Encapsulating V2O3 Nanoparticles in Hierarchical Porous Carbon Nanosheets via C-O-V Bonds for Fast and Durable Potassium-Ion Storage

Vanadium oxide (V2O3) has been considered as a promising anode material for potassium-ion batteries (PIBs), but challenging as well for the low electron/ion conductivity and poor structural stability. To tackle these issues, herein, a novel sheetlike hybrid nanoarchitecture constructed by uniformly encapsulating V2O3 nanoparticles in amorphous carbon nanosheets (V2O3@C) with the generation of C-O-V bonding is presented. Such a subtle architecture effectively facilitates the infiltration of electrolyte, relieves the mechanical strain, and reduces the potassium-ion diffusion distance during the repetitive charging/discharging processes. The generated C-O-V bonding not only accelerated charge transfer across the carbon-V2O3 interface but also strengthened the structural stability. Benefiting from the synergistic effects, the as-prepared V2O3@C nanosheets display fast and durable potassium storage behaviors with a reversible capacity of 116.6 mAh g(-1) delivered at 5 A g(-1), and a specific capacity of 147.9 mAh g(-1) retained after 1800 cycles at a high current density of 2 A g(-1). Moreover, the insertion/extraction mechanism of V2O3@C nanosheets in potassium-ion storage is systematically demonstrated by electrochemical analysis and ex situ technologies. This study will shed light on the fabricating of other metal oxides anodes for highperformance PIBs and beyond.