Fig. 1: Structure and charge storage properties of various TiO2(A) NPs.
From: Surface-redox sodium-ion storage in anatase titanium oxide
The initial sodiation and desodiation curves (a) and cycling performance at 0.1 A g−1 (b) of different TiO2 NPs, respectively. c Ex-situ XRD patterns of different TiO2 NPs. Below 18 nm the (de)sodiated NPs are X-ray amorphous, whereas larger ones (>18 nm) remain crystalline. The ex-situ HRTEM images of TiO2-100 nm (d), TiO2−25 nm (e), and TiO2−10 nm (f) at the fully sodiated state, showing the amorphous NaxTiO2 shell and crystalline TiO2(A) core structure. Scale bar: 10 nm. HAADF-STEM image (g) and EELS spectra of Ti-L2,3 (h) of sodiated TiO2−25 nm. Scale bar: 5 nm.
