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In comparison with well-protected rigid batteries with liquid electrolytes, solid-state batteries (ssBs) are more beneficial, offering high flexibility, high wearability and leakage prevention. Currently, ssBs with the capability of bending and twisting have been extensively studied. However, it remains a challenge to develop a highly stretchable ssB with the maintenance of high performance. Herein, we report a stable solid-state zinc ion battery (ssZIB) based on a cellulose nanofiber (CNF)–polyacrylamide (PAM) hydrogel electrolyte and a Mg0.23V2O5·1.0H2O cathode. The designed CNF–PAM hydrogel shows high stretchability and robust mechanical stability. Moreover, the porous CNF–PAM hydrogel electrolyte provides efficient pathways for the transportation of zinc ions. And the robust layered structure of V2O5·1.0H2O pillared with Mg2+ ions and water supports the fast insertion/extraction of zinc ions in the lattice. Therefore, the designed ssZIB shows unprecedented high capacity at high current with durable cycling life. At a current density of 5 A g−1 (charging time of around 3 minutes), the ssZIBs can deliver a high reversible capacity of 216 mA h g−1 after 2000 cycles and retain 98.6% of the initial capacity, showing a high capacity and long-life durability at high currents. Furthermore, the designed spring ssZIBs can work under stretching with the strain reaching 650%. And the designed ssZIBs are still operational even under repeated bending, freezing, and heating conditions. The ssZIBs show robust mechanical stability, high stretchability and impressive electrochemical performance, providing a potential pathway to expand the application of ZIBs to a broad range of practical energy storage devices. [ABSTRACT FROM AUTHOR]

A solid-state electrolyte with reliable electrochemical performance, mechanical robustness and safety features is strongly pursued to facilitate the progress of flexible batteries. Here, we demonstrate a shape-deformable and thermally stable plastic crystal composite polymer electrolyte (denoted as "PC-CPE") as a new class of solid-state electrolyte to achieve this challenging goal. The PC-CPE is composed of UV (ultraviolet)-cured ethoxylated trimethylolpropane triacrylate (ETPTA) macromer/close-packed Al2O3 nanoparticles (acting as the mechanical framework) and succinonitrile-mediated plastic crystal electrolyte (serving as the ionic transport channel). This chemical/structural uniqueness of the PC-CPE brings remarkable improvement in mechanical flexibility and thermal stability, as compared to conventional carbonate-based liquid electrolytes that are fluidic and volatile. In addition, the PC-CPE precursor mixture (i.e., prior to UV irradiation) with well-adjusted rheological properties, via collaboration with a UV-assisted imprint lithography technique, produces the micropatterned PC-CPE with tunable dimensions. Notably, the cell incorporating the self-standing PC-CPE, which acts as a thermally stable electrolyte and also a separator membrane, maintains stable charge/discharge behavior even after exposure to thermal shock condition (=130 °C/0.5 h), while a control cell assembled with a carbonate-based liquid electrolyte and a polyethylene separator membrane loses electrochemical activity. [ABSTRACT FROM AUTHOR]