Suppressing vacancies and crystal water of sodium manganese iron-based Prussian blue analogue by potassium doping for advanced sodium-ion batteries

• Published in: Chemical engineering science Vol. 302; p. 120848
• Main Authors: Xu, Lin, Liu, Yan, Chen, Ming, Wu, Wenwei, Qiu, Shiming, Wu, Hongli, Zheng, Meiqi, Zhang, Xinguang, Wu, Xuehang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 05.02.2025
• Subjects: Cathode materials; Potassium doping; Prussian blue analogue; Sodium-ion batteries; Sodium-manganese hexacyanoferrate; Potassium doping; Cathode materials; Sodium-ion batteries; Sodium-manganese hexacyanoferrate; Prussian blue analogue
• ISSN: 0009-2509
• DOI: 10.1016/j.ces.2024.120848

[Display omitted] •Prussian blue analogue NaKMHCF is synthesized by a modified co-precipitation method.•K+ doping plays a role in suppressing vacancies and crystal water.•NaKMHCF can provide the excellent cycling performance and rate capability. Sodium manganese iron-based Prussian blue analogue (MnFe-PBAs) is regarded as potential cathode material for sodium-ion batteries due to its simple synthesis process, low production cost, and high theoretical capacity. Unfortunately, electrochemical performances of MnFe-PBAs are inevitably hindered owing to the crystal vacancies and crystal water produced from aqueous co-precipitation process. Herein, highly crystallized cubic potassium-doped sodium manganese iron-based Prussian blue analogue is synthesized by a modified co-precipitation method. By introducing a larger ionic radius potassium (K) to substitute the part of Na in the MnFe-PBAs, a coexistence composite of sodium and potassium phases is obtained with less crystal water and fewer vacancies compared with pure sodium phase compound, resulting that potassium-doped sodium manganese iron-based Prussian blue analogue (Na1.08K0.74Mn[Fe(CN)6]0.86⋅□0.14⋅1·.86H2O, NaKMHCF) can deliver high discharge specific capacity (129.3 mAh/g at 10 mA g−1), excellent rate performance (82.3 mAh/g at 1500 mA g−1) as well as high cycling stability (77.0 % capacity retention at 500 mA g−1 after the 500th cycle). Besides, the full cell, based on NaKMHCF as cathode material and sodium titanium phosphate (NTP) as anode material, confirms its potential as high-performance cathode material for SIBs.