Suppression Mechanisms of the Solid-Electrolyte Interface Formation at the Triple-Phase Interfaces in Thin-Film Li-Ion Batteries

Sou Yasuhara; Shintaro Yasui; Takashi Teranishi; Osami Sakata; Takuya Hoshina; Takaaki Tsurumi; Yutaka Majima; Mitsuru Itoh

doi:10.1021/acsami.1c05090

Suppression Mechanisms of the Solid-Electrolyte Interface Formation at the Triple-Phase Interfaces in Thin-Film Li-Ion Batteries

ACS Appl Mater Interfaces. 2021 Jul 28;13(29):34027-34032. doi: 10.1021/acsami.1c05090. Epub 2021 Jul 14.

Authors

Sou Yasuhara^{1

2}, Shintaro Yasui^{1

3}, Takashi Teranishi⁴, Osami Sakata⁵, Takuya Hoshina², Takaaki Tsurumi², Yutaka Majima¹, Mitsuru Itoh¹

Affiliations

¹ Laboratory for Materials and Structures, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
² School of Materials and Chemical Technology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
³ Laboratory for Advanced Nuclear Energy, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
⁴ Graduate School of Natural Science and Technology, Okayama University, 1-1-1, Tsushimanaka, Kita-ku, Okayama-shi, Okayama 700-8530, Japan.
⁵ Synchrotron X-ray Station at SPring-8 and Synchrotron X-ray Group, National Institute for Materials Science (NIMS), 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan.

PMID: 34258995
DOI: 10.1021/acsami.1c05090

Abstract

Side reactions of the charge/discharge in Li-ion batteries (LIBs) generate a solid-electrolyte interface (SEI) onto an electrode surface, resulting in the degradation of the lifetime of a cell. The suppression of SEI formations has attracted much attention for achieving longer cyclable LIBs. Our research group has previously reported that few SEI were observed at triple-phase interfaces (TPIs) consisting of BaTiO₃, LiCoO₂, and electrolyte interfaces in LIBs with excellent cyclability and ultrahigh-speed chargeability. An investigation on the suppression mechanisms of SEI formations at TPIs should yield important information on understanding the undesirable side reactions. Therefore, we have explored the suppression mechanisms of SEI formations by preparing epitaxial thin films and evaluating the surface of the samples after the electrochemical treatment. The results of X-ray photoelectron spectroscopy and scanning electron microscopy with energy-dispersive X-ray analysis measurements suggested that the decomposition of LiPF₆ was suppressed at TPIs, implying that the generation of PF₅ via the decomposition of LiPF₆ contributed to SEI formation.

Keywords: charge/discharge; solid-electrolyte interface; thin-film Li-ion.