异质原子掺杂调控石墨烯纳米带限域过渡金属氧化物负极材料的储钠性能及机理研究

Sodium-ion batteries (SIBs) have been widely studied as alternative energy storage devices that can compete with prevailing Li rechargeable batteries because of the widespread reserve of Na resources and potential cost merits suitable for large-scale applications. However, the intercalation reaction anode materials with a lower capacity have limited the energy density of SIBs. In order to improve the electrochemical performance of SIBs, the design of heteroatom-doped graphene nanoribbons (GNRs) confining transition-metal-oxide nanocomposite as a high-performance SIB anode is proposed in this work. The SIB anode materials with a quasi-one-dimensional hybrid nanostructure and excellent electrochemical properties were synthesized by using B and N heteroatom-doped GNRs and RuO2 as the host materials. This research focuses on the reaction mechanism of the preparation process and the establishment of work mechanism for preparation parameters on the elemental composition and microstructure; the intrinsic relationship between the structure and properties of the material is obtained by analyzing the physical and chemical properties and evaluating the electrochemical performance. Enhancement of sodium storage behavior and mechanism of RuO2 from the conversion reaction and interfacial charge storage reaction by nano-confinement of B- and N-heteroatom-doped GNR edges will be revealed. The research results can provide a scientific proof for enhancing the electrochemical performance of SIBs and pave a new way for the study of novel high-performance electrode materials.

由于钠资源的大量储备和适于大规模应用的潜在成本优势，钠离子电池（SIBs）已被广泛研究作为替代的储能器件能竞争过当前普遍流行的锂离子电池。然而，具有较低容量的插入型反应的负极材料限制了SIBs的能量密度。为了改善SIBs的电化学性能，本项目提出设计异质原子掺杂的石墨烯纳米带（GNRs）限域过渡金属氧化物纳米复合材料用作为高性能SIBs负极的思路，以B、N异质原子掺杂的GNRs与RuO2作为主体材料，合成出具有准一维纳米复合结构与优异电化学性能的SIBs负极材料。重点研究制备过程的反应机理，建立制备参数对成分、微观结构的作用机制；解析材料的理化性质，测评电化学性能，得到材料结构与性能之间的内在关系；揭示B、N异质原子掺杂调控GNRs边缘纳米限域效应增强RuO2基于转变反应与界面电荷储存反应的储钠行为与机理。为提高SIBs的电化学性能提供科学依据，并为新型高性能电极材料的研究提供新思路。

石墨烯纳米带（Graphene nanoribbons，GNRs）是由碳原子以sp2杂化轨道结合成为六角蜂窝结构并形成为准一维形态的石墨烯材料，具有优异的物理化学稳定性、高的导电和导热性、优良的力学性质、大的比表面积等特点，赋予GNRs具备良好的电极材料性质，本项目主要依靠GNRs通过尺寸限制、边缘形态化和官能化修饰作用，展示出的可调控电学性质以及GNRs的边缘呈现出高活性特性，增强外来物质分子在其表面的吸附，维持材料结构的稳定性，制备出了以GNRs为基体的纳米复合电极材料。当GNRs作为导电支柱材料用于锂（钠）离子电池复合电极时，GNRs通过其边缘效应有效增强了锂（钠）在复合材料中的储存。本项目的开展，一方面，探索不同方法制备出石墨烯纳米带复合负极材料，为新材料的制备提供了新思路；另一方面，对制备出的材料的理学性质和电化学性能进行深入研究，重点理解了电极的储能机制，并为新材料的设计和制备提供指导作用，具有较为重要的科学意义。