Cobalt/cerium-based ternary Prussian blue analogs as battery type electrode for supercapacitor applications

Abstract

Supercapacitors are energy storage devices with remarkable properties including high power density, prolonged operational life, and hasty charging/discharging profile; however, a primary barrier to broad development is reduced energy density. Consequently, efforts have been undertaken to fabricate supercapacitors electrodes that resemble battery-type behavior. Owing to the unique structural characteristics and redox active sites, Prussian blue analogs (PBAs) are becoming attractive electrode materials. Herein, we presented the fabrication of ternary PBA-based electrode i.e., cerium cobalt hexacyanoferrate (CeCoHCF) with improved electrical properties and their characterization through different analytical techniques (SEM, FTIR, EDX, XPS, and XRD). The incorporation of cerium and cobalt together in PBA framework imparts a positive effect on the electrochemical properties. The as-synthesized CeCoHCF exhibits a significant specific capacity of 268.8 mA h g−1 at 1 A g−1 under alkaline conditions (3 M KOH) along with 88.6 % of capacity retention over 1000 cycles. Furthermore, the fabricated electrode exhibited the specific capacity 159.4 mA h g−1 at 1 A g−1 in neutral media (1 M Na2SO4). To investigate the practical application, symmetric supercapacitor device was fabricated that provides improved energy and power density as well as a wide operational voltage of around 1.2 V. Conclusively, PBA-based material can be potential candidates for future storage applications, owing to their outstanding electrochemical performance, chemical resilience, simplicity of synthesis, and low cost.