Rational design of a novel MnO2-FeSe2 nanohybrid with nanowires/cubic architecture as promising supercapattery electrode materials

A promising MnO2-FeSe2 nanohybrid is reported for the first time by the wet-chemical assisted route and directly utilized as a synergistic electrode for supercapattery applications. The optimized electrochemical performance of the MnO2-FeSe2 nanohybrid is realized when tested for capacitive signature and active redox reactions. Testing for capacitive signature and active redox reactions reveals the MnO2-FeSe2 nanohybrid's enhanced electrochemical performance. The MnO2-FeSe2 nanohybrid has a greater capacitance due to the cyclic voltammetry's bigger enclosed loop area, higher current response, and longer discharge time frame. Also, due to the synergistic impact between the two pseudocapacitive materials in the three-mode assembly, the least resistance in the impedance plot was attained when compared with MnO2 and FeSe2 electrodes. Based on these striking results, MnO2-FeSe2||AC||KOH supercapattery displayed a highly stable performance (95.3% retention) at the highest current response when run for 10,000 repeated discharge-charge cycles. It achieved a high energy of 55.39 Wh/kg at the power delivery of 4320 W/kg by expanding the upper voltage cutoff to 1.7 V in an aqueous medium. Our research paves a new way to develop metal selenide nanohybrid electrodes with conventional pseudocapacitive materials that could efficiently boost the electrochemical properties of the parent materials owing to the synergistic effect. The acquired results displayed the potential growth of MnO2 and FeSe2 nanohybrid as the future active materials for sustainable and clean energy storage devices.