Recent Advances in Reversible Metal Electrodeposition-Based Smart Windows

Smart windows are significant for their energy-saving function and visual comfort in our daily lives. This review focuses on the latest advancements in reversible metal electrodeposition (RME) smart window technology, examining related issues primarily in terms of long-term operation, high-contrast, and color neutrality in the privacy state. The electrolyte condition is crucial as it significantly impacts factors like nucleation and growth, Faradaic efficiency of optical cycling, bistability, color neutrality, and repeatability. Overcoming these bottlenecks requires designing an appropriate combination of metal ions and additives in the electrolyte. Although aqueous electrolytes have been predominantly used due to their cost-effectiveness, their narrow electrochemical window has raised concerns for real applications. This limitation would lead to the generation of hydrogen or oxygen gases, potentially damaging smart windows. Recent developments have considered non-aqueous electrolytes as a solution, offering a wider electrochemical window, broader operational temperature ranges, and long-term electrolyte stability. These could be key to overcoming the current challenges in smart windows. This review summarizes recent developments in RME smart windows, addressing their current characteristics, improvements, and limitations to provide insights into future pathways for reversible metal electrodeposition-based smart window development.