Fig. 1: (LiNiO2)L | (LixNi2-xO2)RS composite cathode.
From: Topotaxially grown composite cathodes for cobalt-free high-energy long-life Li-ion batteries
a SXRD pattern of the 600C-6h sample showing a composite structure with 87 wt% layered (L; red) and 13 wt% rocksalt (RS; blue) phases. The inset shows the overlap of the 104L and 200RS peaks. A full-scale plot of the SXRD pattern with refinement information is provided in Fig. S7. b Schematic illustration of the rocksalt structure of a Li-containing nickel oxide with its four cubic <111 > RS vectors as accessible directions to initialize the layer ordering in the topotaxial transformation. c Cross-sectional HAADF-STEM image (scale bar = 10 nm) of the (LiNiO2)L|(LixNi2-xO2)RS composite obtained by sintering at 600 °C for 6 h. d Fast Fourier transform (FFT) patterns (scale bars = 4 nm−1) from the area marked by circles labeled d1, d2 and d3, respectively, showing RS (d1) and two layered orientation domains L1 (d2) and L2 (d3) in the composite. Magnified images (scale bars = 1 nm) from areas marked by (e) purple, (f) red and (g) green rectangles in (c), showing boundaries between (e) RS and layered domain L2, (f) layered domains L1 and L2, and (g) layered domain L2 and its antiphase domain L2A. The images are shown in false color for clarity. The lines in (e–g) mark the labeled planes (the planes are perpendicular to the screen). The layered structure model is embedded in (f) and (g), respectively. Here, L1 and L2 represent the two layer-structured domains with their (001) planes parallel to RS (111) and \((\bar{1}11)\) planes, respectively, e.g., (001)L1||(111)RS and (001)L2||\((\bar{1}11)\)RS, as shown in (d). A colored version of the HAADF-STEM image showing the phase boundaries, and enlarged views of e, f and g are provided in Supplementary Information as Figs. S7 and S8, respectively. Source data for a are provided as a Source Data file.
