysulfides and dynamically promote the redox reaction. As the cathode of Li-S batteries, MoS2/Ni3S2@S exhibits excellent electrochemical performance and has an initial discharge capacity of 1445.4 mA h g−1 at 0.1 C. Moreover, the capacity of 739 mA h g−1 is maintained after 1000 cycles under 1 C, with an average coulomb efficiency is 97.4%. It can be seen that the multi-functional sulfur host material MoS2/Ni3S2 has great application prospects in Li-S batteries. © 2020 Elsevier B.V.