Recent development of aqueous zinc‐ion battery cathodes and future challenges: Review

Summary Due to the increasing energy demand and to help integrate renewable energy into the energy mix, large‐scale energy storage has become essential. Among the different large‐scale secondary battery technologies, zinc‐ion batteries (ZIBs) have attracted huge attention due to their lower cost, better safety, and environmental positivity. The aqueous electrolyte in ZIBs allows the batteries to be constructed under normal atmospheric conditions and substantially reduces the assembling complexity. However, due to its low working voltage, cathode materials are often restricted, and rectifying voltage is a crucial function. Increasing the cathode voltage necessitates an increase in the electrolyte's thermodynamic stability. Additionally, the process of zinc‐ion storage should be studied in greater depth and new variants of characterization can be used to precisely understand the storage mechanism. In this regard, this article has reviewed with recent research findings addressing these issues and possible advancements made in the ZIB technology, highlighting future possibilities. Among the aqueous electrolyte‐based energy storage devices, ZIB was observed to be the most ideal one. Zn has better characteristic properties as an anode than other metallic materials (eg, Mg and Al), such as high electrical conductivity, easy processability, high compatibility/stability in water, non‐flammability, low toxicity, comparatively lower price and abundance. Zn anode possesses a high theoretical capacity (820 mAh g−1), suitable redox potential (−0.76 V vs standard hydrogen electrode [SHE]) in aqueous electrolyte, and relatively low polarizability compared with Mg and Al.