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Abstract Developing suitable cathodes of sodium‐ion batteries (SIBs) with robust electrochemical performance and industrial application potential is crucial for the commercialization of large‐scale stationary energy storage systems. Layered sodium transition metal oxides, NaxTmO2(Tm representing transition metal), possessing considerable specific capacity, high operational potential, facile synthesis, cost‐effectiveness, and environmentally friendly characteristics, stand out as viable cathode materials. Nevertheless, the prevailing challenge of air‐induced degradation in most NaxTmO2significantly increases costs associated with production, storage, and transportation, coupled with a rapid decay in reversible capacity. This inherent obstacle inevitably impedes the advancement and commercial viability of SIBs. To address this challenge, it is essential to decode the chemistry of degradation caused by air exposure and develop protective strategies accordingly. In this review, a comprehensive and in‐depth understanding of the fundamental mechanisms associated with air‐induced degradation is provided. Additionally, the current state‐of‐the‐art effective protective strategies are explored and discuss the corresponding sustainability and scalability features. This review concludes with an outlook on present and future research directions concerning air‐stable cathode materials, offering potential avenues for upcoming investigations in advancing alkali metal layered oxides.
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This content will become publicly available on February 1, 2026
Review of Layered Transition Metal Oxide Materials for Cathodes in Sodium-Ion Batteries
The growing interest in sodium-ion batteries (SIBs) is driven by scarcity and the rising costs of lithium, coupled with the urgent need for scalable and sustainable energy storage solutions. Among various cathode materials, layered transition metal oxides have emerged as promising candidates due to their structural similarity to lithium-ion battery (LIB) counterparts and their potential to deliver high energy density at reduced costs. However, significant challenges remain, including limited capacity at high charge/discharge rates and structural instability during extended cycling. Addressing these issues is critical for advancing SIB technology toward industrial applications, particularly for large-scale energy storage systems. This review provides a comprehensive analysis of layered sodium transition metal oxides, focusing on their structural properties, electrochemical performance, and degradation mechanisms. Special attention is given to the intrinsic and extrinsic factors contributing to their instability, such as structural phase transitions, and cationic/anionic redox behavior. Additionally, recent advancements in material design strategies, including doping, surface modifications, and composite formation, are discussed to highlight the progress toward enhancing the stability and performance of these materials. This work aims to bridge the knowledge gaps and inspire further innovations in the development of high-performance cathodes for sodium-ion batteries.
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- PAR ID:
- 10627919
- Publisher / Repository:
- MDPI
- Date Published:
- Journal Name:
- Micromachines
- Volume:
- 16
- Issue:
- 2
- ISSN:
- 2072-666X
- Page Range / eLocation ID:
- 137
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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