The rapid deployment of renewable electricity in the United States, Hong Kong, and the broader Asia-Pacific region requires safe, low-cost, and scalable electrochemical energy storage technologies. Lithium-ion batteries have enabled transformative progress, but their reliance on flammable organic electrolytes, critical mineral supply chains, and stringent manufacturing conditions limits their suitability for all stationary and distributed energy storage applications. Aqueous batteries, by contrast, offer intrinsic safety, simplified manufacturing, and improved environmental compatibility. However, their energy density remains limited by the narrow stability window of water and by the lack of metal anodes that can operate reversibly without severe hydrogen evolution, dendrite growth, or corrosion. Tin (Sn) metal has recently emerged as a compelling anode for aqueous batteries because it combines several properties rarely found in one metal chemistry: relatively low redox potential, high specific capacity, high hydrogen evolution reaction overpotential, good cyclability, low toxicity, and favorable electrodeposition behavior. This proposal aims to develop a reversible aqueous Sn-ion battery by discovering cathode hosts that can store Sn2+ and pairing them with a stabilized Sn metal anode.
