Research progress of alkaline aqueous batteries. (A) Schematic illustration of the fabrication of the FZABs. (B) Schematic illustration to the structure of the aligned CNT in the FZABs. (C) GCD curves of a FZABs at current densities of 1 A g⁻¹. (A–C) Reproduced with permission from [103]. Copyright©2015, John Wiley and Sons. (D) Schematic illustration of 500% stretchable. (E) Power density curves of fiber-shaped highly stretchable FZABs at fully released state and 500% tensile strain with PANa-cellulose hydrogel electrolyte. (D, E) Reproduced with permission from [104]. Copyright©2019, John Wiley and Sons. (F) Schematics of the all-solid-state fiber-shaped Zn-Co battery. (G) Ragone plot of the all-solid-state fiber-shaped Zn-Co battery based on the volume of the whole flexible battery. (F, G) Reproduced with permission from [105]. Copyright©2019, John Wiley and Sons. (H) Schematic diagram of the flexible quasi-solid-state fiber-shaped Ni-NiO//Zn battery. (I) Cycling performance of the quasi-solid-state fiber-shaped Ni-NiO//Zn battery at various current densities. (H, I) Reproduced with permission from [106]. Copyright©2017, John Wiley and Sons. (J) Schematics of the fiber-shaped NiCo-Fe battery. (K) GCD curves of the fiber-shaped NiCo-Fe battery. (J, K) Reproduced with permission from [22]. Copyright©2019, John Wiley and Sons.