MULTISCALE CHARACTERISATION OF HIGH-ENERGY LITHIUM-SULFUR BATTERIES

A combination of operando multimodal X-ray characterisation techniques were used to study the morphological evolution and chemical modification of sulfur battery electrodes in a working electrochemical cell. It was possible to demonstrate the heterogeneous behaviour of the 3D electrodes and to better understand the reaction mechanisms of this promising battery chemistry.

STRUCTURE OF MATERIALS

146 ESRF

Grain boundary mobilities in polycrystals, J. Zhang (a,b), W. Ludwig (c), Y.B. Zhang (d), H.H. Sørensen (e), D.J. Rowenhorst (f), A. Yamanaka (g), P.W. Voorhees (a) and H.F. Poulsen (b), Acta Mater. 191, 211- 220 (2020); https://doi.org/10.1016/j.

actamat.2020.03.044. (a) Department of Materials Science and Engineering, Northwestern University (USA) (b) Department of Physics, DTU (Denmark) (c) ESRF (d) Department of Mechanical Engineering,

DTU (Denmark) (e) Department of Applied Mathematics and Computer Science, DTU (Denmark) (f) The US Naval Research Laboratory (USA) (g) Tokyo University of Agriculture and Technology (Japan)

[1] J. Zhang et al. Acta Mater. 129, 229-238 (2017).

PRINCIPAL PUBLICATION AND AUTHORS

REFERENCES

fit. The close correspondence of the boundary morphologies between experiment and simulation validates the fitting approach. Figures 127d-e show the results for 344 boundaries where the fitting was particularly good. The results reveal that there is no apparent correlation with any of the five degrees of freedom related to crystallography in striking contrast to the prediction of classical models in the field.

Directly comparing 3D experiments and 3D simulations is an approach that can be used in many other fields in materials science, e.g., plastic deformation and phase transformations [1]. With hundreds of millions of points in space-time, this approach can guide theory and validate models in an unprecedented way. In particular, in favourable cases, all relevant material parameters can be extracted from one experiment using representative samples and processing tools.

Lithium rechargeable batteries have been the subject of tremendous research efforts over the last three decades, due to the growing demand for consumer electronics, especially portable devices. Lithium-ion batteries, in particular, have been considerably developed over the past decades, resulting in high performance and highly mature commercial battery technology. But more recently, the significant interest in electric vehicles has pushed research further, to develop better, safer, cheaper and more efficient lithium batteries.

Fig. 128: a) Schematic representation of the airtight pressure- controlled operando Li/S cell characterised at ID15A. b) X-ray diffraction pattern of a sulfur electrode, recorded in the operando cell, using the conventional XRD technique (black) and XRD-CT (red), showing the significant gain in resolution when using XRD-CT. Reprinted from principal publication with kind permission from Elsevier.