Defects, Entropy, and the Stabilization of Alternative Phase Boundary Orientations in Battery Electrode Particles
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Materials Science Division
- Rice Univ., Houston, TX (United States). Department of Materials Science and NanoEngineering
- Pennsylvania State Univ., University Park, PA (United States). Dept. of Material Sciences and Engineering
Using a novel statistical approach that efficiently explores the space of possible defect configurations, our present study investigates the chemomechanical coupling between interfacial structural defects and phase boundary alignments within phase-separating electrode particles. Applied to the battery cathode material LiXFePO4 as an example, the theoretical analysis reveals that small, defect-induced deviations from an ideal interface can lead to dramatic shifts in the orientations of phase boundaries between Li-rich and Li-lean phases, stabilizing otherwise unfavorable orientations. Significantly, this stabilization arises predominantly from configurational entropic factors associated with the presence of the interfacial defects rather than from absolute energetic considerations. The specific entropic factors pertain to the diversity of defect configurations and their contributions to rotational/orientational rigidity of phase boundaries. Comparison of the predictions with experimental observations indicates that the additional entropy contributions indeed play a dominant role under actual cycling conditions, leading to the conclusion that interfacial defects must be considered when analyzing the stability and evolution kinetics of the internal phase microstructure of strongly phase-separating systems. Possible implications for tuning the kinetics of (de)lithiation based on selective defect incorporation are discussed. Ultimately, this understanding can be generalized to the chemomechanics of other defective solid phase boundaries.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC52-07NA27344; SC0002626; LLNL-SR-648484; CMMI-1235092
- OSTI ID:
- 1262185
- Report Number(s):
- LLNL-JRNL-673242
- Journal Information:
- Advanced Energy Materials, Vol. 6, Issue 6; ISSN 1614-6832
- Publisher:
- WileyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Three-dimensional phase evolution and stress-induced non-uniform Li intercalation behavior in lithium iron phosphate
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journal | January 2020 |
Two-dimensional lithium diffusion behavior and probable hybrid phase transformation kinetics in olivine lithium iron phosphate
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journal | October 2017 |
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