石墨烯纳米卷及其同轴核-壳复合材料的构建、衍生与电化学性能研究

As a novel graphene-based nanomaterials, graphene nanoscrolls are tubular-structured and open at both ends and interlayer galleries, and thus possess unique physicochemical characteristics different from graphene and multi-walled carbon nanotubes. But so far, the effective fabrication technology remains a bottleneck which restricts the research and applications of graphene nanoscrolls. To escape the bottleneck and achieve full utilization of their structure and properties, this project aims to prepare high-quality graphene nanoscrolls and their coaxial core-shell nanocomposites in green and clean hydrothermal environment using directional induction-self scroll technique. By selecting various types of nanowires, designing hydrothermal oxidation-reduction method and exploring derivative routes, the influence of nanowires on graphene scrolling behaviors will be deeply investigated to ascertain the general rules for the preparation of coaxial core-shell nanocomposites. Emphasis is placed on developing a novel method and mechanism of simple and direct synthesis from graphite to graphene nanoscrolls. Furthermore, according to the reducibility of Te, abundant core-shell composites with different morphologies and structures can be prepared via derivatization. With the flexible protection and scrolled configuration of graphene nanoscrolls, the core nanomaterials will be endowed with enhanced mechanical stability and high ion/electron transfer rate, which could improve their electrochemical energy storage performance or conversion efficiency. The results would provide feasible technical basis and valuable data for the development of graphene nanoscrolls in new energy field.

石墨烯纳米卷是一种异形结构石墨烯基纳米材料，具有类管状结构和非封闭状态的两端及内外边缘，表现出许多源于石墨烯且区别于石墨烯和碳纳米管的物理化学性能，但纳米卷的有效制备仍面临诸多挑战，是制约其研究与应用的最大瓶颈。为突破该瓶颈，实现纳米卷结构与性能的充分利用，本项目拟采用定向诱导-自卷曲技术，在绿色、纯净的水热环境中，合成石墨烯纳米卷及其同轴核-壳复合材料。通过纳米线类型的选择、水热氧化-还原法的设计及衍生思路的探索，深入研究纳米线对石墨烯卷曲行为的影响，明确核-壳复合材料制备的一般规律；重点发展石墨到石墨烯纳米卷简单、直接的制备新方法新原理；利用碲的还原性，衍生系列形貌结构丰富的核-壳复合材料。借助石墨烯纳米卷的柔性保护和卷曲构造，增强机械稳定性，增加离子/电子迁移速率，提高核纳米材料的电化学能量储存性能或转换效率，为石墨烯纳米卷在新能源领域的发展提供切实可行的技术依据和数据积累。

石墨烯具有超好的物理化学性质，充分利用其结构与性能优势，成为了材料电化学领域需要思考的一个重要问题。本项目利用氧化石墨烯丰富的表面官能团，探明了石墨烯与过渡金属氧化物在水热环境中的复合生长规律，发展了多种纳米线、纳米棒和纳米片与石墨烯复合的制备方法。利用高温热处理过程中相结构的 变化，揭示了石墨烯的柔性复合规律和金属氧化物异质界面的形成过程，获得了一系列形貌结构丰富、电化学性能优异的石墨烯与金属氧化物柔性复合纳米材料。衍生探索了碳材料与过渡金属氧化物的原位复合，利用具有周期性结构的杂化材料和高温相结构的变化，明确了氮掺杂碳纳米棒原位析出二氧化钼纳米颗粒的复合过程，分析了其超长循环寿命的储能机理。进一步探明了金属氧化物表面硫化和异质界面的形成规律，明确了高晶相金属氧化物基底和水热条件控制是实现表面硫化和创造部分硫化的关键，表面硫化极大地丰富了原位复合材料的表观形貌、物相类型，推动了异质结构纳米复合材料在电催化和能量储存领域中的应用。本项目的实施能为石墨烯和异质界面在电化学方面提供技术依据和数据积累；使纳米复合材料在基础研究方面获得新突破，在新能源领域展现潜在的应用前景。