FIGS. 28A, 28B, and 28C are photographic images and plots showing the flexibility and the electrical performances of the Zn-based batteries of FIGS. 8A and 8B under various bending states; and

FIGS. 29A, 29B, and 29C are photographic images showing an example operation of the Zn-air batteries of FIG. 8B.

The inventors have, through their own research, trials and experiments, devised that flexible or wearable electronics may be implemented in sportswear, military uniforms, and implantable medical devices. These devices may require high performance and highly reliable power sources with excellent flexibility and safety.

Without wishing to be bound by theory, solid-state aqueous rechargeable energy storage and conversion technologies offer inherent safety, flexibility and cost-effectiveness, which may constitute a critical element in personalized portable and flexible electronics.

Among various aqueous rechargeable batteries, in some example embodiments, Zn-based such as Zn//NiCo and Zn-air batteries are preferable due to their high mass energy density (the former has a high output voltage of ?1.8 V leading to energy density comparable to, and the later delivers energy density ?5 times higher than lithium-ion batteries), as well as high abundance and large-scale production of Zn (?2 orders of magnitude lower cost than lithium), etc.