Designing a reference electrode – An approach to fabricate laser perforated reference electrodes for lithium-ion batteries

Rutz, Daniel; Bauer, Ingolf; Brauchle, Felix; Jacob, Timo

doi:10.1016/j.electacta.2022.141768

Cited by 6 publications

(25 citation statements)

References 60 publications

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“…LFP Electrode Preparation: The LFP electrodes later used as reference electrodes were prepared generally based on our previously published manufacturing procedure. [16] For the electrodes in this study, a pilot plant equipped with a roll-to-roll process under a dry atmosphere (dew point of less than À50 °C) was used. The slurries were prepared in a planetary mixer to have a content of 92% commercial LFP, 3% of commercial polyvinylidene fluoride (PVDF), and 5% of C45 carbon (Imerys, France).…”

Section: Methodsmentioning

confidence: 99%

“…LFP Electrode Laser Perforation: The laser perforation and washing procedure were based on the previously described method for the production of REs applied in pouch cells. [16] In brief, the electrode LFP sheets were fixed in a holder and perforated using a 40 W ultrashort pulse Nd:YAG laser coupled to a 2D scanner (%25 μm spot size). The perforations followed a hexagonal closely arranged pattern with hole diameters of %50 μm and web widths of %50 μm.…”

Section: Methodsmentioning

confidence: 99%

“…Formation Protocol and Rate Tests: For formation, the cells containing REs were galvanostatically cycled on a BaSyTec system at 25 °C between 2.8 and 4.2 V for one C/10 cycle, followed by charging to 30% SoC. Afterward, the RE was conditioned in a similar way as described before, [16] reaching 50% SoC LFP and a constant potential of 3.428 V versus Li/Li þ . The reference voltage between the graphite anode and the RE was monitored for all following cycles.…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, we could determine the anode potential at the cell cutoff voltage pointswhich correspond to the minimum of the capacity voltage curves-at higher C rates. For the calculation of the anode profiles, a PRE potential value of U LFP vs Li=Li þ = 3.428 V and the following formula was used [16]…”

Section: Rate Testsmentioning

confidence: 99%

“…In our previous work, we presented an alternative approach for a laser‐perforated RE (PRE) based on lithium iron oxide (LFP, LiFePO 4 ). [ 16 ] Microperforations and web widths of ≈50 μm of the meshed RE prevent a blockage of the Li‐ion pathway during cycling. Previous tests of our PRE located in the middle of pouch cells with ≈90 cm 2 of electrode area showed no influence on the cell capacity at low to moderate C‐rates.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Application of Perforated Reference Electrodes in Small Cell Formats for Rate Tests and Electrochemical Impedance Spectroscopy

Stehle,

Rutz,

Bazzoun

et al. 2023

Energy Tech

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The use of reference electrodes (REs) in lithium‐ion batteries allows enhanced electrochemical analysis of individual electrodes via potential monitoring or electrochemical impedance spectroscopy (EIS). The previous publication presents a concept for a laser‐perforated RE (PRE). Herein, this PRE is applied in ≈60 mAh graphite/NMC811 pouch cells. Despite more than 17% of the electrode surface being covered by the PRE, only negligible capacity differences are observed for charge rates up to 2C compared to cells without PRE. At higher rates up to 5C, the blocking effect is present but stable. Reproducible and plausible anode voltage curves are obtained and the beginning of Li plating is detected. Cell EIS spectra are in good agreement with comparison cells without RE. The impedance spectra of the individual electrodes recorded by the PRE are confirmative and, with one exception, artifact‐free. The results demonstrate that our PRE can be reliably applied for investigating lab‐scale electrode coatings in small pouch cell formats.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Rate Testsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Application of Perforated Reference Electrodes in Small Cell Formats for Rate Tests and Electrochemical Impedance Spectroscopy

Stehle,

Rutz,

Bazzoun

et al. 2023

Energy Tech

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show abstract

An Experimental Method to Determine the Measurement Error of Reference Electrodes within Lithium‐Ion Batteries

et al. 2023

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Reference electrodes (REs) play a crucial role in the accurate assessment and control of battery potentials, but their confidence is overestimated. Researchers have tracked the source of the error to the RE design that blocks the lithium‐ion path between anode and cathode. These errors or potential deviations are mostly modeled or less‐frequently estimated after observing Li plating post‐mortem. This is the first study to showcase an experimental method that allows a more precise error quantification in‐operando of a RE. The key idea is to relate the error‐affected reference potential to an unaffected quantity, such as the cell dilatation. Although our experimental setups are special, this approach can also be applied to different setups and REs. Using the presented method, we provoked Li plating in NMC811/graphite pouch cells and determined the potential deviation of our perforated RE to be 12 mV under fast charging conditions. In contrast to previous studies, we found the error to be positive, offering a new explanation of the error mechanism of REs.

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The Optimal Amount of Lithium Difluorophosphate as an Additive for Si‐Dominant Anodes in an Application‐Oriented Setup

Stehle,

Rutz,

Bazzoun

et al. 2023

ChemSusChem

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Fluoroethylene carbonate (FEC) and vinylene carbonate (VC) are considered the most effective electrolyte additives for improving the solid electrolyte interphase (SEI) of Si‐containing anodes while lithium difluorophosphate (LiDFP) is known to improve the interphases of cathode materials and graphite. Here, we combine VC, FEC, and different amounts of LiDFP in a highly‐concentrated electrolyte to investigate the effect on Si‐dominant anodes in detail. Cycle life tests, electrochemical impedance spectroscopy and rate tests with anode potential monitoring were conducted in Si/NCM pouch cells. The results reveal that adding LiDFP to the electrolyte improves all performance criteria of the full cells, with a concentration of 1 wt.% being the optimal value for most cases. Post‐mortem analyses using scanning electron microscopy and x‐ray photoelectron spectroscopy showed that a more beneficial SEI film was formed for higher LiDFP concentrations, which led to less decomposition of electrolyte components and a better‐maintained anode microstructure.

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Designing a reference electrode – An approach to fabricate laser perforated reference electrodes for lithium-ion batteries

Cited by 6 publications

References 60 publications

Application of Perforated Reference Electrodes in Small Cell Formats for Rate Tests and Electrochemical Impedance Spectroscopy

Application of Perforated Reference Electrodes in Small Cell Formats for Rate Tests and Electrochemical Impedance Spectroscopy

An Experimental Method to Determine the Measurement Error of Reference Electrodes within Lithium‐Ion Batteries

The Optimal Amount of Lithium Difluorophosphate as an Additive for Si‐Dominant Anodes in an Application‐Oriented Setup

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