Hierarchical PANI-RGO-ZnO ternary nanocomposites for symmetric tandem supercapacitor

The development of energy storage materials with high specific energy for futuristic applications is high in demand. Hybrid electric vehicles, solar energy harvesting, and commercial energy management systems are a few of the prospective applications of supercapacitors. We report the fabrication of symmetric tandem supercapacitors (STSC) using PANI-RGO-ZnO nanocomposite. The in-situ polymerization of PANI ensures the formation of a well-mixed nanocomposite. The detailed morphological analysis reveals that the PANI-RGO-ZnO 2:1 (PANI:ZnO) possesses a higher surface area, which contributes significantly towards excellent ionic diffusion resulting in a high specific capacitance (~40 F g⁻¹) at a current density of 0.05 A g⁻¹. The fabricated symmetric supercapacitor device (SSC) exhibits excellent electrochemical performance and high capacitance retention of ~86% over 5000 cycles at a scan rate of 100 mV s⁻¹. The SSC device reveals notable specific energy and specific power of ~5.61 Wh kg⁻¹ and ~403 W kg⁻¹, respectively. The STSC system exhibited a steady voltage ~6.0 V, and demonstrated the performance of the fabricated device by glowing LEDs and operating a DC motor. The exquisite properties of the SSC electrode can be attributed to the synergistic effects of ZnO, PANI, and RGO in PANI-RGO-ZnO 2:1 nanocomposite.