Sodium uptake in cell construction and subsequent in operando electrode behaviour of Prussian blue analogues, Fe[Fe(CN)6]1−x·yH2O and FeCo(CN)6
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Date
2014-07-23
Journal Title
Journal ISSN
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Publisher
Royal Society of Chemistry
Abstract
The development of electrodes for ambient temperature sodium-ion batteries requires the study of new materials and the understanding of how crystal structure influences properties. In this study, we investigate where sodium locates in two Prussian blue analogues, Fe[Fe(CN)6]1-x·yH2O and FeCo(CN)6. The evolution of the sodium site occupancies, lattice and volume is shown during charge-discharge using in situ synchrotron X-ray powder diffraction data. Sodium insertion is found to occur in these electrodes during cell construction and therefore Fe[Fe(CN)6]1-x·yH2O and FeCo(CN)6 can be used as positive electrodes. NazFeFe(CN)6 electrodes feature higher reversible capacities relative to NazFeCo(CN)6 electrodes which can be associated with a combination of structural factors, for example, a major sodium-containing phase, ∼Na0.5FeFe(CN)6 with sodium locating either at the x = y = z = 0.25 or x = y = 0.25 and z = 0.227(11) sites and an electrochemically inactive sodium-free Fe[Fe(CN)6]1-x·yH2O phase. This study demonstrates that key questions about electrode performance and attributes in sodium-ion batteries can be addressed using time-resolved in situ synchrotron X-ray diffraction studies. © 2014 Royal Society of Chemistry Open Access CC Licence
Description
Keywords
Ions, Battery charge state, Crystal structure, Ferrocyanides, Sodium, Crystal lattices, Electrodes, Electrochemical cells, X-ray diffraction
Citation
Pramudita, J. C., Schmid, S., Godfrey, T., Whittle, T., Alam, M., Hanley, T.,Brand, H. E. A., & Sharma, N. (2014). Sodium uptake in cell construction and subsequent in operando electrode behaviour of Prussian blue analogues, Fe [Fe (CN) 6] 1− x· y H 2 O and FeCo (CN) 6. Physical Chemistry Chemical Physics, 16(44), 24178-24187. doi:10.1039/c4cp02676d