One-step synthesis of novel core-shell bimetallic hexacyanoferrate for high performance sodium-storage cathode  

作　　者：Daxian Zuo Cuiping Wang Jiajia Han Qinghao Han Yanan Hu Junwei Wu Huajun Qiu Qian Zhang Xingjun Liu 

机构地区：[1]College of Materials and Fujian Key Laboratory of Materials Genome and Xiamen Key Laboratory of High Performance Metals and Materials,Xiamen University,Xiamen 361005,China [2]Institute of Materials Genome and Big Data,Harbin Institute of Technology,Shenzhen 518055,China [3]State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Shenzhen 518055,China

出　　处：《Journal of Materials Science & Technology》2022年第19期180-190,共11页材料科学技术（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.51771158 and 11975191);the Guangdong Natural Science Foundation(No.2018A030313721);the Shenzhen International Collaboration Project(No.GJHZ20180928155621530).

摘　　要：Recently, the design of core-shell hierarchical architecture plays an important role in improving the electrochemical performance of Prussian blue analogue cathodes(PBAs). Unfortunately, the inconvenient stepwise preparation and the strict lattice-matching requirement have restricted the development of coreshell PBAs. Herein, we demonstrate a one-step synthesis strategy to synthesize core-shell manganese hexacyanoferrate(MnFeHCF@MnFeHCF) for the first time. And the formation mechanism of the core-shell hierarchical architecture is investigated by first-principles calculations. It is found that the as-obtained Mn FeHCF@MnFeHCF act out the superior intrinsic natures, which not only can obtain a larger specific surface area and lower Fe(CN)_(6) vacancies but also can activate more Na-storage sites. Compared with the manganese hexacyanoferrate(MnHCF), the iron hexacyanoferrate(FeHCF), and even the traditional coreshell nickel hexacyanoferrate(FeHCF@NiHCF) prepared by a stepwise method, the Mn Fe HCF@MnFeHCF demonstrates a superior rate performance, which achieves a high capacity of 131 mAh g^(−1) at 50 mA g^(−1) and delivers a considerable discharge capacity of about 100 mAh g^(−1) even at 1600 mA g^(−1). Meantime, the capacity retention can reach up to nearly 80% after 500 cycles. The improved performances could be mainly originated from two aspects: on the one hand, Mn substitution is helpful to enhance the material conductivity;on the other hand, the core-shell structure with matched lattice parameters is more favorable to enhance the diffusion coefficient of sodium ions. Beside, the structural transformation of MnFeHCF@MnFeHCF upon the extraction/insertion of sodium ions is instrumental in releasing the interior stress and effectively maintaining the integrity of the crystal structure.

关 键 词：CATHODE Prussian blue analogue Core-shell structure First-principles calculations Electrochemical performance 

分 类 号：TM912[电气工程—电力电子与电力传动] TB30[一般工业技术—材料科学与工程]