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Schleker PPM, Grosu C, Paulus M, Jakes P, Schlögl R, Eichel RA, Scheurer C, Granwehr J. Electrolyte contact changes nano-Li 4Ti 5O 12 bulk properties via surface polarons. Commun Chem 2023; 6:113. [PMID: 37286703 DOI: 10.1038/s42004-023-00913-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 05/30/2023] [Indexed: 06/09/2023] Open
Abstract
It is of general interest to combine the faradaic processes based high energy density of a battery with the non-faradaic processes based high power density of a capacitor in one cell. Surface area and functional groups of electrode materials strongly affect these properties. For the anode material Li4Ti5O12 (LTO), we suggest a polaron based mechanism that influences Li ion uptake and mobility. Here we show electrolytes containing a lithium salt induce an observable change in the bulk NMR relaxation properties of LTO nano particles. The longitudinal 7Li NMR relaxation time of bulk LTO can change by almost an order of magnitude and, therefore, reacts very sensitively to the cation and its concentration in the surrounding electrolyte. The reversible effect is largely independent of the used anions and of potential anion decomposition products. It is concluded that lithium salt containing electrolytes increase the mobility of surface polarons. These polarons and additional lithium cations from the electrolyte can now diffuse through the bulk, induce the observed enhanced relaxation rate and enable the non-faradaic process. This picture of a Li+ ion equilibrium between electrolyte and solid may help with improving the charging properties of electrode materials.
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Affiliation(s)
- P Philipp M Schleker
- Institut für Grundlagen der Elektrochemie IEK-9, Forschungszentrum Jülich, Wilhelm-Johnen Straße, 52425, Jülich, Germany.
| | - Cristina Grosu
- Institut für Grundlagen der Elektrochemie IEK-9, Forschungszentrum Jülich, Wilhelm-Johnen Straße, 52425, Jülich, Germany
- Institut für Chemie, Technische Universität München, 85748, Garching b, München, Germany
| | - Marc Paulus
- Institut für Grundlagen der Elektrochemie IEK-9, Forschungszentrum Jülich, Wilhelm-Johnen Straße, 52425, Jülich, Germany
- Institut für Physikalische Chemie (IPC), RWTH Aachen University, D-52074, Aachen, Germany
| | - Peter Jakes
- Institut für Grundlagen der Elektrochemie IEK-9, Forschungszentrum Jülich, Wilhelm-Johnen Straße, 52425, Jülich, Germany
- Institut für Physikalische Chemie (IPC), RWTH Aachen University, D-52074, Aachen, Germany
| | - Robert Schlögl
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6, 14195, Berlin, Germany
| | - Rüdiger-A Eichel
- Institut für Grundlagen der Elektrochemie IEK-9, Forschungszentrum Jülich, Wilhelm-Johnen Straße, 52425, Jülich, Germany
- Institut für Physikalische Chemie (IPC), RWTH Aachen University, D-52074, Aachen, Germany
| | - Christoph Scheurer
- Institut für Grundlagen der Elektrochemie IEK-9, Forschungszentrum Jülich, Wilhelm-Johnen Straße, 52425, Jülich, Germany
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6, 14195, Berlin, Germany
| | - Josef Granwehr
- Institut für Grundlagen der Elektrochemie IEK-9, Forschungszentrum Jülich, Wilhelm-Johnen Straße, 52425, Jülich, Germany
- Institut für Technische und Makromolekulare Chemie (ITMC), RWTH Aachen University, D-52074, Aachen, Germany
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Daniel DT, Szczuka C, Jakes P, Eichel RA, Granwehr J. Laplace inverted pulsed EPR relaxation to study contact between active material and carbon black in Li-organic battery cathodes. Phys Chem Chem Phys 2023; 25:12767-12776. [PMID: 37128728 DOI: 10.1039/d3cp00378g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The addition of conductive additives during electrode fabrication is standard practice to mitigate a low intrinsic electronic conductivity of most cathode materials used in Li-ion batteries. To ensure an optimal conduction pathway, these conductive additives, which generally consist of carbon particles, need to be in good contact with the active compounds. Herein, we demonstrate how a combination of pulsed electron paramagnetic resonance (EPR) relaxometry and inverse Laplace transform (ILT) can be used to study such contact. The investigated system consists of PTMA (poly(2,2,6,6-tetramethylpiperidinyloxy-4-ylmethacrylate)) monomer radicals, which is a commonly used redox unit in organic radical batteries (ORB), mixed at different ratios with Super P carbon black (CB) as the conductive additive. Inversion recovery data were acquired to determine longitudinal (T1) relaxation time constant distributions. It was observed that not only the position and relative amplitude, but also the number of relaxation modes varies as the composition of PTMA monomer and CB is changed, thereby justifying the use of ILT instead of fitting with a predetermined number of components. A hypothesis for the origin of different relaxation modes was devised. It suggests that the electrode composition may locally affect the quality of electronic contact between the active material and carbon black.
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Affiliation(s)
- Davis Thomas Daniel
- Institute of Energy and Climate Research (IEK-9), Forschungszentrum Jülich, Jülich, 52425, Germany.
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Aachen 52056, Germany
| | - Conrad Szczuka
- Institute of Energy and Climate Research (IEK-9), Forschungszentrum Jülich, Jülich, 52425, Germany.
| | - Peter Jakes
- Institute of Energy and Climate Research (IEK-9), Forschungszentrum Jülich, Jülich, 52425, Germany.
| | - Rüdiger-A Eichel
- Institute of Energy and Climate Research (IEK-9), Forschungszentrum Jülich, Jülich, 52425, Germany.
- Institute of Physical Chemistry, RWTH Aachen University, Aachen 52056, Germany
| | - Josef Granwehr
- Institute of Energy and Climate Research (IEK-9), Forschungszentrum Jülich, Jülich, 52425, Germany.
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Aachen 52056, Germany
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Damodaran K. Recent advances in NMR spectroscopy of ionic liquids. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 129:1-27. [PMID: 35292132 DOI: 10.1016/j.pnmrs.2021.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 12/17/2021] [Accepted: 12/28/2021] [Indexed: 06/14/2023]
Abstract
This review presents recent developments in the application of NMR spectroscopic techniques in the study of ionic liquids. NMR has been the primary tool not only for the structural characterization of ionic liquids, but also for the study of dynamics. The presence of a host of NMR active nuclei in ionic liquids permits widespread use of multinuclear NMR experiments. Chemical shifts and multinuclear coupling constants are used routinely for the structure elucidation of ionic liquids and of products formed by their covalent interactions with other materials. Also, the availability of a multitude of NMR techniques has facilitated the study of dynamical processes in them. These include the use of NOESY to study inter-ionic interactions, pulsed-field gradient techniques for probing transport properties, and relaxation measurements to elucidate rotational dynamics. This review will focus on the application of each of these techniques to investigate ionic liquids.
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Affiliation(s)
- Krishnan Damodaran
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States.
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Merz S, Wang J, Galvosas P, Granwehr J. MAS-NMR of [Pyr 13][Tf 2N] and [Pyr 16][Tf 2N] Ionic Liquids Confined to Carbon Black: Insights and Pitfalls. Molecules 2021; 26:6690. [PMID: 34771100 PMCID: PMC8587276 DOI: 10.3390/molecules26216690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 11/16/2022] Open
Abstract
Electrolytes based on ionic liquids (IL) are promising candidates to replace traditional liquid electrolytes in electrochemical systems, particularly in combination with carbon-based porous electrodes. Insight into the dynamics of such systems is imperative for tailoring electrochemical performance. In this work, 1-Methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide and 1-Hexyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide were studied in a carbon black (CB) host using spectrally resolved Carr-Purcell-Meiboom-Gill (CPMG) and 13-interval Pulsed Field Gradient Stimulated Echo (PFGSTE) Magic Angle Spinning Nuclear Magnetic Resonance (MAS-NMR). Data were processed using a sensitivity weighted Laplace inversion algorithm without non-negativity constraint. Previously found relations between the alkyl length and the aggregation behavior of pyrrolidinium-based cations were confirmed and characterized in more detail. For the IL in CB, a different aggregation behavior was found compared to the neat IL, adding the surface of a porous electrode as an additional parameter for the optimization of IL-based electrolytes. Finally, the suitability of MAS was assessed and critically discussed for investigations of this class of samples.
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Affiliation(s)
- Steffen Merz
- Fundamental Electrochemistry (IEK-9), Institute of Energy and Climate Research, Forschungszentrum Juelich, 52425 Juelich, Germany; (S.M.); (J.G.)
| | - Jie Wang
- MacDiamid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University Wellington, Wellington 6140, New Zealand;
| | - Petrik Galvosas
- MacDiamid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University Wellington, Wellington 6140, New Zealand;
| | - Josef Granwehr
- Fundamental Electrochemistry (IEK-9), Institute of Energy and Climate Research, Forschungszentrum Juelich, 52425 Juelich, Germany; (S.M.); (J.G.)
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, 52056 Aachen, Germany
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Paulus MC, Paulus A, Eichel RA, Granwehr J. Independent component analysis combined with Laplace inversion of spectrally resolved spin-alignment echo/T
1 3D 7Li NMR of superionic Li10GeP2S12. Z PHYS CHEM 2021. [DOI: 10.1515/zpch-2021-3136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Abstract
The use of independent component analysis (ICA) for the analysis of two-dimensional (2D) spin-alignment echo–T
1
7Li NMR correlation data with transient echo detection as a third dimension is demonstrated for the superionic conductor Li10GeP2S12 (LGPS). ICA was combined with Laplace inversion, or discrete inverse Laplace transform (ILT), to obtain spectrally resolved 2D correlation maps. Robust results were obtained with the spectra as well as the vectorized correlation maps as independent components. It was also shown that the order of ICA and ILT steps can be swapped. While performing the ILT step before ICA provided better contrast, a substantial data compression can be achieved if ICA is executed first. Thereby the overall computation time could be reduced by one to two orders of magnitude, since the number of computationally expensive ILT steps is limited to the number of retained independent components. For LGPS, it was demonstrated that physically meaningful independent components and mixing matrices are obtained, which could be correlated with previously investigated material properties yet provided a clearer, better separation of features in the data. LGPS from two different batches was investigated, which showed substantial differences in their spectral and relaxation behavior. While in both cases this could be attributed to ionic mobility, the presented analysis may also clear the way for a more in-depth theoretical analysis based on numerical simulations. The presented method appears to be particularly suitable for samples with at least partially resolved static quadrupolar spectra, such as alkali metal ions in superionic conductors. The good stability of the ICA analysis makes this a prospect algorithm for preprocessing of data for a subsequent automatized analysis using machine learning concepts.
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Affiliation(s)
- Marc Christoffer Paulus
- Institute of Energy and Climate Research – Fundamental Electrochemistry (IEK-9), Forschungszentrum Jülich GmbH , 52425 Jülich , Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University , 52056 Aachen , Germany
| | - Anja Paulus
- Institute of Energy and Climate Research – Fundamental Electrochemistry (IEK-9), Forschungszentrum Jülich GmbH , 52425 Jülich , Germany
- Institute of Physical Chemistry, RWTH Aachen University , 52056 Aachen , Germany
| | - Rüdiger-Albert Eichel
- Institute of Energy and Climate Research – Fundamental Electrochemistry (IEK-9), Forschungszentrum Jülich GmbH , 52425 Jülich , Germany
- Institute of Physical Chemistry, RWTH Aachen University , 52056 Aachen , Germany
| | - Josef Granwehr
- Institute of Energy and Climate Research – Fundamental Electrochemistry (IEK-9), Forschungszentrum Jülich GmbH , 52425 Jülich , Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University , 52056 Aachen , Germany
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Bridges CA, Martins ML, Jafta CJ, Sun XG, Paranthaman MP, Liu J, Dai S, Mamontov E. Dynamics of Emim + in [Emim][TFSI]/LiTFSI Solutions as Bulk and under Confinement in a Quasi-liquid Solid Electrolyte. J Phys Chem B 2021; 125:5443-5450. [PMID: 34003647 DOI: 10.1021/acs.jpcb.1c02383] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Quasi-liquid solid electrolytes are a promising alternative for next-generation Li batteries. These systems combine the safety of solid electrolytes with the desired properties of liquids and are typically formed by solutions of Li salts in ionic liquids incorporated into solid matrices. Here, we present a fundamental understanding of the transport properties in solutions of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][TFSI]), either in bulk form or incorporated in a boron nitride (BN) matrix. We performed a series of quasi-elastic neutron scattering experiments that, given the high incoherent neutron scattering cross section of hydrogen, allowed us to focus on the Emim+ dynamics. First, [Emim][TFSI]/LiTFSI solutions (0.5 and 2.5 mol·kg-1) were investigated and we show how the increase in the concentration reduces the Emim+ mobility and increases the activation energy of their long-range motions. Then, the 0.5 mol·kg-1 solution was incorporated into the BN matrix and we report that the diffusivities of the Emim+ cations that remain mobile under confinement are highly accelerated in comparison with the bulk sample and the activation energy of these motions is drastically reduced. We present the experimental evidence that this effect is related to the content of the Emim+ cations immobilized near the surfaces of the BN pores.
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Affiliation(s)
- C A Bridges
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - M L Martins
- Neutron Scattering Division, Oak Ridge National Laboratory, P.O. Box 2008 MS6455, Oak Ridge, Tennessee 37831, United States
| | - C J Jafta
- Electrification and Energy Infrastructures, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - X G Sun
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - M P Paranthaman
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - J Liu
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - S Dai
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - E Mamontov
- Neutron Scattering Division, Oak Ridge National Laboratory, P.O. Box 2008 MS6455, Oak Ridge, Tennessee 37831, United States
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