Figure 4 | Scientific Reports

Figure 4

From: Nanotube-structured Na2V3O7 as a Cathode Material for Sodium-Ion Batteries with High-rate and Stable Cycle Performances

Figure 4

(a) XRD patterns of the Na2V3O7 electrode as-prepared and after charge and discharge processes. For clarity, the peak of Na2V3O7 with the strongest intensity is enlarged in panel (b). Normalized X-ray absorption near-edge spectroscopy (XANES) spectra at the V K-edges of Na2−xV3O7 electrode with different charge states of x = 0, 0.5, and 1. The edge energies at the normalized absorbance of 0.5 at the fronts of the peaks are compared in the spectra of Na2−xV3O7 in panel (d).

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