Fig. 2
From: Alkaline earth metal vanadates as sodium-ion battery anodes
Characterization of CVO-450 and CVO-550 nanowires. a XRD patterns of CVO-450 and CVO-550. b, c Crystal structures of the CaV4O9; the green and red balls represent Ca and O ions, respectively, and the grey polyhedrals represent the V–O pyramids. d, e EDS mapping of CVO-450 and CVO-550, respectively. The scale bar is 6 µm for d and 3 µm for e. f–h TEM and HRTEM images of CVO-450; the inset of h is the SAED pattern of CVO-450. The scale bars of f–h and the inset of h are 200 nm, 50 nm, 5 nm, and 2 nm–1, respectively. i–k TEM and HRTEM images of CVO-550; the inset of k is the SAED pattern of CVO-550. The scale bars of i–k and the inset of k are 500 nm, 100 nm, 5 nm, and 2 nm–1, respectively
