High Ionic Conductivity with Improved Lithium Stability of CaS- and CaI2-Doped Li7P3S11 Solid Electrolytes Synthesized by Liquid-Phase Synthesis

Kazuhiro Hikima; Ikuyo Kusaba; Hirotada Gamo; Nguyen Huu Huy Phuc; Hiroyuki Muto; Atsunori Matsuda

doi:10.1021/acsomega.2c00546

High Ionic Conductivity with Improved Lithium Stability of CaS- and CaI₂-Doped Li₇P₃S₁₁ Solid Electrolytes Synthesized by Liquid-Phase Synthesis

ACS Omega. 2022 May 6;7(19):16561-16567. doi: 10.1021/acsomega.2c00546. eCollection 2022 May 17.

Authors

Kazuhiro Hikima¹, Ikuyo Kusaba¹, Hirotada Gamo¹, Nguyen Huu Huy Phuc¹, Hiroyuki Muto^{1

2}, Atsunori Matsuda¹

Affiliations

¹ Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku, Toyohashi, Aichi 441-8580, Japan.
² Institute of Liberal Arts and Sciences, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku, Toyohashi, Aichi 441-8580, Japan.

Abstract

Li₇P₃S₁₁ solid electrolytes (SEs) subjected to liquid-phase synthesis with CaS or CaI₂ doping were investigated in terms of their ionic conductivity and stability toward lithium anodes. No peak shifts were observed in the XRD patterns of CaS- or CaI₂-doped Li₇P₃S₁₁, indicating that the doping element remained at the grain boundary. CaS- or CaI₂-doped Li₇P₃S₁₁ showed no internal short circuit, and the cycling continued, indicating that not only CaI₂ including I^- but also CaS could help increase the lithium stability. These results provide insights for the development of sulfide SEs for use in all-solid-state batteries in terms of their ionic conductivity and stability toward lithium anodes.