清华大学刘凯研究组取得一项新突破。他们的研究开发出了超分子硼酸锂间相化学合理调控的阳极分解途径。相关论文发表在2025年3月3日出版的《德国应用化学》杂志上。

研究组设计并合成了两种硼酸锂：（2-甲氧基-15-冠-5）三氟硼酸锂（C-LiMCFB）和（15-甲氧基-2,5,8,11,14- pentaoxhexadecan）三氟硼酸锂（L-LiMCFB），分别以环15-冠-5 （15C5）和线性五乙二醇单甲基醚（PEGME）为主基团连接在硼中心。在C-LiMCFB中，15C5与Li+的超分子多齿螯合/脱螯合可以依次失活/激活C-O键的阳极分解，从而导致B-O和C-O键的受控裂解途径。控制界面化学导致在NCM811表面形成均匀的CEI层，富含与LiF交织的锂硼氧离子。

这种新颖的CEI结构在机械稳定性、粘附性和韧性方面取得了卓越的平衡，为NCM811阴极提供了非常理想的保护。这些新型超分子硼基锂盐的发现，不仅为合理调整电解质解开了超分子化学，而且为高能锂金属电池中CEI的形成机制提供了更深入的认识。

据介绍，稳定的阴极-电解质界面（CEI）的合理裁剪和分子水平工程，对于提高下一代高能层状富镍氧化物基锂金属电池的性能至关重要。然而，开发具有合理控制界面化学的定制电解质添加剂仍然具有很大的挑战性。

附：英文原文

Title: Controlled Anodic Decomposition Pathway of Supramolecular Lithium Borate for Rationally Tuned Interphase Chemistry

Author: Haiyu Zhou, Wenhui Hou, Da Zhu, Pan Zhou, Xuwen Peng, Zhi Liu, Shuaishuai Yan, Yang Lu, Yu Ou, Fengxiang Liu, Yingchun Xia, Hao Liu, Qingbin Cao, Xuan Song, Decai Guo, Hong Xu, Kai Liu

Issue&Volume: 2025-03-03

Abstract: The rational tailoring and molecular-level engineering of stable cathode-electrolyte interphases (CEIs) are paramount to advancing the performance of next-generation high energy, layered nickel-rich oxide based lithium metal batteries. However, developing well-tailored electrolyte additives with rationally controlled interfacial chemistry remains highly challenging. Here, we designed and synthesized two lithium borates: lithium (2-methoxy-15-crown-5)trifluoroborate (C-LiMCFB) and lithium (15-methoxy-2,5,8,11,14-pentaoxahexadecan)trifluoroborate (L-LiMCFB), incorporating cyclic 15-crown-5 (15C5) and linear pentaethylene glycol monomethyl ether (PEGME) as respective host groups tethered to the boron center. In C-LiMCFB, the supramolecular polydentate chelation/de-chelation of the 15C5 with Li+ could sequentially deactivate/activate the anodic decomposition of the C-O bonds, therefore leading to the controlled cleavage pathway of B-O and C-O bonds. The controlled interfacial chemistry leads to the formation of a uniform CEI layer, rich in lithium boron-oxygen clusters interwoven with LiF, on the NCM811 surface. This novel CEI configuration demonstrates an exceptional balance of mechanical robustness, adhesiveness, and toughness, providing highly desirable protection for the NCM811 cathode. The discovery of these novel supramolecular boron-based lithium salts not only unlocks supramolecular chemistry for rational electrolyte tuning but also provides a deeper understanding of the CEI formation mechanism in high-energy lithium metal batteries.

DOI: 10.1002/anie.202500425

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202500425