Chalcocarbogels as High-Capacity and Cycle-Stable Electrode Materials for Lithium and Sodium Ion Batteries

The low capacities of commercial Li ion batteries and cycle instabilities of amorphous metal sulfide based batteries impose constraints on their utilization for large-scale energy storage. We report here the acid-free, room-temperature (RT), and solution-based synthesis of a chalcogenide-carbonaceous hybrid aerogel, termed as “chalcocarbogel”, comprising molybdenum sulfide (MoS_x) and graphene oxide (GO). The chalcocarbogel is a nanoparticle-aggregated, porous, amorphous gel consisting of Mo₃S₁₃ and Mo₂S₁₂-like structures as determined by synchrotron X-ray PDF, XANES, and EXAFS. The MoS_x-GO chalcocarbogel demonstrates high specific capacities of ∼1215 and ∼807 mAh g^-1 for Li/MoS_x-GO and Na/MoS_x-GO cells, respectively, for a 50 mAg^-1 discharge rate during the first cycle. After the activation cycles, the MoS_x-GO chalcocarbogel stabilizes, maintaining high specific capacities of approximately ∼700 mAh g^-1 for Li/MoS_x-GO and ∼473 mAh g^-1 for Na/MoS_x-GO cells, while continuously cycling. The MoS_x-GO aerogel reported here serves as a promising platform to develop chalcocarbogels for applications spanning both Li and Na ion batteries.