Advancements in Achieving High Reversibility of Zinc Anode for Alkaline Zinc-Based Batteries

Rechargeable alkaline zinc-based batteries (ZBBs) have attracted extensive research attention due to their advantages of low cost, high specific energy, and high safety. Although the investigation of cathodes for alkaline secondary ZBBs has reached a relatively advanced stage, the exploration of zinc anodes is still in its infancy. Zinc anodes in alkaline electrolytes encounter challenges such as dendrite formation, passivation, corrosion during periods of cell inactivity, and hydrogen evolution during cycling, thereby limiting their rechargeability and storability. Drawing upon the latest research on zinc anodes, six fundamental strategies that encompass a wide range of aspects are identified and categorized, from electrode modifications and electrolytes to charge protocols. Specifically, these strategies include 3D structures, coatings, alloying, additives, separators, and charge protocols. They serve as an insight summary of the current research progress on zinc anodes. Additionally, the complementary nature of these strategies allows for flexible combinations, enabling further enhancement of the overall performance of zinc anodes. Finally, several future directions for the advancement of practical alkaline Zn anode are proposed. This comprehensive review not only consolidates the existing knowledge but also paves the way for broader research opportunities in the pursuit of high-performance alkaline zinc anodes. The poor reversibility of zinc anodes hampers the development of rechargeable alkaline zinc-based batteries due to dendrite formation, passivation, corrosion, and hydrogen evolution. In this review, optimization strategies including 3D structures, protective layers, alloying, additives, separators, and charge protocols, are suggested and summarized to overcome the challenges associated with Zn anodes and fully unlock their potential in alkaline zinc-based batteries.image