Polyaniline grown on poly(vinyl alcohol)/ionic liquid composite film as electrodes for flexible and self-healable solid-state polymer supercapacitors

Flexible solid-state supercapacitors are considered as one kind of competitive energy storage devices due to the excellent flexibility and high specific capacitance. It attracts considerable attention in recent years. In this paper, binder-free polymer electrodes with outstanding electrochemical performance and mechanical properties were fabricated using poly (vinyl alcohol)/ionic liquid (PVA/IL) composite films as the substrates for the in-suit polymerization of aniline. Scanning electron microscope, cyclic voltammetry, galvanostatic charge-discharge, and tensile test were applied to study the effect of IL content on the structure and properties of the polymer electrodes polyaniline/poly(vinyl alcohol)/ionic liquid (PANI/PVA/IL). The electrode PANI/PVA/IL-1.0 has the optimal comprehensive performance. The specific capacitance and conductivity were 266.6 mF cm−2 and 6.49 S m−1 at 1 mA cm−2. The tensile strength and elongation at break could reach 1.27 MPa and 509.19%, respectively. PANI/PVA/IL-1.0 was used to assemble the symmetrical polymer supercapacitor with polymer gel electrolyte (PVA/H2SO4/IL). The area specific capacitance was 251.2 mF cm−2 at 1 mA cm−2 with the capacitance retention of 77.2% after 1000 charge-discharge cycles. Moreover, the solid-state polymer supercapacitor could keep excellent electrochemical performance even under different bending angles or after self-healing, which provides potential applications in electronic encapsulation, flexible energy-storage devices, and high stretchable electric devices etc.