离子液体溶胶-凝胶法构筑浒苔基有序介孔碳的合成机理与储能机制研究

Ordered mesoporous carbons (OMCs) have been extended as one of the most attractive and environmentally friendly materials for electrochemical energy storage recently. However, most of carbon precursors are toxic and carcinogenic, such as phenol, resorcinol, formaldehyde, hydroxyhydroquinone and so on. Additionally, water or commonly existing organic solvents can’t be used to dissolve the really nontoxic and extensive biomass wastes due to their own strong hydrogen bonding, leading to the failure of self-assemble between carbon precursor and template molecular and the formation of ordered mesopores. Based on the hydrogen bonding theory, van der Waals force theory and electrostatic theory coupled with ionic liquid-assisted sol-gel method, OMCs with controllable pores will be prepared by using marine solid waste, Enteromorpha prolifera, as carbon precursor. The single factor method and response surface methodology will be applied to investigate the optimum synthesis route. Meanwhile, the effects and relations of operating conditions with the physical-chemical properties and electrochemical energy storage will also be established systematically. Furthermore, the potential synthesis mechanism based on ionic liquid-assisted sol-gel method, including the associated strength between precursor and template, the assemble or transformation of ordered mesostructures, and the pore formation, will be evaluated via in-situ and real-time technologies. This study is not only great theoretical significance to realize the synthesis of OMCs derived from environmentally friendly precursor, but also develop a new way for the high-value utilization of biomass wastes in practice.

有序介孔碳作为绿色主流储能材料之一十分常见，其常规碳前驱体有：苯酚、间二苯酚、甲醛、苯三酚等，均具有一定的毒性。若采用无毒且来源广泛的固废生物质为碳前驱体时，生物质自身固有的氢键作用导致其不溶于常规水系或有机溶剂，主-客体无法匹配“组装”，进而无法实现长程有序性。针对这一科学问题，基于氢键、范德华力及静电力等作用理论和离子液体溶胶-凝胶技术，提出以固废生物质-浒苔为碳前驱体，制备孔径尺寸可调控的有序介孔碳材料。本研究拟利用单因素法和响应面模型优化合成路径，探究反应条件与材料理化性质、储能特性之间的相互作用及影响规律；利用原位实时分析手段探究前驱体与模板剂之间缔合程度、有序介观结构组装规律、转变规律及成孔规律，阐明离子液体作用下纯生物质基有序介孔碳的合成机理。该研究有助于为环境友好型有序介孔碳前驱体的开发奠定理论基础，同时也为浒苔等固废生物质资源化和高值化利用开辟新出路。

鉴于常规有序介孔碳制备碳前驱体有毒和固废生物质资源化循环利用两方面，本研究开展了以下三方面工作：（一）分别利用1-丙烯基-3-甲基咪唑氯盐和1-丁基-3-甲基咪唑氯盐溶解浒苔、玉米芯、竹粉、废海带等四种固废生物质制备凝胶，并将凝胶炭化热解制备成有序介孔碳，探究其有序度。（二）以固废生物质提取物丹宁为碳前驱体，F127作为模板剂，乙醇作为溶剂，乙酸镍为原位金属修饰，采用球磨法耦合溶剂挥发自组装制备有序介孔碳。（三）利用浒苔、废海带、废裙带菜等海藻基固废生物质为碳前驱体，以其自身的天然无机盐做模板制备介孔碳，并研究了其储能特性，分析了原位模板法孔径的形成机制。结果表明：固废生物质的成分特别复杂，不仅含有纤维素、半纤维素、木质素等，还含有很多的无机盐、灰分等杂质。导致以上固废生物质基碳前躯体在离子液体作用下，无法完全溶解形成均匀的凝胶，从而导致后续与模板F127混合过程中虽可形成有序中间体，但碳前驱体与模板之间氢键结合力不强，热解过程中有序结构易被破坏，导致最终产品无法获得均匀大面积的有序介观结构；利用球磨法制备的中间体有序，但热解之后有序结构被破坏，且制备材料的比电容较低，仅为100 F/g左右；利用海藻基固废生物质可制备出具有高比表面（1140 m2/g）且高比电容容量（279 F/g）介孔碳，但材料的整体有序度较差。