异质原子掺杂碳材料的可控制备及储钠机制研究

Sodium ion battery (NIB) is the research highlight for new generation of energy storage devices, due to its resource abundance, low cost and environmental friendly. At present, hard carbon with non-graphitizing macrostructure and graphite-interlayer microstructure is the most practical anode for NIB. Aiming at its disadvantages of low sodium-storage capacity, low first Coulombic efficiency and poor rate capability, this research project proposes investigations on improving the electrochemical properties of carbon materials by heteroatoms doping. One, two and multiple heteroatoms doped carbon anodes are facilely synthesized, using organic compounds rich in heteroatoms as precursors. We will investigate the functional mechanism of species, amounts and proportions of heteroatoms on the geometric structure and electronic property of materials, taking advantage of the instrument adjusting technology and material characterization. Meanwhile, this project will reveal the inner connection and regularity between physicochemical characteristics and sodium storage performance, establish suitable surface structure and electrochemical environment for the reversible sodium storage, and elaborate the electrochemical sodium-storage mechanism, combined with theoretical calculation and electrochemical performance analysis. The research goal is to promote the first Coulombic efficiency, sodium storage performance and safety of carbon materials, utilizing characteristics and synergistic effects of different heteroatoms. These results will provide feasible strategy based on heteroatoms doping, establish representational carbon anode material, and provide theoretical basis and technical guidance for the design and development of high performance NIB.

钠离子电池具有资源丰富，成本低廉和环境友好等特点，是新一代储能器件的研究热点。硬碳材料具有非石墨宏观结构和石墨夹层微观结构，是目前最接近实用化的钠离子电池负极。针对其储钠容量低、首次库伦效率低和倍率性能差等问题，本项目提出采用异质元素掺杂碳的方式对碳材料进行改性研究。采用富含异质元素的有机物为前驱体，通过简单易行的方法构筑一元、二元以及多元异质元素掺杂碳材料。利用仪器调控技术和材料表征，研究异质元素掺杂的种类、数量和比例对材料几何和电子结构的作用机理；结合理论计算和性能分析，揭示材料物理、化学与储钠特性的内在联系和规律，构建适合可逆储钠的表面结构和电化学环境，阐述电化学储钠机制。利用不同异质元素的特性和协同效应，以提高碳材料的首次库伦效率、储钠性能和安全性为目标，提出切实可行的异质元素掺杂改性策略，建立具有代表性的碳负极材料，为设计和发展性能优越的钠离子电池提供理论依据和技术指导。

钠离子电池具有资源丰富，成本低廉和环境友好等特点，是新一代储能器件的研究热点。硬碳材料具有非石墨宏观结构和石墨夹层微观结构，是目前最接近实用化的钠离子电池负极。针对其储钠容量低、首次库伦效率低和倍率性能差等问题，本项目提出采用异质元素掺杂碳的方式对碳材料进行改性研究。.在项目实施过程中，采用不同含氮和硫的前驱体，通过简单高效的方法制备出氮硫共掺杂的3D多孔碳材料和碳纳米片，第一性原理计算表明氮硫共掺杂的协同效应不仅可以提高碳材料的电负性和钠离子的吸附能力，而且可以降低钠离子的扩散障碍以提高其迁移性。材料均表现出较高的可逆比容量，良好的循环稳定性和优越的倍率性能；此外，通过引入聚苯乙烯球作为模板，制备出氮磷共掺杂多孔碳以及氮掺杂三维泡状结构多孔石墨烯，多孔结构可以提供离子和电子的快速传输路径、增加钠离子的吸附并缓解充放电过程中的基体膨胀，杂原子掺杂则可以增加活性位，通过引入额外的缺陷可以提高反应活性，进而提高材料的储钠性能；我们进一步采用水热法合成了NaxFeFe(CN)6，探究盐酸对于材料结构和储钠性能的作用机制，成功地与前期所制备碳材料组装成全电池。该项目的完成为钠离子电池的实际应用提供理论依据和技术支持。.本项目研究成果发表在Advanced Functional Materials，Energy Storage Materials，Journal of Materials Chemistry A和Chemical Communications等杂志，共计SCI论文12篇，申请国家发明专利3项，圆满完成预期目标。