ABSTRACT MXenes, a rapidly expanding class of 2D transition‐metal carbides, nitrides, and carbonitrides, have emerged as a foundational material platform for future technologies. This review provides a comprehensive summary of their multifunctional properties, including electrical conductivity (~2.5 × 10 6 S/m), mechanical strength (~534 GPa), tunable surface chemistry, and distinctive optical, thermal conductivity (~86–140 W/m K), and magnetic behaviors. Emphasis is placed on the evolution of synthesis strategies, highlighting the transition from conventional hazardous etchants to green and sustainable approaches, and examining the implications of these methods on material quality, performance, and environmental impact. Additionally, this review discusses the synthesis, fabrication, and application of MXene composites, including hybrids with metals, polymers, carbon nanotubes (CNTs), and graphene. These applications include electromagnetic‐shielding devices, batteries, electrodes, flexible sensors, electrocatalysts, ion‐selective membranes, and microelectromechanical systems (MEMS). These composites have demonstrated advanced performance in diverse fields such as energy storage (super capacitors and lithium‐ion batteries), achieving ~405 F g −1 specific capacitances and volumetric capacitances ~370 F cm −3 and cyclic stability ~92%, solar energy conversion with power conversion efficiency up to 16.80%, sensing technologies, biomedical platforms (e.g., cancer therapy, antibacterial systems) showing negligible cytotoxicity ~600 μg mL −1 and photothermal conversion of 52.2%, and environmental remediation. A defining feature of this review is the integration of life cycle assessment (LCA) as a framework for quantitatively evaluating the environmental impacts of MXene synthesis, using 1 g as a functional unit at the laboratory scale. This analysis underscores the critical importance of aligning materials innovation with sustainability principles.
Akbar et al. (Mon,) studied this question.