Perspectives on solution processing of two-dimensional MXenes

Since the discovery of two-dimensional (2D) transition metal carbides and nitrides, known as MXenes, research on these wonder 2D inorganic compounds has become increasingly intensified with their members quickly expanding. MXenes' state-of-the-art applications are heavily dependent on their processing strategies and manufacturing methods. Nevertheless, the solution processing of MXenes has not been comprehensively reviewed. This review summarizes progress regarding solution processing of MXenes over the past decade as well as outlines key perspectives for future scalable manufacturing strategies. Etching of MAX phases and delamination of MXene are briefly introduced. Rheological properties of MXene dispersions and wetting of the MXene inks, which are crucial for the achievement of high-resolution printing and homogeneous coating, are discussed in detail. We have discussed the ink formulation strategies and fine-tuning of the ink properties to match with that of the targeted substrates to yield efficient yet high-quality printed/coated films/structures. As such, we demonstrate a "map of guidelines" for solution-based processing of MXenes toward high-performance applications, such as electrochemical energy storage, conductive electrodes, electromagnetic interference shielding, and so on.