Design strategy for MXene and metal chalcogenides/oxides hybrids for supercapacitors, secondary batteries and electro/photocatalysis

MXenes, a group of newly discovered two-dimensional (2D) materials since 2011, have been demonstrated with great potential in energy storage and conversion for their exceptional electrical conductivity, large surface areas, huge variety in composition and high flexibility. Up to now, the MXenes been synthesized always have surface terminal groups, such as -OH, -O or -F, which endows the materials with high hydrophilicity, rich surface chemistry to be further processed and yet challenges in restacking. As the electrochemical and electrocatalytic properties are highly relay on the material composition and surface chemical properties, hybridizing MXene with functional materials such as transitional metal chalcogenides (TMC) and transitional metal oxides (TMO) could dnot only prevents the restacking but also introduces synergistic functionalities into the composites. Therefore, elaborately design and synthesis of MXene/TMC or MXene/TMO architectures with tunable morphologies and enhanced electrochemical properties are of great importance. Herein, this review provides a comprehensive discussion on the MXene/TMC or MXene/TMO hybrids in the application for supercapacitors, secondary batteries and electrocatalysis. Specifically, the preparation methods for hybridization are presented firstly in five categories, where the characteristics of each method in relation to the structure and morphology of resulting product are compared. Advances on recent reported MXene/TMC and MXene/TMO hybrids in the application of supercapacitors, secondary batteries, and electrocatalysis are discussed in detail and their performances are also summarized. Finally, the major challenges and future prospects are also highlighted regarding improving electrode performances.