Recent Advances in Electrolyte Additives for Aqueous Zn Metal Batteries: Functional Mechanisms, Interfacial...

Aqueous Zn metal batteries (AZMBs) represent a transformative advancement in sustainable energy storage, offering inherent safety and scalability. However, Zn metal anodes face critical challenges, including dendrite proliferation and parasitic side reactions driven by aqueous electrolytes. This review comprehensively examines electrolyte additive engineering as a strategic approach to stabilize Zn electrochemistry. By categorizing additives based on their functional mechanisms, their roles in modulating ion transport, interfacial dynamics, and deposition behavior are elucidated. Key strategies include electrostatic shielding to homogenize ion distribution, crystallographic orientation control to inhibit dendrite growth, solvation structure modification to reduce water reactivity, and in situ interface engineering to construct protective layers. Additional approaches address hydrogen evolution and pH instability through electrolyte restructuring and buffering effects. The synergistic interplay of these mechanisms highlights the multifunctional potential of additives in enhancing cycling stability and reversibility. Further, emerging trends such as dynamic self-healing interfaces, multi-additive formulations, and extreme-condition adaptability are critically assessed, underscoring the need for advanced characterization tools to decode complex interfacial processes. The review concludes with a forward-looking perspective on sustainable additive design, emphasizing application-driven innovations. By bridging fundamental insights with practical scalability, this work aims to accelerate the development of high-performance AZMBs for next-generation energy storage systems.