A self-healable silk fibroin-based hydrogel electrolyte for silver-zinc batteries with high stability

Due to the intrinsic safety, mechanical flexibility and cost-effectiveness, aqueous batteries with hydrogel electrolytes are particularly advantageous for wearable electronics. Herein, a self-healable silk fibroin-based hydrogel electrolyte with semi-interpenetrating network structure was developed, which possesses both high ionic conductivity (14.4 mS cm⁻¹) and excellent mechanical strength. The supramolecular hydrogen bonding interaction between the amide bond and the polypeptide of silk fibroin enables the hydrogel electrolyte with superior self-healable capability, which largely improves the interfacial compatibility between electrode and electrolyte, thus suppressing the growth of Zn dendrites. The resultant Ag-Zn battery delivers a high capacity of 110 mAh g⁻¹ at 0.5 A g⁻¹ with good cycling stability of 85.7% capacity retention after 800 cycles.