过渡金属掺杂SnO2@导电聚合物阵列的构筑及其储锂性能研究

Aiming at poor structure stability, low rate capability, short cycle life of the current SnO2-based anode materials, this project proposes to design and construct a transition metal doping in SnO2@conductive polymer array electrode. By adjust the reaction condition a highly stable array structure is obtained, improving its conductivity and structure stability through compositing with conductive polymer and doping with transition metal. Discussing the formation mechanism of compositing and doping, revealing the influence of the microstructure and composition on the structure stability and cycle performance. From the theoretical level, the proposed project will verify the inner link of microstructure, compositing ratio, doping ratio, and the electrochemical performance. Moreover, this project will elaborate the influencing mechanism fo coating species and doping sites on the electrochemical properties. From a technical point of view, the project will develop a SnO2-based nanoarray electrode with good structure stability, high energy density, and high power density. The research results will provide theory and technology basis for the preparations and applications of array electrodes with high performance, which have important scientific significances and practical values.

针对目前SnO2负极材料结构稳定性差、倍率性能低、循环寿命短等问题，本项目提出设计并构筑金属掺杂SnO2@导电聚合物纳米阵列电极。通过调控反应条件获得高稳定性阵列结构，通过导电聚合物复合和过渡金属单质掺杂实现导电性和结构稳定性的提高，探讨复合、掺杂电极的形成机制，揭示其微观结构、组成对其结构稳定性和长循环性能的影响。从理论层面上，探明微观结构、复合和掺杂比例同电化学性能之间的内在联系和规律，并阐述不同包覆物质种类和金属单质掺杂位置对提高电化学性能的影响机制。从技术层面上，研制出结构稳定好、高能量密度、高功率密度的SnO2基纳米阵列电极。研究成果将为高性能的阵列电极的制备和应用提供理论和技术基础，具有重要的科学意义和实用价值。

开发高性能锂离子电池电极材料是一大研究热点。Sn基材料作为负极材料具有较高的理论比容量，但在脱嵌锂过程中普遍存在较大的体积变化，电极材料的结构稳定性较差。针对此问题，本项目从电极结构设计和复合结构构筑方面着手，首先从宏观结构上对电极进行设计和构筑，提升电极结构稳定性，利用三维Ni网构筑无粘结剂SnO2/石墨烯/Ni网复合电极，SnO2纳米颗粒和石墨烯交替重叠构成三明治夹层结构，有效缓冲SnO2的体积变化，复合电极材料具有良好的电化学性能，在1 A/g下500次循环之后比容量可达757 mAh/g。其次对微观复合材料结构进行调控，利用7,7,8,8醌二甲烷离子(TCNQ.-)作为锚定剂，改善了复合材料中Sn颗粒的复合位点和分散度，Sn/氮掺杂石墨烯复合材料取得更好的电化学性能。进一步将TCNQ-作为锚定剂合成Sb/氮掺杂石墨烯复合材料，同样可以改善复合材料电化学性能，证实了本项目所开发改性手段具有一定的普适性，可以推广到其他材料改性。