Self-powered electrochromic devices offer a promising approach for energy-saving smart windows but often suffer from slow self-recharging and limited cycling stability. A potential-gradient electrolyte consisting of KCl and K₂S₂O₈ solutions separated by a cation exchange membrane (CEM) is designed for a Zn/Prussian blue (PB) electrochromic energy-storage device [1]. The potential difference between Zn and PB drives spontaneous reduction of PB for self-bleaching, while K₂S₂O₈ enables rapid oxidation of Prussian white back to PB for self-coloration. The device achieves fast self-bleaching and self-coloration times of 3.6 and 10.3 s, respectively. The CEM prevents direct contact between Zn and K₂S₂O₈, suppressing Zn corrosion and improving cycling stability. This potential-gradient electrolyte strategy provides a simple route toward fast and stable self-switching electrochromic devices.
References
[1] P. Wang, Y. Zhou, F. Yang, G. Wu, J. Wang and D. Ma, ACS Energy Lett., 2025, 10, 6047-6053.
 

electrochromic device; solid electrolyte interphase; interface engineering; quasi solid state electrolyte; long cycling stability