Electrochemical Activation in Vanadium Oxide with Rich Oxygen Vacancies for High-Performance Aqueous Zinc-Ion Batteries
Fangan Liang, Min Chen, Shu-Chao Zhang, Zhengguang Zou, Chuanqi Ge, Shengkun Jia, Shangwang Le, Fagang Yu, Jinxia Nong
Abstract
Environmental concerns promote the development of sustainable energy storage devices. Resource-rich vanadium oxides with easily adjustable valence still exhibit unsatisfactory electrochemical performance stemming from poor electrical conductivity and friable structure as aqueous zinc-ion battery (AZIB) cathodes. Herein, vanadium oxide (VO-300) enriched with oxygen vacancies is acquired via a convenient solvothermal method in combination with subsequent heat treatment, which exhibits a remarkable rate performance of 411.98 mAh·g –1, and an excellent cycling life for 1500 cycles with 92.8% retention at 10 A·g –1 . The enhanced electrochemical performances of VO-300 can be attributed to more oxygen vacancies, which provide more active sites for zinc-ion storage, expand layer spacing, and increase the conductivity of V 2 O 5 . More pivotal, the activation phenomenon is analyzed, and a two-carrier conversion insertion mechanism of H + domination to Zn 2+ domination is proposed. Based on this mechanism, the V 2 O 5 is transformed into Zn x V 2 O 5 · n H 2 O as an active material for subsequent zinc-ion storage, leading to faster electrochemical kinetics. This work not only demonstrates the potential application of V 2 O 5 as a zinc-ion cathode but also provides new insights into the zinc-ion storage mechanism.