Intermolecular Chemistry in Solid Polymer Electrolytes for High-Energy-Density Lithium Batteries

Solid polymer electrolytes (SPEs) have aroused wide interest in lithium batteries because of their sufficient mechanical properties, superior safety performances, and excellent processability. However, ionic conductivity and high-voltage compatibility of SPEs are still yet to meet the requirement of future energy-storage systems, representing significant barriers to progress. In this regard, intermolecular interactions in SPEs have attracted attention, and they can significantly impact on the Li+ motion and frontier orbital energy level of SPEs. Recent advances in improving electrochemcial performance of SPEs are reviewed, and the underlying mechanism of these proposed strategies related to intermolecular interaction is discussed, including ion-dipole, hydrogen bonds, pi-pi stacking, and Lewis acid-base interactions. It is hoped that this review can inspire a deeper consideration on this critical issue, which can pave new pathway to improve ionic conductivity and high-voltage performance of SPEs.