Anionic Redox Activities Boosted by Aluminum Doping in Layered Sodium-Ion Battery Electrode.

Sodium-ion batteries (SIBs) have attracted widespread attention for large-scale energy storage, but one major drawback, i.e., the limited capacity of cathode materials, impedes their practical applications.

Elucidating the Redox Behavior in Different P-type Layered Oxides for Sodium-Ion Batteries.

Sodium layered transition-metal oxides have attracted great attention for advanced Na-ion batteries (NIBs) because of their rich structural diversity and superior specific capacity provided by not only cation redox reactions but also possible oxygen-related anionic redox reactions. However, they usually undergo severe electrochemical performance fading, especially the voltage retention during the cationic and anionic redox processes. Herein, we design and synthesize a couple of novel sodium lithium magnesium aluminum manganese oxides (NaLiMgAlMnO) with the same Na coordination environment but different oxide layer stacking sequences, namely, P2-NLMAMO and P3-NLMAMO.

Quantification of Anionic Redox Chemistry in a Prototype Na-Rich Layered Oxide.

Harnessing anionic redox reactions is of prime importance for boosting the capacity of sodium-ion batteries (NIBs). However, quantifying the cyclability of anionic redox reactions is still challenging. Herein, we conduct a qualitative and quantitative investigation of the cationic and anionic redox reactions of a prototype Na-rich layered oxide, namely, NaRuO, by a combination of bulk-sensitive X-ray absorption spectroscopy and full-range mapping of resonant inelastic X-ray scattering.

Elucidation of Anionic and Cationic Redox Reactions in a Prototype Sodium-Layered Oxide Cathode.

The ever-increasing demand for large-scale energy storage has driven the prosperous investigation of sodium-ion batteries (NIBs). As a promising cathode candidate for NIBs, P2-type NaNiMnO (NaNMO), a prototype sodium-layered oxide, has attracted extensive attention because of its high operating voltage and high capacity density. Although its electrochemical properties have been extensively investigated, the fundamental charge compensation mechanism, that is, the cationic and anionic redox reactions, is still elusive.