A physically crosslinked, self-healing hydrogel electrolyte for nano-wire PANI flexible supercapacitors

The ability of self-healing for wearable electronic devices are critical, for their vulnerability and irreversible damages while practical applications. Herein, we report a ferric enhancing dual physical cross-linking polyelectrolyte for supercapacitors. The gel electrolyte is copolymerized by using acrylic acid as a hydrophilic monomer and stearyl methacrylate as a hydrophobic monomer in an aqueous ferric nitrate solution with cationic surfactant cetyltrimethylammonium bromide and subsequently immersed in the sulfuric acid solution. With the help of hydrogen bonding and ionic bonding, the prepared hydrogel containing 1 mol L-1 H2SO4 exhibits good mechanical performance (extensibility > 2400%, and stress > 230 kPa), excellent ionic conductive (> 30 mS cm(-1)), and good self-healing efficiency. Base on this polyelectrolyte, we successfully assemble the self-healing supercapacitor by two identical electrodeposited nano-wire PANI electrodes. The self-healing device achieves an excellent energy density of 19.33 Wh kg(-1) at power densities of 0.67 kW kg(-1), self-healable ability (similar to 86% capacitance retention after healing behavior), aging durability, and cycling stability. Our results provide a valid and straightforward strategy to design self-healing energy storage devices.