fig4

Figure 4. Calendar issues influencing the durability of ZIBs. SEM images of (A) the Cu surface and (B) the Cu thickness without aging. (C) TEM image of deposited Zn without aging. SEM images of (D) Cu surface and (E) Cu thickness after aging for 24 h. (F) TEM image of deposited Zn after aging for 24 h. Insets in (A and D) are the corresponding optical images^[52]. Copyright 2023 American Chemical Society. (G) Optical images of hydrogen evolution in (i) the initial state; (ii) 10 h after electrode aging in the electrolyte; and (iii) Hydrogen bubble observed in an in-situ optical microscope^[53]. Copyright 2021 John Wiley & Sons. (H) Illustration of the mechanism for the capacity loss in aqueous ZIBs during calendar aging^[52]. Copyright 2023 American Chemical Society.