金属氧化物异质微球的可控构筑及其电化学性能研究

The controllable and selective synthesis of nanotructured transition metal oxides materials and its application in supercapacitors have attracted growing interest in recent years. However, there are seveal disadvantages associated with the development of nanostructured metal oxide electrodes for supercapacitors, such as low conductivity, easily aggregation, low tap density particles leading to lower volumetric energy densities and poor cycling. In order to address these disadvantages, our project proposal proposes a new kind of sphere-like 3D metal oxides hierarchical heterostructures consisting of 1D nanowires. The main process is as follows: Frist, the 3D single metal oxides hierachical structure materials is prepared based on self-assembled technology of 1D nanowires. Then, we can achieve the 3D metal oxides hierarchical heterostructures by surface modification of 3D single metal oxides hierachical materials. Meanwhile, the organizational structure, crystal growth and structural regulations of 3D metal oxides hierarchical heterostructure microsheres will be investigated in detail. At last, we will frabicate the supercapacitor based the 3D metal oxides hierarchical heterostructures and investigate their electrochemistry properties and structure-activity relationship, based on which the index appraisal system and the evaluation model are founded. Through the implementation of this project, it will contribute to the application of the transition metal oxides for supercapacitor by supplying research foundation and technical support.

本项目针对过渡金属氧化物(如CoOx和MnOx等)纳米电极材料存在的导电性差、易团聚、振实密度低和稳定性差等问题，以纳米结构形貌优化设计为指导，基于一维(1D)纳米结构自组装技术，利用模板分子诱导，构建由1D纳米结构组装的三维(3D)海胆状-分级微球，然后对微球表面的1D基元，进行表面修饰，获得3D分级异质微球结构，使其既能克服以上问题缺陷，又能保留其纳米结构优势。对3D分级异质微球进行组织结构、形成机制和调控方法的研究，探明影响其结构形貌与性能的规律；考察3D分级异质微球材料的电化学电容器储能过程中成分与结构的演变规律以及表面与界面差异对材料储能的影响，从微观上揭示其性能改善的本质；研究3D分级异质微球材料电容器储能过程中的综合表现，揭示其构效关系与协同作用机制，并建立适当评价模型。本项目的实施，将为推动纳米结构过渡金属氧化物电化学储能材料的应用提供理论研究基础与技术支撑。

过渡金属氧化物纳米材料(如CoOx和MnOx等)在电化学储能领域具有广泛的应用，但是也存在导电性差、易团聚、振实密度低和稳定性差等问题。本项目，首先通过自组装方法，获得了多种一维(1D)和二维(2D)单元组装的三维(3D)海胆状与花状微球。并对其进行表面修饰，通过导向自组装工艺，构建了多种3D分级异质微球结构。该类型3D分级异质微球，均展现出比单一微球更优秀的电化学超级电容器性能，这主要归结与复合材料协同作用机制，以及独特的3D分级结构提供了丰富的孔道结构，有利于电解液扩散传输。另外，项目也通过多步自组装生长，直接在电容器集流体表面生长类似CoOx @ MnOx的异质核壳阵列。同样基于这种协同作用机制与有序孔道结构，使器件展示出优秀的超级电容器性能。如，在1 mA cm-2下，获得了3.03 F cm-2的极高比容量。再者，本项目还发现了“奥斯瓦尔德熟化-两步取向搭接机制”决定了3D书状CoO的构建，“尿素浓度控制生长机制”指导了狼牙棒状的ZnO分级核壳结构的构建，丰富了3D复杂纳米结构的生长机制。最后，本项目也适当开展了层状材料(层状双羟基金属氧化物LDH，金属硫化物CuS)的结构调控及其在电容器与钠离子电池中的应用。本项目经过三年的研究，作为第一标注资助项目发表论文10篇，如在国际期刊Adv. Energy. Mater., Electrochimi. Acta, Int. J. Hydrogen Energy, Sci. China Mater.,等上。本项目相关成果将为多种3D分级异质结构的构造提供一定的理论指导，也将为超级电容器，钠离子电池电极材料的设计与开发提供一定的科学依据。