Li Yang, Arnold William, Thapa Arjun, Jasinski Jacek B, Sumanasekera Gamini, Sunkara Mahendra, Druffel Thad, Wang Hui
Conn Center for Renewable Energy Research, University of Louisville, Louisville, Kentucky 40292, United States.
Department of Mechanical Engineering, University of Louisville, Louisville, Kentucky 40292, United States.
ACS Appl Mater Interfaces. 2020 Sep 23;12(38):42653-42659. doi: 10.1021/acsami.0c08261. Epub 2020 Sep 9.
Sulfide-based lithium (Li)-ion conductors represent one of the most popular solid electrolytes (SEs) for solid-state Li metal batteries (SSLMBs) with high safety. However, the commercial application of sulfide SEs is significantly limited by their chemical instability in air and electrochemical instability with electrode materials (metallic Li anode and oxide cathodes). To address these difficulties, here, we design and successfully demonstrate a novel sulfide-incorporated composite electrolyte (SCE) through the combination of inorganic sulfide Li argyrodite (LiPS) with poly(vinylidenefluoride--hexafluoropropylene) (PVDF-HFP) polymer. In this composite structure, LiPS is embedded in PVDF-HFP polymer matrix, making the SCE flexible and air-stable and achieve great chemical and electrochemical stability. Meanwhile, the presence of sulfide facilitates Li-ion transport in SCE, leading to a superior room-temperature ionic conductivity of 1.1 × 10 S cm. Using the SCE with enhanced stability while maintaining high conductivity, Li||Li symmetric cells achieved stable cycling up to 1000 h at 0.2 mA cm. In addition, LiFePO (LFP)||SCE||Li cells can deliver an impressive specific capacity of 160 mAh g over 150 cycles. These features indicate that LiPS/PVDF-HFP SCE is a promising candidate to contribute to the practical development of SSLMBs.
基于硫化物的锂离子导体是用于具有高安全性的固态锂金属电池（SSLMBs）的最受欢迎的固体电解质（SEs）之一。然而，硫化物SEs的商业应用受到其在空气中的化学不稳定性以及与电极材料（金属锂阳极和氧化物阴极）的电化学不稳定性的显著限制。为了解决这些难题，在此，我们通过将无机硫化物锂硫银锗矿（LiPS）与聚（偏二氟乙烯 - 六氟丙烯）（PVDF - HFP）聚合物相结合，设计并成功展示了一种新型的含硫化物复合电解质（SCE）。在这种复合结构中，LiPS嵌入在PVDF - HFP聚合物基体中，使SCE具有柔韧性且对空气稳定，并实现了良好的化学和电化学稳定性。同时，硫化物的存在促进了SCE中锂离子的传输，导致其在室温下具有1.1×10 S cm的优异离子电导率。使用具有增强稳定性同时保持高电导率的SCE，Li||Li对称电池在0.2 mA cm下可实现长达1000 h的稳定循环。此外，LiFePO（LFP）||SCE||Li电池在150次循环中可提供高达160 mAh g的令人印象深刻的比容量。这些特性表明LiPS/PVDF - HFP SCE是有助于SSLMBs实际发展的有前途的候选者。
