All-solid-state supercapacitors using a highly-conductive neutral gum electrolyte

Recently, the development of safe, stable, and long-life supercapacitors has attracted considerable interest driven by the fast-growth of flexible wearable devices. Herein, we report an MnO2-based symmetric all-solid-state supercapacitor, using a neutral gum electrolyte that was prepared by embedding aqueous sodium sulfate solution in a biopolymer xanthan gum. Resulting from the high ion conductivity 1.12 S m(-1), good water retention, and high structure adaption of such gum electrolyte, the presently described supercapacitor showed high electrochemical performance with a specific capacitance of 347 F g(-1) at 1 A g(-1) and an energy density of 24 mW h cm(-2) The flexible supercapacitor possesses excellent reliability and achieves a retaining capacitance of 82% after 5000 cycles. In addition, the as-prepared supercapacitor demonstrated outstanding electrochemical stability at temperatures between -15 degrees C to 100 degrees C.