Synergistic integration of mixed metal phosphate and poly(1H-pyrrole) for high-performance asymmetric supercapacitor

Abstract

Transition metal phosphates offer attractive charge-storage capability and environmental stability, yet their practical use is limited by modest energy density and durability in electrolyte-rich conditions. Here, a zinc-incorporated nickel–cobalt phosphate (MMP) was synthesized hydrothermally and integrated with poly(1H-pyrrole) (physical mixing approach). The incorporation has enticingly enhanced electrical conductivity, ion-transport kinetics, and structural robustness. The optimized MMP-PPY2 (25 wt% poly(1H-pyrrole)), composite achieved high specific capacity of 1347.6C g⁻¹ at 1.2 A g⁻¹. An asymmetric supercapacitor assembled using MMP-PPY2 as the positive electrode and activated carbon as the negative electrode delivered an energy density of 104.9 Wh kg⁻¹ and a power density of 11 900 W kg⁻¹, retaining 97.9% of its capacity after 4000 cycles. These results highlight the strong potential of phosphate-based hybrid composites for high-performance asymmetric supercapacitor applications.