Design of hierarchical CuS/graphene architectures with enhanced lithium storage capability

Metal-sulfides electrode materials usually suffer from poor cyclability and low rate capability in rechargeable batteries as a result of the pulverization of active materials and the loss of sulfur material induced by polysulfide dissolution. Herein, we reported a delicate and scalable route for rational design of CuS/graphene composites. Hierarchical CuS microparticles comprising of large amounts of self-assembled and well-arranged nanosheets uniformly mixed with flexible graphene layers. The obtained CuS/graphene electrodes exhibited high specific capacities, excellent cycling stability and desirable rate capability when being evaluated as anode materials for lithium-ion batteries. The high specific capacities of 568 mA h g ⁻¹ after 100 cycles at 50 mA g ⁻¹ and 143 mA h g ⁻¹ at 1000 mA g ⁻¹ (in rate testing) were achieved, suggesting a very promising candidate for high-performance lithium-ion batteries. The rationally designed structures of the CuS/graphene composites offered stable-hosts for Li ⁺ insertion and alleviated the volume changes upon cycling. The presence of the graphene in composite not only constructed conductive paths and a network for fast transport of Li ⁺ , but also effectively reduced the dissolution of polysulfides into electrolyte. This graphene-based composite with hierarchical structure could be used as a safe, low-cost, and versatile material for extensively potential applications.