Designing of a High Performance NiMgPO₄/CNT Electrode Material for a Battery-Supercapacitor Hybrid Device

Improved pseudo-capacitance performance can be obtained by phosphates and transition-metal oxides by achieving oxidation states that boost redox (reduction-oxidation) processes. In this work, the nickel magnesium phosphate (NiMgPO 4 ) is synthesized using the hydrothermal method, Additional, carbon nanotubes (CNTs) are blended with NiMgPO 4 . To build the supercapattery device (NiMgPO 4 @CNT//AC) and evaluate its electrochemical characteristics, we used NiMgPO 4 @CNT as the anode & activated carbon as cathode. We also used X-ray diffraction, scanning electron micrscopy, Brunauer–Emmett–Teller, and X-ray photoelectron spectroscopy techniques to analyze the crystal structure, surface area, and elemental composition. The nanocomposite NiMgPO 4 @CNT demonstrated a high specific capacity of 1243 C g −1 or 2071.66 F g −1 in a three-electrode system, which was much more than that of the separate reference materials. The supercapattery device shows a specific capacity of 251 C g −1 , energy density of 44.5 Wh kg −1 and power density of 1030 W kg −1 is observed. The hybrid electrode exhibited a capacity retention of 85% after 5000 cycles and a columbic efficiency of 91% during the stability measurement. These findings emphasize NiMgPO4@CNT’s potential as an electrode composite material that holds promise for high-performance supercapattery device building.