M₄X₃ MXenes: Application in Energy Storage Devices

MXene has garnered widespread recognition in the scientific community due to its remarkable properties, including excellent thermal stability, high conductivity, good hydrophilicity and dispersibility, easy processability, tunable surface properties, and admirable flexibility. MXenes have been categorized into different families based on the number of M and X layers in M_n+1X_n, such as M₂X, M₃X₂, M₄X₃, and, recently, M₅X₄. Among these families, M₂X and M₃X₂, particularly Ti₃C₂, have been greatly explored while limited studies have been given to M₅X₄ MXene synthesis. Meanwhile, studies on the M₄X₃ MXene family have developed recently, hence, demanding a compilation of evaluated studies. Herein, this review provides a systematic overview of the latest advancements in M₄X₃ MXenes, focusing on their properties and applications in energy storage devices. The objective of this review is to provide guidance to researchers on fostering M₄X₃ MXene-based nanomaterials, not only for energy storage devices but also for broader applications.