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.
Developing high performance bifunctional transition metal catalysts would be significantly beneficial for electrocatalytic oxidation of urea-rich wastewater. Herein, we synthesize a V2O3 nanosheet anchored N-doped-carbon encapsulated Ni heterostructure (Ni@C–V2O3/NF) for the reactions of urea oxidation (UOR) and hydrogen evolution (HER). Electrochemical results indicate that it exhibits small potentials of 1.32, 1.39, and 1.43 V for UOR and low overpotentials of 36, 254, and 355 mV for HER at ±10, ± 500 and ±1000 mA cm–2, respectively. It can work at 100 mA cm–2 for over 72 h as cathode and anode electrode without obvious attenuation, suggesting an outstanding durability. The reason for this behavior could be ascribed to the N-doped-carbon coating structure, the synergetic effects between Ni and V2O3, and the nano/micro nanosheets architecture self-supported on nickel foam. This work could provide a promising, inexpensive, and green method for the degradation of urea-rich wastewater and hydrogen production.