Abstract
The novel polymer metal chelate electrolytes were prepared by incorporation of cobalt sulfate into poly(acrylic acid) host matrix. The fabricated supercapacitors reached the highest energy density of 21.25 Wh kg−1 at a power density of 117.69 W kg−1 and successfully operated the RGB LED light.
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•A novel polymer metal chelate based electrolyte was used for flexible supercapacitors.•The specific capacitance of the device was improved up to 341.33 F g−1.•The same device maintained 92.7% of initial performance for 10.000 cycles.•A coulombic efficiency was recorded around 92% when it reached about 10.000 cycles.•Supercapacitor showed a remarkable cyclic and mechanical performance under bent and twisted conditions.
The novel polymer metal chelate electrolytes (polychelates) were prepared by incorporation of cobalt sulfate (Co) into poly(acrylic acid) (PAA) host matrix. Quasi-solid state supercapacitor devices were fabricated using polychelates, PAA-CoX (X: 3, 5, 7, and 10) where X represents the doping fraction (w/w) of Co in PAA. All polymer metal electrolytes were showed excellent bending-stretching properties, thermal stability and electrochemical durability with an optimum ionic conductivity of 3.15 × 10−4 S cm−1. Hierarchically porous activated carbon and nano-sized conductive carbon were used to form carbon composite symmetrical device electrodes. The electric double-layer capacitor (EDLC) and redox reactions of Co-incorporated polychelates at the interfaces of porous activated carbon provided an optimum specific capacitance of 341.33 F g−1 with a device of PAA-Co7, which is at least 15 times enhancement compared to the device of pristine PAA. The PAA-Co7 device also provided energy density of 21.25 Wh kg−1 at a power density of 117.69 W kg−1. A prolonged cyclic stability of the device exhibited superior capacitive performance after 10,000 charge–discharge cycles and the maintained 90% of its initial performance. In addition, the supercapacitor with a dimension of 1.5 cm × 3 cm containing PAA-Co7 successfully operated the red-blue-green (RGB) LED light.