Full-temperature all-solid-state dendrite-free Zn-ion electrochromic energy storage devices for intelligent applications

Zn-ion electrochromic energy storage devices (ZEESDs) incorporate electrochromism and energy storage into one platform that can visually indicate the working status through a real-time color change, attracting considerable attention in energy-saving buildings and intelligent electronics. However, typical ZEESDs generally consist of Zn metal electrodes and normal liquid electrolytes, resulting in the dendrite issues and restricted operating temperatures as well as inferior cycle stability. Herein, an all-solid-state dendrite-free ZEESD was constructed based on polyaniline (PANI) positive electrode, monoclinic WO3 (m-WO3) negative electrode and Zn2+-based gel electrolyte. Benefiting from the complementary synergistic effect of electrodes and electrolytes, the resultant ZEESD avoids heavy Zn metals, addresses the dendrite formation problem, and exhibits remarkable electrochromic and electrochemical performances. The prototype ZEESD possesses high energy/power density (97 Wh kg- 1/976.2 W kg- 1 and 28.6 & mu;Wh cm-2/0.27 mW cm-2), large optical modulation (-52.4%@630 nm), high coloration efficiency (96.8 cm2 C-1 at 630 nm), along with outstanding cycling stability (-94.4% capacity retention even after 6000 cycles). Impressively, the quasi-solid-state electrolyte maintained outstanding electrochemical activity enabling the ZEESD to cycle efficiently even under hash temperatures, presenting enormous potential for intelligent electronics in all-climate (-30 degrees C to 60 degrees C) conditions. This work provides a novel strategy to construct next-generation dendrite-free Zn-ion electrochromic energy storage devices for innovative consumer electronics even in harsh environments.