Facile and scalable preparation of 3D SnO₂/holey graphene composite frameworks for stable lithium storage at a high mass loading level

Nano-structured SnO₂ electrode materials and their composites show extraordinary promise for lithium-ion batteries (LIBs) with exceptional gravimetric capacities. However, studies to date have usually been limited to laboratory cells with too low mass loading and thus too low areal capacity to have significant practical impact. Herein, we develop a convenient and scalable method to produce holey graphene oxide (HGO), which can be directly used for assembling SnO₂/holey graphene composite frameworks (SHGFs) with 3D network structures. The 3D network structure offers a fully conjugated graphene network for excellent electron conduction and a fully interconnected hierarchical porous structure for ion transport; therefore, the binder-free SHGF electrode exhibits dramatically improved rate performance compared to its SnO₂/graphene framework counterparts, and the SHGF electrode with a high mass loading of 4 mg cm^-2 can deliver stable areal capacities of 2.9 and 2.3 mA h cm^-2 at current densities of 2 and 8 mA cm^-2, respectively. This work represents a critical step toward capturing the full potential of the SnO₂ electrode materials in practical applications.