Synergistic performance of co-precipitated CoCuFe Prussian blue analogue and hydrothermally synthesized V₂C MXene in a solid-state asymmetric supercapacitor

Abstract

Asymmetric supercapacitors (ASCs) have gained significant attention for their high energy density and extended potential window, ensuring optimal power density. This study presents a solid-state ASC using CoCuFe Prussian blue analogue (PBA) as the positive electrode and hydrothermally grown Vanadium MXene (V2C) as the negative electrode. SEM analysis reveals CoCuFe PBA's coagulated skeleton-like structure and V2C MXene's nanosheet-like morphology. In a three-electrode configuration, CoCuFe PBA shows a specific capacitance of 441 F/g at 0.8 A/g (0 to 0.5 V), while V2C MXene achieves 243 F/g at −1 to 0 V with a 2 M KOH electrolyte. The CoCuFe PBA//V2C ASC device achieves 185 F/g at 1 A/g with a PVA-KOH electrolyte at 1.5 V. This combination facilitates rapid ion diffusion, yielding an energy density of 57.8 Wh/kg and a power density of 1500 W/kg. The device also retains 82 % of its capacitance after 10,000 charge-discharge cycles at 6 A/g, demonstrating excellent stability and potential for high-performance supercapacitors.