A Gold Micro-Reference Electrode for Impedance and Potential Measurements in Lithium Ion Batteries

Solchenbach, Sophie; Pritzl, Daniel; Kong, Edmund Jia Yi; Landesfeind, Johannes; Gasteiger, Hubert A.

doi:10.1149/2.0581610jes

Cited by 140 publications

(243 citation statements)

References 54 publications

(122 reference statements)

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“…Interfacial resistance of graphite anodes after formation at 25 • C in graphite/LNMO cells (this study) compared to graphite anodes in graphite/LFP cells from our earlier study. 13 The VC concentration is recalculated in units of mg VC /m 2 Graphite to assess for the slightly different areal loadings (namely ∼2.6 mAh/cm 2 geo in the graphite/LNMO cells and ∼2.2 mAh/cm 2 geo in the graphite/LFP cells, based on 340 mAh/g graphite ). The error bars represent the standard deviation between two measurements.…”

Section: Discussionmentioning

confidence: 99%

“…The investigated electrolytes consisted only of EC or VC with 1 M LiPF 6 (all from BASF SE, Germany). To distinguish between electrolyte oxidation and carbon corrosion, we used isotopically labelled 13 C-carbon electrodes coated on a polyester separator as working electrodes (see above). The oxidative stability of the electrolytes was investigated by a linear potential sweep from OCV (∼3 V vs. Li/Li + ) to 5.5 V vs. Li/Li + at a scan rate of 0.1 mV/s.…”

Section: Methodsmentioning

confidence: 99%

“…Electrochemical characterization.-Swagelok T-cells with a Gold Wire Reference Electrode (GWRE) 13 were assembled in an argon filled glove box (O 2 and H 2 O < 0.1 ppm, MBraun, Germany) using two glass fiber separators (11 mm diameter, 200 μm thickness, glass microfiber #691, VWR, Germany) and 60 μL of electrolyte. The electrolyte consisted of standard LP57 (1 M LiPF 6 in EC: EMC (3:7 wt/wt) < 10 ppm H 2 O, BASF, Germany) without and with different amounts of vinylene carbonate (VC, BASF SE, Germany), which was added at concentrations of 0.09, 0.17 0.52 and 2 wt% to the electrolyte.…”

Section: Methodsmentioning

confidence: 99%

“…The values for the HFR of anode and cathode are ∼4.0 and ∼3.5 cm 2 , respectively; the cause for the slight difference in these HFR values (which are expected to be identical for a symmetric placement of the GWRE) was described elsewhere. 13 The overall resistances of the anode (R Anode ) and the cathode (R Cathode ) are in both cases ∼10 cm 2 .…”

Section: 17mentioning

confidence: 97%

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Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi_0.5Mn_1.5O₄Cells

Pritzl

Solchenbach

Wetjen

et al. 2017

J. Electrochem. Soc.

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124

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Vinylene Carbonate (VC) is an effective electrolyte additive to produce a stable solid electrolyte interphase (SEI) on graphite anodes, increasing the capacity retention of lithium-ion cells. However, in combination with LiNi 0.5 Mn 1.5 O 4 (LNMO) cathodes, VC drastically decreases cell performance. In this study we use on-line electrochemical mass spectrometry (OEMS) and electrochemical impedance spectroscopy (EIS) with a micro-reference electrode to understand the oxidative (in-)stability of VC and its effect on the interfacial resistances of both anode and cathode. We herein compare different VC concentrations corresponding to VC to graphite surface area ratios typically used in commercial-scale cells. At low VC concentrations (0.09 wt%, corresponding to 1 wt% in commercial-scale cells), an impedance increase exclusively on the anode and an improved capacity retention is observed, whereas higher VC concentrations (0.17 wt -2 wt%, corresponding to 2 wt -23 wt% in commercial-scale cells) show an increase in both cathode and anode impedance as well as worse cycling performance and overcharge capacity during the first cycle. By considering the onset potentials for VC reduction and oxidation in graphite/LNMO cells, we demonstrate that low amounts of VC can be reduced before VC oxidation occurs, which is sufficient to effectively passivate the graphite anode. During the first charge of a lithium ion battery (LiB), the so called solid electrolyte interphase (SEI) 1 is formed on the surface of the negative electrode. The standard electrolyte for LiBs consists of a mixture of cyclic and linear carbonates, e.g., ethylene carbonate (EC) and ethyl methyl carbonate (EMC), typically with lithium hexafluorophosphate (LiPF 6 ) as salt. Starting from a potential of ∼0.8 V vs. Li/Li + , EC is reduced electrochemically into ethylene gas and lithium ethylene dicarbonate (LEDC), which is a key component of the SEI.2,3 Vinylene carbonate (VC) is one of the most effective additives to modify the SEI on graphite anodes, as it is reduced at potentials more positive than 1.0 V vs. Li/Li + and hence suppresses the reduction of EC. 4,5Aurbach et al. have used VC as electrolyte additive in an EC/DMC (dimethyl carbonate) based electrolyte and that time reported a reduction of the irreversible capacity in the first cycles and an improved cycling stability at elevated temperatures for graphite anodes. The SEI resulting from the reduction of VC consists mainly of poly (vinylene carbonate) (poly(VC)). 4,6Important studies on the impact of different VC concentrations in graphite/NMC pouch cells have been carried out by the Dahn group. For example, Burns et al. 7 investigated the effect of different concentrations of VC (0, 1 and 2 wt%) on cycle life and impedance growth of full-cells with graphite anodes and either LCO (LiCoO 2 ) or NMC (Li(Ni 0.42 Mn 0.42 Co 0.16 )O 2 ) cathodes, employing galvanostatic cycling experiments coupled with high precision coulombic efficiency and electrochemical impedance spectroscopy (EIS) measurements. For cel...

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: 17mentioning

confidence: 97%

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Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi_0.5Mn_1.5O₄Cells

Pritzl

Solchenbach

Wetjen

et al. 2017

J. Electrochem. Soc.

Self Cite

124

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“…This is largely related to the fact that in commercialscale cells, the ratio of active materials to electrolyte solution and void volume is typically ∼10 times higher compared to the lab-scale cells used here. 37,56 Strehle et al 16 recently showed that under these conditions, the majority of CO 2 released from VC reduction would remain dissolved in the electrolyte solution instead of being released into the gas headspace of the cell. This is illustrated by first estimating the amount of dissolved CO 2 by Henry's law 2: where n CO2(el) is the amount of CO 2 dissolved in the liquid electrolyte solution, V el is the volume of the electrolyte solution, c el is the total molar concentration of the electrolyte solution (i.e., solvent and salt) and K H is the Henry constant of CO 2 in the electrolyte solution in units of pressure.…”

Section: Discussionmentioning

confidence: 99%

Lithium Oxalate as Capacity and Cycle-Life Enhancer in LNMO/Graphite and LNMO/SiG Full Cells

Solchenbach

Wetjen

Pritzl

et al. 2018

J. Electrochem. Soc.

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In the present study, we explore the use of lithium oxalate as a "sacrificial salt" in combination with lithium nickel manganese spinel (LNMO) cathodes. By online electrochemical mass spectrometry (OEMS), we demonstrate that the oxidation of lithium oxalate to CO 2 (corresponding to 525 mAh/g) occurs quantitatively around 4.7 V vs. Li/Li + . LNMO/graphite cells containing 2.5 or 5 wt% lithium oxalate show an up to ∼11% higher initial discharge capacity and less capacity fade over 300 cycles (12% and 8% vs. 19%) compared to cells without lithium oxalate. In LNMO/SiG full-cells with an FEC-containing electrolyte solution, lithium oxalate leads to a better capacity retention (45% vs 20% after 250 cycles) and a higher coulombic efficiency throughout cycling (∼1%) compared to cells without lithium oxalate. When CO 2 from lithium oxalate oxidation is removed after formation, a similar capacity fading as in LNMO/SiG cells without lithium oxalate is observed. Hence, we attribute the improved cycling performance to the presence of CO 2 in the cells. Further analysis (e.g., FEC consumption by 19 F-NMR) indicate that CO 2 is an effective SEI-forming additive for SiG anodes, and that a combination of FEC and CO 2 has a synergistic effect on the lifetime of full-cells with SiG anodes. Lithium nickel manganese spinel (LiNi 0.5 Mn 1.5 O 4 , LNMO) is a promising cathode material for high energy lithium ion batteries due to its high operating potential around 4.7 V vs. Li/Li + , its high rate capability, structural stability and the absence of cobalt. However, its lower specific capacity (146 mAh/g LNMO ) compared to layered oxide materials (e.g. lithium nickel manganese cobalt oxide (NMC), specific capacity 150-250 mAh/g NMC ) 1 is regarded as a major drawback. In full-cells, the practically achievable capacity of LNMO is even lower, as the formation of the solid-electrolyte interphase (SEI) on the graphite anode consumes active lithium. For many layered oxide cathodes, however, the first cycle irreversible capacity of the cathode is similar to the capacity needed for SEI formation (∼20 mAh/g NMC ), and hence the practical discharge capacity of the cathode and the remaining active lithium are more or less balanced again. 2,3 In contrast, the first cycle irreversible capacity of LNMO (∼6 mAh/g LNMO ) is much lower than the capacity needed for SEI formation. This leads to a mismatch between active lithium and practical cathode capacity, i.e., there is not enough active lithium available to fully discharge the LNMO cathode during subsequent cycling.In cells with silicon-based anodes, active lithium losses on the anode are even higher compared to graphite, as the expansion of the silicon particles during the first lithiation leads to a continuous exposure of fresh, unpassivated silicon surface. 4 On this new surface, electrolyte reduction occurs instantaneously, which reduces the total lithium reservoir in the cell. Therefore, different ideas to increase the amount of active lithium in lithium ion full-cells have been suggested, ...

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A Toolbox of Reference Electrodes for Lithium Batteries

Xiao

Yan

et al. 2021

Adv Funct Materials

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Electrochemical energy storage systems play an increasingly important role in our daily lives. The detection/estimation of the state of electrochemical cells is therefore a prerequisite for the development of safe, high-performance batteries. Reference electrodes (REs) are an effective tool for monitoring the status of batteries and are of critical significance in this field. However, the practical construction of a durable RE for long-term research and industrial applications is still challenging. In this article, the fundamental principles of a three-electrode system featuring the presence of REs are elucidated. The design parameters of REs in lithium batteries, including active materials, manufacturing, geometry, and placement, are comprehensively summarized, and the typical applications of REs in practical lithium-ion batteries to facilitate working/failure mechanism analysis and methods to monitor Li plating are analyzed. Finally, the challenges and future trends of the exploitation and deployment of REs in lithium batteries are presented.

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A Gold Micro-Reference Electrode for Impedance and Potential Measurements in Lithium Ion Batteries

Cited by 140 publications

References 54 publications

Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi_0.5Mn_1.5O₄Cells

Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi_0.5Mn_1.5O₄Cells

Lithium Oxalate as Capacity and Cycle-Life Enhancer in LNMO/Graphite and LNMO/SiG Full Cells

A Toolbox of Reference Electrodes for Lithium Batteries

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A Gold Micro-Reference Electrode for Impedance and Potential Measurements in Lithium Ion Batteries

Cited by 140 publications

References 54 publications

Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi0.5Mn1.5O4Cells

Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi0.5Mn1.5O4Cells

Lithium Oxalate as Capacity and Cycle-Life Enhancer in LNMO/Graphite and LNMO/SiG Full Cells

A Toolbox of Reference Electrodes for Lithium Batteries

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Product

Resources

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Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi_0.5Mn_1.5O₄Cells

Analysis of Vinylene Carbonate (VC) as Additive in Graphite/LiNi_0.5Mn_1.5O₄Cells