近日，西湖大学向宇轩团队探讨了固态-电解质界面中LiF的非均相性质。这一研究成果发表在2025年9月10日出版的《自然》杂志上。

电解质-电极界面是无数化学和物理过程的基础。在电池化学中，固态电解质间相（SEI）的形成对于保证可充电锂离子电池（LIBs）的可逆运行起着关键作用。然而，表征低结晶度和高灵敏度SEI的精确化学成分是一个巨大的挑战。

以氟化锂（LiF，一种被广泛研究和认为是SEI关键成分）为例，研究组对¹⁹F固态核磁共振（NMR）进行了研究，并发现在SEI中形成的LiF （LiFSEI）具有丰富的光谱特征，这些特征源于有限的LiF - LiH固溶体的形成：富氢相(LiH_1-yF_y)和富f相(LiF_1-xH_x)，通过⁶Li同位素核磁共振、同步加速器x射线衍射和冷冻电镜（cryo-EM）进一步验证。

通过表征在各种电解质中形成的SEI，研究组证实了LiH_1-yF_y在高库仑效率电解质中，这可以通过LiF - LiH固溶体比LiF表现出更高的离子电导率来解释。作为概念验证，研究组证明，与锂金属电池中的富LiF涂层相比，富LiH_1-yF_y涂层具有明显的优势。这种对SEI组分异质性质的修正理解将为电极-电解质界面设计提供新的见解。

附：英文原文

Title: Probing the heterogeneous nature of LiF in solid–electrolyte interphases

Author: Liu, Xiangsi, Li, Shuyang, Yuan, Chen, Zheng, Bizhu, Cheng, Gangya, Chen, Yufan, Lu, Xingyu, Gu, Danyu, Lv, Baijiang, Li, Hao, Yan, Zihan, Qian, Hui, Zhu, Yizhou, Sun, Dalin, Song, Yun, Xiang, Yuxuan

Issue&Volume: 2025-09-10

Abstract: The electrolyte–electrode interface serves as the foundation for a myriad of chemical and physical processes. In battery chemistry, the formation of a well-known solid–electrolyte interphase (SEI) plays a pivotal role in ensuring the reversible operations of rechargeable lithium-ion batteries (LIBs)1,2. However, characterizing the precise chemical composition of the low crystallinity and highly sensitive SEI presents a formidable challenge3. Here, taking lithium fluoride (LiF)—a widely studied and considered crucial SEI component4,5,6,7—as an example, we use 19F solid-state nuclear magnetic resonance (NMR) and identify that LiF formed in SEI (LiFSEI) has fruitful spectroscopy features that originated from the formation of limited LiF–LiH solid solutions: H-rich phase (LiH1yFy) and F-rich phase (LiF1xHx), which is further validated by 6Li isotope NMR, synchrotron X-ray diffraction and cryo-electron microscopy (cryo-EM). By characterizing SEI formed in various electrolytes, we confirm the dominance of LiH1yFy in high-coulombic-efficiency electrolyte, which can be rationalized by the fact that LiF–LiH solid solution shows improved ionic conductivity over LiF. As a proof of concept, we demonstrate that LiH1yFy-rich coating layer presents obvious advantages compared with LiF-rich coating layer in lithium-metal batteries. This revised understanding of the heterogeneous nature of SEI components would provide new insights for electrode–electrolyte interface design.

DOI: 10.1038/s41586-025-09498-7

Source: https://www.nature.com/articles/s41586-025-09498-7