Journal article

Authors list: Riegger, LM; Otto, SK; Sadowski, M; Jovanovic, S; Kötz, O; Harm, S; Balzat, LG; Merz, S; Burkhardt, S; Richter, FH; Sann, J; Eichel, RA; Lotsch, BV; Granwehr, J; Albe, K; Janek, J

Publication year: 2022

Pages: 3659-3669

Journal: Chemistry of Materials

Volume number: 34

Issue number: 8

ISSN: 0897-4756

eISSN: 1520-5002

DOI Link: https://doi.org/10.1021/acs.chemmater.1c04302

Publisher: American Chemical Society

Abstract: 
Thiophosphate solid electrolytes containing metalloid ions such as siliconor germanium show a very high lithium-ion conductivity and the potential to enable solid-state batteries (SSBs). While the lithium metal anode (LMA) is necessary to achievespecific energies competitive with liquid lithium-ion batteries (LIBs), it is also well knownthat most of the metalloid ions used in promising thiophosphate solid electrolytes arereduced in contact with an LMA. This reduction reaction and its products formed at thesolid electrolyte|LMA interface can compromise the performance of an SSB due toimpedance growth. To study the reduction of these metalloid ions and their impact moreclosely, we used the recently synthesized Li7SiPS8as a member of the tetragonalLi10GeP2S12(LGPS) family. Stripping/plating experiments and the temporal evolution of the impedance of symmetric Li|Li7SiPS8|Litransference cells show a severe increase in cell resistance. We characterize the reduction of Li7SiPS8after lithium deposition with insitu X-ray photoelectron spectroscopy, time-of-flight secondary-ion mass spectrometry, and solid-state nuclear magnetic resonancespectroscopy. The results indicate a continuous reaction without the formation of elemental silicon. For elucidating the reactionpathways, density functional theory calculations are conducted followed by ab initio molecular dynamics simulations to study theinterface evolution atfinite temperature. The resulting electronic density of states confirms that no elemental silicon is formed duringthe decomposition. Our study reveals that Li7SiPS8cannot be used in direct contact with the LMA, even though it is a promisingcandidate as both a separator and a catholyte material in SSBs

Harvard Citation style: Riegger, L., Otto, S., Sadowski, M., Jovanovic, S., Kötz, O., Harm, S., et al. (2022) Instability of the Li(7)SiPS(8 )Solid Electrolyte at the Lithium Metal Anode and Interphase Formation, Chemistry of Materials, 34(8), pp. 3659-3669. https://doi.org/10.1021/acs.chemmater.1c04302

APA Citation style: Riegger, L., Otto, S., Sadowski, M., Jovanovic, S., Kötz, O., Harm, S., Balzat, L., Merz, S., Burkhardt, S., Richter, F., Sann, J., Eichel, R., Lotsch, B., Granwehr, J., Albe, K., & Janek, J. (2022). Instability of the Li(7)SiPS(8 )Solid Electrolyte at the Lithium Metal Anode and Interphase Formation. Chemistry of Materials. 34(8), 3659-3669. https://doi.org/10.1021/acs.chemmater.1c04302