Effect of Mg-doping on the degradation of LiNiO2-based cathode materials by combined spectroscopic methods

High Spatial Resolution Hyperspectral Imaging with Machine-Learning Techniques

“…We also successfully applied NMF to a series of EELS datasets for the extraction of atom site-specific core-loss spectra, where the relative excitation probabilities of the spectra varied with the diffraction condition because of the electron channeling effects [22][23][24][25]. In these applied data analyses, the nonnegative constraint of the elements of extracted basis spectra and spatial intensity distributions were effective, and the resulting spectra extracted by NMF were consistent with the computational results obtained by first principles calculations [15][16][17][18][19][22][23][24][25].…”

“…Contrary to NMF, the methods mentioned above such as PCA allow the spatial intensities and spectra to have negative values, which hampers the direct physical interpretation of the resolved spectral profiles. We adopted the modified alternating least-square (MALS) fitting algorism of NMF [14] to map the different phases in the degradation of Li battery cathodes [15][16][17][18][19] and the chemical states of nitrogen in nitrogen-doped TiO 2 [20,21]. We also successfully applied NMF to a series of EELS datasets for the extraction of atom site-specific core-loss spectra, where the relative excitation probabilities of the spectra varied with the diffraction condition because of the electron channeling effects [22][23][24][25].…”

Effects of fluorine doping on structure, surface chemistry, and electrochemical performance of LiNi0.8Co0.15Al0.05O2

“…However, the capacity fade can be delayed in ways that lower the chemical reaction kinetics or the migration trend of transition metal ions under the same oxygen arrangement. Cation substitution (Mg 2+ [12][13][14]) and surface modification (Ni 3 PO 4 [15], AlF 3 [16], SiO 2 [17], TiO 2 [18], LiCoO 2 [19,20], FePO 4 [21], Li 2 ZrO 3 [22], Li 2 BO 3 [23]) are effective approaches to suppressing the phase transformation and side reactions at the interface, thus improving the structural stability and slowing the capacity fade to some extent.…”

Degradation Analysis of LiCoO₂Positive Electrode Material of a Li-Ion Battery Using the Li K-Edge Signal Obtained from STEM-EELS Measurements

“…The ALS method was applied to these EELS data [7][8][9][10][11][13][14][15]. As an initial ALS estimation, the orthogonal projection approach (OPA) was used [16,17].…”

“…Such a large matrix of spectral data is suitable for analysis via a chemometrics approach. To obtain individual pure spectra from the series of spectra without a reference spectrum, we applied a self-modeling curve-resolution technique (the alternating least-squares (ALS) method) [7][8][9][10][11] to the series of spectra to perform spectral decomposition. The degradation process of LiCoO 2 was analyzed based on the series of decomposed spectra.…”