Room-Temperature Assembled MXene-Based Aerogels for High Mass-Loading Sodium-Ion Storage

Highlights Room temperature graphene oxide-assisted assembly of 3D Ti 3 C 2 T x MXene aerogels have been realized by introducing interfacial mediators (amino-propyltriethoxysilane, Mn 2+ , Fe 2+ , Zn 2+ , and Co 2+ ). The methodology not only suppresses the oxidation degradation of Ti 3 C 2 T x , but also generates porous aerogels with a high Ti 3 C 2 T x content (87 wt%) and robustness. As freestanding electrode of the as-prepared Ti 3 C 2 T x -based aerogel with a practical-level mass loading of 12.3 mg cm -2 still delivers an areal capacity of 1.26 mAh cm -2 at a current density of 0.1 A g -1 . Low-temperature assembly of MXene nanosheets into three-dimensional (3D) robust aerogels addresses the crucial stability concern of the nano-building blocks during the fabrication process, which is of key importance for transforming the fascinating properties at the nanoscale into the macroscopic scale for practical applications. Herein, suitable cross-linking agents (amino-propyltriethoxysilane, Mn 2+ , Fe 2+ , Zn 2+ , and Co 2+ ) as interfacial mediators to engineer the interlayer interactions are reported to realize the graphene oxide (GO)-assisted assembly of Ti 3 C 2 T x MXene aerogel at room temperature. This elaborate aerogel construction not only suppresses the oxidation degradation of Ti 3 C 2 T x but also generates porous aerogels with a high Ti 3 C 2 T x content (87 wt%) and robustness, thereby guaranteeing the functional accessibility of Ti 3 C 2 T x nanosheets and operational reliability as integrated functional materials. In combination with a further sulfur modification, the Ti 3 C 2 T x aerogel electrode shows promising electrochemical performances as the freestanding anode for sodium-ion storage. Even at an ultrahigh loading mass of 12.3 mg cm −2 , a pronounced areal capacity of 1.26 mAh cm −2 at a current density of 0.1 A g −1 has been achieved, which is of practical significance. This work conceptually suggests a new way to exert the utmost surface functionalities of MXenes in 3D monolithic form and can be an inspiring scaffold to promote the application of MXenes in different areas.