无机物增强型阴离子交换复合膜电解质的研究

Anion exchange membrane (AEM) based chemical batteries have been attracted many attentions due to their superiority on such as the possibility of using non-noble metals as the electrode catalyst, no leakage of the liquid electrolyte and less corrosion of alkali towards the materials,low permeability of the available liquid fuels as well as easy integration and facilitate operations. However, the migration rate of hydroxide ions is slow. Moreover, the polymer materials for the AEMs degrade easily in alkaline medium. All of these problems result in low performance of the cell based on the AEMs. Therefore the AEMs with longevity and high durability are needed. According to these problems, we propose to prepare the AEMs with enhanced properties by inorganic substances. The high stability towards strong alkali and the alkaline nature of the inorganic substances are supposed to benefit the durability and hydroxide ion conduction of the AEMs, respectively. The structure of the inorganic substances will be modified with organic founctional groups in order to achieve high consistency of the inorganic and organic compounds. The electrostatic interaction and principles of the sol-gel will be utilized as well. The inorganic substances with layered structure and exchangeable ions can be used to prepare inorganic-organic composite membranes with a high conductivity. The degradation mechanism of the polymer in alkaline medium will be studied. The routes for fabrication of inorganic and organc composite membranes will be investigated. The structure and the phase distribution of the composite membranes will be designed and adjusted aiming at high performance of the AEMs modified by inorganic substances. This proposal will make studies on phase distribution and consistency of the inorganic and organic compounds at micro-mesoscopic levels. The property complementarities of the inorganic and organic compounds are expected to achieve by the composite AEMs as well as to search for new routes for preparation of novel membrane electrolytes.

以阴离子交换膜为电解质的化学电池因可使用非贵金属催化剂、无液体渗漏且对材料腐蚀性小、液体燃料透过率低以及易组装等优势而受到研究者的青睐。然而由于氢氧根离子迁移速率较慢,且聚合物膜材料在碱性介质中易降解等问题，致使碱性膜电池在输出功率、使用寿命和稳定可靠性等方面的性能亟待提高。对此，本项目提出研制无机增强型阴离子交换复合膜，旨在利用无机物的强稳定性和碱性，改善阴离子膜电解质的稳定性和导电率；通过对无机物结构的有机化修饰并利用静电作用及溶胶凝胶原理，解决无机有机复合材料的相容性；利用无机矿物的层间结构和离子交换特性制备具有高电导率的无机/有机复合膜；研究聚合物在强碱介质中的降解规律以及与无机材料的复合途径,设计调整复合膜的结构和相态分布，制备具有高性能的无机物修饰的阴离子交换膜。该研究将在微-介观尺度调控有机无机材料的相态和相容性，实现有机无机物在性能上的互补,为研制新型膜电解质进行有益探索。

阴离子交换膜为电解质的化学电池可使用非贵金属催化剂、无液体渗漏且对材料腐蚀性小、液体燃料透过率低以及易组装等优势而备受关注。然而由于聚合物膜材料电导率低，且在碱性介质中易降解等问题，致使碱性膜电池在输出功率、稳定可靠性及使用寿命等性能亟待提高。对此，本项目提出研制无机增强型阴离子交换复合膜，以改善阴离子膜电解质的导电率和稳定可靠性。. 对聚合物基体材料的结构包括主链、侧基、交联结构以及交联剂的结构和性能等进行了设计和优化，以利于提升膜电解质材料的整体性能；研究了不同功能基团以及其化学结构环境对膜电解质性能的影响；筛选无机材料和无机成分进行表面修饰和结构改性，在粒径大小、荷电状态、亲疏水性质等不同方面进行改性和研究，以提升其与聚合物基体材料的相容性和掺杂效果；研制了一系列不同种类的离子导体膜电解质，并对其电导率、机械性能、化学稳定性、甲醇透过率、结构和形貌、单电池性能等进行了全面的分析表征；研究了膜电解质的相关传质过程以及降解机理。. 揭示了阴离子交换膜在碱性介质中的自由基降解新机制。在碱性介质非隔绝氧气的条件下，证实了自由基的产生，且自由基抑制剂通过与自由基反应，可阻止季铵盐的降解，进而提升了阴离子交换膜的耐碱稳定性，为研制耐碱性阴离子交换膜，提升其稳定可靠性提供了新思路。筛选出多种无机矿物质或无机化合物进行了结构修饰和改性，并用其修饰改性离子导体膜电解质，制备了无机物掺杂量高达30%的复合膜。各类无机相与有机基体的良好相容性，提升了复合膜的性能。引入自由基抑制剂合成膜电解质，明显提升了膜电解质在碱性工作介质中的稳定性，可在80 ℃耐受1MKOH 1000 h。此外，对辅助抗氧剂与主抗氧剂以不同摩尔比进行复配掺杂得到的膜电解质，可以在60 ℃、2 M KOH 中浸泡超过1200 h后，依然可保持其原有电导率接近80 %。引入深度学习智能技术，构建智能神经网络模型，为膜电解质的设计合成、及性能预测将起到良好的指导作用。