Progress on multiphase layered transition metal oxide cathodes of sodium ion batteries

• Published in: Chinese chemical letters Vol. 31; no. 9; pp. 2167 - 2176
• Main Authors: Wang, Qi, Chu, Shiyong, Guo, Shaohua
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-09-2020; Center of Energy Storage Materials&Technology, College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, National Laboratory of Solid State Microstructures, and Collaborative Innovation Center of Advanced Microstructure, Nanjing University, Nanjing 210093, China
• Subjects: Biphase materials; Cathodes; Layered transition metal oxides; Sodium ion batteries; Triphase materials; Triphase materials; Sodium ion batteries; Layered transition metal oxides; Biphase materials; Cathodes
• ISSN: 1001-8417; 1878-5964
• DOI: 10.1016/j.cclet.2019.12.008

Since single phase transition metal layered oxide materials have been deeply discussed, multiphase materials that integrate the superiority of single P2, P3, O3 or other phases through synergetic effect have not been well researched. In this review, we summarized the recent progress of transition metal layered oxide multiphase cathode materials of sodium ion batteries, analyzed the mechanism and specified the future research direction.
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As one of the most promising secondary batteries in large-scale energy storage, sodium ion batteries (SIBs) have attracted wide attention due to the abundant raw materials and low cost. Layered transition metal oxides are one kind of popular cathode material candidates because of its easy synthesis and large theoretical specific capacity. Yet, the most common P2 and O3 phases show distinct structural characteristics respectively. O3 phase can serve as a sodium reservoir, but it usually suffers from serious phase transition and sluggish kinetics. For the P2 phase, it allows the fast sodium ion migration in the bulk and the structure can maintain stable, but it is lack of sodium, showing a great negative effect on Coulombic efficiency in full cell. Thus, single phase structure almost cannot achieve satisfied comprehensive sodium storage performances. Under these circumstances, exploiting novel multiphase cathodes showing synergetic effect may give solution to these problems. In this review, we summarize the recent development of multiphase layered transition metal oxide cathodes of SIBs, analyze the mechanism and prospect the future potential research directions.