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

Abstract

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 110.2 mA 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.