5.2 SEM Study of Cycled Electrodes
Figure 5.19 Titania nanotube layer after reaction with lithium.The structural rigidity of nanostructured materials is a positive property in order to achieve extended cycle life in advanced electrodes. To assess the stability of the self-assembled titania nanotubes, ex situ SEM images of cycled electrodes after 50 cycles at 2.6 V charge voltage are collected in Fig. 5.19. For the sample supported onto a Si substrate, the characteristic nanotube geometry — about 600 nm nanotube length (cross-sectional view), and between 50 and 200 nm diameter (top view) — is preserved. These analyses demonstrate the robustness of the nanotube morphology for those samples grown onto Si substrate, which survive after repeated cycling.