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Jian Yu Huang - One of the best experts on this subject based on the ideXlab platform.
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in situ transmission electron microscopy observation of pulverization of aluminum nanowires and evolution of the thin surface al2o3 layers during lithiation Delithiation cycles
Nano Letters, 2011Co-Authors: Nicholas S Hudak, Dale L Huber, Steven J Limmer, John P Sullivan, Jian Yu HuangAbstract:Lithiation–Delithiation cycles of individual aluminum nanowires (NWs) with naturally oxidized Al2O3 surface layers (thickness 4–5 nm) were conducted in situ in a transmission electron microscope. Surprisingly, the lithiation was always initiated from the surface Al2O3 layer, forming a stable Li–Al–O glass tube with a thickness of about 6–10 nm wrapping around the NW core. After lithiation of the surface Al2O3 layer, lithiation of the inner Al core took place, which converted the single crystal Al to a polycrystalline LiAl alloy, with a volume expansion of about 100%. The Li–Al–O glass tube survived the 100% volume expansion, by enlarging through elastic and plastic deformation, acting as a solid electrolyte with exceptional mechanical robustness and ion conduction. Voids were formed in the Al NWs during the initial Delithiation step and grew continuously with each subsequent Delithiation, leading to pulverization of the Al NWs to isolated nanoparticles confined inside the Li–Al–O tube. There was a corresp...
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in situ transmission electron microscopy observation of pulverization of aluminum nanowires and evolution of the thin surface al2o3 layers during lithiation Delithiation cycles
Nano Letters, 2011Co-Authors: Yang Liu, Nicholas S Hudak, Dale L Huber, Steven J Limmer, John P Sullivan, Jian Yu HuangAbstract:Lithiation-Delithiation cycles of individual aluminum nanowires (NWs) with naturally oxidized Al(2)O(3) surface layers (thickness 4-5 nm) were conducted in situ in a transmission electron microscope. Surprisingly, the lithiation was always initiated from the surface Al(2)O(3) layer, forming a stable Li-Al-O glass tube with a thickness of about 6-10 nm wrapping around the NW core. After lithiation of the surface Al(2)O(3) layer, lithiation of the inner Al core took place, which converted the single crystal Al to a polycrystalline LiAl alloy, with a volume expansion of about 100%. The Li-Al-O glass tube survived the 100% volume expansion, by enlarging through elastic and plastic deformation, acting as a solid electrolyte with exceptional mechanical robustness and ion conduction. Voids were formed in the Al NWs during the initial Delithiation step and grew continuously with each subsequent Delithiation, leading to pulverization of the Al NWs to isolated nanoparticles confined inside the Li-Al-O tube. There was a corresponding loss of capacity with each Delithiation step when arrays of NWs were galvonostatically cycled. The results provide important insight into the degradation mechanism of lithium-alloy electrodes and into recent reports about the performance improvement of lithium ion batteries by atomic layer deposition of Al(2)O(3) onto the active materials or electrodes.
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reversible nanopore formation in ge nanowires during lithiation Delithiation cycling an in situ transmission electron microscopy study
Nano Letters, 2011Co-Authors: Shan Huang, Tom S Picraux, Ju Li, Jian Yu HuangAbstract:Retaining the high energy density of rechargeable lithium ion batteries depends critically on the cycle stability of microstructures in electrode materials. We report the reversible formation of nanoporosity in individual germanium nanowires during lithiation–Delithiation cycling by in situ transmission electron microscopy. Upon lithium insertion, the initial crystalline Ge underwent a two-step phase transformation process: forming the intermediate amorphous LixGe and final crystalline Li15Ge4 phases. Nanopores developed only during Delithiation, involving the aggregation of vacancies produced by lithium extraction, similar to the formation of porous metals in dealloying. A Delithiation front was observed to separate a dense nanowire segment of crystalline Li15Ge4 with a porous spongelike segment composed of interconnected ligaments of amorphous Ge. This front sweeps along the wire with a logarithmic time law. Intriguingly, the porous nanowires exhibited fast lithiation/Delithiation rates and excellent me...
Pradeep R Guduru - One of the best experts on this subject based on the ideXlab platform.
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stress evolution in composite silicon electrodes during lithiation Delithiation
arXiv: Materials Science, 2013Co-Authors: Vijay A Sethuraman, Michael J Chon, Annam Nguyen, Siva P. V. Nadimpalli, Hailong Wang, Daniel P. Abraham, Allan F. Bower, Vivek B. Shenoy, Pradeep R GuduruAbstract:We report real-time average stress measurements on composite silicon electrodes made with two different binders [Carboxymethyl cellulose (CMC), and polyvinylidene fluoride (PVDF)] during electrochemical lithiation and Delithiation. During galvanostatic lithiation at very slow rates, the stress in a CMC-based electrode becomes compressive and increases to 70 MPa, where it reaches a plateau and increases slowly thereafter with capacity. The PVDF-based electrode exhibits similar behavior, although with lower peak compressive stress of about 12 MPa. These initial experiments indicate that the stress evolution in a Si composite electrode depends strongly on the mechanical properties of the binder. Stress data obtained from a series of lithiation/Delithiation cycles suggests plasticity induced irreversible shape changes in contacting Si particles, and as a result, the stress response of the system during any given lithiation/Delithiation cycle depends on the cycling history of the electrode. While these results constitute the first in-situ stress measurements on composite Si electrodes during electrochemical cycling, the diagnostic technique described herein can be used to assess the mechanical response of a composite electrode made with other active material/binder combinations.
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Stress Evolution in Composite Silicon Electrodes during Lithiation/Delithiation
Journal of The Electrochemical Society, 2013Co-Authors: Vijay A Sethuraman, Michael J Chon, Annam Nguyen, Siva P. V. Nadimpalli, Hailong Wang, Daniel P. Abraham, Allan F. Bower, Vivek B. Shenoy, Pradeep R GuduruAbstract:We report real-time average stress measurements on composite silicon electrodes made with two different binders [Carboxymethyl cellulose (CMC), and polyvinylidene fluoride (PVDF)] during electrochemical lithiation and Delithiation. During galvanostatic lithiation at very slow rates, the stress in a CMC-based electrode becomes compressive and increases to 70 MPa, where it reaches a plateau and increases slowly thereafter with capacity. The PVDF-based electrode exhibits similar behavior, although with lower peak compressive stress of about 12 MPa. These initial experiments indicate that the stress evolution in a Si composite electrode depends strongly on the mechanical properties of the binder. Stress data obtained from a series of lithiation/Delithiation cycles suggests plasticity induced irreversible shape changes in contacting Si particles, and as a result, the stress response of the system during any given lithiation/Delithiation cycle depends on the cycling history of the electrode. While these results constitute the first in-situ stress measurements on composite Si electrodes during electrochemical cycling, the diagnostic technique described herein can be used to assess the mechanical response of a composite electrode made with other active material/binder combinations.
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real time measurement of stress and damage evolution during initial lithiation of crystalline silicon
Physical Review Letters, 2011Co-Authors: Michael J Chon, Vijay A Sethuraman, Venkat Srinivasan, Anthony Mccormick, Pradeep R GuduruAbstract:Crystalline to amorphous phase transformation during initial lithiation in (100) Si wafers is studied in an electrochemical cell with Limetalas thecounter andreferenceelectrode.During initiallithiation,amoving phase boundary advances into thewafer starting from the surface facing the lithium electrode, transforming crystalline Si into amorphous LixSi. The resulting biaxial compressive stress in the amorphous layer is measured in situ, and it was observed to be ca. 0.5 GPa. High-resolution TEM images reveal a very sharp crystalline-amorphous phase boundary, with a thickness of � 1n m. Upon Delithiation, the stress rapidly reverses andbecomes tensile,and the amorphous layer begins to deform plastically ataround 0.5 GPa.With continued Delithiation, the yield stress increases in magnitude, culminating in a sudden fracture of the amorphous layer into microfragments, and the cracks extend into the underlying crystalline Si.
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in situ measurement of biaxial modulus of si anode for li ion batteries
Electrochemistry Communications, 2010Co-Authors: Vijay A Sethuraman, N Van Winkle, Michael J Chon, Maxwell Shimshak, Pradeep R GuduruAbstract: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 Li 0.32 Si to ca. 35 GPa for Li 3.0 Si. Such a significant reduction in elastic modulus has important implications for modeling stress evolution and mechanical degradation in Si-based anodes.
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in situ measurements of stress evolution in silicon thin films during electrochemical lithiation and Delithiation
Journal of Power Sources, 2010Co-Authors: Vijay A Sethuraman, Michael J Chon, Maxwell Shimshak, Venkat Srinivasan, Pradeep R GuduruAbstract:We report in situ measurements of stress evolution in a silicon thin-film electrode during electrochemical lithiation and Delithiation by using the multi-beam optical sensor (MOS) technique. Upon lithiation, due to substrate constraint, the silicon electrode initially undergoes elastic deformation, resulting in rapid rise of compressive stress. The electrode begins to deform plastically at a compressive stress of ca. −1.75 GPa; subsequent lithiation results in continued plastic strain, dissipating mechanical energy. Upon Delithiation, the electrode first undergoes elastic straining in the opposite direction, leading to a tensile stress of ca. 1 GPa; subsequently, it deforms plastically during the rest of Delithiation. The plastic flow stress evolves continuously with lithium concentration. Thus, mechanical energy is dissipated in plastic deformation during both lithiation and Delithiation, and it can be calculated from the stress measurements; we show that it is comparable to the polarization loss. Upon current interruption, both the film stress and the electrode potential relax with similar time constants, suggesting that stress contributes significantly to the chemical potential of lithiated silicon.
Vijay A Sethuraman - One of the best experts on this subject based on the ideXlab platform.
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stress evolution in composite silicon electrodes during lithiation Delithiation
arXiv: Materials Science, 2013Co-Authors: Vijay A Sethuraman, Michael J Chon, Annam Nguyen, Siva P. V. Nadimpalli, Hailong Wang, Daniel P. Abraham, Allan F. Bower, Vivek B. Shenoy, Pradeep R GuduruAbstract:We report real-time average stress measurements on composite silicon electrodes made with two different binders [Carboxymethyl cellulose (CMC), and polyvinylidene fluoride (PVDF)] during electrochemical lithiation and Delithiation. During galvanostatic lithiation at very slow rates, the stress in a CMC-based electrode becomes compressive and increases to 70 MPa, where it reaches a plateau and increases slowly thereafter with capacity. The PVDF-based electrode exhibits similar behavior, although with lower peak compressive stress of about 12 MPa. These initial experiments indicate that the stress evolution in a Si composite electrode depends strongly on the mechanical properties of the binder. Stress data obtained from a series of lithiation/Delithiation cycles suggests plasticity induced irreversible shape changes in contacting Si particles, and as a result, the stress response of the system during any given lithiation/Delithiation cycle depends on the cycling history of the electrode. While these results constitute the first in-situ stress measurements on composite Si electrodes during electrochemical cycling, the diagnostic technique described herein can be used to assess the mechanical response of a composite electrode made with other active material/binder combinations.
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Stress Evolution in Composite Silicon Electrodes during Lithiation/Delithiation
Journal of The Electrochemical Society, 2013Co-Authors: Vijay A Sethuraman, Michael J Chon, Annam Nguyen, Siva P. V. Nadimpalli, Hailong Wang, Daniel P. Abraham, Allan F. Bower, Vivek B. Shenoy, Pradeep R GuduruAbstract:We report real-time average stress measurements on composite silicon electrodes made with two different binders [Carboxymethyl cellulose (CMC), and polyvinylidene fluoride (PVDF)] during electrochemical lithiation and Delithiation. During galvanostatic lithiation at very slow rates, the stress in a CMC-based electrode becomes compressive and increases to 70 MPa, where it reaches a plateau and increases slowly thereafter with capacity. The PVDF-based electrode exhibits similar behavior, although with lower peak compressive stress of about 12 MPa. These initial experiments indicate that the stress evolution in a Si composite electrode depends strongly on the mechanical properties of the binder. Stress data obtained from a series of lithiation/Delithiation cycles suggests plasticity induced irreversible shape changes in contacting Si particles, and as a result, the stress response of the system during any given lithiation/Delithiation cycle depends on the cycling history of the electrode. While these results constitute the first in-situ stress measurements on composite Si electrodes during electrochemical cycling, the diagnostic technique described herein can be used to assess the mechanical response of a composite electrode made with other active material/binder combinations.
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analysis of electrochemical lithiation and Delithiation kinetics in silicon
Journal of The Electrochemical Society, 2013Co-Authors: Vijay A Sethuraman, Venkat Srinivasan, John NewmanAbstract:Analysis of lithiation and Delithiation kinetics in pulse-laser-deposited crystalline thin-film silicon (Si) electrodes is presented. Data from open-circuit relaxation experiments are used in conjunction with a model based on Tafel kinetics and double-layer capacitance to estimate the apparent transfer coefficients (αa, αc) and exchange current density to capacitance ratio (i0/Cdl )f or lithiation and Delithiation reactions in a lithiated silicon (LixSi) system. Parameters estimated from data sets obtained during firstcycle amorphization of crystalline Si, as well as from cycled crystalline Si and amorphous Si thin-film electrodes do not show much variation, indicating that they are intrinsic to lithiation/Delithiation in Si. A methodology to estimate the side-reaction rate on a well-cycled electrode and its role in the evolution of the open-circuit potential of the LixSi system are discussed. We conclude that the large potential offset between lithiation and Delithiation reactions at any given state of charge is partially caused by a large kinetic resistance (i.e., small i0). Using the estimated parameters, the model is shown to predict successfully the behavior of the system under galvanostatic lithiation and Delithiation.
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analysis of lithiation and Delithiation kinetics in silicon
arXiv: Materials Science, 2012Co-Authors: Vijay A Sethuraman, Venkat Srinivasan, John W NewmanAbstract:Analysis of lithiation and Delithiation kinetics in pulse-laser-deposited crystalline thin-film silicon (Si) electrodes is presented. Data from open-circuit relaxation experiments are used in conjunction with a model based on Tafel kinetics and double-layer capacitance to estimate the apparent transfer coefficients ({\alpha}a, {\alpha}c), and exchange current density to capacitance ratio (i0/Cdl) for lithiation and Delithiation reactions in a lithiated silicon (LixSi) system. Parameters estimated from data sets obtained during first-cycle amorphization of crystalline Si, as well as from cycled crystalline Si and amorphous Si thin-film electrodes do not show much variation, indicating that they are intrinsic to lithiation/Delithiation in Si. A methodology to estimate the side-reaction rate and its role in the evolution of the open-circuit potential of the LixSi system are discussed. We conclude that the large potential offset between lithiation and Delithiation reactions at any given state of charge is partially caused by a large kinetic resistance (i.e., small i0). Using the estimated parameters, the model is shown to predict successfully the behavior of the system under galvanostatic lithiation and Delithiation.
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real time measurement of stress and damage evolution during initial lithiation of crystalline silicon
Physical Review Letters, 2011Co-Authors: Michael J Chon, Vijay A Sethuraman, Venkat Srinivasan, Anthony Mccormick, Pradeep R GuduruAbstract:Crystalline to amorphous phase transformation during initial lithiation in (100) Si wafers is studied in an electrochemical cell with Limetalas thecounter andreferenceelectrode.During initiallithiation,amoving phase boundary advances into thewafer starting from the surface facing the lithium electrode, transforming crystalline Si into amorphous LixSi. The resulting biaxial compressive stress in the amorphous layer is measured in situ, and it was observed to be ca. 0.5 GPa. High-resolution TEM images reveal a very sharp crystalline-amorphous phase boundary, with a thickness of � 1n m. Upon Delithiation, the stress rapidly reverses andbecomes tensile,and the amorphous layer begins to deform plastically ataround 0.5 GPa.With continued Delithiation, the yield stress increases in magnitude, culminating in a sudden fracture of the amorphous layer into microfragments, and the cracks extend into the underlying crystalline Si.
Man On Lai - One of the best experts on this subject based on the ideXlab platform.
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nanoporous mnox thin film electrodes synthesized by electrochemical lithiation Delithiation for supercapacitors
Journal of Power Sources, 2011Co-Authors: Hui Xia, Man On LaiAbstract:Abstract Nanoporous MnO x thin-film electrodes are synthesized using a combination of pulsed laser deposition (PLD) and electrochemical lithiation/Delithiation methods. A dense Mn 3 O 4 thin-film deposited by PLD can transform into a nanoporous MnO x thin-film after electrochemical lithiation/Delithiation. A nanoporous MnO x thin-film electrode exhibits significantly improved supercapacitive performance compared with an as-deposited Mn 3 O 4 thin-film electrode. A MnO x thin-film finally transforms into a MnO 2 thin-film through an electrochemical oxidation process during continuous cyclic voltammetry scanning.
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Nanoporous MnOx thin-film electrodes synthesized by electrochemical lithiation/Delithiation for supercapacitors
Journal of Power Sources, 2011Co-Authors: Hui Xia, Man On LaiAbstract:Abstract Nanoporous MnO x thin-film electrodes are synthesized using a combination of pulsed laser deposition (PLD) and electrochemical lithiation/Delithiation methods. A dense Mn 3 O 4 thin-film deposited by PLD can transform into a nanoporous MnO x thin-film after electrochemical lithiation/Delithiation. A nanoporous MnO x thin-film electrode exhibits significantly improved supercapacitive performance compared with an as-deposited Mn 3 O 4 thin-film electrode. A MnO x thin-film finally transforms into a MnO 2 thin-film through an electrochemical oxidation process during continuous cyclic voltammetry scanning.
Michael J Chon - One of the best experts on this subject based on the ideXlab platform.
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stress evolution in composite silicon electrodes during lithiation Delithiation
arXiv: Materials Science, 2013Co-Authors: Vijay A Sethuraman, Michael J Chon, Annam Nguyen, Siva P. V. Nadimpalli, Hailong Wang, Daniel P. Abraham, Allan F. Bower, Vivek B. Shenoy, Pradeep R GuduruAbstract:We report real-time average stress measurements on composite silicon electrodes made with two different binders [Carboxymethyl cellulose (CMC), and polyvinylidene fluoride (PVDF)] during electrochemical lithiation and Delithiation. During galvanostatic lithiation at very slow rates, the stress in a CMC-based electrode becomes compressive and increases to 70 MPa, where it reaches a plateau and increases slowly thereafter with capacity. The PVDF-based electrode exhibits similar behavior, although with lower peak compressive stress of about 12 MPa. These initial experiments indicate that the stress evolution in a Si composite electrode depends strongly on the mechanical properties of the binder. Stress data obtained from a series of lithiation/Delithiation cycles suggests plasticity induced irreversible shape changes in contacting Si particles, and as a result, the stress response of the system during any given lithiation/Delithiation cycle depends on the cycling history of the electrode. While these results constitute the first in-situ stress measurements on composite Si electrodes during electrochemical cycling, the diagnostic technique described herein can be used to assess the mechanical response of a composite electrode made with other active material/binder combinations.
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Stress Evolution in Composite Silicon Electrodes during Lithiation/Delithiation
Journal of The Electrochemical Society, 2013Co-Authors: Vijay A Sethuraman, Michael J Chon, Annam Nguyen, Siva P. V. Nadimpalli, Hailong Wang, Daniel P. Abraham, Allan F. Bower, Vivek B. Shenoy, Pradeep R GuduruAbstract:We report real-time average stress measurements on composite silicon electrodes made with two different binders [Carboxymethyl cellulose (CMC), and polyvinylidene fluoride (PVDF)] during electrochemical lithiation and Delithiation. During galvanostatic lithiation at very slow rates, the stress in a CMC-based electrode becomes compressive and increases to 70 MPa, where it reaches a plateau and increases slowly thereafter with capacity. The PVDF-based electrode exhibits similar behavior, although with lower peak compressive stress of about 12 MPa. These initial experiments indicate that the stress evolution in a Si composite electrode depends strongly on the mechanical properties of the binder. Stress data obtained from a series of lithiation/Delithiation cycles suggests plasticity induced irreversible shape changes in contacting Si particles, and as a result, the stress response of the system during any given lithiation/Delithiation cycle depends on the cycling history of the electrode. While these results constitute the first in-situ stress measurements on composite Si electrodes during electrochemical cycling, the diagnostic technique described herein can be used to assess the mechanical response of a composite electrode made with other active material/binder combinations.
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real time measurement of stress and damage evolution during initial lithiation of crystalline silicon
Physical Review Letters, 2011Co-Authors: Michael J Chon, Vijay A Sethuraman, Venkat Srinivasan, Anthony Mccormick, Pradeep R GuduruAbstract:Crystalline to amorphous phase transformation during initial lithiation in (100) Si wafers is studied in an electrochemical cell with Limetalas thecounter andreferenceelectrode.During initiallithiation,amoving phase boundary advances into thewafer starting from the surface facing the lithium electrode, transforming crystalline Si into amorphous LixSi. The resulting biaxial compressive stress in the amorphous layer is measured in situ, and it was observed to be ca. 0.5 GPa. High-resolution TEM images reveal a very sharp crystalline-amorphous phase boundary, with a thickness of � 1n m. Upon Delithiation, the stress rapidly reverses andbecomes tensile,and the amorphous layer begins to deform plastically ataround 0.5 GPa.With continued Delithiation, the yield stress increases in magnitude, culminating in a sudden fracture of the amorphous layer into microfragments, and the cracks extend into the underlying crystalline Si.
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in situ measurement of biaxial modulus of si anode for li ion batteries
Electrochemistry Communications, 2010Co-Authors: Vijay A Sethuraman, N Van Winkle, Michael J Chon, Maxwell Shimshak, Pradeep R GuduruAbstract: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 Li 0.32 Si to ca. 35 GPa for Li 3.0 Si. Such a significant reduction in elastic modulus has important implications for modeling stress evolution and mechanical degradation in Si-based anodes.
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in situ measurements of stress evolution in silicon thin films during electrochemical lithiation and Delithiation
Journal of Power Sources, 2010Co-Authors: Vijay A Sethuraman, Michael J Chon, Maxwell Shimshak, Venkat Srinivasan, Pradeep R GuduruAbstract:We report in situ measurements of stress evolution in a silicon thin-film electrode during electrochemical lithiation and Delithiation by using the multi-beam optical sensor (MOS) technique. Upon lithiation, due to substrate constraint, the silicon electrode initially undergoes elastic deformation, resulting in rapid rise of compressive stress. The electrode begins to deform plastically at a compressive stress of ca. −1.75 GPa; subsequent lithiation results in continued plastic strain, dissipating mechanical energy. Upon Delithiation, the electrode first undergoes elastic straining in the opposite direction, leading to a tensile stress of ca. 1 GPa; subsequently, it deforms plastically during the rest of Delithiation. The plastic flow stress evolves continuously with lithium concentration. Thus, mechanical energy is dissipated in plastic deformation during both lithiation and Delithiation, and it can be calculated from the stress measurements; we show that it is comparable to the polarization loss. Upon current interruption, both the film stress and the electrode potential relax with similar time constants, suggesting that stress contributes significantly to the chemical potential of lithiated silicon.