Micro embossing of graphite-based anodes for lithium-ion batteries to improve cell performance

Sandherr, Jens; Kleefoot, Max-Jonathan; Nester, Sara; Weisenberger, Christian; Silva, A.K.M. De; Michel, Dominik; Reeb, Sarah; Fingerle, Mathias; Riegel, Harald; Knoblauch, Volker

doi:10.1016/j.est.2023.107359

Cited by 8 publications

(2 citation statements)

References 44 publications

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“…This software uses a neural network algorithm that has specifically been trained to distinguish pore space, active material, and the carbon-binder domain (CBD) in NMC-like battery electrode microstructures. A similar workflow for graphite-like battery electrode microstructures can be found in a recent related publication [40].…”

Section: Image Generation and Post-processingmentioning

confidence: 98%

Systematic Workflow for Efficient Identification of Local Representative Elementary Volumes Demonstrated with Lithium-Ion Battery Cathode Microstructures

Kellers,

Lautenschlaeger,

Rigos

et al. 2023

Batteries

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The concept of a representative elementary volume (REV) is key for connecting results of pore-scale simulations with continuum properties of microstructures. Current approaches define REVs only based on their size as the smallest volume in a heterogeneous material independent of its location and under certain aspects representing the same material at the continuum scale. However, the determination of such REVs is computationally expensive and time-consuming, as many costly simulations are often needed. Therefore, presented here is an efficient, systematic, and predictive workflow for the identification of REVs. The main differences from former studies are: (1) An REV is reinterpreted as one specificsub-volume of minimal size at a certain location that reproduces the relevant continuum properties of the full microstructure. It is therefore called a local REV (lREV) here. (2) Besides comparably cheap geometrical and statistical analyses, no further simulations are needed. The minimum size of the sub-volume is estimated using the simple statistical properties of the full microstructure. Then, the location of the REV is identified solely by evaluating the structural properties of all possible candidates in a very fast, efficient, and systematic manner using a penalty function. The feasibility and correct functioning of the workflow were successfully tested and validated by simulating diffusive transport, advection, and electrochemical properties for an lREV. It is shown that the lREVs identified using this workflow can be significantly smaller than typical REVs. This can lead to significant speed-ups for any pore-scale simulations. The workflow can be applied to any type of heterogeneous material, even though it is showcased here using a lithium-ion battery cathode.

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Section: Image Generation and Post-processingmentioning

confidence: 98%

Systematic Workflow for Efficient Identification of Local Representative Elementary Volumes Demonstrated with Lithium-Ion Battery Cathode Microstructures

Kellers,

Lautenschlaeger,

Rigos

et al. 2023

Batteries

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show abstract

“…Recently, mechanical microembossing was presented as a novel approach for creating holes in electrode coatings: Bryntesen et al created line and hole structures in electrode coatings with blades or shaped silicon wafers [ 30 ] and Sandherr et al used an embossing stamp with a needle‐type surface structure to create conical holes in electrodes. [ 31 ] In both works, the force was applied by laboratory presses, which are not compatible with continuous electrode manufacturing in roll‐to‐roll processes. However, the approach can also be realized using an embossing roller, [ 32 ] with the potential to achieve high throughputs comparable to calendering of electrodes for lithium‐ion batteries.…”

Section: Introductionmentioning

confidence: 99%

Comparative Evaluation of Graphite Anode Structuring for Lithium‐Ion Batteries Using Laser Ablation and Mechanical Embossing

Hille,

Keilhofer,

Mazur

et al. 2024

Energy Tech

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Lithium‐ion batteries inherently suffer from a target conflict between a high energy density and a high power density. The creation of microscopic holes in the electrodes alleviates the trade‐off by facilitating lithium‐ion diffusion. This study presents a novel concept for electrode structuring called structure calendering, combining mechanical embossing (MEC) and calendering. It is compared to the widely investigated laser ablation (LAS) process by structuring graphite anodes and examining their geometrical, mechanical, and electrochemical properties. It is shown that structure calendering results in wider and deeper holes of higher reproducibility than laser structuring. As a consequence of the different hole‐creation mechanisms, laser structuring induces a surface elevation around the holes while clogged pores are observed in the lateral walls of mechanically structured holes. In pull‐off tests, no pronounced impact of electrode structuring on the mechanical electrode properties is discerned. Structuring of electrodes using both methods yields significantly reduced electrode tortuosities and enhanced discharge rate performances. From a production engineering perspective, structure calendering has advantages over laser structuring in terms of material loss, processing rate, and investment costs, while the latter offers higher flexibility, precision, and presumably lower maintenance efforts. In conclusion, structure calendering represents an attractive process alternative to laser structuring.

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Advances and Future Prospects of Micro‐Silicon Anodes for High‐Energy‐Density Lithium‐Ion Batteries: A Comprehensive Review

Sun,

Liu,

Wang

et al. 2024

Adv Funct Materials

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Silicon (Si), stands out for its abundant resources, eco‐friendliness, affordability, high capacity, and low operating potential, making it a prime candidate for high‐energy‐density lithium‐ion batteries (LIBs). Notably, the breakthrough use of nanostructured Si (nSi) has paved the way for the commercialization of Si anodes. Despite this, challenges like high processing costs, severe side reactions, and low volumetric energy density have impeded widespread industrial adoption. Micron‐scale Si (µSi) has always faced setbacks compared to nSi due to its greater volume expansion. However, recent years have witnessed a resurgence of interest in µSi‐based anodes. Capitalizing on its inherent advantages, including low cost and high tap density, µSi has once again captured the attention of both academic and industrial communities. This review begins by contrasting the strengths and weaknesses of µSi and nSi, then outline potential solutions to enhance µSi performance, covering aspects like structural regulation, composite anodes, binder design, and electrolyte exploration. Additionally, this work explores the application of machine learning‐assisted high‐throughput screening. Concluding the review, this work provides insights into the future prospects of µSi in LIBs, outlining challenges and proposing integrated coping strategies. This review anticipates that it will provide valuable perspectives for the commercial application of high‐energy‐density Si‐based anodes.

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Micro embossing of graphite-based anodes for lithium-ion batteries to improve cell performance

Cited by 8 publications

References 44 publications

Systematic Workflow for Efficient Identification of Local Representative Elementary Volumes Demonstrated with Lithium-Ion Battery Cathode Microstructures

Systematic Workflow for Efficient Identification of Local Representative Elementary Volumes Demonstrated with Lithium-Ion Battery Cathode Microstructures

Comparative Evaluation of Graphite Anode Structuring for Lithium‐Ion Batteries Using Laser Ablation and Mechanical Embossing

Advances and Future Prospects of Micro‐Silicon Anodes for High‐Energy‐Density Lithium‐Ion Batteries: A Comprehensive Review

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