Dual-ion “Rocking-Chair” chemistry: A vanadium dioxide anode with pre-intercalated zinc ions and protons for zinc metal-free zinc-ion batteries

Rechargeable zinc-ion batteries (ZIBs) have gained significant attention due to their high theoretical capacity, low cost, and inherent safety. However, ZIBs with zinc metal anodes suffer from critical issues such as gas evolution, zinc dendrite formation, and low utilization of anode materials, which hinder their large-scale applications. To address these challenges, we report a vanadium dioxide anode with pre-intercalated zinc ions and protons (VO2(B)) as a promising alternative to zinc metal. The VO2(B) anode exhibits a zinc and proton co-insertion mechanism, enabling a high capacity of 360 mAh g−1, excellent rate capability, and superior cycling stability over 10,000 cycles. We further assembled a "rocking-chair" full-battery by pairing VO2(B) anode with α-MnO2 cathode, which operates based on the reversible migration of both protons and zinc ions between the anode and cathode. This zinc metal-free full battery design, offering high specific energy density, successfully circumvents the inherent challenges of zinc metal anodes, paving the way for the development of high-performance, sustainable energy storage solutions.