Superior electrochemical performance of neodymium oxide-based Nd₂CeMO₃ (M = Er, Sm, V) nanostructures for supercapacitor application

Rare earth neodymium oxide-based Nd₂CeMO₃ (M = Er, Sm, V) nanostructures were synthesized using a simple and versatile sol–gel method for supercapacitor applications and characterized with various analytical techniques. X-ray diffraction confirmed the effective doping of Ce and the co-doping of Er, Sm, and V in the Nd₂O₃ matrix having a single hexagonal phase. FTIR further confirmed the formation of neodymium oxide matrix having metal–oxygen-metal bonding vibration. FE-SEM images revealed nanoplates type morphology, and EDX evident the existence of desired elements Nd, Ce, Er, Sm, V, and O in grown samples. IV results showed that the electrical conductivity of co-doped samples was high. The electrochemical measurements such as CV, GCD, EIS, and ECSA exhibited that all the fabricated nanostructures have pseudo-capacitive nature. However, the Er-Ce co-doped Nd₂O₃ electrode has higher specific capacitance (1319F/g), energy density (225 Wh/kg), and power density (82.4 W/kg), using 1 M KOH electrolyte having 5 A/g current density. Further, the single Ce doped and Sm, V co-doped electrodes have shown higher performance than pure Nd₂O₃ electrodes. In addition, the Nd₂CeErO₃ electrode presented superb cycling stability; maintained 96 % initial specific capacitance at the 1000th cycle. The formation of the plate-like morphology in the Nd₂CeErO₃ electrode provides a larger surface area for ions transportation, also higher conductivity, fast charge transfer (EIS results), and high electrochemical active surface area (ECSA results) are considered responsible for boosting supercapacitive behavior. This superficial and scalable fabrication methodology (co-doping) offers an effective route to boost the electrochemical performance of Nd₂O₃ and introduce novel electrode designs for next-generation supercapacitor advancements.