微波辅助的连续微撞击流反应器的设计、构建及在宏量合成高性能石墨烯基复合储能材料中的应用研究

Mass production of transition metallic compound/graphene energy storage materials which can provide high power density and high energy density has attracted great attention in the energy material research field. However, the internal poor micromixing and mass transfer of stirred tank reactor will result in serious aggregation and self-restacking of graphene nanosheets and nanoparticles, as a consequence, the graphene-based composite materials prepared in stirred tank reactor are usually low specific energy and poor electrochemical stability. It was suggested that micro-impinging stream reactor (MISR) has a perfect micromixing efficiency, while microwave field can greatly intensify molecular movement and collision. Therefore, in this proposal, a microwave-assisted continuous micro-impinging stream reactor (MA-CMISR), which was based on MISR reactor and microwave heating technology, is constructed to intensify the micromixing of the reacting systems. The effects of both geometric parameters and operation parameters, e.g., reactor structure, Reynolds number and microwave power of MA-CMISR, on the micromixing efficiency will be studied by experiments with the parallel competing reaction system. The mathematic model of micromixing time and the intensification mechanism of microwave/micro-impinging stream coupling technology on micromixing performance will be established. Furthermore, various experiments will be conducted to study the effect of microwave/micro-impinging stream coupling technology on the morphology, microstructure, component dispersion, and energy storage performances of graphene-based composite materials which were prepared in MA-CMISR. It is believed that MA-CMISR will be a continuous, green and powerful process intensification technology for the mass production of graphene-based energy storage materials, which is of great significance for their research and applications.

宏量合成兼具高功率密度和高能量密度的过渡金属化合物/石墨烯复合储能材料是当前能源材料领域的最前沿研究之一。然而，目前广泛使用的搅拌槽反应器较差的流体微观混合与传质效率，导致石墨烯片和负载纳米颗粒严重自我堆砌和团聚，所制备的石墨烯基复合材料比能量低、稳定性差。为此，本课题拟结合微撞击流优良的微观混合效率和微波场快速强化分子湍动与相互碰撞的特性，设计构建微波辅助的连续微撞击流反应器（MA-CMISR）。以平行竞争反应为模型体系，系统考察微观混合效率随反应器结构、流体雷诺数、微波功率等的变化规律，阐明微波-微撞击流耦合技术对微观混合性能的强化机理并构建微观混合时间的数学模型。进一步应用MA-CMISR制备石墨烯基复合储能材料（如NixCo(1-x)O/RGO、NiCo2S4/RGO），优化材料的形貌、结构、组分分布以及电化学性能，形成MA-CMISR宏量合成高性能石墨烯基复合储能材料的新技术。

本课题是针对当前沉淀法宏量合成纳米材料过程中反应器微观混合差，带来局部过饱和度不均匀的现象，以及在混合金属离子和氧化石墨烯溶液（GO）制备石墨烯基复合材料时，GO严重聚沉带来组分分布不均匀的现象，构建了连续微撞击流反应器（TS-MISR）来可控、宏量合成石墨烯基复合储能材料。首先利用MISR可控合成粒径为20~30nm的Ni-Co-B核壳结构（NCBs）、粒径~50nm的Ni-Co-O材料，它们作为超级电容器材料表现出较高的比电容、倍率性能和循环稳定性，各自与活性炭组装的不对称超级电容器展现出较高的能量密度和功率密度。. 接着，利用TS-MISR来可控、宏量合成镍钴氧/石墨烯复合材料（NCG），它含有大量超小NCO颗粒（2-3nm）均匀分散在二维RGO片层上以产生大的比表面积（293.2m2/g），丰富的适宜孔隙，从而为NCG材料构建良好的二维导电网络和较短的电解液OH-传输通道，进一步提高NCG材料的比电容（2281F/g）、倍率性能和循环稳定性（5000圈后94.3%保持率）。TS-MISR还进一步拓展合成石墨烯均匀包覆的桑葚状CoCO3颗粒，它作为锂离子电池负极材料在0.1A/g电流密度下有1750mAh/g的可逆容量，且在2A/g下循环2000圈后仍有1000+mAh/g的比容量。可见，TS-MISR合成的CoCO3/RGO是一种很有应用潜力的锂离子电池负极材料。. 此外，微波辐射能使分子运动更加剧烈，增加分子间碰撞的机会，这也可能会强化流体的微观混合性能。因此我们还耦合微波反应技术构建微波辅助的微撞击流反应器（MA-MISR），通过适用于高温的Cu(OH)2/γ-丁内酯酸钠平行竞争反应体系考察微波功率、流体雷诺数Rej、流量比R等对MA-MISR微观混合效果的影响规律。发现流体入口雷诺数Rej的提高和微波的引入可以显著提高流体的微观混合效果。最后应用MA-MISR来可控、快速合成铁钴硫/石墨烯基复合材料，从而形成MA-MISR可控制备石墨烯基复合材料的高效新技术，为相关功能复合材料的宏量合成提供理论指导和技术支撑。.