Graphene‐integrated CuCo 2 S 4 microspheres as a sustainable anode material for high‐performance Li‐ion batteries

Abstract

Commercial lithium–ion batteries (LIBs) are insufficient to bridge the energy density gap between demand and supply in advanced heavy and portable electronic devices because of graphite anodes (poor theoretical capacity: 372 mAh g−1). Ternary chalcogenide metal‐sulfides are promising as alternative anode materials in high power and energy densities but suffer from capacity fading with poor long‐term cycling stability due to the dissolution of polysulfide species created during the lithium‐ion insertion/de‐insertion process. Here, we report the hydrothermal synthesis of graphene integrated CuCo2S4 microparticles as a high‐capacity and sustainable anode material for LIBs. We solve the concentration gradient of lithium polysulfide at the interface of electrode/electrolyte via integrating graphene into the active metal sulfide anode material. The mechanically flexible and highly conductive nature of graphene helps relieve undesirable elongation and shrinkage during battery cycling, suppressing active material dissolution and enhancing electron/ion transport through the electrochemical double‐layer (EDL). Our one step approach demonstrates towards the practical application of advanced metal sulfide anodes for LIBs.