MXene material for supercapacitor applications: A comprehensive review on properties, synthesis and machine learning for supercapacitance performance prediction

Rapidly increasing population has raised demand for energy thus elevating the research on energy storage devices. Supercapacitors, with its wide range of features including high capacitance, high power density, and high cyclic stability has proved itself to be a remedy to the energy crisis faced globally. The advent of MXenes, a class of two-dimensional transition metal carbides or nitrides (TMCN) having excellent features including good electrical conductivity, pseudocapacitive nature and hydrophilic nature makes it as a potential material for the efficient electrode for supercapacitor application. This material offers a blend of metallic conductivity and abundant redox-active sites, therefore enabling charge storage mechanisms like electric double-layer capacitance and pseudocapacitance mechanisms contributing to clean and affordable energy. In this paper, we review the advancements in research on MXene material for supercapacitor application, including the properties, synthesis techniques of MXene ranging from HF etching to environment friendly fluoride-free approaches, MXene-based materials for supercapacitor application, and much more. Additionally, ML approaches for predicting supercapacitor performance are also discussed. This review provides a holistic and forward-thinking perspective of MXenes in supercapacitor applications, addressing critical challenges and outlining future research directions that are indispensable to bridge the gap that exists between academic advancement and industrial implementation.