Zinc Manganite as an Efficient Battery-grade Material for Supercapattery Devices

Abstract 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 10 kW kg⁻ ¹ and an energy density of 22 W h kg⁻ ¹, highlighting its considerable promise in the field.