Ultra-high Areal Capacity Realized in Three-Dimensional Holey Graphene/SnO₂ Composite Anodes

Nanostructured alloy-type electrode materials and its composites have shown extraordinary promise for lithium-ion batteries (LIBs) with exceptional gravimetric capacity. However, studies to date are usually limited to laboratory cells with too low mass loading (and thus too low areal capacity) to exert significant practical impact. Herein, by impregnating micrometer-sized SnO₂/graphene composites into 3D holey graphene frameworks (HGF), we show that a well-designed 3D-HGF/SnO₂ composite anode with a high mass loading of 12 mg cm^-2 can deliver an ultra-high areal capacity up to 14.5 mAh cm^-2 under current density of 0.2 mA cm^-2 and stable areal capacity of 9.5 mAh cm^-2 under current density of 2.4 mA cm^-2, considerably outperforming those in the state-of-art research devices or commercial devices. This robust realization of high areal capacity defines a critical step to capturing the full potential of high-capacity alloy-type electrode materials in practical LIBs.