Dolotko, O.

Ehrenberg, H.

Knapp, M.

Monchak, M.

Mühlbauer, M.J.

Senyshyn, A.

Mühlbauer, M. J.

KITopen

M.J. Mühlbauer1,2, O. Dolotko1, M. Knapp2, M. Monchak1,2, A. Senyshyn1, H. Ehrenberg2 1Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Garching, Germany Lithium-Ion Batteries from a Neutron Point of View Contact: Dr. M.J. Mühlbauer Prof. Dr. H. Ehrenberg   E-mail: Martin.Muehlbauer@kit.edu E-mail: Helmut.Ehrenberg@kit.edu  Phone: +49.89.289.14373  Phone: +49.721.608.47915   Motivation and objectives  Results •  The improvement of Lithium-ion batteries needs new materials and advanced cell concepts. •  Complex interactions between components require a characterization of materials at least on cell level. •  Life-time modelling and safety issues need to be considered on complete devices. •  Proceeding of fatigue can only be studied by non-destructive methods. •  Multi-phase refinements of the underlying crystal structures, including light elements and microstructure parameters. •  Improving spatial resolution in order to resolve components on a length scale of ~10-100 µm. •  Correlation of state-of-charge (SOC) and state-of-health (SOH) with structural details. •  Revealing working and fatigue mechanisms. •  Establishing comprehensive life-time models and failure scenarios (supported by complementary methods)  Approach Complementary X-ray data for details of cell geometry Neutron Diffraction: •  Sensible for changes on an atomic    length scale •  Sensitivity to light atoms; discrimination of transition elements •  Accurate determination of atomic positions and Debye-Waller factors •  Averaging over sample volume Neutron Imaging: •  Sensible for changes on a length scale of micrometers •  Deep penetration of neutrons into the matter •  meV energy for epithermal neutrons •  High absorption cross section for lithium; sufficient absorption contrast for transition elements •  3D representation of the whole sample volume Time Deviation from the expected stage formation of lithiated graphites at low lithium content Exchange of lithium causes the neutron attenuation to change according to the state of charge A. Senyshyn, M.J. Mühlbauer, K. Nikolowski, T. Pirling, H. Ehrenberg, J. Power Sources 203 (2012) 126-129 Charge and discharge of cells with simultaneous acquisition of neutron diffraction and imaging data Time resolved neutron diffraction revealing an asymmetry in lithium intercalation A. Senyshyn, O. Dolotko, M.J. Mühlbauer, K. Nikolowski, H. Fuess, H. Ehrenberg, Journal of The Electrochemical Society, 160 (5) A3198-A3205 (2013) Due to volume change of the electrodes the electrolyte level inside the reservoir is altered Lithium occupation of cathode and anode for different states of fatigue O. Dolotko, A. Senyshyn, M.J. Mühlbauer, K. Nikolowski, F. Scheiba, H. Ehrenberg, Journal of The Electrochemical Society, 159 (12) A1-A7 (2012) 0 200 400 600 800 10003035404550556065707580859095100 25°C 50°CCharged stateDischarged stateLi occupation in LixCoO2, %Number of cycles0 200 400 600 800 10000102030LiC6 (cycled at 50°C)Phase fraction, wt.%Number of cyclesLiC12 (cycled at 25°C)LiC12 (cycled at 50°C)LiC6 (cycled at 25°C)“filled” “empty” charged discharged 4.0 V 4.2 V 3.0 V 2Institute for Applied Materials – Energy Storage Systems, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany 

Lithium-ion batteries from a neutron point of view

https://publikationen.bibliothek.kit.edu/220103777/3817003

Lithium-ion batteries from a neutron point of view

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