Morino Yusuke, Otoyama Misae, Okumura Toyoki, Kuratani Kentaro, Shibata Naoya, Ito Daisuke, Sano Hikaru
Murata Manufacturing Co., Ltd., 1-10-1 Higashikotari, Nagaokakyo-shi, Kyoto 617-8555, Japan.
National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
ACS Omega. 2024 Sep 6;9(37):38523-38531. doi: 10.1021/acsomega.4c03685. eCollection 2024 Sep 17.
Although moisture-induced deterioration mechanisms in sulfide solid electrolytes to enhance atmospheric stability have been investigated, the additional impact of CO exposure remains unclear. This study investigated the generation of HS from LiSnS under HO and CO exposure. LiSnS was exposed to Ar gas at a dew point of 0 °C with and without 500 ppm of CO, and its ion conductive properties were evaluated. Although the lithium-ion conductivity of LiSnS decreased regardless of the presence of CO, the amount of HS generated with CO was five times higher. To elucidate the underlying mechanism, X-ray diffraction and Raman spectroscopy were used. Without CO, hydrate LiSnS·4HO formation markedly increased, whereas, with CO, it increased a little. The difference revealed distinct deterioration mechanisms leading to a decrease in lithium-ion conductivity: without CO, adsorbed HO and LiSnS·4HO contributed to the decrease, while with CO, a weak acid dissociation reaction could reduce the thermodynamic stability of the moisture-exposed LiSnS surface including LiSnS·4HO and adsorbed HO, promoting HS release and carbonate formation. This was supported by the recovery of lithium-ion conductivity after vacuum heating. The concerted influence of HO and CO provides valuable insights into the fundamental deterioration mechanisms in sulfide solid electrolytes that could be applied in battery manufacturing processes.
尽管已经对硫化物固体电解质中由水分引起的劣化机制进行了研究，以提高其大气稳定性，但CO暴露的额外影响仍不清楚。本研究调查了在HO和CO暴露下LiSnS中HS的生成情况。将LiSnS在露点为0°C的Ar气中暴露，分别有无500 ppm的CO，并对其离子导电性能进行了评估。尽管无论有无CO，LiSnS的锂离子电导率都会降低，但有CO时生成的HS量要高出五倍。为了阐明潜在机制，使用了X射线衍射和拉曼光谱。没有CO时，水合物LiSnS·4HO的形成显著增加，而有CO时，其增加幅度较小。这种差异揭示了导致锂离子电导率降低的不同劣化机制：没有CO时，吸附的HO和LiSnS·4HO导致电导率降低，而有CO时，弱酸解离反应会降低包括LiSnS·4HO和吸附的HO在内的暴露于水分的LiSnS表面的热力学稳定性，促进HS释放和碳酸盐形成。真空加热后锂离子电导率的恢复证实了这一点。HO和CO的协同影响为硫化物固体电解质中基本的劣化机制提供了有价值的见解，这些见解可应用于电池制造过程。
