On the dynamics of transition metal migration and its impact on the performance of layered oxides for sodium-ion batteries: NaFeO₂as a case study

Abstract

Reversibility of transition metal migration in layered oxides as cathodes for sodium ion batteries at the expense of polarization increase.

Probing the charged state of layered positive electrodes in sodium-ion batteries: reaction pathways, stability and opportunities

“…While transition metal migration can be expected to induce a contraction in the interlayer distance, shrinkage of the c lattice parameter upon extraction of sodium ions has also been related to ordering of the sodium ion vacancies and phase transitions. 71,75,76 However, rationalising these alternative explanations is somewhat more challenging. As such, uncertainties regarding the role of transition metal migration in phase transformations, such as formation of the "Z phase" from an initial P2-type structure, still remain.…”

“…To identify the preferential site for Fe migration in NaFeO 2 Silván et al performed simulations to model the migration of Fe to Na octahedral sites or Na tetrahedral sites in different proportions. 71 By comparing these results with operando XRD pattern evolution it was possible to identify that the Fe in NaFeO 2 preferentially migrates to the tetrahedral sites. This suggests that tetrahedral sites in the Na layer need to be available for transition metal migration to occur.…”

Challenges of today for Na-based batteries of the future: From materials to cell metrics

“…as the Na + content changes upon cycling. Furthermore, in O3-type layered oxides the structural reversibility deteriorates, especially while cycling at high potentials aimed to utilize the full 1Na capacity [28][29][30][31]. To avoid this structural instability and to improve cycle life, the sodium layered oxides are used with c. a.…”

Electronic Properties, Phase Transformation, and Anionic Redox of Monoclinic Na2MnO3 Cathode Material for Sodium‐Ion Batteries: First‐Principle Calculations

“…[2,4] Thus, extensive study and intensive computational design for new Na + storage materials with high working potential and large specific capacity are essential for SIB development. [5] Many analogs of successful LIB cathode materials, such as layered transition metal (TM) oxides, [6][7][8] sulfides, [9,10] polyanionic materials, [11,12] oxyanionic compounds, [13] and Prussian blue analogs, [14,15] have been shown to be suitable SIB cathode materials. However, the limited available capacities (< 150 mA h g À 1 ) of these materials indicate that alternative cathode materials achieving larger specific capacity and/or higher discharge voltage are urgently needed.…”

“…Many analogs of successful LIB cathode materials, such as layered transition metal (TM) oxides, sulfides, polyanionic materials, oxyanionic compounds, and Prussian blue analogs, have been shown to be suitable SIB cathode materials. However, the limited available capacities (<150 mA h g −1 ) of these materials indicate that alternative cathode materials achieving larger specific capacity and/or higher discharge voltage are urgently needed.…”