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Modeling of LiFePO4 Charging/Discharging Dynamics Based on the Many-Unit Concept: Validation Against Operando XRD Data
Modeling of LiFePO4 Charging/Discharging Dynamics Based on the Many-Unit Concept: Validation Against Operando XRD Data
Monday, October 12, 2015: 15:15
101-B (Phoenix Convention Center)
LiFePO4 (LFP) was proposed as a battery material over 15 years ago and has been implemented in commercial cells for about 10 years now. In spite of its maturity, LFP is still the subject of intensive research, particularly related to the phase-separating nature of the material. A number of interesting and unusual experimental features of the LFP system have been reported in the literature, including the zero-current potential hysteresis,1 rate-dependent lithiation/delithiation mechanism,2 cycle-path dependence3 and the memory effect.4 All of these observations were successfully predicted using a simple mesoscopic model that we recently published and that relies on a many-unit approach.5 In this presentation, we demonstrate an extended mesoscopic model for phase-change materials and its validation by simulating operando X-ray diffraction results recently reported in the literature.6,7 This validation step helps refine the physical representation of the electrode because it simultaneously accounts for phase dynamics as revealed by the XRD data and the electrochemical features of LFP. This work paves the way towards a mathematical model that unifies all the experimental observations reported for this material over the years.
References:
1. W. Dreyer, J. Jamnik, C. Guhlke, R. Huth, J. Moskon and M. Gaberscek, Nature Mater., 2010, 9, 448–453.
2. R. Malik, A. Abdellahi and G. Ceder, J. Electrochem. Soc., 2013, 160, A3179–A3197.
3. V. Srinivasan and J. Newman, Electrochem. Solid State Lett., 2006, 9, A110–A114.
4. T. Sasaki, Y. Ukyo and P. Novak, Nature Mater., 2013, 12, 569–575.
5. M. Farkhondeh, M. Pritzker, M. Fowler, M. Safari, and C. Delacourt, Phys. Chem. Chem. Phys., 2014, 16, 22555.
6. H. Liu, F. C. Strobridge, O. J. Borkiewicz, K. M. Wiaderek, K. W. Chapman, P. J. Chupas, C. P. Grey, Science, 2014, 344, 1480.
7. X. Zhang, M. van Hulzen, D. P. Singh, A. Brownrigg, J. P. Wright, N. H. van Dijk, and M. Wagemaker, NanoLett., 2014, 14, 2279.