ORALS

SESSION: SISAMTuePM2-R2	Mizutani International Symposium (6th Intl. Symp. on Science of Intelligent & Sustainable Advanced Materials (SISAM))
Tue. 29 Nov. 2022 / Room: Ballroom A
Session Chairs: Hiroshi Sakurai; Session Monitor: TBA

16:20: [SISAMTuePM210] OS Invited
Characterization of Battery Materials by X-ray Compton Scattering
Hiroshi Sakurai¹ ; Kosuke Suzuki¹ ; Tsuyoshi Takami² ; Yoshiharu Uchimoto² ; Naruki Tshuji³ ; Arun Bansil⁴ ; Bernardo Barbiellini⁵ ; Kazushi Hoshi¹ ; Yoshiharu Sakurai³ ; ¹Gunma University, Kiryu, Japan; ²Kyoto University, Kyoto, Japan; ³JASRI, Sayo, Japan; ⁴Northeastern University, Boston, United States; ⁵LUT University, Lappeenranta, Finland;
Paper Id: 401 [Abstract]

Compton-scattered X-ray spectra correspond to the electron momentum density in matter and reflect the wave function in the ground state [1]. Therefore, it is relatively easy to interpret the observed Compton-scattered X-ray spectrum by ab initio electronic structure calculations. The observed information is bulk-sensitive because prover X-rays have energies above 100 keV and are highly penetrating through materials. This research focuses on lithium-ion secondary battery materials. In green technologies such as electric vehicles, improvement of rechargeable battery materials is a key to enhance energy density and charge-discharge stability. In practical batteries, it is important to understand redox reactions and their spatial distribution. From a view point of redox reactions, we measured spinel LixMn2O4, a Li-ion battery cathode material. We found that the redox orbital in the lithium insertion and extraction process is mainly the oxygen 2p orbital [2], although the redox orbital has been considered to be manganese 3d states [3,4]. Furthermore, analysis of the shape of Compton-scattered X-ray spectra can be used as a new nondestructive testing (NDT) technique. We proposed S-parameter analysis to observe the spatial distribution of redox reactions in commercial batteries [5]. Our research shows that Compton scattering measurements can provide insight into the mechanism of lithium batteries and point the way to improved battery materials and new battery designs.

References:
references
[1] M. J. Cooper et al.,X-ray Compton Scattering (Oxford University Press, Oxford, 2004).
[2] K. Suzuki et al. Phys. Rev. Lett. 114, 087401 (2015).
[3] H. Berg et al., J. Mater. Chem. 9, 2813 (1999).
[4] G. E. Grechnev et al. Phys. Rev. B 65, 174408 (2002).
[5] K. Suzuki et al., J. Appl. Phys. 119, 025103 (2016).