石墨烯二维纳米通道物理静电吸附石英晶体微天平检测和分子动力学模拟研究

Electric double-layer capacitors (EDLCs), based on the electric double-layer structure, have attracted substantial attention due to the extraordinary characteristics, such as high power density, ultrafast charging/discharging rate, and superior lifespan. Graphene, a novel two-dimensional carbon material, has been recognized as promising electrode materials for EDLCs. Compared with porous carbon, graphene nanomaterials exhibit many intrinsic effects on advancing the energy storage capability of EDLCs, including size effect and edge effect et al. At the nanoscale, the mass transport and charge transfer within graphene nanomaterials are dynamic and non-equilibrium processes, challenging the conventional experimental measurement techniques, simulation approaches and classical EDL theory. This project demonstrates the combined in situ electrochemical quartz crystal microbalance (EQCM) and molecular dynamics simulation (MD) to characterize the electrolyte charging mechanisms within two-dimensional graphene channels. Specifically, MD simulation is employed to quantitatively reveal the microscopic EDL structure of ions and solvents, including local concentration, number density and angle distribution et al. On the other hand, EQCM can serve as an in situ gravimetric probe for monitoring the mass change in the electrode materials, thus providing unique information on the electrolyte dynamics and kinetics in real time. The proposed methodology can provide new molecular-level insights into the charging mechanisms within the two-dimensional graphene channels and elucidate the process-structure-property relationship in EDLC system. The as-obtained results can offer a great opportunity for further pushing our basic understanding of electrolyte transport to design and optimize graphene nanomaterials for high-performance EDLCs. Moreover, the outputs of this project can boost the development of conventional EDL theory and in situ experiment measurement technologies, benefiting the application of graphene nanomaterials to the energy storage and conversion systems.

基于双电层结构的物理静电吸附在能源环境领域有着广泛的应用。相比于传统多孔介质，石墨烯纳米材料在物理静电吸附中呈现出特殊效应，其中关键科学问题是对热力学非平衡态下二维纳米通道内能质传递机理进行精确描述。本项目拟提出石英晶体微天平和分子动力学模拟相结合的研究方法，通过优势互补揭示纳米受限空间中载能粒子微观双电层结构和动力学输运规律。在此基础上，对所得传递规律加以数理描述，构建微纳尺度传质模型，提出强化物理静电吸附的有效途径。针对具有不同形貌特征的石墨烯纳米材料开展基础物性、传质特性和储能性能检测，构建微观结构和宏观性能的关联机制，对传质模型进行校验与修正，实现高性能储能。项目所得成果将有助于拓展经典传质理论的学术内涵，推动飞秒、纳米时空尺度下微观检测技术的发展，具有重要的学术价值和应用前景。

固液静电吸附在能源环境领域有着广泛的应用。相比于传统多孔介质，石墨烯纳米通道静电吸附呈现出一系列的特殊效应。本项目通过分子动力学模拟（MD）、原位石英晶体微天平（EQCM）和光诱导力显微技术（PiFM）等，研究了石墨烯纳米通道静电吸附储能机理。通过MD模拟，揭示了离子液体、凝胶电解液、水系电解液等在石墨烯纳米通道内的双电层结构和动力学参数，重点考察了尺寸效应、边缘效应、溶剂效应、电场作用的影响。通过PiFM检测，在国际上率先发现了光诱导电场在石墨烯纳米级厚度边缘局域化聚集的异常现象。通过结合恒定电势MD模拟和传输线模型，定量揭示了微观传输与宏观阻抗的关联。通过EQCM原位检测，提出了基于石墨烯边缘电场聚集的电容增强方法和离子选择性输运原理，建立了描述电场驱动下纳米通道内离子传输的非平衡热力学模型。制备了具有不同层间距、官能团种类/比例的石墨烯纳米通道，全面掌握其基础传热传质特性。提出了高电导率、低粘度、宽电压窗口的二元离子液体电解液，所装配超级电容的能量密度和功率密度显著优于商用体系。项目全面完成了既定目标，研究成果发表SCI论文18篇，EI论文2篇，包括Advanced Energy Materials（影响因子29.698）、Energy Storage Materials（影响因子20.831）、Nano-Micro Letters（影响因子23.655）等期刊。项目负责人合著专著1部，参编教材1部。授权中国发明专利3项和日本发明专利1项。项目负责人参加国际会议1次，并获得2022年“最佳研究者奖”（Best Researcher Award）。项目负责人作特邀报告1次，在传热传质学术会议作基金墙报交流1次。项目培养博士研究生4人，硕士研究生7人。项目负责人在项目执行期间获聘浙江大学副研究员。作为项目负责人，获批浙江省自然科学基金、博士后科学基金特别资助项目、国家重点实验室开放课题和企业委托项目等。受邀担任Advances in Applied Sciences，Applied Chemical Engineering，Energy Research，Global Journal of Energy Technology Research Updates等期刊编委。