Cost-Effective Assembly of High-Performance Yumberry-Like Nickel Phosphate Aggregates for High-Energy Density Hybrid Supercapacitors

Electrochemical energy storage devices (EESDs) are the elementary key to fulfilling the demands of renewable energy storage as compared to other conventional energy storage devices, which are powerless to achieve the worldwide needs of energy owing to their low energy density (ED) (batteries) and power density (PD) (supercapacitor). This study presents the cost-effective assembly of high-performance Yumberry-like nickel phosphate (Ni 3 (PO 4 ) 2 ) aggregates for hybrid supercapacitors, addressing the demand for efficient energy storage devices. The Ni 3 (PO 4 ) 2 micro-size particles were synthesized via a hydrothermal method and characterized using various advanced techniques. The electrochemical performance of these particles was evaluated in a three-electrode system, demonstrating an excellent specific capacity of 549.19 C/g at a scan rate (SR) of 5 mV/s. The assembled supercapattery device exhibited a high ED of 88.03 Wh/kg at a current density (CD) of 2 A/g and a PD of 9.333 kW/kg at 14 A/g CD, with good cyclic stability (98.7%) after 2000 cycles. Dunn's model and power law analysis confirmed the device's hybrid energy storage behavior, highlighting the contribution of both capacitive and diffusive processes. This work offers a sustainable approach to developing high-performance supercapattery devices with potential applications in energy storage.