MXene-transition metal chalcogenide hybrid materials for supercapacitor applications

The rapid growth of technologies and miniaturization of electronic devices demand advanced the use of high-powered energy storage devices. The energy storage device are utilized in modern wearable electronics, stretchable screens, and electric vehicles. Due to their favorable electrochemical properties, nanomaterials have been used as electrodes for supercapacitors (SCs) with high power density, but they generally suffer from lower energy density than batteries. Compared to various nanomaterials, MXenes and transition metal chalcogenides (TMCs) have shown great potential for energy storage applications such as SCs. TMCs are gaining attention due to their stable electrochemical nature, adjustable surface activity, high electric conductivity, abundant chemically active sites, and stable cycling performance. However, the interlayer restacking and agglomeration of 2D materials limit their cycling performance. To overcome this, TMCs@MXene heterostructures have been developed, offering structurally stable electrodes with enhanced chemical active sites. In this review, we discuss recent advances in the development of different TMCs@MXene-based hybrids for the design of high performance SCs with improved specific capacitance, cycling life, energy density, and power density. The recent developments of this research field focusing on MXene-transition metal sulfides, MXene-transition metal selenides, and MXene-transition metal tellurides are elaborately discussed. Theoretical calculations carried out to understand the charge-storage mechanisms in these composites are reviewed. The importance of bimetallic TMCs and MXene heterostructure for enhanced energy storage is also highlighted.