Inorganic electrochromic devices (ECDs) hold great promise for smart energy‑saving windows. Nevertheless, their practical deployment is severely restricted by electrode‑electrolyte interfacial degradation, parasitic side reactions, dendrite growth, electrolyte leakage and mechanical failure under repeated switching or bending deformation. This report summarizes our recent progress on interface‑oriented long‑life design of inorganic electrochromic devices, including Li‑based and multivalent‑ion (Al³⁺) WO₃‑NiO and Prussian blue‑zinc (PB‑Zn). We demonstrate four interfacial engineering approaches: (1) UV‑curable‑polymer‑network quasi‑solid‑state electrolyte (QSSE) for leakage suppression, improved electrode‑electrolyte adhesion and robust in‑situ SEI generation; (2) in‑situ organic‑inorganic hybrid SEI (LiF, ZnF₂‑rich nanocrystals) to homogenize metal‑ion deposition, suppress solvent decomposition and avoid electrode structural collapse; (3) ALD‑derived oxide interlayers (ALD‑Al₂O₃, ALD‑AZO) for band‑structure modulation, accelerated charge‑transfer kinetics and favorable SEI development; (4) photo‑rejuvenation to mitigate ion trapping in amorphous electrochromic matrix and recover degraded optical properties. Enabled by the above interfacial engineering, optimized devices show high‑performance electrochromic metrics and markedly improved durability: quasi‑solid WO₃‑NiO ECD (>50 000 cycles); flexible PB‑Zn EESD (93.72 % optical retention 10 000 cycles); Al³⁺‑based ECD (>20 000 cycles). This work identifies material‑electrolyte‑interface co‑design as a viable path to address the durability limitation of inorganic electrochromic devices, providing scalable insights for practical smart energy‑saving windows.
 

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