Binder Free Three-Dimensional Hybrid Cathode for Stable and High-Performance Li-S Batteries

Lithium-sulfur batteries (LSBs) represent a promising energy storage technology with a potential for next-generation high-energy storage systems due to their high specific capacity, abundant resources, low cost, non-toxicity, and environmentally friendly characteristics. However, due to many critical limitations such as insulating nature of elemental sulfur, poor lithium polysulfide (LiPS) conversion kinetics, polysulfide shuttle effect resulting in capacity fading, and low cyclic stability, commercialization of LSBs are far from realization. One of the most essential strategy to mitigate the issues with LSBs is to prevent polysulfide shuttling thereby maximizing the sulfur utilization and enhance the overall Li-S battery performance. In this work, we develop a binder free three-dimensional hybrid cathode for Li-S battery using multiwall carbon nanotubes (CNTs) and molybdenum sulfide (MoS2) as a catalyst, collectively enhancing LiPS conversion and ion transport ability and hence increased energy density, both gravimetric and volumetric. Different uniform mixtures of CNTs, MoS2, and conductive carbon black are prepared and loaded with high sulfur loading of ~6 mg cm-2. Various electrochemical performance parameters influencing cathode performance with respect to both gravimetric and volumetric energy densities are studied. Parameters that help improve the overall battery performance are identified and discussed.