一维介孔纳米过渡金属氧化物准单晶在集流体上的可控制备、表面修饰改性及其超级电容性能

Eelectrochemical supercapacitors filled the gap between traditional dielectric capacitors and batteries/fuel cells. They have high energy density, high power density and long cycling life, and therefore, attracted significant attention. In this project, one-dimensional mesoporous nano-sized transition metal oxides with quasi-single-crystalline structure controllable grown on current collector and surface modification are prepared via a template-free controllable growth method. Their structure and morphology are analyzed by X-ray diffraction spectroscopy, scanning electron microscopy and transmission electron microscope. Their electrochemical supercapacitances are tested by cyclic voltammetry, galvanostatic charge–discharge test and electrochemical impedance spectroscopy. Mechanisms that determining the controllable growth and the morphology of the one-dimensional mesoporous nano-sized transition metal oxides and surface modification are investigated. The dependence of the electrochemical supercapacitance performances on the composition, structure, morphology and surface modification are studied. The rules governing the electrochemical supercapacitance performances and the charge storage mechanism are interpreted. The structure and morphology of the metal oxides with optimized electrochemical supercapacitance performances are determined. Asymmetrical hybrid electrochemical supercapacitors are assembled with electrostatic carbon materials as one electrode and the optimized compound modified one-dimensional mesoporous nano-sized transition metal oxides quasi-single-crystalline supported on current collector as the other electrode. Their electrochemical supercapacitance performances are investigated. The results will lay a scientific foundation for the preparation of electrode materials with mesoporous structure, large specific surface areas, high conductivity, fast kinetics and high charge/discharge capacities.

超级电容器将传统的物理电容器和电池/燃料电池结合起来，具有高能量密度、高比功率和长循环寿命等特点, 因而受到广泛的关注。本项目通过无模板可控生长等方法，在集流体表面可控制备一维介孔纳米过渡金属氧化物准单晶，并进行表面修饰改性；以XRD、SEM和TEM等方法进行结构分析，用循环伏安法、充放电性能测试和电化学阻抗谱等方法测试其超级电容性能，研究一维介孔纳米过渡金属氧化物准单晶在集流体上的形貌调控、可控生长和表面改性机理，关联电极活性物质的组成-结构-形貌-改性和电容性能间的关系，揭示影响其超级电容性能的规律，阐明其储荷机理。进而确定较佳的电极材料及其结构和形貌，制备性能较佳的经表面改性的直接生长在集流体上的一维介孔纳米过渡金属氧化物准单晶电极，与碳纳米管电极组成混合超级电容器，考察其超级电容性能。为具有介孔结构、大比表面积、导电性好、反应动力学速率快和高充放电容量的电极材料的制备奠定科学基础。

超级电容器将传统的物理电容器和电池/燃料电池结合起来，具有高能量密度、高比功率和长循环寿命等特点, 因而受到广泛的关注。本项目通过无模板可控生长等方法，在集流体表面可控制备一维介孔纳米过渡金属氧化物、硫化物、硒化物及其与碳材料和导电聚合物的复合物，并进行表面修饰改性；以XRD、SEM和TEM等方法进行结构分析，用循环伏安法、充放电性能测试和电化学阻抗谱等方法测试其超级电容性能，研究一维介孔纳米过渡金属氧化物在集流体上的形貌调控、可控生长和表面改性机理，关联电极活性物质的组成-结构-形貌-改性和电容性能间的关系， 揭示了纳米过渡金属及其氧化物、硫化物与碳材料的相互协同作用，发现了过渡金属纳米片在石墨烯纳米片上的原位生长机理，有效提高了电荷的传输速率，缩短了电子传递路径，大幅提升其电化学性能。采用微波辅助、碳化还原或电化学沉积法，在石墨烯导电基体上实现了纳米过渡金属及其氧化物、硫化物的可控生长，直接获得了超级电容器用高活性电极，规避了传统电极需要粘结剂和导电剂而导致的电化学活性物质利用率低等问题。开创了无需粘结剂导电剂的自支撑高效电极制备技术，显著提升了电极的活性，提高了电极材料的利用效率，揭示了影响其超级电容性能的规律，阐明其储荷机理。利用简易的水热合成或电化学共沉积法，成功制备了以泡沫镍等为基体的自支撑高效能量存储电极，显著提升了电极的活性，提高了活性材料的利用效率。开创了纳米片电极结构的可控构筑技术，揭示了纳米晶格调变与电极电容性能提升之间的内在关系，发现了具有交联结构的多孔碳和氢氧化物纳米片的高效合成方法。为具有介孔结构、大比表面积、导电性好、反应动力学速率快和高充放电容量的电极材料的制备奠定科学基础。