In situ mitigating cation mixing of Ni-rich cathode at high voltage via Li2MnO3 injection

Comparative study of polycrystalline and single-crystal NCM811 cathode materials: the role of crystal defects in electrochemical performance

“…The decrease in the a-parameter during charging indicates the oxidation of Ni 2+ / Ni 3+ to form higher valence Ni 4+ , resulting in a decrease in the ion radius and a reduction in the distance between adjacent atoms. 83 The trend of the c-parameter shows that the structural phase transition in the c-direction of single crystal samples is more signicant than that of polycrystalline samples during the charge-discharge process. This violent phase transition process may have an adverse effect on lithium ion de-intercalation, thereby affecting the release of material capacity.…”

Heat Generation Power of the LiNi0.8Co0.1Mn0.1O2 Cathode at Higher Charging Cutoff Voltages

“…The content variations of Ni 2+ and Ni 3+ were determined from the 2p 3/2 peaks of Ni 2+ (at 858.4 eV) and Ni 3+ (at 861.3 eV) and are compared in Table . Notably, the content of Ni 2+ in NCM811 increases with the charge/discharge cycle number and charging cutoff voltage increasing, indicating severe Li + /Ni 2+ mixing under higher charging cutoff voltages …”

“…Notably, the content of Ni 2+ in NCM811 increases with the charge/discharge cycle number and charging cutoff voltage increasing, indicating severe Li + /Ni 2+ mixing under higher charging cutoff voltages. 51 XRD patterns of NCM811 after charge/discharge cycling at different charging cutoff voltages were recorded and are shown in Figure 4. The (003) plane of the NCM811 crystal is occupied by transition metal (TM) ions, while the (104) plane contains both TM and Li + .…”

“…After deconvolution, the Ni 2p 3/2 and 2p 1/2 peaks of Ni 2+ and Ni 3+ can be distinguished. The content variations of Ni 2+ and Ni 3+ were determined from the 2p 3/2 peaks of Ni 2+ (at 51 XRD patterns of NCM811 after charge/discharge cycling at different charging cutoff voltages were recorded and are shown in Figure 4. The (003) plane of the NCM811 crystal is occupied by transition metal (TM) ions, while the (104) plane contains both TM and Li + .…”

Synergy of Epitaxial Layer and Bulk Doping Enables Structural Rigidity of Cobalt‐Free Ultrahigh‐Nickel Oxide Cathode for Lithium‐Ion Batteries

“…Therefore, to release strain energy, Ca cations have a strong tendency to segregate onto the surface. [28,29] After lithiation, almost no Ca cations are detected in the bulk. Hence, NAC exhibits a highly ordered layered structure in the bulk (Figure S10b, Supporting Information), which is well consistent with the Rietveld refinement results.…”