Plasma assisted single-step synthesis of carbon-coated SrFe2O4 electrodes for enhancing supercapacitor and oxygen evolution reaction

Developing highly efficient, conductive, and porous electrode materials for superior electrochemical bifunctional applications presents a formidable challenge, particularly when considering impurity-free large-scale production. This investigation focuses on synthesizing a composite material of highly conductive amorphous carbon-coated SrFe₂O₄ nanoparticles to enhance supercapacitor and oxygen evolution performance. The C@SrFe₂O₄ nanoparticles were synthesized through a thermal plasma process utilizing argon, methane, and carbon dioxide gas environments. The prepared samples' phase, crystal structure, morphology, elemental composition, and chemical state analysis were thoroughly examined. The electrochemical performance of the prepared samples, including Fe₃O₄, SrO, and C@SrFe₂O₄ electrodes, was evaluated for their suitability in electrochemical capacitor applications. Remarkably, C@SrFe₂O₄ nanoparticles exhibited notable electrochemical pseudocapacitive behavior, demonstrating a significantly higher specific capacitance of 588.7 F/g at a current density of 1 A/g. Moreover, at a current density of 10 A/g, the C@SrFe₂O₄ electrode exhibited outstanding cycling stability, maintaining 91 % of its initial capacitance over 5000 charge-discharge cycles. Furthermore, it showcased exceptional and uniform electrocatalytic activity for the OER, requiring only 186 mV in overpotentials to achieve a current density of 10 mA/ cm². These findings underscore the potential of mesoporous C@SrFe₂O₄ nanoparticles as promising materials for supercapacitors and OER applications.