Sulfonated rGO from waste dry cell graphite rod and its hybrid with PANI as electrode for supercapacitor

Development of high-performance energy storage devices is a vital research area to meet the present-day energy demand. In the work carried toward the development of high-performance electrodes, recently identified materials are hybrid materials. In this direction, we select a hybrid of sulfonated reduced graphene oxide and polyaniline, which is prepared by the conversion of graphite rod used in the zinc-carbon cell to graphene oxide, then to reduced graphene oxide followed by sulfonation, and finally, incorporation in the polymerization of aniline. IR, XRD, TGA, and EDAX analyses support the formation of hybrid. The electrochemical performances in terms of specific capacitance, rate capability, cycle stability, etc., of the hybrid electrode are higher than its components. Excellent Ragone plot is observed, i.e., less change in energy densities of 22, 22, 21, 20, and 20 W h kg(-1) at power densities of 150, 300, 600, 900, and 1200 W kg(-1), respectively. Specific capacitance value decreases with cycle numbers from 386 at the 2nd cycle to 320 F g(-1) at 1400 cycles, then increases to 342 F g(-1) at 2000th cycle due to wettability of the hybrid. Besides, the hybrid shows less solution and charge-transfer resistance with a high phase angle value of 79 degrees.