In situ Measurement of Biaxial Modulus of Si Anode for Li-ion Batteries

Abstract

We report in situ measurement of biaxial moduli of a Si thin-film electrode as a function of its lithium concentration. During lithiation, biaxial compressive stress is induced in the Si film and it undergoes plastic flow. At any state-of-charge (SOC), a relatively small delithiation-relithiation sequence unloads and reloads the film elastically. From the stress and strain changes during a delithiation-relithiation cycle, the biaxial modulus of the film is calculated. Stress change is obtained by measuring the change in substrate curvature using a Multi-beam Optical Sensor; the elastic strain change is obtained from the change in SOC. By repeating these measurements at several different values of SOC, the biaxial modulus was seen to decrease from ca. 70 GPa for Li0.32Si to ca. 35 GPa for Li3.0Si. Such a significant reduction in elastic modulus has important implications for modeling stress evolution and mechanical degradation in Si-based anodes.

arXiv comment8 pages, 3 figures

References in corpus (2)

• In Situ Measurements of Stress Evolution in Silicon Thin Films During Electrochemical Lithiation and Delithiation
• Increased Cycling Efficiency and Rate Capability of Copper-coated Silicon Anodes in Lithium-ion Batteries

Cited by in corpus (9)

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• Real-Time Stress Measurements in Lithium-ion Battery Negative-electrodes
• Measurement and modeling of the mechanical and electrochemical response of amorphous Si thin film electrodes during cyclic lithiation
• Quantifying Capacity Loss due to Solid-Electrolyte-Interphase Layer Formation on Silicon Negative Electrodes in Lithium-ion Batteries
• Analysis of Lithiation and Delithiation Kinetics in Silicon
• On plastic deformation and fracture in Si films during electrochemical lithiation/delithiation cycling
• Real-time Stress Measurements in Germanium Thin Film Electrodes during Electrochemical Lithiation/delithiation Cycling
• Faster Lead-Acid Battery Simulations from Porous-Electrode Theory: I. Physical Model