New insights into designing high-rate performance cathode materials for sodium ion batteries by enlarging the slab-spacing of the Na-ion diffusion layer

Abstract

We propose new insights into designing high-rate performance cathode materials for sodium-ion batteries through enlarging the interplanar spacing.

Improving the Performance of Layered Oxide Cathode Materials with Football‐Like Hierarchical Structure for Na‐Ion Batteries by Incorporating Mg2+ into Vacancies in Na‐Ion Layers

“…194). [15][16][17] Thea bsence of extra peaks indicates that the Mg 2+ + can be incorporated completely into the vacancies in the Na-ion layers,w hich suggestss uccessful material design. The shift of the (0 02)p eak toward al ower angle indicates the expanded interplanar distance of the (0 02)p eak ( Figure 1b).…”

“…The shift of the (0 02)p eak toward al ower angle indicates the expanded interplanar distance of the (0 02)p eak ( Figure 1b). [17,19,20] Furthera nalysisw as performed by using NPD as NPD is sensitivet ol ight elements, such as Na and O, and also can clearly distinguish adjacent elements compared to XRD, which makes NPD av ery promising tool to probe crystal structures. The refined NPD resultsa re shown in Figure1c and d, and the refined crystallographic parameters are presented in Tables 1a nd 2.…”

“…Herein, as ar esulto ft he intrinsic vacancies in the Na-ion layers of P2-Na x TMO 2 (x < 1), Mg 2+ + can be incorporated into the available vacancies in the Na-ion layers to tune the microstructure of P2-Na 0.7 Mn 0.8 Ni 0.1 Co 0.1 O 2 (Mg0) without disturbing other components in the structure. Such as trategy differs significantly from ion substitution with as acrificial TM-ion type and concentration in previousr eports [14][15][16][17][18] because of the completely constant Na content in Na-ion layers,i dentical TM-The development of advanced cathode materials is still ag reat interestf or sodium-ionb atteries. The feasiblec ommercialization of sodium-ion batteries relies on the design and exploitation of suitablee lectrode materials.…”

“…The material structure wasa nalyzed by using neutron powder diffraction (NPD), which demonstratest hat Mg incorporation into Na-ion layers leads to ar educed lattice parameter a but an expanded lattice parameter c andv olume V. However,M gi ncorporation into Na-ion layersi ncreases both the thickness of TMO 2 slabs and the space for Na-ion diffusion, which is dramatically different from the case of Mg substitution. [17] Compared to that of Mg0, the enhanced rate capability and cycling stability of Mg05 originate from the improved structural stability,e xpanded spacing of Na-ion layers from the incorporation of Mg 2+ + into Na-ionv acancies, and the unique football-like hierarchical structure.…”

Dual‐Role Surface Modification of Layered Oxide Cathodes for High‐Power Sodium‐Ion Batteries

“…As shown in Figure 2a, the Mn 2p spectra of the NaMCN has two prominent peaks at 653.6 eV and 642.1 eV, assigned to Mn 2p1/2 and Mn 2p3/2 respectively, suggesting a 4 + valence for Mn ions. [15] However, for the 0.1 K-NaMCN, both of these two peaks show slight shift of 0.38 eV to lower binding energies, which indicates a coexistence of Mn 3 + and Mn 4 + ions on the surface. The decrease in the valence of Mn ions is caused by the introduction of excess Mn species.…”