Y-Doped Na₂ZrO₃: A Na-Rich Layered Oxide as a High-Capacity Cathode Material for Sodium-Ion Batteries

Abstract

The renewed interest in sodium-ion batteries reflects the persistent concern about the lithium resources that have widespread applications but an uneven distribution, and the overwhelming need for large-scale energy storage. Most exploration has focused on the conventional layered oxides Na x MO2 that stem from lithium-ion cathodes. However, exploring cathode materials with high capacities, long cycle lives, and low costs because of the large ionic radius and high atomic weight of sodium is a great challenge. Here we report a Na-rich layered oxide, yttrium-doped Na2ZrO3, that serves as a cathode material in sodium-ion batteries. This material delivers a large reversible capacity of ∼180 mAh g–1 and a good cycle life with no sign of obvious capacity decay over 1500 cycles along with a low cost. The redox reactivity of oxygen is shown to be involved in the sodium extraction–insertion processes. This work not only provides a cathode contender to conventional layered oxides Na x MO2 but also suggests that broad classes of defective Na-rich layered oxides could be discovered.

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

“…[16][17][18][19] Inspired by this paradigm, great efforts have also been devoted to introducing anionic redox activity into Naion electrodes. [20][21] Most recently, Na3RuO4 was introduced as a pure prototype Na-rich layered oxide for SIBs, which delivers an outstanding electrochemical performance. [22][23] However, the charge compensation mechanism of Na3RuO4 undergoes different hypotheses: (i) Qiao et al…”

Nonstoichiometry and Li‐ion transport in lithium zirconate: The role of oxygen vacancies

“…Since this study assumes stoichiometric oxygen composition, oxygen vacancies, potentially affecting Li + transport, are not considered. The importance of oxygen vacancies has been emphasized in Y‐doped monoclinic‐structured Na 2 ZrO 3 , where Y 3+ substituting Zr 4+ was suggested to create oxygen vacancies thereby improving Na + conductivity as confirmed by impedance measurements . However, to the best of our knowledge, the influence of oxygen vacancies on the electrical conductivity of doped LZO has not been reported.…”

Zirconium‐Based Materials for Electrochemical Energy Storage

“…Besides, as shown in Figure , Song et al . report a special Na‐rich layered oxide (yttrium‐doped Na 2 ZrO 3 ), which serves as the excellent cathode material in SIBs.…”