Zinc manganite as an efficient battery-grade material for supercapattery devices

In the current context, supercapatteries emerge as highly desirable candidates capable of merging both energy and power density within a single device. Battery-type metal oxide materials, combined with capacitive-based materials, stand out as promising candidates for high-performance supercapatteries. This investigation centers on the synthesis of nanocrystalline ZnMn2O4 (ZMO) and CoMn2O4 (CMO) through a straightforward hydrothermal method, followed by their physico-electrochemical characterization. Electrochemical analysis reveals that ZMO exhibits notably enhanced charge storage capability compared to CMO. This superiority can be attributed to favourable electro-structural properties, and stable redox chemistry of ZMO. The real-time performance of ZnMn2O4 was further assessed by fabricating a hybrid asymmetric supercapattery device (ZnMn2O4||NrGO), which achieves a specific capacity of 232 C g−1 at a current density of 1 A g−1. The hybrid asymmetric device underwent rigorous stability testing for 4000 cycles at a current density of 2 A g−1, showcasing remarkable performance with a 92 % retention of its initial capacity. The device demonstrated a power density of 980 W kg−1 and an energy density of 63 Wh kg−1, highlighting its considerable promise in the field. •➢Spinel-based metal oxides (ZnMn2O4 and CoMn2O4) were synthesized using microwave and hydrothermal heating and their electrochemical performances are compared.•ZnMn2O4 shown better charge storage property and rate capability than CoMn2O4 due to difference in their spinel structures.•The full cell performance of ZnMn2O4 (positive electrode) is evaluated fabricating a hybrid asymmetric device using NrGO as negative electrode.•The hybrid asymmetric supercapattery device (ZnMn2O4.||NrGO) attains a power density of 980 W kg−1 while maintaining an energy density of 63 Wh kg−1 proving a potential practical charge storage device.•The plausible electrochemical mechanism occurs in two-electrode system is presented.