In Situ Measurements of Stress-Potential Coupling in Lithiated Silicon

Abstract

An analysis of the dependence of electric potential on the state of stress of a lithiated-silicon electrode is presented. Based on the Larché and Cahn chemical potential for a solid solution, a thermodynamic argument is made for the existence of the stress-potential coupling in lithiated-silicon; based on the known properties of the material, the magnitude of the coupling is estimated to be ca. 60 mV/GPa in thin-film geometry. An experimental investigation is carried out on silicon thin-film electrodes in which the stress is measured in situ during electrochemical lithiation and delithiation. By progressively varying the stress through incremental delithiation, the relation between stress change and electric-potential change is measured to be 100 - 120 mV/GPa, which is of the same order of magnitude as the prediction of the analysis. The importance of the coupling is discussed in interpreting the hysteresis observed in potential vs. state-of-charge plots, and the role of stress in modifying the maximum charge capacity of a silicon electrode under stress.

21 pages, 5 figures

References in corpus (3)

• In Situ Measurements of Stress Evolution in Silicon Thin Films During Electrochemical Lithiation and Delithiation
• Surface Structural Disordering in Graphite upon Lithium Intercalation/Deintercalation
• Increased Cycling Efficiency and Rate Capability of Copper-coated Silicon Anodes in Lithium-ion Batteries

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• Voltage Hysteresis of Silicon Nanoparticles: Chemo-Mechanical Particle-SEI Model
• Measurement of Volume Changes and Associated Stresses in Ge Electrodes Due to Na/Na${}^{+}$ Redox Reactions
• Experimental calibration of a Cahn-Hilliard phase-field model for phase transformations in Li-Sn electrodes