Development and performances analysis of eco-friendly pullulan/ polyvinyl alcohol composites based all-solid-state supercapacitors

Next-generation electronic devices, including embedded microsystems and wearable technologies, require the development of safe, and low-cost energy storage systems to meet the 21st-century society demands. In this context, several ecological binders have been developed and amended in order to achieve high-performance carbon-based supercapacitors. This work demonstrates a solid state-based supercapacitor using Pullulan (Pu)/Polyvinyl Alcohol (PVA) composite as an eco-friendly binder for the first time, for carbon-based electrodes development. Furthermore, PVA/KOH/Glycerol (GCy) blends are used as conductive electrolytes towards safe and light weight devices manufacturing. The electrodes are fabricated through simple and low-cost hand-painting (paint brush) on Nickel foam substrates. The device shows an interesting areal capacitance of 176 mF cm−2 at 10 mV s−1, energy and power densities of 25 µWh cm−2 and 3.2 mW cm−2 respectively, at 0.5 A g−1. More importantly, the device demonstrates robust mechanical strength with excellent reversibility across various bending angles (0°, 90°, 180°), with a capacitance retention of 90% after 10 000 charging/discharging cycles while maintaining an important coulombic efficiency (>95%). The outcomes of this work are quite promising compared to many reported studies, opening wide potential application in the field of handheld electronics.