MXene and dielectric polymer matrix: Energy storage applications

Two-dimensional (2D) transition-metal carbides, nitrides, and carbonitrides, collectively called MXenes, represent an expanding class of functional materials with more than a dozen compositions synthesized. Their high electrical conductivity, tunable surface chemistry, and distinctive layered morphology show significant potential in energy storage, electromagnetic interference (EMI) shielding, electrocatalysis, plasmonics, and composite reinforcement. MXenes follow the general formula Mn+1XnTx, where M denotes an early transition metal, X represents carbon and/or nitrogen, and Tx corresponds to surface terminations such as –O, –OH, or –F. Prototypical examples include Ti₂CTx, Ti₃C₂Tx, and Nb₄C₃Tx. This review evaluates recent literature on MXene synthesis, structural configurations, and physicochemical properties. Comparative assessment of representative MXene phases is performed to explain the composition–structure–property relationships within the [MX]nM stacking framework. Recent findings demonstrate that MXenes exhibit high charge transport capability, active surface sites, and interlayer architectures conducive to ion intercalation and catalytic reactions. The combined effect between MXene surface terminations, structural anisotropy, and electronic characteristics enables targeted applications, redefining their status as promising next-generation functional materials. Major challenges include susceptibility to oxidation, batch-to-batch synthesis variability, and limited understanding of long-term environmental stability. This review aims to combine current advancements, identify unresolved scientific challenges, and propose future strategies for optimizing MXenes for high-performance energy, catalytic, and composite technologies.