2D MXene integrated strategies: A bright future for supercapacitors

Recently, a class of two-dimensional (2D) transition-metal carbide and nitride materials denoted as MXene have emerged with a formula of Mn+1XnTx (n = 1–3). It has properties like 2D lamellar structure, the larger density of the active sites, impressive conductivity, and intercalation charge storage mechanism turn out to be ideal alternative for energy storage applications. This review highlights different synthesis methods of MXene and MXene-based composites with metals, metal oxides, carbonaceous materials and conducting polymers. We have also illustrated the structural, morphological analysis and performed a comparative study of the electrochemical properties such as capacitance values, energy density, power density and cyclic retention, etc. Further, we have discussed MXene's application as an electrode material in several applications but specifically focussed on supercapacitors (SCs) due to its superior properties like higher electron-transfer rate, enhanced faradaic reaction rate, etc. The current shortcomings and future opportunities associated with the MXene and MXene-based composites were briefly explained for developing enhanced, size-optimized, flexible, and wearable supercapacitor applications.