Durable, flexible self- standing hydrogel electrolytes enabling high- safety rechargeable solid- state zinc metal batteries

The boom of flexible and wearable electronic devices boosts the development of flexible batteries with high safety and stability. However, traditional lithium-ion batteries dominating portable energy storage devices are significantly restricted by their intrinsic safety hazards. Herein we report a solid-state battery based on a self-standing gelatin-based hydrogel electrolyte (GHE), whose high ionic conductivity, robust mechanical strength, and intimate contact with electrodes enable the Zn metal anode and LiMn2O4 cathode to reversibly and stably cycle. Benefiting from the superior stability towards water, flexibility of the GHE and well-designed cell structure, the solid-state full cells of Zn/GHE/LiMn2O4 can deliver a high specific capacity of 110.2mA h g(-1) and resist cutting, soaking in water, bending, twisting and crimping. The newly developed solid-state Zn metal battery with high safety and stability sheds light on the application of rechargeable batteries in flexible and wearable devices.