晶格无序度可控纳米结构的制备及其电化学储能机理研究

The current research of supercapacitor electrode materials are focus in nanocrystalline materials, but nanocrystalline materials are facing the problems of difficult to expand or shrink and ion diffusion anisotropy characteristics, which restrict the cycle life and high-rate charging/discharging performance of supercapacitor. Moreover, the high synthetic temperature in conventional process usually leads to the increase of cost and the complexity of production, which hinders its practical application. By taking the advantages of isotropic, free volume, multi active site structure, amorphous nano materials can maintain structural stability and improve the adsorption and the transport efficiency of electrolyte ions in the charge/discharge process, thus having great potential as electrode material. This project aims to fabricate active materials with controllable lattice disorder for supercapacitor through two approaches: “Bottom-up”(synthesis) and “Top-down”(amorphization). The research interest mainly focus in the controllable synthesis of structure with lattice disorder and its regulating mechanism; the exploration of thermodynamic and kinetic models for electrons and ions in structures with or without disorder and at their interfaces; and finally achieving supercapacitors with high energy density, high power density, long cycle life and high-rate charging/discharging performance. In this project, we concentrate on the application of amorphous structure as active material in supercapacitor and expand the material category and theoretical basis of supercapacitors, which have important theoretical value and great industrial prospect.

目前超级电容器活性材料的研究主要集中于纳米晶材料，但纳米晶材料具有离子扩散各向异性且结构上难以扩张或收缩，削弱了超级电容器的循环寿命和快速充放电性能，再加之其较复杂的高温合成工艺，使纳米晶材料基超级电容器在应用推广中出现瓶颈。非晶纳米材料具有各向同性、自由体积大、活性位点多等结构优点，在充放电过程中可很好地保持结构稳定性并提高电解液离子的吸附及传输效率，作为电极材料具有巨大的潜力。本项目将采用“自下而上”纳米合成和“自上而下”晶格无序化处理的途径制备晶格无序度可控的超级电容器活性材料，重点研究晶格无序度结构的可控制备及其调控机制，探索充放电过程中电子和电解液离子在无序结构、有序结构以及二者界面的热力学和动力学模型，开发能量密度和功率密度双高、循环寿命长、快速充放电性能好的超级电容器。本项目聚焦具有晶格无序度的纳米电极材料，拓展了超级电容器的材料范畴和理论模型，具有重要的理论价值和工业前景。

目前超级电容器活性材料的研究主要集中于纳米晶材料，但纳米晶材料具有离子扩散各向异性且结构上难以扩张或收缩，削弱了超级电容器的循环寿命和快速充放电性能，再加之其较复杂的高温合成工艺，使纳米晶材料基超级电容器在应用推广中出现瓶颈。非晶纳米材料具有各向同性、自由体积大、活性位点多等结构优点，在充放电过程中可很好地保持结构稳定性并提高电解液离子的吸附及传输效率，作为电极材料具有巨大的潜力。本研究以“晶格无序结构可控制备”为指导思想，设计并研制了一系列具有优异电化学性能的材料体系。针对超级电容器，开发了具有表面无序结构的三维多孔TiO2/Ti复合材料，研究了具有电化学诱导晶体结构转变行为的尖晶石型材料体系（MgMn2O4和Co3O4），并开发了两种基于复合结构（聚吡咯包覆Fe2O3纳米管和Co2V2O7纳米笼负载石墨烯）的高性能超级电容器。针对无酶电化学传感，研究了表面无序改性对选择性晶面暴露CeO2纳米晶过氧化氢电化学传感性能的作用机理，构建了基于Cu2O选择性负载BiOI纳米片和N掺杂石墨烯包覆Ni/NiO两种复合电极材料。利用晶格无序结构综合调控材料的晶体结构和电子结构，获得优秀的电化学传感性能。通过系统的测试和理论分析，研究了微观界面处的载流子热力学和动力学过程，揭示了晶格无序度对材料电化学性能的影响机制，为设计新型高效的电化学材料体系提供了理论指导。本研究关于高效电化学材料体系及器件的研究，将为新型优质电化学储能和传感器件的研发提供有力的技术支持和理论指导。