Reversible structural evolution of sodium-rich rhombohedral Prussian blue for sodium-ion batteries

• Published in: Nature communications Vol. 11; no. 1; pp. 980 - 9
• Main Authors: Wang, Wanlin, Gang, Yong, Hu, Zhe, Yan, Zichao, Li, Weijie, Li, Yongcheng, Gu, Qin-Fen, Wang, Zhixing, Chou, Shu-Lei, Liu, Hua-Kun, Dou, Shi-Xue
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 20.02.2020; Nature Publishing Group; Nature Portfolio
• Subjects: 639/638/161; 639/638/298; 639/638/675; Cathodes; Chemical precipitation; Cycles; Electrochemical analysis; Electrochemistry; Electrode materials; Evolution; Humanities and Social Sciences; Ion storage; multidisciplinary; Nucleation; Phase transitions; Pigments; Rechargeable batteries; Science; Science (multidisciplinary); Sodium; Sodium-ion batteries; X ray powder diffraction; X-ray diffraction
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-14444-4

Iron-based Prussian blue analogs are promising low-cost and easily prepared cathode materials for sodium-ion batteries. Their materials quality and electrochemical performance are heavily reliant on the precipitation process. Here we report a controllable precipitation method to synthesize high-performance Prussian blue for sodium-ion storage. Characterization of the nucleation and evolution processes of the highly crystalline Prussian blue microcubes reveals a rhombohedral structure that exhibits high initial Coulombic efficiency, excellent rate performance, and cycling properties. The phase transitions in the as-obtained material are investigated by synchrotron in situ powder X-ray diffraction, which shows highly reversible structural transformations between rhombohedral, cubic, and tetragonal structures upon sodium-ion (de)intercalations. Moreover, the Prussian blue material from a large-scale synthesis process shows stable cycling performance in a pouch full cell over 1000 times. We believe that this work could pave the way for the real application of Prussian blue materials in sodium-ion batteries. Here the authors deploy a scalable synthesis route to prepare sodium-rich Na 2− x FeFe(CN) 6 cathode materials for sodium-ion battery. The highly reversible structural evolution during cycling between rhombohedral, cubic and tetragonal phases is the key to enable the good performance.