高性能可充镁电池的构建及其物理化学本质问题的研究

In order to develop high performance rechargeable magnesium batteries, it is necessary to find electrolytes with high anodic stability and low vapor pressure and matchable cathodes with large capacity and good kinetic performance. In the project, boron-based or nitrogen-based magnesium salts, which replace the traditional aluminum-based magnesium salts, dissolved in mixed ether solvents are used as novel electrolytes, and MgxMySiO4 (M=Mn, Fe, Co, x+y=2) with advanced structures, organic polysulfides or oxocarbon organic compounds are chosen as novel cathode materials to constitute the rechargeable magnesium batteries with independent intellectual property rights. The change of electrolytes and cathodes brings about different interfacial properties. The interfacial components of electrode/electrolyte are analyzed and the forming mechanism is discussed. Furthermore, the internal relation between interfacial properties and battery performance is studied to establish the compatibility mechanism of the novel electrolytes and cathodes. The work will lay a foundation for the thorough research and wide application of high performance rechargeable magnesium batteries.

高性能可充镁电池的发展需要开发具有氧化分解电位高、蒸汽压低的电解液和与之相匹配的容量大、动力学性能良好的正极材料。本项目提出以硼基或氮基镁盐取代传统的铝基镁盐、以混合醚为溶剂的新型电解液体系，并采用具有一定微观结构的MgxMySiO4（M为Mn、Fe、Co，x+y=2）、有机多硫聚合物或含氧有机物为新型正极材料，组成具有自主知识产权的可充镁电池。电解液、正极材料体系的改变，必然会引起电解液/电极材料界面性质的改变。通过深入分析电极/电解液界面的组成，探讨形成和变化机理，系统研究界面性质与电池综合性能的内在联系，建立新型电解液体系与新型正极材料的相容机制。通过上述工作，为高性能可充镁电池的深入研究和广泛应用奠定基础。

可充镁电池因为体积比容量高、成本低、安全性高等优点而受到广泛的关注。目前可充镁电池面临的主要问题是电解液电化学窗口较低、正极材料中Mg2+扩散速率较慢。项目以硼基或氮基镁盐取代传统的铝基镁盐、以混合醚为溶剂的新型电解液体系，并采用具有一定微观结构的MgxMySiO4（M为Mn、Fe、Co，x+y=2）、有机多硫聚合物或含氧有机物为新型正极材料，组成可充镁电池。通过分析电极/电解液界面的组成，探讨形成和变化机理，系统研究界面性质与电池综合性能的内在联系，建立新型电解液体系与新型正极材料的相容机制。组成的可充镁电池在1C速率下，可逆放电容量达到130 mAh g-1，循环100次后容量保持在85%以上。