Solvation structure design for stabilizing MXene in transition metal ion solutions

Although MXene has attracted great interest in diverse fields, it is susceptible to oxidation in water (H 2 O) with transition metal ions such as Co 2+ , Fe 2+ , and Cu 2+ , which is pronounced at high temperatures. This impedes the preparation of MXene‐based composites and their functional applications. Here, this study revealed that Co 2+ increases the maximum and average atomic charge of H in H 2 O to improve the reactivity of H 2 O, which leads to the fact that Co 2+ catalyzes the oxidation of Ti 3 C 2 T x MXene. Furthermore, the addition of N,N‐dimethyl formamide (DMF) reduces the H 2 O activity and improves the oxidation stability of Ti 3 C 2 T x in the presence of Co 2+ via preferentially forming coordination bonds with Co 2+ . This strategy is also effective in enhancing the oxidation tolerance of Ti 3 C 2 T x to Fe 2+ in H 2 O. Moreover, it is feasible to enhance the oxidation stability of Ti 2 CT x MXene in H 2 O with the existence of Co 2+ . By virtue of these, the CoO/Ti 3 C 2 T x composite was successfully prepared without obvious Ti 3 C 2 T x oxidation, which is desirable to harness the advantages of Ti 3 C 2 T x as the complementary component for lithium‐ion batteries. This work provides a straightforward paradigm to enhance the oxidation resistance of MXene in H 2 O in the presence of transition metal ions and at high temperatures, which opens a new vista to use MXene for target applications.