Fig. 1.

Morphology and structure of exfoliated MXene (Ti₃C₂T_X) nanosheets and stacked MXene membrane. a SEM image of the delaminated MXene nanosheets on porous anodic aluminum oxide (AAO) (scale bar, 1 μm). Inset is the Tyndall scattering effect in MXene colloidal solution in water. b HRTEM image of the MXene nanosheet with SAED pattern in the inset (scale bar, 5 nm, inset b, 5 nm⁻¹). c AFM image of the MXene nanosheet on cleaved mica. The height profile of the nanosheet corresponds to the blue dashed line (scale bar, 500 nm). Note that the adsorbed molecules, such as H₂O, also contribute the detected thickness of 1.5 nm. d SEM image of the MXene membrane surface (scale bar, 500 nm). Inset is a photograph of a MXene membrane. e Cross-sectional SEM image of the MXene membrane (scale bar, 1 μm). Inset is a tweezer bent membrane. f Cross-sectional TEM image of the MXene membrane with 2D channels (scale bar, 10 nm). g XRD patterns of the MAX (Ti₃AlC₂) powder and MXene (Ti₃C₂T_X) membrane with inset of the magnified XRD pattern at low Bragg angles. h Illustration of the spacing between the neighboring MXene nanosheets in the membrane