fig4

Figure 4. (A) Top-view and (B) cross-sectional SEM images of CNTs@TrW. (C) High magnification view of CNTs@TrW cell wall. (D) Schematics of the charge transport mechanism in thick CNTs@TrW hybrid. The cell walls have cellulose fibers embedded in the lignin matrix, where the cell walls can be saturated with electrolytes transported from cellulose fibers. The cell walls are coated with CNTs to enable electron transport. The lumen filled with electrolytes makes low tortuosity channels for transporting ions to neighboring micropores.