Li–V2O5 Nanospheres as Electrode for Enhanced Ion Transport in Li-Ion Supercapacitors

Abstract

Hollow nanostructured transition-metal oxides have emerged as promising candidates for high-performance supercapacitor applications, owing to their advantageous ion diffusion pathways and substantially increased electrochemically active surface area. Herein, lithium-doped V2O5 nanospheres were synthesized using hydrothermal growth of VOOH nanospheres, followed by thermal annealing. Structural and spectroscopic analyses suggest that effective Li incorporation modulates the local electronic and bonding environment in V2O5 while preserving the orthorhombic crystal framework. Electrochemical investigations demonstrated that Li incorporation significantly enhanced the charge-storage kinetics and ion transport behavior of V2O5 electrodes. The highest specific capacitance of 450 F/g at 0.5 A/g was achieved together with improved rate capability and reduced polarization behavior. Electrochemical kinetic analysis revealed an enhanced diffusion-controlled pseudocapacitive contribution after Li incorporation, suggesting facilitated electrolyte ion transport within the hollow nanosphere architecture. Furthermore, the assembled AC//Li-5 V2O5 asymmetric supercapacitor device achieved a maximum energy density of 12.8 Wh/kg at a power density of 480 W/kg and retained 89% capacitance after 5000 charge–discharge cycles with nearly 100% Coulombic efficiency. The present work demonstrates that lithium-induced structural and electronic modulation represent an effective strategy for improving ion transport kinetics and diffusion-dominated charge storage in hollow V2O5 nanostructures for advanced energy-storage applications.