Electrolytes play an important role in transporting metal ions (e.g., Li+) in metal ion batteries, while understanding the relationship between the electrolyte properties and behaviors is still challenging. Herein, we detect the existence of weak solvent–solvent interactions in electrolytes by nuclear magnetic resonance (NMR), particularly discovering that such interactions have a significant function of stabilizing the electrolytes, which has never been reported before. As a paradigm, we renovated the understanding of the role of ethylene carbonate (EC) solvent in the lithium-ion battery electrolyte. We find that the EC solvent can stabilize the linear carbonate solvent electrolyte, particularly the diethyl carbonate (DEC) electrolyte, by the weak intermolecular interactions, enhancing the energy difference between the orbitals of the Li+(EC)x(DEC)y complex, in turn demonstrating strong capability against reduction. Our viewpoint was further demonstrated in other metal ion batteries (e.g., Na+, K+), whose discovery is significant for designing electrolytes and in-depth understanding of the battery performance.
Bibliographical noteKAUST Repository Item: Exported on 2023-02-20
Acknowledgements: The authors greatly thank the National Natural Science Foundation of China (Grant 22122904) for funding support. This work is also supported by the National Natural Science Foundation of China (Grants 21978281, 22109155, and U21A20330). The authors also thank the Bureau of International Cooperation Chinese Academy of Sciences, CAS-NST Joint Research Projects (Grant 121522KYSB20200047), and the Scientific and Technological Developing Project of Jilin Province (Grant YDZJ202101ZYTS022). The computational work was done on the KAUST supercomputer.