Metal Sulfide-Decorated Carbon Sponge as a Highly Efficient Electrocatalyst and Absorbant for Polysulfide in High-Loading Li2S Batteries

Owing to its high theoretical specific capacity (1166 mA h g(-1)) and particularly its advantage to be paired with a lithium-metal-free anode, lithium sulfide (Li2S) is regarded as a much safer cathode for next-generation advanced lithium-sulfur (Li-S) batteries. However, the low conductivity of Li2S and particularly the severe polysulfide shuttle of lithium polysulfide (LiPS) dramatically hinder their practical application in Li-S batteries. To address such issues, herein a bifuctional 3D metal sulfide-decorated carbon sponge (3DTSC), which is constructed by 1D carbon nanowires cross-linked with 2D graphene nanosheets with high conductivity and polar 0D metal sulfide nanodots with efficient electrocatalytic activity and strong chemical adsorption capability for LiPSs, is presented. Benefiting from the well-designed multiscale, multidimensional 3D porous nanoarchitecture with high conductivity, and efficient electrocatalytic and absorption ability, the 3DTSC significantly mitigates LiPS shuttle, improves the utilization of Li2S, and facilitates the transport of electrons and ions. As a result, even with a high Li2S loading of 8 mg cm(-2), the freestanding 3DTSC-Li2S cathode without a polymer binder and metallic current collector delivers outstanding electrochemical performance with a high areal capacity of 8.44 mA h cm(-2).