• Energy Research

With the rapid development of the wearable devices and flexible supercapacitors (FSCs), urgent demand for electrodes with high specific capacitance and excellent flexibility have been put forward. Herein, a self-standing conducting polymer hydrogel electrode has been successfully synthesized by in situ polymerization of aniline (ANI) in aqueous solution of polyvinyl alcohol (PVA), phytic acid (PA) and sodium chloride (NaCl). The prepared PANI/PVA/NaCl (PPN) hydrogel electrode shows high specific capacitance (1544 mF cm−2 at current density of 1 mA cm−2), good flexibility (elongation at fracture of 110%), satisfactory electrochemical stability (92% capacitance retention after 500 repeated bending cycles) and excellent cycling stability (78.2% capacitance retention after 10000 cycles) due to the uniform 3D interconnected structure driven by NaCl pseudo template. In order to further explore the potential application prospects of the synthesized hydrogel in flexible devices, a series of all-hydrogel-state FSCs are assembled based on the prepared PPN hydrogel electrodes and typical PVA/H2SO4 electrolyte. The assembled FSCs exhibit high energy density of 51.1 μWh cm−2 at power density of 250 μW cm−2 and long-life stability of 81.10% capacitance retention after 10000 charge/discharge cycles. This work provides a new synthesis strategy for the high performance energy storage electrodes and devices.