Publications by authors named "Sven Uhlenbruck"

6 Publications

  • Page 1 of 1

Physical Vapor Deposition in Solid-State Battery Development: From Materials to Devices.

Adv Sci (Weinh) 2021 Jun 19;8(11):e2002044. Epub 2021 Mar 19.

Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research: Materials Synthesis and Processing (IEK-1), Wilhelm-Johnen-Straße, Jülich, 52425, Germany.

This review discusses the contribution of physical vapor deposition (PVD) processes to the development of electrochemical energy storage systems with emphasis on solid-state batteries. A brief overview of different PVD technologies and details highlighting the utility of PVD for the fabrication and characterization of individual battery materials are provided. In this context, the key methods that have been developed for the fabrication of solid electrolytes and active electrode materials with well-defined properties are described, and demonstrations of how these techniques facilitate the in-depth understanding of fundamental material properties and interfacial phenomena as well as the development of new materials are provided. Beyond the discussion of single components and interfaces, the progress on the device scale is also presented. State-of-the-art solid-state batteries, both academic and commercial types, are assessed in view of energy and power density as well as long-term stability. Finally, recent efforts to improve the power and energy density through the development of 3D-structured cells and the investigation of bulk cells are discussed.
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http://dx.doi.org/10.1002/advs.202002044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8188201PMC
June 2021

High Capacity Garnet-Based All-Solid-State Lithium Batteries: Fabrication and 3D-Microstructure Resolved Modeling.

ACS Appl Mater Interfaces 2018 Jul 21;10(26):22329-22339. Epub 2018 Jun 21.

Forschungszentrum Juelich GmbH , Wilhelm-Johnen Str. , 52425 Juelich , Germany.

The development of high-capacity, high-performance all-solid-state batteries requires the specific design and optimization of its components, especially on the positive electrode side. For the first time, we were able to produce a completely inorganic mixed positive electrode consisting only of LiCoO and Ta-substituted LiLaZrO (LLZ:Ta) without the use of additional sintering aids or conducting additives, which has a high theoretical capacity density of 1 mAh/cm. A true all-solid-state cell composed of a Li metal negative electrode, a LLZ:Ta garnet electrolyte, and a 25 μm thick LLZ:Ta + LiCoO mixed positive electrode was manufactured and characterized. The cell shows 81% utilization of theoretical capacity upon discharging at elevated temperatures and rather high discharge rates of 0.1 mA (0.1 C). However, even though the room temperature performance is also among the highest reported so far for similar cells, it still falls far short of the theoretical values. Therefore, a 3D reconstruction of the manufactured mixed positive electrode was used for the first time as input for microstructure-resolved continuum simulations. The simulations are able to reproduce the electrochemical behavior at elevated temperature favorably, however fail completely to predict the performance loss at room temperature. Extensive parameter studies were performed to identify the limiting processes, and as a result, interface phenomena occurring at the cathode active material/solid-electrolyte interface were found to be the most probable cause for the low performance at room temperature. Furthermore, the simulations are used for a sound estimation of the optimization potential that can be realized with this type of cell, which provides important guidelines for future oxide based all-solid-state battery research and fabrication.
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http://dx.doi.org/10.1021/acsami.8b06705DOI Listing
July 2018

Suppression of Aluminum Current Collector Dissolution by Protective Ceramic Coatings for Better High-Voltage Battery Performance.

Chemphyschem 2017 Jan 29;18(1):156-163. Epub 2016 Nov 29.

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

Batteries based on cathode materials that operate at high cathode potentials, such as LiNi Mn O (LNMO), in lithium-ion batteries or graphitic carbons in dual-ion batteries suffer from anodic dissolution of the aluminum (Al) current collector in organic solvent-based electrolytes based on imide salts, such as lithium bis(trifluoromethanesulfonyl) imide (LiTFSI). In this work, we developed a protective surface modification for the Al current collector by applying ceramic coatings of chromium nitride (Cr N) and studied the anodic Al dissolution behavior. By magnetron sputter deposition, two different coating types, which differ in their composition according to the CrN and Cr N phases, were prepared and characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and their electronic conductivity. Furthermore, the anodic dissolution behavior was studied by cyclic voltammetry and chronocoulometry measurements in two different electrolyte mixtures, that is, LiTFSI in ethyl methyl sulfone and LiTFSI in ethylene carbonate/dimethyl carbonate 1:1 (by weight). These measurements showed a remarkably reduced current density or cumulative charge during the charge process, indicating an improved anodic stability of the protected Al current collector. The coating surfaces after electrochemical treatment were characterized by means of SEM and XPS, and the presence or lack of pit formation, as well as electrolyte degradation products could be well correlated to the electrochemical results.
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http://dx.doi.org/10.1002/cphc.201601095DOI Listing
January 2017

About the Compatibility between High Voltage Spinel Cathode Materials and Solid Oxide Electrolytes as a Function of Temperature.

ACS Appl Mater Interfaces 2016 Oct 29;8(40):26842-26850. Epub 2016 Sep 29.

Department of Materials Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.

The reactivity of mixtures of high voltage spinel cathode materials LiNiMnO, LiFeMnO, and LiCoMnO cosintered with LiAlTi(PO) and LiLaZrTaO electrolytes is studied by thermal analysis using X-ray-diffraction and differential thermoanalysis and thermogravimetry coupled with mass spectrometry. The results are compared with predicted decomposition reactions from first-principles calculations. Decomposition of the mixtures begins at 600 °C, significantly lower than the decomposition temperature of any component, especially the electrolytes. For the cathode + LiLaZrTaO mixtures, lithium and oxygen from the electrolyte react with the cathodes to form highly stable LiMnO and then decompose to form stable and often insulating phases such as LaZrO, LaO, LaTaO, TiO, and LaMnO which are likely to increase the interfacial impedance of a cathode composite. The decomposition reactions are identified with high fidelity by first-principles calculations. For the cathode + LiAlTi(PO) mixtures, the Mn tends to oxidize to MnO or MnO, supplying lithium to the electrolyte for the formation of LiPO and metal phosphates such as AlPO and LiMPO (M = Mn, Ni). The results indicate that high temperature cosintering to form dense cathode composites between spinel cathodes and oxide electrolytes will produce high impedance interfacial products, complicating solid state battery manufacturing.
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http://dx.doi.org/10.1021/acsami.6b09059DOI Listing
October 2016

Li7La3Zr2O12 Interface Modification for Li Dendrite Prevention.

ACS Appl Mater Interfaces 2016 04 13;8(16):10617-26. Epub 2016 Apr 13.

Institute of Energy and Climate Research, Materials Synthesis and Processing (IEK-1), Forschungszentrum Jülich GmbH , 52425 Jülich, Germany.

Al-contaminated Ta-substituted Li7La3Zr2O12 (LLZ:Ta), synthesized via solid-state reaction, and Al-free Ta-substituted Li7La3Zr2O12, fabricated by hot-press sintering (HP-LLZ:Ta), have relative densities of 92.7% and 99.0%, respectively. Impedance spectra show the total conductivity of LLZ:Ta to be 0.71 mS cm(-1) at 30 °C and that of HP-LLZ:Ta to be 1.18 mS cm(-1). The lower total conductivity for LLZ:Ta than HP-LLZ:Ta was attributed to the higher grain boundary resistance and lower relative density of LLZ:Ta, as confirmed by their microstructures. Constant direct current measurements of HP-LLZ:Ta with a current density of 0.5 mA cm(-2) suggest that the short circuit formation was neither due to the low relative density of the samples nor the reduction of Li-Al glassy phase at grain boundaries. TEM, EELS, and MAS NMR were used to prove that the short circuit was from Li dendrite formation inside HP-LLZ:Ta, which took place along the grain boundaries. The Li dendrite formation was found to be mostly due to the inhomogeneous contact between LLZ solid electrolyte and Li electrodes. By flatting the surface of the LLZ:Ta pellets and using thin layers of Au buffer to improve the contact between LLZ:Ta and Li electrodes, the interface resistance could be dramatically reduced, which results in short-circuit-free cells when running a current density of 0.5 mA cm(-2) through the pellets. Temperature-dependent stepped current density galvanostatic cyclings were also carried out to determine the critical current densities for the short circuit formation. The short circuit that still occurred at higher current density is due to the inhomogeneous dissolution and deposition of metallic Li at the interfaces of Li electrodes and LLZ solid electrolyte when cycling the cell at large current densities.
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http://dx.doi.org/10.1021/acsami.6b00831DOI Listing
April 2016

Three-Dimensional, Fibrous Lithium Iron Phosphate Structures Deposited by Magnetron Sputtering.

ACS Appl Mater Interfaces 2015 Oct 6;7(40):22594-600. Epub 2015 Oct 6.

Institute of Energy and Climate Research, Materials Synthesis and Processing (IEK-1), Forschungszentrum Jülich GmbH , 52425 Jülich, Germany.

Crystalline, three-dimensional (3D) structured lithium iron phosphate (LiFePO4) thin films with additional carbon are fabricated by a radio frequency (RF) magnetron-sputtering process in a single step. The 3D structured thin films are obtained at deposition temperatures of 600 °C and deposition times longer than 60 min by using a conventional sputtering setup. In contrast to glancing angle deposition (GLAD) techniques, no tilting of the substrate is required. Thin films are characterized by X-ray diffraction (XRD), Raman spectrospcopy, scanning electron microscopy (SEM), cyclic voltammetry (CV), and galvanostatic charging and discharging. The structured LiFePO4+C thin films consist of fibers that grow perpendicular to the substrate surface. The fibers have diameters up to 500 nm and crystallize in the desired olivine structure. The 3D structured thin films have superior electrochemical properties compared with dense two-dimensional (2D) LiFePO4 thin films and are, hence, very promising for application in 3D microbatteries.
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http://dx.doi.org/10.1021/acsami.5b07090DOI Listing
October 2015
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