Fig. 2: Characterizations of lattice structures and analysis of Mn valence and Mn-O hybridization in the pristine samples.
From: Entropy-increased LiMn2O4-based positive electrodes for fast-charging lithium metal batteries
a Correlation between the radii of the doped cations and the refined cell parameters observed in the synthesized LMOs. These include LMOs doped singly with Cu, Fe, Mg, Ni, and Zn (red spots), LMO singly doped with Ti (emerald green spot), LMOs singly doped with Mn, V, Cr, and Al (navy blue spots), and the EI-LMO (the gray horizontal line). b Schematic illustrations of the increased cation disorder in LMO structure with the increased entropy. Blue, yellow, green, red and purple squares and the lighter-colored squares illustrate the different doped atoms and the surrounding affected lattice (Heteroatoms and their localized structures). The gray squares illustrate the lattice regions that remain unaffected (Unaffected lattice). c SAED patterns of Cu-LMO, Fe-LMO, Mg-LMO, Zn-LMO, and Ni-LMO along the [100] axis. The dotted circles and dotted squares represent the diffraction spots and streaks of superstructure. d, e SAED d and FFT e patterns of CuFe-LMO. f, g SAED f and FFT g patterns of EI-LMO. h Element mappings of EI-LMO sample, including Mn, Ni, Zn, O, Fe, Mg and Cu. i, j HAADF STEM images of EI-LMO projected along the [110] axis (i) and [121] axis j, respectively. k Comparison of EELS spectra covering O K-edge and Mn L-edge between EI-LMO and LMO. The spectra are normalized to the zero-loss peak.
