Intercalation pseudocapacitance in 2D N-doped V2O3 nanosheets for stable and ultrafast lithium-ion storage

Abstract

2D N-doped V₂O₃ (N-V₂O₃) nanosheets were fabricated as anode materials for Li-ion batteries by a facile sol–gel method and a subsequent deoxidation–nitridation strategy. Benefiting from the 3D V–V tunnel structure, sufficient active sites and nitrogen modifications, N-V₂O₃ nanosheets exhibit improved Li⁺ diffusion kinetics, robust structure and enhanced conductivity. As a result, N-V₂O₃ nanosheets show a high specific capacity, long cycling life and high rate capability (136 mA h g⁻¹ even after 1000 cycles at 2 A g⁻¹) as anode materials for Li-ion batteries. It is instructive to note that the efficient Li⁺ storage of N-V₂O₃ is dominated by intercalation pseudocapacitance. In the mechanism of intercalation pseudocapacitance, lithium ions are intercalated into the 3D V–V tunnels and adsorbed to the V–O active sites without crystalline phase transition. This mechanism combines long cycling life with short charging/discharging times, which is suitable for stable and ultrafast Li-ion storage.