A carbon sponge supporting a MoS2-Mo2C heterostructure as the Li2S host for high-performance lithium sulfur batteries

Despite their high theoretical capacity and energy density, lithium-sulfur (Li–S) batteries still face challenges such as soluble lithium polysulfides (LiPSs) shuttling and sluggish redox kinetics. In this work, we used a novel MoS 2 -Mo 2 C heterostructure anchored on a carbon sponge (CS) as a Li 2 S host to solve these problems. A simple hydrothermal process following carbothermal reduction was used to construct the MoS 2 -Mo 2 C heterostructure, enabling control of the phases and integration of MoS 2 and Mo 2 C. Structural characterization confirmed the coherent interface of the heterostructure with a precise orientation relationship between the two phases and their uniform distribution. An evaluation of the adsorption and catalytic performance of the material showed that it has an exceptional LiPSs adsorption capacity with faster conversion from Li 2 S 4 to Li 2 S 2 . Density functional theory calculations further confirmed these results. As a result, the cathode had a high initial discharge capacity of 693 mAh g −1 at 0.2 C and achieved stable cycling at 2 C for 500 cycles with a low decay rate of 0.107% per cycle. The heterostructure design, coupled with the macroporous CS framework, effectively prevented the shuttling and increased sulfur utilization, offering a promising way to produce practical high-energy-density Li–S batteries. Download: Download high-res image (95KB) Download: Download full-size image