Development of Carbon Nanotube-Supported Metal (Mo, Ga, Bi)-Doped Polyacrylic Acid Electrodes for Supercapacitor Applications

Polyacrylic acid (PAAc) polymer was synthesized using a radical polymerization method that involved sequential mixing of monomer, cross-linker, accelerator, and initiator. Subsequently, polymer composites with carbon nanotube (CNT) and molybdenum (Mo), gallium (Ga), and bismuth (Bi))/CNT catalysts were synthesized using identical parameters. The hydrogels were characterized using X-ray diffraction (XRD), scanning electron microscopy-energy-dispersive X-ray analysis (SEM-EDX) and mapping, infrared reflection-absorption spectroscopy (IRRAS), and micro-Raman spectroscopy. The PAAc-graft(g)-(Mo/CNT) electrode, which acts as a supercapacitor electrode, displayed a significant specific capacitance of 160.80 F g-1 at 10 mV s-1. After 5000 cycles, PAAc-g-(Mo/CNT), PAAc-g-(Ga/CNT), and PAAc-g-(Bi/CNT) demonstrated capacitance retention of 80.7%, 75.9%, and 62.5%, respectively. Comparing the results from cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance tests, it was determined that the electrode containing Mo exhibits superior and more robust electrochemical stability than electrodes containing Ga and Bi.