Surface Degeneration of Li3PS4–LiI Glass-Ceramic Electrolyte by Exposure to Humidity-Controlled Air and Its Recovery by Thermal Treatment

Sulfide-based solid electrolytes are desirable for use in all-solid-state batteries owing to their high ionic conductivity and plasticity. However, they generally degrade upon exposure to water and can generate toxic hydrogen sulfide even in dry-room atmospheres. To prevent their degradation, surfac...

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Main Authors: Hikaru SANO, Yusuke MORINO, Yasuyuki MATSUMURA, Koji KAWAMOTO, Hiroyuki HIGUCHI, Noriyuki YAMAMOTO, Atsunori MATSUDA, Hirofumi TSUKASAKI, Shigeo MORI, Atsushi SAKUDA, Akitoshi HAYASHI
Format: Article
Language:English
Published: The Electrochemical Society of Japan 2023-05-01
Series:Electrochemistry
Subjects:
Online Access:https://www.jstage.jst.go.jp/article/electrochemistry/91/5/91_23-00029/_html/-char/en
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author Hikaru SANO
Yusuke MORINO
Yasuyuki MATSUMURA
Koji KAWAMOTO
Hiroyuki HIGUCHI
Noriyuki YAMAMOTO
Atsunori MATSUDA
Hirofumi TSUKASAKI
Shigeo MORI
Atsushi SAKUDA
Akitoshi HAYASHI
author_facet Hikaru SANO
Yusuke MORINO
Yasuyuki MATSUMURA
Koji KAWAMOTO
Hiroyuki HIGUCHI
Noriyuki YAMAMOTO
Atsunori MATSUDA
Hirofumi TSUKASAKI
Shigeo MORI
Atsushi SAKUDA
Akitoshi HAYASHI
author_sort Hikaru SANO
collection DOAJ
description Sulfide-based solid electrolytes are desirable for use in all-solid-state batteries owing to their high ionic conductivity and plasticity. However, they generally degrade upon exposure to water and can generate toxic hydrogen sulfide even in dry-room atmospheres. To prevent their degradation, surface stabilization is required and further research into the degradation mechanism is necessary. In the present study, the stability of Li3PS4–LiI glass ceramic (LPSI) has been examined under low-humidity conditions. In contrast to an argyrodite-type solid electrolyte, exposure of LPSI to dry air with a dew point of −20 °C resulted in low H2S-gas generation and reduced ionic conductivity of LPSI. Since the conductivity mostly recovered after vacuum heating at 100 °C, the H2S generation is not considered to be the major reason for the reduction in conductivity. On the contrary, it is suggested that water molecules are present on the LPSI powder particles after dry-air exposure, resulting in the formation of a degraded LPSI layer and low ionic conductivity, and that most of the water molecules are removed during vacuum heating, resulting in the recovery of conductivity. Furthermore, optimal vacuum-heating conditions were obtained from X-ray diffraction and temperature-programmed desorption-mass spectrometry measurements, indicating an optimal temperature and heating time of 100 °C and 2 h, respectively. Impedance measurements were used to probe the degradation of the surface layer. The condition of the surface layer was affected by the pellet-forming pressure, and it was easier to detect the degradation of the surface layer when the pellets were formed at low pressures. This paper contributes to the formulation of guidelines for the development of water-resistant solid electrolytes.
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spelling doaj.art-7e5e98cbffeb49a1bd59cd33991524b52023-05-31T01:16:19ZengThe Electrochemical Society of JapanElectrochemistry2186-24512023-05-0191505700405700410.5796/electrochemistry.23-00029electrochemistrySurface Degeneration of Li3PS4–LiI Glass-Ceramic Electrolyte by Exposure to Humidity-Controlled Air and Its Recovery by Thermal TreatmentHikaru SANO0https://orcid.org/0000-0002-7557-0767Yusuke MORINO1https://orcid.org/0000-0002-6973-7786Yasuyuki MATSUMURA2Koji KAWAMOTO3Hiroyuki HIGUCHI4Noriyuki YAMAMOTO5Atsunori MATSUDA6https://orcid.org/0000-0002-6493-1205Hirofumi TSUKASAKI7https://orcid.org/0000-0003-0523-5469Shigeo MORI8Atsushi SAKUDA9https://orcid.org/0000-0002-9214-0347Akitoshi HAYASHI10https://orcid.org/0000-0001-9503-5561Consortium for Lithium Ion Battery Technology and Evaluation Center (LIBTEC)Consortium for Lithium Ion Battery Technology and Evaluation Center (LIBTEC)Consortium for Lithium Ion Battery Technology and Evaluation Center (LIBTEC)Consortium for Lithium Ion Battery Technology and Evaluation Center (LIBTEC)Idemitsu Kosan Co., Ltd.Idemitsu Kosan Co., Ltd.Toyohashi University of TechnologyGraduate School of Engineering, Osaka Metropolitan UniversityGraduate School of Engineering, Osaka Metropolitan UniversityGraduate School of Engineering, Osaka Metropolitan UniversityGraduate School of Engineering, Osaka Metropolitan UniversitySulfide-based solid electrolytes are desirable for use in all-solid-state batteries owing to their high ionic conductivity and plasticity. However, they generally degrade upon exposure to water and can generate toxic hydrogen sulfide even in dry-room atmospheres. To prevent their degradation, surface stabilization is required and further research into the degradation mechanism is necessary. In the present study, the stability of Li3PS4–LiI glass ceramic (LPSI) has been examined under low-humidity conditions. In contrast to an argyrodite-type solid electrolyte, exposure of LPSI to dry air with a dew point of −20 °C resulted in low H2S-gas generation and reduced ionic conductivity of LPSI. Since the conductivity mostly recovered after vacuum heating at 100 °C, the H2S generation is not considered to be the major reason for the reduction in conductivity. On the contrary, it is suggested that water molecules are present on the LPSI powder particles after dry-air exposure, resulting in the formation of a degraded LPSI layer and low ionic conductivity, and that most of the water molecules are removed during vacuum heating, resulting in the recovery of conductivity. Furthermore, optimal vacuum-heating conditions were obtained from X-ray diffraction and temperature-programmed desorption-mass spectrometry measurements, indicating an optimal temperature and heating time of 100 °C and 2 h, respectively. Impedance measurements were used to probe the degradation of the surface layer. The condition of the surface layer was affected by the pellet-forming pressure, and it was easier to detect the degradation of the surface layer when the pellets were formed at low pressures. This paper contributes to the formulation of guidelines for the development of water-resistant solid electrolytes.https://www.jstage.jst.go.jp/article/electrochemistry/91/5/91_23-00029/_html/-char/enelectrochemical ac impedancesulfide-based li–p–s–i glass-ceramic electrolyteall-solid-state lithium-ion batterydegeneration mechanism
spellingShingle Hikaru SANO
Yusuke MORINO
Yasuyuki MATSUMURA
Koji KAWAMOTO
Hiroyuki HIGUCHI
Noriyuki YAMAMOTO
Atsunori MATSUDA
Hirofumi TSUKASAKI
Shigeo MORI
Atsushi SAKUDA
Akitoshi HAYASHI
Surface Degeneration of Li3PS4–LiI Glass-Ceramic Electrolyte by Exposure to Humidity-Controlled Air and Its Recovery by Thermal Treatment
Electrochemistry
electrochemical ac impedance
sulfide-based li–p–s–i glass-ceramic electrolyte
all-solid-state lithium-ion battery
degeneration mechanism
title Surface Degeneration of Li3PS4–LiI Glass-Ceramic Electrolyte by Exposure to Humidity-Controlled Air and Its Recovery by Thermal Treatment
title_full Surface Degeneration of Li3PS4–LiI Glass-Ceramic Electrolyte by Exposure to Humidity-Controlled Air and Its Recovery by Thermal Treatment
title_fullStr Surface Degeneration of Li3PS4–LiI Glass-Ceramic Electrolyte by Exposure to Humidity-Controlled Air and Its Recovery by Thermal Treatment
title_full_unstemmed Surface Degeneration of Li3PS4–LiI Glass-Ceramic Electrolyte by Exposure to Humidity-Controlled Air and Its Recovery by Thermal Treatment
title_short Surface Degeneration of Li3PS4–LiI Glass-Ceramic Electrolyte by Exposure to Humidity-Controlled Air and Its Recovery by Thermal Treatment
title_sort surface degeneration of li3ps4 lii glass ceramic electrolyte by exposure to humidity controlled air and its recovery by thermal treatment
topic electrochemical ac impedance
sulfide-based li–p–s–i glass-ceramic electrolyte
all-solid-state lithium-ion battery
degeneration mechanism
url https://www.jstage.jst.go.jp/article/electrochemistry/91/5/91_23-00029/_html/-char/en
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