Controlling Zn2+ hydration shell dynamics for long-life zinc anodes in zinc-ion energy storage

Zinc (Zn) anodes are highly suitable candidates for aqueous rechargeable zinc-ion energy storage, offering high capacity, excellent safety, affordability, and significant potential for energy storage in mini-grid and off-grid applications. However, Zn-based anodes face challenges related to poor long-term cycling performance due to uncontrolled dendrite formation, passivation, and the hydrogen evolution reaction (HER), which occurs due to the direct interaction of water molecules with the Zn anode surface. In this study, we explore strategies for reconstructing Zn anodes by utilising 2D V₂O₅ to regulate hydrated Zn 2+ ions and minimise the direct interaction of water molecules with Zn anodes, thereby suppressing side reactions. The advanced V₂O₅-coated Zn (V₂O₅/Zn) anodes exhibit an extended lifespan compared to bare Zn, as well as significant dendrite-free behaviour. Theoretical simulations reveal that Zn 2+ ion transport occurs through the interlayer spacing of V₂O₅ via the desolvation of hydrated Zn 2+ ions. Furthermore, full-cell aqueous Zn-ion batteries (ZIBs) incorporating V₂O₅/Zn//polyaniline (PANI) configurations exhibit superior rate capability, higher capacity, and extended cycle life compared to Zn//PANI batteries. Similarly, V₂O₅/Zn anodes demonstrate enhanced long-term cycling stability and improved capacity in Zn-ion capacitors (ZICs) when paired with activated carbon cathodes, outperforming devices using pristine Zn anodes. • V₂O₅ coating regulates Zn2⁺ hydration shell dynamics at Zn anode surfaces. • Suppresses dendrite growth, passivation, and hydrogen evolution side reactions. • Zn2⁺ desolvation through V₂O₅ interlayers facilitates smooth ion transport. • V₂O₅/Zn anodes enable long-life Zn-ion batteries with PANI cathodes. • Enhanced capacity and cycling stability achieved in Zn-ion capacitors.