Determining the Phase Diagram of Li_xFePO_4
- Creators
- Dodd, J. L.
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Yazami, R.
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Fultz, B.
Abstract
The phase diagram for Li_xFePO_4 has been determined for different lithium concentrations and temperatures. X-ray diffraction analysis was used to determine phase fractions at temperatures between room temperature and 400 °C for Li_xFePO_4 at different states of lithiation. The two low- temperature phases, heterosite and triphylite, have previously been shown to transform to a disordered solid solution at elevated temperatures. This disordered phase allows for a continuous transition between the heterosite and triphylite phases and is stable at relatively low temperatures. At intermediate temperatures the proposed phase diagram resembles a eutectoid system, with eutectoid point at around x=0.6 and 200 °C. Kinetics of mixing and unmixing transformations are reported, including the hysteresis between heating and cooling. The enthalpy of this transition is at least 700 J/mol.
Additional Information
© 2006 ECS - The Electrochemical Society. The content of this paper has been published in the journal Electrochemical and Solid State Letters, Volume 9, Number 3, as "Phase Diagram of Li_xFePO_4." The authors thank Dr. Khalil Amine, Dr. Ilias Belharouak and Argonne National Laboratory for providing the LiFePO_4 material. This work was supported by the U.S. Dept. of Energy under grant DE-FG03-00ER15035.Additional details
- Alternative title
- Determining the Phase Diagram of LixFePO4
- Eprint ID
- 89620
- Resolver ID
- CaltechAUTHORS:20180913-133203503
- DE-FG03-00ER15035
- Department of Energy (DOE)
- Created
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2018-09-14Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field