High-Entropy-Doped V2O5 for Efficient NH4+/Zn2+ Energy Storage

Abstract Aqueous energy storage systems (AESS) offer advantages such as safety and environmental friendliness. Among them, the rapid charge-discharge capabilities of ammonium-ion batteries (AIBs) and the high energy density of zinc-ion batteries (ZIBs) complement each other. Although V2O5 holds promise as a key electrode material in both AIBs and ZIBs, it is limited by its slow kinetics and structural instability. Herein, V2O5·0.47H2O (HEVOH) with extended interlayer spacing and an optimized electronic structure is successfully constructed via a high-entropy doping strategy, effectively solving the issues of slow kinetics and structural instability of V2O5, and demonstrating outstanding performance in both AIBs and ZIBs. When used in AIBs, it delivers a capacity of 137.6 mAh g–1 at 0.20 A g–1, with a capacity retention of 92.7% at 1.00 A g–1 after 3000 cycles. When used in ZIBs, it achieves a capacity of 543.6 mAh g–1 at 0.10 A g–1, maintaining 76.6% capacity at 10.00 A g–1 after 7000 cycles. The NH4+ storage mechanism involves interlayer intercalation, hydrogen bond reconstruction, and oxygen vacancy generation. The Zn2+ storage mechanism is interlayer intercalation and reversible deposition of Zn4SO4(OH)6·4H2O to construct a dynamic interface protective layer. This work provides a direction for the universal design of high-performance AESS.