Stabilizing Anionic Redox and Tuning Its Extent in Na-Rich Cathode Materials through Electronic Structure Engineering

The capacity of sodium-ion batteries (SIBs) can be enhanced by incorporating anionic redox into Na-rich cathode materials. However, excessive participation of oxygen in the redox process during the cycling often leads to several undesired issues including oxygen release. In this study, using first-principles computational methods through a systematic investigation and detailed analysis, we demonstrate an electronic structure tuning strategy through the aliovalent doping method to tune the amount of anionic redox in SIBs. Furthermore, we provide a method for achieving reversible anionic redox and emphasize that reversible anionic redox is not solely dependent on the covalent interaction between the transition metal and oxygen but is influenced by multiple factors that govern the electronic structure of the material. Using the aforementioned strategy, we identify an Al-doped Na-rich material, Na2Ru0.5Al0.5O3, which exhibits reversible cationic and anionic redox. Additionally, we rationalize the dominance of cationic redox in pristine Na2RuO3

sj-txt-9-dhj-10.1177_20552076221109553 - Supplemental material for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use

Supplemental material, sj-txt-9-dhj-10.1177_20552076221109553 for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use by Evan Morgan, Patrick Schnell, Priti Singh and Naleef Fareed in Digital Health</p

sj-docx-3-dhj-10.1177_20552076221109553 - Supplemental material for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use

Supplemental material, sj-docx-3-dhj-10.1177_20552076221109553 for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use by Evan Morgan, Patrick Schnell, Priti Singh and Naleef Fareed in Digital Health</p

sj-txt-17-dhj-10.1177_20552076221109553 - Supplemental material for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use

Supplemental material, sj-txt-17-dhj-10.1177_20552076221109553 for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use by Evan Morgan, Patrick Schnell, Priti Singh and Naleef Fareed in Digital Health</p

sj-txt-11-dhj-10.1177_20552076221109553 - Supplemental material for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use

Supplemental material, sj-txt-11-dhj-10.1177_20552076221109553 for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use by Evan Morgan, Patrick Schnell, Priti Singh and Naleef Fareed in Digital Health</p

sj-txt-6-dhj-10.1177_20552076221109553 - Supplemental material for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use

Supplemental material, sj-txt-6-dhj-10.1177_20552076221109553 for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use by Evan Morgan, Patrick Schnell, Priti Singh and Naleef Fareed in Digital Health</p

sj-txt-14-dhj-10.1177_20552076221109553 - Supplemental material for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use

Supplemental material, sj-txt-14-dhj-10.1177_20552076221109553 for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use by Evan Morgan, Patrick Schnell, Priti Singh and Naleef Fareed in Digital Health</p

sj-txt-15-dhj-10.1177_20552076221109553 - Supplemental material for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use

Supplemental material, sj-txt-15-dhj-10.1177_20552076221109553 for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use by Evan Morgan, Patrick Schnell, Priti Singh and Naleef Fareed in Digital Health</p

sj-txt-8-dhj-10.1177_20552076221109553 - Supplemental material for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use

Supplemental material, sj-txt-8-dhj-10.1177_20552076221109553 for Outpatient portal use among pregnant individuals: Cross-sectional, temporal, and cluster analysis of use by Evan Morgan, Patrick Schnell, Priti Singh and Naleef Fareed in Digital Health</p

Unraveling the Mechanistic Details of Ru–Bis(pyridyl)borate Complex Catalyst for the Dehydrogenation of Ammonia Borane

Ru–Bis­(pyridyl)­borate complex (CAT) is an efficient catalyst for ammonia borane (AB) dehydrogenation. Although the mechanistic pathway of this catalyst has been theoretically investigated previously, the gap between the experimental findings and the computational results could not be bridged thus far. In our study, using density functional theory calculations, we elucidate the mechanism of AB dehydrogenation of CAT at a variable degree of ligand hydrogenation. Our results confirm that the acetonitrile ligands get reduced in the presence of AB and remain hydrogenated. Moreover, in line with experiments, we find that AB dehydrogenation on CAT proceeds via a concerted mechanism (with the free energy energetic span between 25.4 and 32.5 kcal/mol). We find that the ligand reduction alters the electronic structure and activity of CAT and the highest activity of the catalyst is expected at the fifth degree of hydrogenation of ligands with an energetic span of 25.4 kcal/mol. Additionally, the mechanism for the removal of molecular H2 from the catalysts also alters with the degree of ligand hydrogenation. Furthermore, our results show that optimal H2 binding free energy calculations can be used as a descriptor to identify the most active sites. Finally, this work demonstrates that ligand reduction improves the activity of the catalyst. These results highlight the importance of ligand hydrogenation in probing the activity and operating mechanism of the Ru–bis­(pyridyl)­borate complexes for AB dehydrogenation. Further, we identify a plausible dimer structure and rationalized experimental observation that the deactivation chemistry of this catalyst is different from the Shvo’s catalyst