Electrochemical supercapacitor based on polyaniline/bismuth-doped zinc oxide (PANI/Bi–ZnO) composite for efficient energy storage

Abstract

The performance of high-rate supercapacitors is greatly controlled by the electrical and morphological properties of electrodes. Owing to its unique behavior, polyaniline (PANI) is considered one of the best materials for storing energy. This study emphasizes the fabrication of PANI and PANI/bismuth-doped zinc oxide (PANI/Bi–ZnO) as electrode materials for high-efficiency supercapacitors. The pure PANI and its composite were synthesized through inverse emulsion polymerization and investigated for structural and morphological characterization using UV/Vis spectroscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. These characterization techniques showed that the fabricated materials were suitable for supercapacitor electrodes with improved structural, thermal, and morphological properties. Electrochemical impedance spectroscopy, galvanostatic charging–discharging, and cyclic voltammetry were used to investigate the electrochemical properties. The PANI-based electrode showed ∼564.23 F/g charge storage capacity with ∼60% of capacitance retention, which correspondingly increased to ∼914.05 F/g and ∼88% in PANI/Bi–ZnO composite even after 10,000 charge–discharge cycles. The PANI/Bi–ZnO composite also displayed remarkably high energy density (∼2189.90 Wh/kg) and power density (∼38480.42 W/kg) values. The fabricated electrode is expected to have a large capacity for storing energy and power in commercial electrochemical electrodes.