脂肪族聚碳酸酯基固体聚合物电解质的制备及性能研究

Solid polymer electrolyte has been widely studied recently. However, the room-temperature conductivity is not high enough with one of the reason that the migration of lithium ion and the increase of salt concentration are hindered by the interaction between lithium ion and polymer chain as described by the coordination mechanism of the electric conduction. This project plans to develop a novel kind of solid polymer electrolyte with low coordination ability, high dissolving ability and high solvability for lithium salt, and the conductive mechanism is non-coordination. The aliphatic polycarbonate is chosen as the polymer matrix to load lithium salt with its low coordination and high dissolving abilities for lithium salt. Based on this, the interaction between polymer matrix and lithium salt weakens so as to increase the migration rate of lithium ion and not enhance the glass transition temperature of polymer matrix with the concentration of lithium salt increasing. The influence of chain segment sequence, stereo and polar effect of side group on lithium ion conductivity, migration coefficient and thermostability will be deeply studied. Based on this study, the solid polymer electrolyte will be modified and optimized so that some solid polymer electrolytes with high migration rate and good comprehensive performance will be obtained. Moreover, the conductive mechanism of the developed solid polymer electrolyte based on aliphatic polycarbonate will be investigated.

固体聚合物电解质受到研究者广泛关注，但室温电导率普遍不高，其中一个重要原因在于其“配位-解配位”的导电机理，高分子链与锂离子的相互作用限制了锂离子的快速迁移和负载盐浓度增大。本项目拟开发一类对锂盐具有低配位能力、高溶解和高溶剂化能力，导电机理为非配位机理的固体聚合物电解质。以脂肪族聚碳酸酯为基体负载锂盐，利用碳酸酯键对锂盐高溶解而低配位的特点，减弱二者间的相互作用，增大锂离子迁移速率，同时避免玻璃化温度随锂盐浓度增大而升高，从而制备高盐浓度电解质。深入研究该类聚合物电解质中链段序列结构、侧基极性和空间位阻对于锂离子导电率、锂离子迁移系数、热稳定性等物理和电化学性能的影响。在此研究结果的基础上，进行改性和优化，制得部分锂离子迁移速率高、综合性能优良的固体聚合物电解质。对脂肪族聚碳酸酯基固体聚合物电解质的导电机理进行考察，以丰富该领域的理论背景。

首先设计并合成了三类用于催化二氧化碳与环氧化合物共聚反应制备脂肪族聚碳酸酯的催化剂，分别为水杨醛缩2,6-二氨基吡啶锌（SDP-Zn）席夫碱配合物催化剂、2,6-吡啶二甲酸锌（PDA-Zn）催化剂、二苯甲酰甲烷缩2,6-二异丙基苯胺锌（DMDA-Zn）配合物催化剂，具有催化效率高、聚合选择性好的特点，可以高效地制备脂肪族聚碳酸酯。接着，制备了PPC基增塑聚合物电解质、PPC-PMMA基聚合物电解质、PPC交联聚合物电解质等脂肪族聚碳酸酯基聚合物电解质，并考察了改性方法、改性条件对其电化学性能、热性能和力学性能的影响规律，确定了适宜的改性条件。本项目执行期间还同时设计并制备了高拉伸、自修复聚合物电解质，包括PAM-PVP-H3PO4、PAM-PVA-H3PO4酸性高拉伸聚合物电解质、PAM-PVP-Na2SO4中性高拉伸聚合物电解质和PVA-卡拉胶-KOH碱性高拉伸聚合物电解质，以及PVA-单宁酸-H3PO4自修复聚合物电解质。这些聚合物电解质在具有高电导率的同时表现出了良好的力学性能。