Fig. 1. Schematic diagram of the applications for MXene porous films.

Fig. 2. MXene porous films for EMI shielding. Schematic illustration of the fabrication for hydrophobic and flexible MXene porous film (a); cross-sectional SEM images of the MXene film (b) and the MXene porous film (c); MXene porous films with different thicknesses (d); effects of the expansion ratio on the measured and calculated EMI SE of the MXene porous films (e); reprinted with permission from Ref. [42]. Copyright 2017, Wiley-VCH. Schematic diagram of the preparation process for rGO porous film, MXene dense film and MXene/rGO porous composite film (f); SEM images of the cross-sections of MXene/rGO porous composite film (g); SET of MXene/rGO porous composite films (h); reprinted with permission from Ref. [44]. Copyright 2021, Elsevier.

Fig. 3. MXene porous films for lithium/sodium ion batteries. Schematic showing the construction of hollow MXene spheres and MXene porous film (a); digital image showing the flexibility of MXene porous film (b); SEM of MXene/PMMA hybrid spheres (c); cross-sectional SEM images of MXene porous film (d); reprinted with permission from Ref. [51]. Copyright 2017, Wiley-VCH. Schematic illustration of the preparation process of the freestanding and flexible MXene porous film (e); SEM images (f, g) and digital photo (h) of MXene porous film; reprinted with permission from Ref. [52]. Copyright 2019, Wiley-VCH.

Fig. 4. MXene porous films for pseudocapacitors. Ion transport in horizontally stacked (a) and vertically aligned (b) MXene films. The blue lines indicate ion transport pathways; Illustration of the surfactant-enhanced lamellar structure of the MXLLC (c); illustration of the alignment method (d); POM image of the MXLLC with shear direction at 45° to the polarizer angle (e); top view of SEM image of the MXLLC (f). Reprinted with permission from Ref. [67]. Copyright 2018, Nature Publishing Group. Schematic illustration of the scheme design of porous MXene architecture (g); stacked MXene structure (h); ionic transport pathway in stacked MXene film (i); formation principle and photograph display of MXene/BC porous composite film (j); cross-section images of MXene/BC porous composite film (k, l); reprinted with permission from Ref. [68]. Copyright 2019, Wiley-VCH.

Fig. 5. MXene porous films for biomedical science. Schematic illustration for synergistic therapy on HCC cells as assisted by DOX-loaded MXene@mMSNs-RGD at the cell level (a); cumulative DOX release from DOX loaded MXene@mMSNs-RGD in phosphate-buffered saline (PBS) at different pH values (b); cumulative DOX release from DOX-loaded MXene@mMSNs-RGD in PBS as triggered by 808 nm NIR lasers at elevated power density (c); relative viabilities of SMMC-7721 cells after different treatments, including control (without any treatment), laser only, DOX only, D@P (D: DOX, P: MXene@mMSNs-PEG), D@P + laser, D@R (R: MXene@mMSNs-RGD) + laser, at varied concentrations and power densities (d); reprinted with permission from Ref. [80]. Copyright 2018, Wiley-VCH. The scheme of the synthetic procedure and stepwise surface PEGylation/targeting modification of CTAC@MXene-MSN (e); Schematic illustration of CTAC@MXene-MSN-PEG-RGD for enhanced chemotherapy and PTT against cancer cells (f); normalized weight loss reduction of MXene@MSN and CTAC@MXene-MSN (g); tumor-inhibition rate of isolated tumors from each group at day 15 post treatment (h). Reprinted with permission from Ref. [81]. Copyright 2018, ivyspring. Schematic illustration for in vitro synergistic therapy of AIPH@MXene@mSiO2 against 4T1 cells (i). Reprinted with permission from Ref. [82]. Copyright 2019, American Chemical Society.