Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.
Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University , Ithaca, New York 14853, United States.
ACS Cent Sci. 2015 Jul 22;1(4):198-205. doi: 10.1021/acscentsci.5b00195. Epub 2015 Jul 10.
Understanding the mechanisms of lithium-ion transport in polymers is crucial for the design of polymer electrolytes. We combine modular synthesis, electrochemical characterization, and molecular simulation to investigate lithium-ion transport in a new family of polyester-based polymers and in poly(ethylene oxide) (PEO). Theoretical predictions of glass-transition temperatures and ionic conductivities in the polymers agree well with experimental measurements. Interestingly, both the experiments and simulations indicate that the ionic conductivity of PEO, relative to the polyesters, is far higher than would be expected from its relative glass-transition temperature. The simulations reveal that diffusion of the lithium cations in the polyesters proceeds via a different mechanism than in PEO, and analysis of the distribution of available cation solvation sites in the various polymers provides a novel and intuitive way to explain the experimentally observed ionic conductivities. This work provides a platform for the evaluation and prediction of ionic conductivities in polymer electrolyte materials.
理解锂离子在聚合物中的传输机制对于聚合物电解质的设计至关重要。我们结合模块化合成、电化学表征和分子模拟来研究新型聚酯基聚合物和聚（环氧乙烷）（PEO）中的锂离子传输。聚合物的玻璃化转变温度和离子电导率的理论预测与实验测量吻合良好。有趣的是，实验和模拟都表明，与聚酯相比，PEO 的离子电导率要高得多，这远远超过其相对玻璃化转变温度的预期。模拟表明，锂离子在聚酯中的扩散机制与 PEO 不同，对各种聚合物中可用阳离子溶剂化位的分布进行分析为解释实验观察到的离子电导率提供了一种新颖而直观的方法。这项工作为评估和预测聚合物电解质材料中的离子电导率提供了一个平台。
