Rational Design of V2O5/VOPO4 Heterostructure Cathode Inducing Interface Optimization for High-Rate and Long-Cycling Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries (AZIBs) represent an environmentally benign energy storage alternative. However, the V2O5 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(H2O)6]2+ deintercalation. Address these issues, we introduce a V2O5/VOPO4 (VOP) heterostructure that that reinforces the crystal structure to suppress vanadium dissolution and establishes a hydrophilic interface reducing the desolvation energy of Zn2+. The heterostructure additionally generates an internal electric field boosting Zn2+ 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.