Recent Development of Nanocomposite Membranes for Vanadium Redox Flow Batteries

Figure 4

SEM images of (a) GO nanosheets and cross sections of (b) SPEEK, (c) SPEEK/GO2, and (d) SPEEK/GO3 membranes. The insets are the corresponding digital photos of the membranes. The scale bar in (a) is 500 nm, while that in (b), (c), and (d) is 20 μm, reproduced with permission of RSC [33].

(a)

(b)

(c)

(d)