Flexible foams of graphene entrapped SnO2–Co3O4 nanocubes with remarkably large and fast lithium storage

Abstract

In developing flexible lithium-ion batteries (LIBs), fabrication of a high-performance electrode with good flexibility and stability is desirable, yet remains challenging. Herein, a flexible integrated electrode is introduced based on layer-by-layer packed graphene sheets entrapped SnO₂–Co₃O₄ nanocubes. The rationally selected composition, polyhedral nanostructures, and proper construction of the specific architecture successfully trigger a synergistic lithium storage effect, assuring the partial reversible conversion of SnO₂ and interfacial lithium storage of graphene, which are responsible for the remarkably high reversible capacity of 1665 mA h g⁻¹ after 100 cycles at 100 mA g⁻¹. Large and stable cyclic performance as well as long cyclic life is also obtained at a high current density of 1 A g⁻¹ (1208 mA h g⁻¹ after 1000 cycles). More importantly, the free-standing electrode can well retain its flexible feature even after 300 repeated electrochemical cycles, making it a promising candidate for a high-performance and stable electrode for flexible LIBs.