高负载量赝电容材料在多级三维导电集流体上的原位生长研究

The development and utilization of clean and renewable sources have aroused great interests in energy application fields. Practical utilization of sustainable energy requires reliable energy storage devices due to the intermittent nature and the heterogeneous geographical distribution of most sustainable energy sources (e.g., solar energy and wind energy). Therefore, development of energy storage technologies for sustainable energy implementation has received extensive and worldwide research attention. Supercapacitors represent a class of energy storage devices that can store electrical energy converted from sustainable sources. In order to further increase the energy density of supercapacitors, here, a three-dimensional hierarchical current collector was developed using electrochemical method. This 3D current collector is capable of providing high surface area and optimal 3D space availability for the electrode. In addition, high mass loading pseudocapacitive materials (e.g. iron oxides and polypyrrole) were integrated with the 3D current collector, constructing highly porous hierarchical architectures for these high mass loading electrodes. The intrinsic relationship between the microstructures and the capacitive performance of the high mass loading electrodes was also systematically studied. The charge (i.e. ion and electron) transfer kinetics of the high mass loading electrodes was substantially improved to face the challenges in large-scale energy storage applications. We believe this study can offer new insights for fundamental material science questions, and therefore facilitate the practical applications of electrochemical energy storage devices (e.g. Li-ion batteries and supercapacitors).

清洁能源的开发和利用是目前能源领域的研究重点。绝大部分清洁能源（如太阳能和风能）在时间和空间上分布不均，因而有效利用这些能源需要可靠的能量存储装置。廉价且安全的超级电容器已然成为清洁能源能量存储装置的良好选择。为了进一步提升超级电容器能量密度，本课题拟采用电化学法构建三维多级导电集流体，增大活性材料负载表面积，增加电极材料的三维空间可利用率。在三维集流体上原位生长高负载量法拉第赝电容材料（例如氧化铁、聚吡咯），构建适合于高负载量活性材料的电极微结构，探究电极微结构与材料电容性能之间的内在联系。从电子传输和离子传导两个方面入手，协同解决高负载量电极材料在大规模储能应用中面临的挑战。相关基础研究工作将会对电化学储能器件（如锂离子电池，尤其是超级电容器）的广泛应用起到推动作用。

超级电容器安全性高，环境友好，成本低廉，在大规模智能电网建设及便携电子器件应用中，极具潜质。但是，现阶段报道的超级电容器电极材料活性物质负载量低，严重制约其实际应用。设计、合成高负载量先进电极材料，构建适用于高负载量电极微结构，已然成为提升超级电容器能量密度、促进其大规模应用的重要前提。本课题采用电化学法构建三维多级导电集流体，增大活性材料负载表面积，增加电极材料的三维空间利用率，在三维集流体上原位生长一系列高负载量法拉第赝电容材料（例如氧化锰，氧化铁，氧化钒，氧化钼，聚吡咯，磷酸锰等），探究高载量电极材料电容性能及储能机理，揭示电极结构与电化学性能间内在联系。主要的研究内容包括：（1）三维碳集流体的构建；（2）介孔可调氧化铁的制备及其电容性能研究；（3）多阴离子掺杂导电聚吡咯的制备及其电容性能研究；（4）异质结构电极材料的电化学构建及其储能机理研究；（5）过渡金属聚阴离子型化合物的电化学沉积及其电容性能研究；（6）金属氧化物在水系电池中性能初探。重要的科学发现有：（1）构建三维碳集流体，激活电极体相储能潜力，实现高载量赝电容材料电容性能跃升；（2）构建多级孔结构，有利于电解液在厚电极内部输运；（3）构建三维异质界面，产生界面电场，利于电子、离子在厚电极中快速传输。此项研究聚焦高性能、高负载量超级电容器材料制备新方法，揭示高负载量电极材料内部微结构与其电容性能之间的内在联系，为法拉第赝电容材料实现商业化应用提供坚实的理论基础与实验依据，对于制备其它高性能化学电源电极材料（例如锂离子电池、水系电池等）也具有一定的借鉴意义。