Recently,the design of core-shell hierarchical architecture plays an important role in improving the elec-trochemical performance of Prussian blue analogue cathodes(PBAs).Unfortunately,the inconvenient step-wise preparation and the strict lattice-matching requirement have restricted the development of core-shell 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 MnFeHCF@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 core-shell nickel hexacyanoferrate(FeHCF@NiHCF)prepared by a stepwise method,the MnFeHCF@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.Mean-time,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 transforma-tion 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.

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

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;Institute of Materials Genome and Big Data,Harbin Institute of Technology,Shenzhen 518055,China;State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Shenzhen 518055,China

材料科学技术（英文版）

[1]Daxian Zuo;Cuiping Wang;Jiajia Han;Qinghao Han;Yanan Hu;Junwei Wu;Huajun Qiu;Qian Zhang;Xingjun Liu-.One-step synthesis of novel core-shell bimetallic hexacyanoferrate for high performance sodium-storage cathode)[J].材料科学技术（英文版）,2022(19):180-190

MnFeHCF,MnHCF,NiHCF

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