Insight mechanism of MXene for the future generation of highly efficient energy storage device

Two-dimensional (2D) MXene and its derivatives have unique structural and electrical properties, making it an excellent ingredient for energy storage uses. The active functional groups on the outer layer of 2D MXene have a key role in altering its charge storage characteristics. They are excellent prospects for numerous energy storage applications due to the different 2D MXene architectures and active functional groups on their surface. Due to its fascinating structure, 2D MXene has many applications in diverse areas, especially energy storage device applications. In addition, the performance of energy storage devices can be improved further by integrating MXene with other low-dimensional materials in the form of van der Waals (vdWs) heterostructure. In this review, we have navigated the recent research process on the emerging 2D MXene and their vdWs heterostructures, focusing on the lattice structure, physical properties, and device applications in energy storage. First, the lattice structure, physical properties, and general synthesis techniques for 2D MXene and their derivatives are provided. Then, the vdWs heterostructure of 2D MXene with other low dimensional materials such as 2D MXene/carbon nanotubes, 2D MXene/organic compound, and 2D MXene/oxides with a focus on the energy storage capacity are summarized. Applications for energy storage, including lithium-ion batteries (LIBs), sodium-ion batteries (SIB), potassium ion batteries (PIBs), and supercapacitors (SCs), are then discussed. Finally, the prognosis, significant difficulties, and future research prospects of 2D MXene and vdWs heterostructure-based energy storage device applications are discussed.