Fig. 3: FESEM, STEM, and sXAS results.
From: Regulating Na content and Mn defects in birnessite for high-voltage aqueous sodium-ion batteries
FESEM images of (a, b) N1, (c, d) N2, and (e, f) N3 samples, respectively. g–i HAADF-STEM images of the N1–N3 samples along the [010] zone axis, respectively. j STEM image of the N3 sample and corresponding EDS mapping of Na, Mn, and O elements. k Mn L-edge sXAS spectra of the N1 (in grey), N2 (in blue), and N3 (in red) samples.
