Aranganathan Viswanathan, Vanchiappan Aravindan, Vanchiappan Aravindan
ABSTRACT A series of PANI/VO 2 /Ni(OH) 2 (PVN) nanocomposites with different weight compositions was synthesized by a single‐step chemical method to determine the best weight composition and, in turn, to study their supercapacitive behavior. A composite with a weight composition of PANI58.33%:VO 2 25.00%:Ni(OH) 2 16.67% (PVN16) provided superior performance as a symmetric supercapacitor cell among the PVN composites synthesized. The obtained performances of PVN16 are a specific capacity ( Q ) of 60.44 C g ‒1 , a specific energy ( E ) of 10.07 W h kg ‒1 , a specific power ( P ) of 0.6 kW kg ‒1 , and a coulombic efficiency ( ƞ ) of 98.18%. In addition, this symmetric device exhibited no reduction in its Q up to 5000 cycles at 0.4 V s ‒1 . The asymmetric supercapacitor cells of the PVN16 were fabricated using activated carbon in the presence of two different aqueous electrolytes, which are 1 M H 2 SO 4 and a liquid by‐product that was obtained after the synthesis of PANI (SLP). The asymmetric cell in the presence (ITP) of SLP provided electrochemical stability up to 1.55 V, better performance, and the E comparable with vanadium redox flow batteries (VRFB). The obtained higher energy storage the parameters of a Q of 102.8 C g ‒1 , an E of 22.13 W h kg ‒1 , a P of 0.775 kW kg ‒1 , and a ƞ of 70.44%. The asymmetric devices exhibited 95% and 73.88% retention of their initial Q up to 5000 cycles at 0.4 V s ‒1 ITP of 1 M H 2 SO 4 and SLP, respectively. The symmetric and asymmetric devices exhibited 15.75% and 22.33% retention of their initial Q up to 17 and 30 A g ‒1 , respectively, ITP of H 2 SO 4 exhibiting their promising rate capability. Since, the PVN16 asymmetric cells ITP of SLP provide higher energy than those of the VRFB, they could be used to fabricate real‐time hybrid supercapacitor devices at desirable working voltages for real applications as energy storage and conversion devices, where both high E and P are required.