中空碳纳米洋葱宏量可控制备及其超电容储能机制研究

The supercapacitor is the developing direction of the new type energy storage devices due to its advantages of high charge/discharge speed and long service life. However, one of the key restriction for the application of supercapacitor is the electrode material whose energy density is still much lower than that of advanced lithium ion battery. Carbon nanomaterial is expected to become an ideal electrode material for supercapacitor due to its unique structures and properties. The goal of this research project is to synthesize high-capacity electrode materials of supercapacitor with hollow carbon nano-onions (HCNOs). Carbon nano-onions with Fe-Ni nanoparticles encapsulated will be synthetized by chemical vapor deposition method, which is used as a template of solid carbon source and is annealed at high temperature. Then, HCNOs with massive production and controllable structure and size will be in-situ obtained.The growth conditions and mechanism for the controllable synthesis of the HCNOs will be comprehensively studied. In combination with the first-principles calculations, the microscopic interaction between carbon and catalysis will be studied for understanding the growth mechanism of HCNOs catalyzed by Fe-Ni alloy. The HCNOs will be functionally modulated by dispersion and purification processes. The key factors that influence the capacitance performance of the HCNOs will be discussed. The adsorption and diffusion behavior of the electrolyte ions in the electrode materials will be investigated, in order to establish a reasonable charge storage model and clarify the electrochemical energy storage mechanism. As a result, the controllable fabrication of HCNOs with massive output and the effective modulation of capacitance performance of HCNOs will be realized, which will provide a theoretical direction and a technical approach to obtain the electrode material with high energy density.

超级电容器具有充电速度快，使用寿命长等优点，是新型储能元器件的发展方向，但其能量密度与先进锂离子电池相比还有较大差距，而制约其发展的关键之一是电极材料。碳纳米材料的独特结构及固有特性可望成为超电容的理想电极材料。本研究以制备具有中空碳纳米洋葱结构的超电容电极材料为目标，采用化学气相沉积法获得碳包覆Fe-Ni合金纳米颗粒，以此为固体碳源模板，通过高温退火原位催化生成宏量的、结构和尺寸可控的碳纳米洋葱，系统研究可控生长条件和影响因素；结合第一性原理模拟，研究碳和催化剂的相互作用，探明合金催化生成中空碳纳米洋葱的机理；通过分散及纯化处理对碳纳米洋葱进行功能调控，探讨影响其电容性能的关键因素，分析电解液离子在该电极体系中的吸附和扩散行为，建立电荷存储模型并阐明储能机理。该研究可望实现中空碳纳米洋葱的宏量可控制备和对其电容性能的有效调控，为获得高能量密度的超电容电极材料提供理论指导及技术途径。

超级电容器作为一种新型储能元件具有高功率密度、充放电时间短、循环稳定性好等优势，填补了传统电容器和电池之间的空白，具有广阔应用前景。碳纳米材料的独特结构及固有特性使其有望成为超电容的理想电极材料。本研究以制备具有碳纳米洋葱结构的超电容电极材料为目标，以Fe、Ni-Fe、Fe基玻璃态合金等纳米颗粒为催化剂，以氧化铝、氧化镁、炭黑、碳布、石墨烯、三维石墨烯等为催化剂载体，采用化学气相沉积法、水热法等获得不同结构、形貌的碳纳米洋葱材料，探究催化剂成分、尺寸、生长温度、时间、气体成分等因素对碳纳米洋葱的影响，以实现其可控制制备。系统研究碳纳米洋葱可控生长条件与形成机制，并首次开发出新型碳纳米链材料；通过分散、纯化及活化处理对碳纳米洋葱进行功能调控，探讨影响其超电容性能的关键因素，研究其“结构-修饰-性能”间的关系，分析电解液离子在该电极体系中的吸附和扩散行为，建立合理的电荷存储模型并阐明储能机理。该研究实现中空碳纳米洋葱的宏量可控制备及对其电容性能有效调控，为获得具有优良电容性能的电极材料提供理论及技术支持。