NTCDA基羰基有机材料作为全固态锂离子电池负极的研究

Carbonyl organic electrode materials with multiple carbonyl functional groups and large conjugated systems have been considered as the promising next generation green battery electrode materials. However, the organic electrode materials usually suffered from dissolution problem in the liquid electrolyte, which significantly restricts their wide application in conventional lithium ion batteries. This problem can be avoided by using solid-state electrolyte in all-solid-state lithium ion batteries. In this study, we plan to synthesize the NTCDA-based sulfurized polymers and polyimide materials based on molecular designing by using rheological phase reaction method, and the crystalline, spatial structure, stability, spectroscopy properties, and redox characteristic of the synthesized materials will be investigated by means of NMR, FT-IR, XRD, XPS, TG-DSC, and TEM. The composite electrode will be produced from the mixture of the synthesized carbonyl organic electrode materials and the polymer solid-state electrolytes, and its electrochemical performances as anode in all-solid-state lithium ion batteries is to be studied. Our main efforts will emphasize on investigating the electrochemical behavior and the actual lithium storage mechanism of these carbonyl organic materials, as well as on exploring the relationship between the electrochemical performance and the molecular structure of carbonyl polymeric materials. This project will provide theoretical foundation and technical support for exploring high-capacity, high-power and high-cycle stability anode materials for novel all-solid-state lithium ion batteries. In addition, it will also offer important scientific insight for the development of new-type organic electrode materials and expanding its application in lithium ion batteries.

羰基有机电极材料拥有多个羰基官能团和大共轭体系，最有望发展成为新一代绿色电池电极材料。然而有机电极材料在液体电解质中普遍存在溶解问题，严重限制了其作为锂离子电池电极材料的广泛应用，如果将该类材料用于全固态锂离子电池则可从根本上避免此类问题。因此，本项目拟通过分子设计、采用流变相法合成基于NTCDA的硫化聚合物和聚酰亚胺类羰基有机电极材料，并分析合成材料的晶态、空间结构、稳定性、光谱学性质和氧化还原特征等。通过制备电极材料与聚合物固体电解质的复合电极，研究其作为全固态锂离子电池负极的电化学性能，重点研究该类材料在固体电解质中的电化学行为与在全固态电池中的实际储锂机理，揭示材料分子结构特别是羰基所处环境与电化学性能之间的内在联系。本项目的研究成果将为发展高容量、大功率的新型全固态锂离子电池材料提供理论和技术支持，对研发新型有机电极材料与拓展其在锂离子电池中的应用也具有重要的指导意义。

发展高容量新型电极材料是提升二次电池能量密度的关键。有机电极材料不同于传统的无机电极材料，具有环境友好性，材料来源广而且便宜，重要的是能可逆的嵌入多个锂离子或钠离子，它是极具应用前景的高容量新型二次电池电极材料。然而，有机材料易溶于常用的液体电解质，并且该类材料在充放电过程中常常发生结构变化，带来较大的体积膨胀与收缩，存在安全隐患，并且材料的动力学性能和循环稳定性较差，极大的限制了其在二次电池中的实际应用。针对该类电极材料存在的问题，改进电极材料和采用固态电解质构建适合该类材料的电极新体系，能够同时解决该类材料的普遍问题。本项目中针对上述问题，在羰基有机电极材料中引入金属原子，形成稳定的金属-有机复合结构，分别成功合成了金属-萘酸酐复合物和金属-蒽醌复合物两类金属-有机电极材料，对比研究了该类材料在固体电解质和传统液体电解质锂电池中的电化学行为特征，并在上述基础上重点研究了该类材料在固体电解质中的储锂反应机制。实验证明金属原子的引入确实增强了材料的电化学性能，所得的金属-有机复合材料显示了增强的电化学性能，高的可逆容量和良好的循环稳定性。采用XRD，XPS，TG，NMR，TEM和电化学表征等实验技术研究了电极的结构、微观组成和电化学性能之间的关系，阐明了该类材料的电化学储锂反应机制，揭示了影响其电化学性能的关键因素，为该类有机电极材料的系统研究和实际开发提供了科学依据。该项目的完成为高容量有机电极材料的实用化提供了理论指导和技术支持。