Solid-state polymer electrolytes and high-concentration liquid electrolytes, such as water-in-salt electrolytes and ionic liquids, are emerging materials to replace the flammable organic electrolytes widely used in industrial lithium-ion batteries. Extensive efforts have been made to understand the ion transport mechanisms and optimize the ion transport properties. This perspective reviews the current understanding of the ion transport and polymer dynamics in liquid and polymer electrolytes, comparing the similarities and differences in the two types of electrolytes. Combining recent experimental and theoretical findings, we attempt to connect and explain ion transport mechanisms in different types of small-molecule and polymer electrolytes from a theoretical perspective, linking the macroscopic transport coefficients to the microscopic, molecular properties such as the solvation environment of the ions, salt concentration, solvent/polymer molecular weight, ion pairing, and correlated ion motion. We emphasize universal features in the ion transport and polymer dynamics by highlighting the relevant time and length scales. Several outstanding questions and anticipated developments for electrolyte design are discussed, including the negative transference number, control of ion transport through precision synthesis, and development of predictive multiscale modeling approaches.

中文翻译：

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小分子和聚合物电解质中的离子传输。

固态聚合物电解质和高浓度液体电解质（如盐包水电解质和离子液体）是新兴的材料，可替代工业锂离子电池中广泛使用的易燃有机电解质。为了理解离子传输机理和优化离子传输性能，已经进行了广泛的努力。该观点回顾了当前对液体和聚合物电解质中离子迁移和聚合物动力学的理解，比较了两种类型电解质的异同。结合最近的实验和理论发现，我们尝试从理论角度连接和解释不同类型的小分子和聚合物电解质中的离子传输机制，将宏观传输系数与微观，分子特性，例如离子的溶剂化环境，盐浓度，溶剂/聚合物分子量，离子对和相关的离子运动。通过强调相关的时间和长度尺度，我们强调了离子迁移和聚合物动力学中的通用特征。讨论了电解质设计的几个突出问题和预期发展，包括负迁移数，通过精密合成控制离子迁移以及开发预测性多尺度建模方法。