Shearing-force-driven delamination of waste residue into oxidatively stable MXene composites for high-performance Si anode

The low yield of MXene is normally related to the delaminating step, contributing to the key technical challenges in moving toward industrial applications. Here, a shearing-force-driven strategy is proposed for re-exfoliating waste MXene residue to prepare oxidatively stable MXene composites in a low-cost manner, where the strong shear stress in the assisted solvent, such as carbon nanotubes (CNTs), chitosan (CS), and polyacrylamide (PAM) aqueous solutions, acts on the surface of MXene (Ti 3 C 2 T x ) through coordination between hydroxyl and Ti atoms, resulting in a rapid and efficient exfoliation of waste Ti 3 C 2 T x residue under stirring. Furthermore, this formed coordinate bond helps to stabilize the low-valent Ti atoms on the surface of MXene, thereby enhancing the oxidative stability of Ti 3 C 2 T x . Besides, the CNT@MXene composite is selected to construct a free-standing membrane to encapsulate Si nanoparticles, achieving a high and reversible capacity after 50 cycles. This work supports the concept of valorizing waste and adopts a fluid shear force-assisted method to re-exfoliate waste residues, which greatly reduces the cost of processing and improves the chemical stability of MXene. More importantly, this work has uncovered a new direction for the commercialization of MXene composites and has significantly improved the real-world applications of MXene-based materials. Graphical abstract