NiCoSe@KMXene Hybrid Nanocomposites: A Novel Bifunctional Platform for Energy Storage and Conversion Applications

As the demand for energy storage and conversion devices continues to rise, the development of electrode materials that are efficient, environmentally sustainable, highly stable, and long-lasting has become a pressing challenge. These materials are required to not only deliver exceptional performance but also align with sustainability goals to effectively address the growing energy and environmental challenges. Transition metal selenides (TMSs) have gained significant attention in research due to their outstanding performance in supercapacitors and hydrogen evolution reactions (HER). They are increasingly regarded as a promising alternative to noble metal-based electrode materials. In this study, A straightforward and efficient two-step hydrothermal method was utilized to synthesize NiCoSe@KMXene nanocomposites with high precision and reproducibility. The resulting NiCoSe@KMXene electrode exhibits an exceptional specific capacitance (Cs) of 2210 F g^-1 at a current density of 2 A g^-1 in supercapacitor applications. Additionally, the as-prepared NiCoSe@KMXene electrode material demonstrates excellent electrocatalytic activity for HER, requiring only 51.8 mV to achieve the current density of 10 mA cm^-2. Furthermore, the as-prepared sample function as both anode and cathode, enabling the construction of a symmetric supercapacitor (SSC) device with a distinctive architecture. This device exhibits outstanding performance, including superior energy density, high power density, and excellent cycling stability. At the current density of 5 A g^-1, the SSC device delivers a remarkable specific capacitance of 232.5 F g^-1, along with an energy density of 296 Wh kg^-1 at a power density of 2.21 kW kg^-1. These results highlight the significant potential of NiCoSe@KMXene materials for energy storage and conversion applications. The strategy employed for the NiCoSe@KMXene nanocomposites offers an innovative approach for synthesizing transition metal-based compounds, eliminating the need for adhesives and enabling more efficient and integrated designs for future applications.