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 (Ti3C2Tx) through coordination between hydroxyl and Ti atoms, resulting in a rapid and efficient exfoliation of waste Ti3C2Tx 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 Ti3C2Tx. 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.

Automated summary

A shearing-force-driven strategy was proposed to re-exfoliate waste MXene residue and prepare oxidatively stable MXene composites in a low-cost manner. The strong shear stress in assisted solvents acts on the surface of MXene, resulting in rapid and efficient exfoliation. The formed coordinate bond helps stabilize the low-valent Ti atoms on the surface of MXene and improves its oxidative stability, leading to enhanced real-world applications of MXene-based materials.