Figure 9.

Demonstration of the “air chargeable” zinc-ion capacitor and its operation under various deformations: Capacity versus “air charging” time and corresponding open-circuit voltage of the capacitor under (a) squeezing, (b) twisting, and (c) folding and compressing deformations. (d–g) Demonstration of the process of “air chargeable” zinc-ion capacitor. (d) A zinc-ion capacitor is used to power a digital hygrometer, and (e) the zinc-ion capacitor is exhausted after working for several hours. (f) Then, the sealing tape is removed and air diffuses in and “air charging” is triggered. (g) The zinc-ion capacitor is successfully charged and starts to power the hygrometer again. Reproduced with permission from [156]. Copyright 2019 Wiley.