Electrochemical Realization of 3D Interconnected MoS3/PPy Nanowire Frameworks as Sulfur‐Equivalent Cathode Materials for Li‐S Batteries

The development of freestanding and binder‐free electrode is an effective approach to perform the inherent capacity of active materials and promote the mechanism study by minimizing the interference from additives. Herein, we construct a freestanding cathode composed of MoS3/PPy nanowires (NWs) deposited on porous nickel foam (NF) (MoS3/PPy/NF) through electrochemical methods, which can work efficiently as sulfur‐equivalent cathode material for Li‐S batteries. The structural stability of the MoS3/PPy/NF cathode is greatly enhanced due to its significant tolerance to the volume expansion of MoS3 during the lithiation process, which we ascribe to the flexible 3D framework of PPy NWs, leading to superior cycling performance compared to the bulk‐MoS3/NF reference. Eliminating the interference of binder and carbon additives, the evolution of the chemical and electronic structure of Mo and S species during the discharge/charge was studied by X‐ray absorption near‐edge spectroscopy (XANES). The formation of lithium polysulfides was excluded as the driving cathode reaction mechanism, suggesting the great potential of MoS3 as a promising sulfur‐equivalent cathode material to evade the shuttle effect for Li‐S batteries. The present study successfully demonstrates the importance of structural design of freestanding electrode enhancing the cycling performances and revealing the corresponding mechanisms. This paper proposed a freestanding cathode (MoS3/PPy/NF) with a 3D‐network structure, which can work efficiently as sulfur‐equivalent cathode material for Li‐S batteries, due to the flexible 3D framework of PPy NWs. The formation of lithium polysulfides was excluded by X‐ray absorption near‐edge spectroscopy (XANES).