MXene, silicene and germanene: preparation and energy storage applications

Energy storage devices such as supercapacitors and batteries have gained great attention due to their high capacity, good recyclability, long life span and ease of use. There is a critical demand for low cost, easily prepared, high performing, light-weight and environment friendly materials to use in energy storage applications. Different nanomaterials, for example, oxides, sulfides, nitrides and chalcogenides are regarded as promising electrode and hydrogen-storage materials. The discovery of graphene leads to prepare and apply various two-dimensional nanomaterials in the fields of energy and environment. Two-dimensional (2D) materials show superiority due to atomic thickness, large surface area and infinite planer distance. Various 2D materials, including MXene, silicene and germanene, were reported for energy storage applications. Researchers have reported different methods to prepare these materials but selective etching is a simple and low-cost method. In the present review, we summarize and discuss the selective etching preparation and energy storage applications of MXene, silicene and germanene.