多酸氧簇基“分子簇电池”的制备及其电化学性能

Polyoxometalates (POMs) is traditionally described as discrete anionic clusters of the early transition metals (mostly molybdenum, tungsten, vanadium, niobium and tantalum). Molecular cluster batteries (MCBs) consist of a lithium anode and cathode-active material based on POMs. In this work, the molecular cluster batteries (MCBs) using POVs as cathode-active material will be studied. It is well known that there is a wide range of oxidation states from +2 to +5 for vanadium. Several electrons will be transferred in redox process. Therefore, POVs will have high specific capacity as cathode materials in MCBs. POVs hollow nanospheres will be designed and prepared via a hydrothermal route. Then, the hollow nanospheres will be filled into the multiwalled carbon nanotubes (MWCNTs) and 1D POVs/MWCNTs nanocomposite will be obtained. The electrochemical performance of POVs will be improved. The relationship between micro-structures and electrochemical performance will be clarified. Based on the electrochemical performance, and the changes of structure and the valence state, charging–discharging mechanism will be revealed. As the crossed domain of multi-subject (inorganic chemistry, material chemistry and physical chemistry), "molecular clusters batteries" are the frontier and a promising field and attract a great deal of attention. The implementation of the project would enrich the research ideas of "molecular clusters batteries", and provide some guidance for the secondary batteries with high specific energy density.

多酸是一类骨架结构中富含Mo、W、V、Nb和Ta的多金属氧簇（POMs）。多钒酸是多酸的一个重要分支。本项目拟研究基于多钒酸（POVs）的“分子簇电池”。钒通常表现为+2、+3、+4和+5四种变价，将在电化学氧化还原过程中转移多个电子，POVs作为“分子簇电池”正极材料将具有高的比容量。本项目拟制备POVs中空球，并将其填充到多壁碳纳米管（MWCNTs）中形成POVs/MWCNTs纳米复合材料，通过对其可控制备得到电化学性能优异的POVs/MWCNTs电极材料，阐明其微观结构形貌与电化学性能之间的关系；研究该材料在氧化还原和电池循环过程中的性能、结构和金属元素价态变化，揭示其充放电机理。“分子簇电池”是无机化学、材料化学和物理化学交叉研究领域中有重大学术意义和应用前景的前沿课题。该项目的成功实施对于丰富“分子簇电池”的研究思路，以及研究新一代高比能量二次电池具有一定的指

多酸是一类骨架结构中富含Mo、W、V、Nb和Ta的多金属氧簇（POMs）。多钒酸是多酸的一个重要分支。我们设计合成了多个结构新颖的多金属氧簇基分子簇电池材料，例如Na4[VV 9VIV 6O36(NO3)], Fe2V10O28, (NH4)2[Mg(H2O)6]2V10O28, (NH4)2[Ca(H2O)7]2V10O28, (NH4)2[Sr(H2O)6]2V10O28, Ba3V10O28, K5FeW12O40, [C76H136N36O52V22] , [Me2NH2]6[VIV12VV6O42] [VON(CH2CH2O)3] , [V10O34]，[C4H6N2VO]2PMo8V6O42， [C5H8N2VO] 2PMo8V6O42，[C6H10N2VO] 2PMo8V6O42，[C7H12N2VO] 2PMo8V6O42等簇，首先对这些结构新颖的电池材料进行了表征。结构解析发现[C76H136N36O52V22]为中性含氮有机配体修饰的最高核钒簇，[Me2NH2]6[VIV12VV6O42] [VON(CH2CH2O)3]为首例经典钒簇和单核钒配合物共结晶化合物，[V10O34]为结构新颖的的十核钒簇，[C4H6N2VO]2PMo8V6O42， [C5H8N2VO] 2PMo8V6O42，[C6H10N2VO] 2PMo8V6O42，[C7H12N2VO] 2PMo8V6O42则为中性含氮有机配体修饰的钒配合物对混合磷钼簇PMo8V6O42的共价修饰。并将部分簇与碳纳米管复合。通过电池测试装置，研究了部分分子簇电池的电化学性质，研究了分子簇电池作为锂离子电池电极材料时的比容量及循环性能等。如Na4[VV 9VIV 6O36(NO3)]在不同电流密度100, 200 和 300 mAg-1条件下，分别循环250，200，200圈后，表现出了416, 320 和 262 mAhg-1的比容量，表明该分子簇电池具有非常不错的比容量和循环稳定性。Fe2V10O28做为正极材料，在电压范围1.5-4.2内，在电流密度100 mA·g-1下，电池电极材料首次放电为315 mAh·g-1，在循环110圈后，容量仍达到138 mAh·g-1。