Fig. 3

Nyquist plots in the high (upper plot) and low (lower plot) frequency range for FTO at 2.9 V vs Li⁺/Li and 1.2 V vs Li⁺/Li after stabilization of the electrochemical behavior (see Fig. 2). Blue and red full arrows indicate the verse of growing frequencies. Black dotted arrows indicate the point determined at the lowest applied frequency of 5 mHz