钴基双金属氧化物/石墨烯复合材料纳米阵列的构筑和电化学性能研究

Current research on supercapacitors focuses on increasing their energy density. The electrode material is the decisive factor of the main performance indicators (power density, energy density and cycle stability, etc.). Therefore, the research and design of high performance electrode materials is the research core of supercapacitor with both high power density and energy density. In this proposal, cobalt-based binary metal oxide with high theoretical capacity and graphene will be chosen as the research object, and the major studies includes the energy storage mechanism of pseudocapacitance, formation mechanism of composite nanoarray, the relationship of the microstructure and electrochemical properties, and this work is dedicated to build a reasonable nano-array structure of composite materials for improving the energy density of supercapacitors. Understanding the pseudocapacitance mechanism of cobalt-based bimetallic oxide/graphene composites is critical for development of supercapacitors electrode materials with higher performance. On the basis of this, the effect of the components and proportion of the composite material on the pseudocapacitance and synergy mechanism between the materials are also investigated to build the relationship of the microstructure and electrochemical properties of and the metal oxide/graphene composite for the improvement the specific capacity, the magnification performance and the cycle performance of the material. Therefore, design, the controllable preparation and electrochemical properties of cobalt-based Binary metal oxide/graphene composites with nanoarray structure show an important significance for both basic research and the practical application.

当前，超级电容器领域的研究热点是如何提高超级电容器的能量密度。电极材料是超级电容器的主要性能指标（功率密度、能量密度和循环稳定性等）的决定因素，因此高性能电极材料的研究与设计是实现兼具高功率密度和能量密度的超级电容器的核心内容。本项目以高理论比容量的钴基双金属氧化物和石墨烯为研究对象，以赝电容储能机理和复合纳米阵列的形成机理、微观结构与电化学性能的关系为主要研究内容，致力于构筑结构合理的复合材料纳米阵列来提高电容器的能量密度。复合材料的赝电容储能机理的理解对进一步发展更高性能的电极材料有着重要意义。在此基础上，探索复合材料的组分构成及机构对赝电容的影响和材料间的协同作用机理，建立微观结构与电化学性能的关系，为改善材料的比容量、倍率性能和循环性能等性能提供依据。因此，基于钴基双金属氧化物/石墨烯复合纳米阵列结构的设计、可控制备和电化学性能研究既有基础研究的意义，又有非常强的实际应用意义。

超级电容器是一种新型绿色环保的储能器件，具有比容量高、功率密度高、充放电速度快和循环稳定性好等优点, 在新能源存储/转化及相关领域具有广泛的应用前景。在保持高功率密度的优势下，提高能量密度对超级电容器的发展具有重要意义。电极材料是超级电容器的主要性能指标（功率密度、能量密度和循环稳定性等）的决定因素。本项目以钴基氧化物电极材料为研究出发点，构筑了多种性能优异的钴基双金属氧化物及其复合材料纳米阵列电极材料，如NiCoO2@rGO纳米片/纳米线异质阵列、MnCoO-rGO纳米线阵列、核壳型Ni3S2/NiCo2O4纳米片阵列、NixCo3-xO4@rGO超细长的网状纳米线阵列、NiCo2O4/NiCoO2/rGO团簇状杂化纳米线阵列、NiCoO2锯齿状纳米阵列等。通过构建独特的纳米阵列结构和引入石墨烯材料复合等策略来改善钴基双金属氧化物的电子传导和离子传输性能，进而调控和优化电极材料的电化学储能性能，有效改善金属氧化物的倍率性能和长循环稳定性能，实现高性能的电极材料的制备和应用，并将其作为正极材料应用到混合型超级电容器器件中，制备出高性能（高能量密度和长循环寿命等）的超级电容器器件，提升了超级电容器的能量密度。同时，本项目探索了复合纳米阵列结构和组分协同提高电极材料的比容量、倍率性能和循环寿命等性能的作用机理以及相关储能机理规律，为合理设计兼具高功率密度和高能量密度的金属氧化物电极材料的制备提供策略方案和参考。