A flexible, cost-effective, and eco-friendly solid state supercapacitor based on PVA/KCl/Carbon black nanocomposite

Much research is being done towards developing innovative materials and devices for energy production and storage. In this study, a less expensive and eco-friendly polymer nanocomposite (PNC), in combination with polyvinyl alcohol (PVA) and KCl/Carbon black (CB), at different weight percent was prepared and embedded between multi-walled carbon nanotube (MWCNT) electrodes for fabricating an all-solid-state supercapacitor (SC) device. Modification in electrode preparation and addition of KCl and CB to PVA/H3PO4 polymer electrolyte enhanced the ionic conductivity and initiated additional pseudo-reaction at electrode-electrolyte interface. Results showed that the SC with PVA/0.75 wt%KCl/0.3 wt%CB nanodielectric membrane has the highest energy storage capability for 0-1 V and reached a maximum energy density of 14.16 Wh/kg (at 1Ag(-1)) and power density of 1.38 KW/kg (at 5Ag(-1)). The PNC membrane showed excellent mechanical stability (up to 45 MPa under tensile loading). In addition, capacitance retention of 91.16% over 3000 cycles and an enhanced self-discharge of 60.63% were observed after 1000 min. The reliability of the same membrane was compared with commercially buyable Nafion (R) 112 membrane.