Synthesis of CoMoO4/NiMoO4 Composites As Supercapacitor Electrodes

The energy crisis and climate change have emerged as global concerns due to the unsustainable reliance on fossil fuels for energy production. This has spurred increased research with the intention of satisfying the global energy demand through renewable sources. Novel and more efficient methods for energy generation and storage are necessary. One promising solution lies in the exploration and application of electrochemical systems, such as supercapacitors, which can store electrical energy through fast surface redox reactions. Supercapacitors offer a range of advantages, including high capacitance, exceptional power density, and long lifecycle. They act as a bridging technology between traditional capacitors and batteries, capable of storing more energy than capacitors while delivering and accepting charges faster than batteries.

This research focuses on the investigation of transition metal molybdates, which have attracted significant attention as promising materials for supercapacitor electrodes due to their exceptional electrochemical characteristics. Our approach employs a straightforward hydrothermal synthesis method to synthesize cobalt-doped NiMoO₄, which is deposited onto a nickel foam substrate without binders. Subsequently, the as-synthesized materials undergo annealing at different temperatures, resulting in the formation of α and β phases at distinct temperature ranges. Despite sharing a similar nanoneedle morphology, these two crystalline phases exhibit contrasting electrochemical behaviors. Specifically, the β phase has a higher specific capacitance while exhibiting inferior long-term stability compared to the α phase. This investigation underscores the significant influence of the crystalline phase of transition metal molybdates on their electrochemical performance.