Flexible free-standing polyaniline/poly(vinyl alcohol) composite electrode with good capacitance performance and shape memory behavior

The increasing demand for portable and flexible energy storage devices drives the development of flexible electrodes and electrolytes. The aim of this work is to fabricate the flexible free-standing polyaniline/poly (vinyl alcohol) (PANI/PVA) composite electrode with good capacitance performance and shape memory behavior. The electrodes were fabricated by chemical oxidation polymerization of aniline in porous PVA (P-PVA) films. The morphology, electrochemical and mechanical properties of PANI/P-PVA electrodes were studied by scanning electron microscope, cyclic voltammetry, galvanostatic charge-discharge, and tensile test etc. The results revealed that the flexible PANI/P-PVA-1 electrode had good specific capacitance of 173.86 ​mF ​cm⁻² at 1 ​mA ​cm⁻², with the capacitance retention of 70.16% after 4000 charge-discharge cycles. Besides, it had excellent heat-induced shape memory effect. The fixed shape could completely recover to its original shape within 10 ​s at 80 ​°C, which is above the glass transition temperature (75.89 ​°C) of PANI/P-PVA-1. The comparatively tensile strength (2.86 ​MPa) and high elongation at break (315.72%) indicated its outstanding flexibility. Up to 200 times folding had no effect on the electrochemical properties. The free-standing polymer electrodes with excellent comprehensive performance provide potential applications in flexible energy-storage devices, electronic encapsulation and high stretchable electric devices etc.