Wang Daiwei, Gwalani Bharat, Wierzbicki Dominik, Singh Vijay, Jhang Li-Ji, Rojas Tomas, Kou Rong, Liao Meng, Ye Lei, Jiang Heng, Shan Shuhua, Silver Alexander, Ngo Anh T, Du Yonghua, Li Xiaolin, Wang Donghai
Department of Mechanical Engineering, The Pennsylvania State University, University Park, PA, USA.
Pacific Northwest National Laboratory, Richland, WA, USA.
Nat Mater. 2025 Feb;24(2):243-251. doi: 10.1038/s41563-024-02057-x. Epub 2025 Jan 6.
Lithium-sulfur (Li-S) all-solid-state batteries (ASSBs) hold great promise for next-generation safe, durable and energy-dense battery technology. However, solid-state sulfur conversion reactions are kinetically sluggish and primarily constrained to the restricted three-phase boundary area of sulfur, carbon and solid electrolytes, making it challenging to achieve high sulfur utilization. Here we develop and implement mixed ionic-electronic conductors (MIECs) in sulfur cathodes to replace conventional solid electrolytes and invoke conversion reactions at sulfur-MIEC interfaces in addition to traditional three-phase boundaries. Microscopic and tomographic analyses reveal the emergence of mixed-conducting domains embedded in sulfur at sulfur-MIEC boundaries, helping promote the thorough conversion of active sulfur into LiS. Consequently, substantially improved active sulfur ratios (up to 87.3%) and conversion degrees (>94%) are achieved in Li-S ASSBs with high discharge capacity (>1,450 mAh g) and long cycle life (>1,000 cycles). The strategy is also applied to enhance the active material utilization of other conversion cathodes.
锂硫（Li-S）全固态电池（ASSB）在下一代安全、耐用且能量密集型电池技术方面具有巨大潜力。然而，固态硫转化反应动力学缓慢，主要局限于硫、碳和固体电解质受限的三相边界区域，这使得实现高硫利用率具有挑战性。在此，我们在硫阴极中开发并应用混合离子电子导体（MIEC）来替代传统固体电解质，并除了传统三相边界外，还在硫 - MIEC界面引发转化反应。微观和断层扫描分析揭示了在硫 - MIEC边界处硫中嵌入的混合导电域的出现，有助于促进活性硫彻底转化为LiS。因此，在具有高放电容量（>1450 mAh g）和长循环寿命（>1000次循环）的Li-S ASSB中，实现了大幅提高的活性硫比率（高达87.3%）和转化程度（>94%）。该策略还应用于提高其他转化阴极的活性材料利用率。
