Effective modulus of Si electrodes considering Li concentration, volume expansion, pore, and Poisson’s ratio of Li-ion batteries

Lee, Junghoon; Kim, Cheol

doi:10.1007/s12206-021-0427-1

Cited by 5 publications

(5 citation statements)

References 22 publications

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“…An explanation for this could be that flake-shaped particles tend to expand in the thickness direction, 25 making calendared graphite electrode expansion independent from external pressure 79 and thus less or not expanding into the pore space. A decrease in the elastic modulus of crystalline and amorphous silicon upon lithiation by a factor of approximately three was reported in the literature, 48,89 which may also play a role, but is not considered or modeled within this study. In Fig.…”

Section: Parameterizationmentioning

confidence: 81%

“…This happens because the volumetric share of the active material within the electrode changes upon active material expansion, 31 and due to SoC-dependent mechanical active material properties. 47,48 Additionally, the mechanical properties are difficult to measure on the electrode level because (1) silicon anodes can become brittle after cycling or formation and are difficult to harvest for characterization measurements, and (2) the electrolyte and SoC configuration change compared to the assembled state.…”

Section: List Of Symbolsmentioning

confidence: 99%

“…Such mechanical softening has been approximated for silicon-containing electrodes in the literature. 48 The cathode share of the total compressive properties increases even further.…”

Section: Parameterizationmentioning

confidence: 99%

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Electrochemical-Mechanical Parameterization and Modeling of Expansion, Pressure, and Porosity Evolution in NMC811∣SiOx-Graphite Lithium-Ion Cells

von Kessel,

Hoehl,

Heugel

et al. 2023

J. Electrochem. Soc.

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Mechanical changes in active materials with large volume expansion such as silicon and nickel not only affect the electrochemical performance of modern batteries but also pose a great challenge to their mechanical design due to pressure increase during operation. We show that the large expansion and consequently changing mechanical properties of silicon and nickel strongly affect the electrochemical and mechanical performance. A multi-scale electrochemical model is developed, parameterized, and validated for a pouch cell with a SiOx-graphite anode (22 wt.-% SiOx) and an NMC|811 cathode. Mechanical parameters such as expansion and compressive properties are determined experimentally using an in-house-developed high-precision cell press and electrode dilatometer, thus parameterizing a semi-empirical mechanical model. We employ a new characterization technique to measure mechanical changes in the cell in-operando and propose a phenomenological parameterization where physical modeling is not yet sufficient. Through electrode porosity, we show that mechanical and electrochemical performance are interdependent, as the latter is reduced upon expansion and pressure development. On the one hand, the active material of the anode seems to expand into the pores at increased pressure, and on the other hand, the mechanical deformation of the cell components can no longer be neglected.

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Section: Parameterizationmentioning

confidence: 81%

Section: List Of Symbolsmentioning

confidence: 99%

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Electrochemical-Mechanical Parameterization and Modeling of Expansion, Pressure, and Porosity Evolution in NMC811∣SiOx-Graphite Lithium-Ion Cells

von Kessel,

Hoehl,

Heugel

et al. 2023

J. Electrochem. Soc.

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“…For example, considerable numbers of lab‐scale researches focus on reducing the size of SiO x to the nanoscale or designing a porous structure with enough space for the volume expansion of SiO x . [ 16 ] These strategies would increase the porosity of the anode, leaving enough void to accommodate the volume expansion, and thus the elastic modulus of SiO x –pore composite is lowered during the lithiation/delithiation, [ 17 ] which in turn alleviates the pulverization of the anode and the loss of capacity. [ 18 ] Nonetheless, it also increases the volume and the surface area of the anode, negatively affecting the energy density of the battery and introducing more parasitic reactions.…”

Section: Introductionmentioning

confidence: 99%

Fundamental Mechanisms and Promising Strategies for the Industrial Application of SiO_x Anode

Zhu

Liu

Shao³

et al. 2023

Adv Funct Materials

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SiOx anode with higher specific capacity than graphite and better capacity retention than pure Si has received great attention from both academia and the industry. However, the further application of SiOx suffers from its low initial Coulombic efficiency and inadequate capacity retention. The academia has reported numerous strategies to overcome these obstacles, such as nanosizing, pore designing, nanoarchitecture, etc., while seldom did they satisfy the requirement of the industry, which asks for anode material with excellent performance in all performance metrics (e.g., specific capacity, initial Coulombic efficiency, capacity retention, tap density). Besides, the reproducibility, production cost, and safety of the strategies are less concerned, leading to the “misalignment” between academia and the industry. In this review, the advancements in the modification strategies, which are already or likely to be accepted by the industry, are introduced in detail and critically evaluated. Moreover, the fundamental mechanisms of SiOx and the relationship between its structure and performance are systematically discussed. In the end, outlooks and suggestions for future research are given to provide meaningful guidance.

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“…4c: U Si,EoC = 106 ± 3 mV versus Li + /Li at cycle 105 for the pOCV measurement at C/50 for the UHP cells). Due to the higher density of the higher lithiated Li 3.5 Si phase, 66 the volume of the lithiated silicon anode decreases. Interestingly, the solid volume for the delithiated samples of V E,s,delit ≈4 mm 3 (blue symbols) is essentially constant.…”

mentioning

confidence: 99%

Effect of Mechanical Pressure on Lifetime, Expansion, and Porosity of Silicon-Dominant Anodes in Laboratory Lithium-Ion Cells

Friedrich,

Stojecevic,

Rapp

et al. 2024

J. Electrochem. Soc.

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The impact of mechanical pressure on electrode stability in full-cells comprising microscale silicon-dominant anodes and NCA cathodes was investigated. We applied different mechanical pressures using spring-compressed T-cells with metallic lithium reference electrodes enabling us to analyze the electrode-specific characteristics. Our investigation covers a wide pressure range from 0.02 MPa (low pressure - LP) to 2.00 MPa (ultra high pressure - UHP) to determine the optimal pressure for cyclic lifetime and energy density. We introduce an experimental methodology considering single-component compression to adjust the cell setup precisely. We characterize the cells using impedance spectroscopy and age them at C/2. In the post-mortem analysis, cross-sections of the aged anodes are measured with scanning electron microscopy. The images are analyzed with regard to electrochemical milling, thickness gain, and porosity decrease by comparing them to the pristine state. The results indicate that cycling at UHP has a detrimental effect on cycle life, being almost two-fold shorter when compared to cycling at normal pressure (NP, 0.20 MPa). Scanning electron microscopy showed a dependency of the thickness and the porosity of the aged silicon anodes on the applied pressure, with coating thickness increasing and porosity decreasing for all pressure settings, and a correlation between thickness and porosity.

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Effective modulus of Si electrodes considering Li concentration, volume expansion, pore, and Poisson’s ratio of Li-ion batteries

Cited by 5 publications

References 22 publications

Electrochemical-Mechanical Parameterization and Modeling of Expansion, Pressure, and Porosity Evolution in NMC811∣SiOx-Graphite Lithium-Ion Cells

Electrochemical-Mechanical Parameterization and Modeling of Expansion, Pressure, and Porosity Evolution in NMC811∣SiOx-Graphite Lithium-Ion Cells

Fundamental Mechanisms and Promising Strategies for the Industrial Application of SiO_x Anode

Effect of Mechanical Pressure on Lifetime, Expansion, and Porosity of Silicon-Dominant Anodes in Laboratory Lithium-Ion Cells

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Effective modulus of Si electrodes considering Li concentration, volume expansion, pore, and Poisson’s ratio of Li-ion batteries

Cited by 5 publications

References 22 publications

Electrochemical-Mechanical Parameterization and Modeling of Expansion, Pressure, and Porosity Evolution in NMC811∣SiOx-Graphite Lithium-Ion Cells

Electrochemical-Mechanical Parameterization and Modeling of Expansion, Pressure, and Porosity Evolution in NMC811∣SiOx-Graphite Lithium-Ion Cells

Fundamental Mechanisms and Promising Strategies for the Industrial Application of SiOx Anode

Effect of Mechanical Pressure on Lifetime, Expansion, and Porosity of Silicon-Dominant Anodes in Laboratory Lithium-Ion Cells

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Product

Resources

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Fundamental Mechanisms and Promising Strategies for the Industrial Application of SiO_x Anode