Rational Design of V<sub>2</sub>O<sub>5</sub>/VOPO<sub>4</sub> Heterostructure Cathode Inducing Interface Optimization for High-Rate and Long-Cycling Aqueous Zinc-Ion Batteries
Shiyao Deng, Xuemin Yan, Yu Jiang, Fengyue Ding, Aixin Li, Ruijie Zhang, Yongheng Qu, Zhizhong Xie, Junxin Duan
Abstract
Aqueous zinc-ion batteries (AZIBs) represent an environmentally benign energy storage alternative. However, the V 2 O 5 cathode suffers from limited cycling stability and rate capability due to structural instability, vanadium dissolution, and high desolvation energy caused by the large size of [Zn(H 2 O) 6 ] 2+ deintercalation. Address these issues, we introduce a V 2 O 5 /VOPO 4 (VOP) heterostructure that that reinforces the crystal structure to suppress vanadium dissolution and establishes a hydrophilic interface reducing the desolvation energy of Zn 2+ . The heterostructure additionally generates an internal electric field boosting Zn 2+ kinetics, synergistically enhancing the rate performance. Density functional theory calculations and in situ X-ray diffraction elucidate the operating mechanism, while a suite of ex situ characterizations confirms improved structural stability, dissolution resistance, and electrochemical performance. The optimized VOP heterostructure achieves a remarkable capacity retention of 194.8 mAh g –1 after 4000 cycles at 10 A g –1, underscoring its effectiveness in bolstering the cathode’s performance for AZIBs.