C-plasma derived precise volumetric buffering for high-rate and stable alloying-type energy storage

The void introduction for high-energy alloying-type electrode has suffered a dilemma between insufficient void leading to structural collapse and excessive void causing low volumetrical utilization ratio. Herein, a novel tunable void structure of SnO₂-void-hierarchically vertical graphene (SnO₂□hVG) nanoarray has been designed via facile C-plasma technique, which facilitates simultaneous encapsulation of protective vertical graphene and moderate void formation. Benefiting from the tunable void and interconnected highly conductive graphene shells and backbones, our all-in-one framework delivers excellent structural integrity and superior Li⁺ storage capabilities due to the precise volume buffering without collapse of structure and extravagant void. As a result, an imposing capacity of 650 mA h g⁻¹ at 2 A g⁻¹ and negligible capability degradation after 1000 cycles can be achieved. This result opens a new opportunity in tunable void design to enhance the electrochemical performance of alloying-type electrode materials.