fig4

Figure 4. (A) Schematic illustration of the fabrication process of GO/BC nano-nano composite structure by membrane-liquid interface method. (B) Photos of Gr/BC samples with varying thickness. (C) The cross-sectional morphologies of freeze-dried Gr/BC showing layered structure. (D) SEM images taken from the surface layers of BC/GO. (E) Magnified SEM image of the “leaf and vein” nanostructure of BC/GO. (F) A photograph of a bent paper without damage. (G) Stress-strain curves of GE/BC sheets with different concentration of graphene. (H) Cyclic voltammogram curves of the CNF/GN electrode with various bending angles. (A, D, E) Reproduced with permission^[29]. Copyright 2018, Springer. (B) Reproduced with permission^[33]. Copyright 2018, Elsevier. (C, F, G) Reproduced with permission^[32]. Copyright 2019, Elsevier. (H) Reproduced with permission^[30]. Copyright 2018, Wiley.