3D Graphene Networks Encapsulated with Ultrathin SnS Nanosheets@Hollow Mesoporous Carbon Spheres Nanocomposite with Pseudocapacitance-Enhanced Lithium and Sodium Storage Kinetics

The lithium and sodium storage performances of SnS anode often undergo rapid capacity decay and poor rate capability owing to its huge volume fluctuation and structural instability upon the repeated charge/discharge processes. Herein, a novel and versatile method is described for in situ synthesis of ultrathin SnS nanosheets inside and outside hollow mesoporous carbon spheres crosslinked reduced graphene oxide networks. Thus, 3D honeycomb-like network architecture is formed. Systematic electrochemical studies manifest that this nanocomposite as anode material for lithium-ion batteries delivers a high charge capacity of 1027 mAh g(-1) at 0.2 A g(-1) after 100 cycles. Meanwhile, the as-developed nanocomposite still retains a charge capacity of 524 mAh g(-1) at 0.1 A g(-1) after 100 cycles for sodium-ion batteries. In addition, the electrochemical kinetics analysis verifies the basic principles of enhanced rate capacity. The appealing electrochemical performance for both lithium-ion batteries and sodium-ion batteries can be mainly related to the porous 3D interconnected architecture, in which the nanoscale SnS nanosheets not only offer decreased ion diffusion pathways and fast Li+/Na+ transport kinetics, but also the 3D interconnected conductive networks constructed from the hollow mesoporous carbon spheres and reduced graphene oxide enhance the conductivity and ensure the structural integrity.