Publications by authors named "Johannes Kasnatscheew"

12 Publications

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Area Oversizing of Lithium Metal Electrodes in Solid-State Batteries: Relevance for Overvoltage and thus Performance?

ChemSusChem 2021 May 28;14(10):2144. Epub 2021 Apr 28.

Helmholtz Institute Münster, IEK-12, Forschungszentrum Jülich GmbH, Corrensstraße 46, 48149, Münster, Germany.

Invited for this month's cover is the group of Dr. Johannes Kasnatscheew from the Research Center Jülich GmbH. The image shows how area oversizing of lithium can affect the overall power of batteries, in particular at lower temperature. The Full Paper itself is available at 10.1002/cssc.202100213.
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http://dx.doi.org/10.1002/cssc.202100778DOI Listing
May 2021

Area Oversizing of Lithium Metal Electrodes in Solid-State Batteries: Relevance for Overvoltage and thus Performance?

ChemSusChem 2021 May 9;14(10):2163-2169. Epub 2021 Apr 9.

Helmholtz Institute Münster, IEK-12, Forschungszentrum Jülich GmbH, Corrensstraße 46, 48149, Münster, Germany.

Systematic and systemic research and development of solid electrolytes for lithium batteries requires a reliable and reproducible benchmark cell system. Therefore, factors relevant for performance, such as temperature, voltage operation range, or specific current, should be defined and reported. However, performance can also be sensitive to apparently inconspicuous and overlooked factors, such as area oversizing of the lithium electrode and the solid electrolyte membrane (relative to the cathode area). In this study, area oversizing is found to diminish polarization and improves the performance in LiNi Mn Co O (NMC622)||Li cells, with a more pronounced effect under kinetically harsh conditions (e. g., low temperature and/or high current density). For validity reasons, the polarization behavior is also investigated in Li||Li symmetric cells. Given the mathematical conformity of the characteristic overvoltage behavior with the Sand's equation, the beneficial effect is attributed to lower depletion of Li ions at the electrode/electrolyte interface. In this regard, the highest possible effect of area oversizing on the performance is discussed, that is when the accompanied decrease in current density and overvoltage overcomes the Sand's threshold limit. This scenario entirely prevents the capacity decay attributable to Li depletion and is in line with the mathematically predicted values.
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http://dx.doi.org/10.1002/cssc.202100213DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8251826PMC
May 2021

Kinetical threshold limits in solid-state lithium batteries: Data on practical relevance of sand equation.

Data Brief 2021 Feb 23;34:106688. Epub 2020 Dec 23.

Helmholtz-Institute Münster, IEK-12, Forschungszentrum Jülich GmbH, Corrensstraße 46, 48149 Münster, Germany.

The here shown data support the article "The Sand Equation and its Enormous Practical Relevance for Solid-State Lithium Metal Batteries". [1] In this data set, all cells include the poly (ethylene oxide)-based solid polymer electrolyte (PEO-based SPE). The behaviour in symmetric Li||Li cells are provided in a three-electrode cell setup, thus with the use of a reference electrode. Moreover, the Sand behaviour is reported for varied negative electrodes with the focus on polarization onset, defined as transition time. The data of the electrochemical response after the variation of additional parameter, SPE thicknesses, are shown, as well. The theoretical Sand equation is linked with practically obtained values also for varied Li salt concentration. Finally, the discharge behaviour is provided including further charge/discharge cycles with the use of LiNiMnCoO (NMC622) as active material for positive electrodes.
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http://dx.doi.org/10.1016/j.dib.2020.106688DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7786044PMC
February 2021

Exploiting the Degradation Mechanism of NCM523 || Graphite Lithium-Ion Full Cells Operated at High Voltage.

ChemSusChem 2021 Jan 29;14(2):491. Epub 2020 Dec 29.

University of Münster, MEET Battery Research Center, Institute of Physical Chemistry, Corrensstr. 46, 48149, Münster, Germany.

Invited for this month's cover is the group of Tobias Placke and Martin Winter at the MEET Battery Research Center (University of Münster). The image shows the failure mechanism of high-voltage operated NCM523 || graphite lithium-ion cells, that is, the dissolution of transition metals (Mn, Co, Ni) from the NCM523 cathode and subsequent deposition at the graphite anode, resulting in formation of Li metal dendrites. The Full Paper itself is available at 10.1002/cssc.202002113.
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http://dx.doi.org/10.1002/cssc.202002870DOI Listing
January 2021

Exploiting the Degradation Mechanism of NCM523 Graphite Lithium-Ion Full Cells Operated at High Voltage.

ChemSusChem 2021 Jan 10;14(2):595-613. Epub 2020 Nov 10.

University of Münster, MEET Battery Research Center, Institute of Physical Chemistry, Corrensstr. 46, 48149, Münster, Germany.

Layered oxides, particularly including Li[Ni Co Mn ]O (NCMxyz) materials, such as NCM523, are the most promising cathode materials for high-energy lithium-ion batteries (LIBs). One major strategy to increase the energy density of LIBs is to expand the cell voltage (>4.3 V). However, high-voltage NCM graphite full cells typically suffer from drastic capacity fading, often referred to as "rollover" failure. In this study, the underlying degradation mechanisms responsible for failure of NCM523 graphite full cells operated at 4.5 V are unraveled by a comprehensive study including the variation of different electrode and cell parameters. It is found that the "rollover" failure after around 50 cycles can be attributed to severe solid electrolyte interphase growth, owing to formation of thick deposits at the graphite anode surface through deposition of transition metals migrating from the cathode to the anode. These deposits induce the formation of Li metal dendrites, which, in the worst cases, result in a "rollover" failure owing to the generation of (micro-) short circuits. Finally, approaches to overcome this dramatic failure mechanism are presented, for example, by use of single-crystal NCM523 materials, showing no "rollover" failure even after 200 cycles. The suppression of cross-talk phenomena in high-voltage LIB cells is of utmost importance for achieving high cycling stability.
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http://dx.doi.org/10.1002/cssc.202002113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7894331PMC
January 2021

Conventional Electrolyte and Inactive Electrode Materials in Lithium-Ion Batteries: Determining Cumulative Impact of Oxidative Decomposition at High Voltage.

ChemSusChem 2020 Oct 17;13(19):5301-5307. Epub 2020 Aug 17.

Helmholtz-Institute Münster (HI MS) IEK-12, Forschungszentrum Jülich GmbH, Corrensstrasse 46, 48149, Münster, Germany.

High-voltage electrodes based on, for example, LiNi Mn 0 (LNMO) active material require oxidative stability of inactive materials up to 4.95 V vs. Li|Li . Referring to literature, they are frequently supposed to be unstable, though conclusions are still controversial and clearly depend on the used investigation method. For example, the galvanostatic method, as a common method in battery research, points to the opposite, thus to a stability of the inactive materials, which can be derived from, for example, the high decomposition plateau at 5.56 V vs. Li|Li and stable performance of the LNMO charge/discharge cycling. This work aims to unravel this apparent contradiction of the galvanostatic method with the literature by a thorough investigation of possible trace oxidation reactions in cumulative manner, that is, over many charge/discharge cycles. Indeed, the cumulated irreversible specific capacity amounts to ≈10 mAh g during the initial 50 charge/discharge cycles, which is determined by imitating extreme LNMO high-voltage conditions using electrodes solely consisting of inactive materials. This can explain the ambiguities in stability interpretations of the galvanostatic method and the literature, as the respective irreversible specific capacity is obviously too low for distinct detection in conventional galvanostatic approaches and can be only detected at extreme high-voltage conditions. In this regard, the technique of chronoamperometry is shown to be an effective and proper complementary tool for electrochemical stability research in a qualitative and quantitative manner.
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http://dx.doi.org/10.1002/cssc.202001530DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7589409PMC
October 2020

Elimination of "Voltage Noise" of Poly (Ethylene Oxide)-Based Solid Electrolytes in High-Voltage Lithium Batteries: Linear versus Network Polymers.

iScience 2020 Jun 3;23(6):101225. Epub 2020 Jun 3.

Helmholtz-Institute Münster, IEK-12, Forschungszentrum Jülich GmbH, Corrensstraße 46, 48149 Münster, Germany. Electronic address:

Frequently, poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) reveal a failure with high-voltage electrodes, e.g. LiNiMnCoO in lithium metal batteries, which can be monitored as an arbitrary appearance of a "voltage noise" during charge and can be attributed to Li dendrite-induced cell micro short circuits. This failure behavior disappears when incorporating linear PEO-based SPE in a semi-interpenetrating network (s-IPN) and even enables an adequate charge/discharge cycling performance at 40°C. An impact of any electrolyte oxidation reactions on the performance difference can be excluded, as both SPEs reveal similar (high) bulk oxidation onset potentials of ≈4.6 V versus Li|Li. Instead, improved mechanical properties of the SPE, as revealed by compression tests, are assumed to be determining, as they mechanically better withstand Li dendrite penetration and better maintain the distance of the two electrodes, both rendering cell shorts less likely.
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http://dx.doi.org/10.1016/j.isci.2020.101225DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7305408PMC
June 2020

Poly(Ethylene Oxide)-based Electrolyte for Solid-State-Lithium-Batteries with High Voltage Positive Electrodes: Evaluating the Role of Electrolyte Oxidation in Rapid Cell Failure.

Sci Rep 2020 Mar 9;10(1):4390. Epub 2020 Mar 9.

Helmholtz-Institute Münster, IEK-12, Forschungszentrum Jülich GmbH, Corrensstraße 46, 48149, Münster, Germany.

Polyethylene oxide (PEO)-based solid polymer electrolytes (SPEs) typically reveal a sudden failure in Li metal cells particularly with high energy density/voltage positive electrodes, e.g. LiNiMnCoO (NMC622), which is visible in an arbitrary, time - and voltage independent, "voltage noise" during charge. A relation with SPE oxidation was evaluated, for validity reasons on different active materials in potentiodynamic and galvanostatic experiments. The results indicate an exponential current increase and a potential plateau at 4.6 V vs. Li|Li, respectively, demonstrating that the main oxidation onset of the SPE is above the used working potential of NMC622 being < 4.3 V vs. Li|Li. Obviously, the SPE│NMC622 interface is unlikely to be the primary source of the observed sudden failure indicated by the "voltage noise". Instead, our experiments indicate that the Li | SPE interface, and in particular, Li dendrite formation and penetration through the SPE membrane is the main source. This could be simply proven by increasing the SPE membrane thickness or by exchanging the Li metal negative electrode by graphite, which both revealed "voltage noise"-free operation. The effect of membrane thickness is also valid with LiFePO electrodes. In summary, it is the cell set-up (PEO thickness, negative electrode), which is crucial for the voltage-noise associated failure, and counterintuitively not a high potential of the positive electrode.
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http://dx.doi.org/10.1038/s41598-020-61373-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7062893PMC
March 2020

Investigation of various layered lithium ion battery cathode materials by plasma- and X-ray-based element analytical techniques.

Anal Bioanal Chem 2019 Jan 29;411(1):277-285. Epub 2018 Oct 29.

MEET Battery Research Center, Institute of Physical Chemistry, University of Münster, Corrensstraße 46, 48149, Münster, Germany.

In this work, the transition metal dissolution (TMD) from the respective ternary layered LiMO (M = Mn, Co, Ni, Al) cathode active material was investigated as well as the lithiation degrees of the cathodes after charge/discharge cyclic aging. Furthermore, increased nickel contents in LiNiCoMnO-based (NCM) cathode materials were studied, to elucidate their influence on capacity fading and TMD. It was found, that the TMD from nickel-rich cathode materials, e.g., LiNiCoMnO or LiNiCoMnO, did not differ significantly from the TMD from the stoichiometric LiNiCoMnO. In detail, the TMD from the cathode did not exceed a maximum of 0.2 wt% and was uniformly distributed on all analyzed cell parts (separator, anode, and electrolyte) using total reflection X-ray fluorescence. Moreover, the investigated electrolyte solutions showed that increased Ni contents come with more nickel dissolution of the respective material. Additionally, inductively coupled plasma optical emission spectroscopy analysis on the respective charge/discharge cyclic-aged cathode active materials revealed lithium losses of 20% after 50 cycles. However, only a minimum amount of capacity loss (= 1.5 mAh g) can be attributed to active material loss.
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http://dx.doi.org/10.1007/s00216-018-1441-8DOI Listing
January 2019

Interfaces and Materials in Lithium Ion Batteries: Challenges for Theoretical Electrochemistry.

Top Curr Chem (Cham) 2018 Apr 18;376(3):16. Epub 2018 Apr 18.

Helmholtz-Institute Münster, IEK-12, Forschungszentrum Jülich GmbH, Corrensstrasse 46, 48149, Münster, Germany.

Energy storage is considered a key technology for successful realization of renewable energies and electrification of the powertrain. This review discusses the lithium ion battery as the leading electrochemical storage technology, focusing on its main components, namely electrode(s) as active and electrolyte as inactive materials. State-of-the-art (SOTA) cathode and anode materials are reviewed, emphasizing viable approaches towards advancement of the overall performance and reliability of lithium ion batteries; however, existing challenges are not neglected. Liquid aprotic electrolytes for lithium ion batteries comprise a lithium ion conducting salt, a mixture of solvents and various additives. Due to its complexity and its role in a given cell chemistry, electrolyte, besides the cathode materials, is identified as most susceptible, as well as the most promising, component for further improvement of lithium ion batteries. The working principle of the most important commercial electrolyte additives is also discussed. With regard to new applications and new cell chemistries, e.g., operation at high temperature and high voltage, further improvements of both active and inactive materials are inevitable. In this regard, theoretical support by means of modeling, calculation and simulation approaches can be very helpful to ex ante pre-select and identify the aforementioned components suitable for a given cell chemistry as well as to understand degradation phenomena at the electrolyte/electrode interface. This overview highlights the advantages and limitations of SOTA lithium battery systems, aiming to encourage researchers to carry forward and strengthen the research towards advanced lithium ion batteries, tailored for specific applications.
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http://dx.doi.org/10.1007/s41061-018-0196-1DOI Listing
April 2018

Graphite Recycling from Spent Lithium-Ion Batteries.

ChemSusChem 2016 Dec 9;9(24):3473-3484. Epub 2016 Dec 9.

MEET Battery Research Center, Institute of Physical Chemistry, University of Münster, Corrensstr. 46, 48149, Münster, Germany.

The present work reports on challenges in utilization of spent lithium-ion batteries (LIBs)-an increasingly important aspect associated with a significantly rising demand for electric vehicles (EVs). In this context, the feasibility of anode recycling in combination with three different electrolyte extraction concepts is investigated. The first method is based on a thermal treatment of graphite without electrolyte recovery. The second method additionally utilizes a subcritical carbon-dioxide (subcritical CO )-assisted electrolyte extraction prior to thermal treatment. And the final investigated approach uses supercritical carbon dioxide (scCO ) as extractant, subsequently followed by the thermal treatment. It is demonstrated that the best performance of recycled graphite anodes can be achieved when electrolyte extraction is performed using subcritical CO . Comparative studies reveal that, in the best case, the electrochemical performance of recycled graphite exceeds the benchmark consisting of a newly synthesized graphite anode. As essential efforts towards electrolyte extraction and cathode recycling have been made in the past, the electrochemical behavior of recycled graphite, demonstrating the best performance, is investigated in combination with a recycled LiNi Co Mn O cathode.
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http://dx.doi.org/10.1002/cssc.201601062DOI Listing
December 2016

Impact of Selected LiPF Hydrolysis Products on the High Voltage Stability of Lithium-Ion Battery Cells.

ACS Appl Mater Interfaces 2016 Nov 4;8(45):30871-30878. Epub 2016 Nov 4.

MEET Battery Research Center/Institute of Physical Chemistry, University of Münster , Corrensstrasse 46, 48149 Münster, Germany.

Diverse LiPF hydrolysis products evolve during lithium-ion battery cell operation at elevated operation temperatures and high operation voltages. However, their impact on the formation and stability of the electrode/electrolyte interfaces is not yet investigated and understood. In this work, literature-known hydrolysis products of LiPF dimethyl fluorophosphate (DMFP) and diethyl fluorophosphate (DEFP) were synthesized and characterized. The use of DMFP and DEFP as electrolyte additive in 1 M LiPF in EC:EMC (1:1, by wt) was investigated in LiNiMnCoO/Li half cells. When charged to a cutoff potential of 4.6 V vs Li/Li, the additive containing cells showed improved cycling stability, increased Coulombic efficiencies, and prolonged shelf life. Furthermore, low amounts (1 wt % in this study) of the aforementioned additives did not show any negative effect on the cycling stability of graphite/Li half cells. DMFP and DEFP are susceptible to oxidation and contribute to the formation of an effective cathode/electrolyte interphase as confirmed by means of electrochemical stability window determination, and X-ray photoelectron spectroscopy characterization of pristine and cycled electrodes, and they are supported by computational calculations.
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http://dx.doi.org/10.1021/acsami.6b09164DOI Listing
November 2016
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