Investigating the electrochemical properties of hydrothermally derived cerium oxalate decahydrate for high energy density supercapacitors

The fundamental electrochemical processes within the electrode materials play a key factor in advancing a wide range of energy storage systems, including batteries and supercapacitors. The design of battery-type hybrid supercapacitors aims to combine the superior power delivery of conventional supercapacitors with the high energy storage capacity of batteries, resulting in devices that provide a more balanced and efficient energy–power profile. This work aims to elucidate the structural, morphological and electrochemical properties of cerium oxalate decahydrate (Ce 2 (C 2 O 4 ) 3 .10H 2 O) synthesised via hydrothermal method. Structural properties were assessed by XRD and FTIR, while XPS analysis identified the oxidation states and composition of cerium oxalate decahydrate. The surface area and pore size of the material are calculated with BET analysis. The columnar morphology of the sample was validated through FESEM and TEM imaging. Electrochemical analyses of the material were conducted using 3 M KOH as electrolyte within a potential window of −0.25 to 0.4 V and the studies confirm a battery-type charge storage mechanism of the material. Systematic electrochemical investigations confirm the superior charge storage properties and high cyclic stability of cerium oxalate decahydrate in three-electrode and asymmetric two-electrode setup. The asymmetric supercapacitor system exhibited a superior capacitance of 243.36 F/g and energy density of 52.81 Wh/kg at 1 A/g in the potential window ranging from 0 to 1.25 V. Consequently, this material owns considerable potential as an electrode for supercapacitor applications.