超高氮掺杂多孔石墨烯包覆钠离子电池无定形磷酸铁正极材料的可控制备及储钠性能研究

Nitrogen-doped porous graphenes have many important applications in the batteries’ materials. However, the study of high nitrogen-doped porous graphene coated cathode materials for sodium ion batteries (SIB) is weak. Particularly, ultra high nitrogen doped porous graphene (N>20wt%) coated SIB cathode material is an important subject in urgent need of systematic research. The relationship between the coating structure and electrochemical performance of ultra-high nitrogen doped porous graphene in SIB and its sodium storage performance are important scientific problems that need to be solved. This project selects amorphous iron phosphate (FePO4) cathode material as the research object, using liquid polyacrylonitrile (LPAN) /Fe2O3 composite slurry as carbon source, and tetrazole compound DABT as nitrogen source, through high temperature sintering -rapid cooling - chemical etching processing, the doped-nitrogen content can be up to 31.31wt%. The ultra-high nitrogen doped porous graphene coated amorphous FePO4 cathode material have been thus prepared. Systematical investigations on microstructure and electrochemical properties of cathode materials prepared are carried out in this project. We can thus understand the relationships between structure and electrochemical properties of ultra-high nitrogen doped porous graphene coated cathode materials of sodium ion battery. Furthermore, we can clarify the sodium storage mechanism of cathode materials of nitrogen doped porous graphene coated amorphous FePO4 cathode materials of sodium ion battery. Therefore, we can establish a complete set of controllable technology and theory for the preparation of ultra-high nitrogen doped porous graphene coated cathode materials of sodium ion battery, providing theoretical guidance for the design and manufacture of new cathode materials of sodium ion battery.

氮掺杂多孔石墨烯在电池材料中具有重要应用，但高含量氮掺杂多孔石墨烯包覆钠离子电池正极材料的研究薄弱，特别是超高氮掺杂多孔石墨烯(N>20wt%)包覆钠离子电池正极材料是亟需系统研究的重要课题。超高氮掺杂多孔石墨烯包覆结构与电化学性能的关联性及储钠性能是钠离子电池发展亟需解决的重要科学问题。本项目以无定形磷酸铁为研究对象，液态聚丙烯腈/三氧化二铁复合浆料为碳源，四唑化合物DABT为氮源，经高温烧结-快速降温-化学刻蚀处理，氮含量可达31.31wt%，制备超高氮掺杂多孔石墨烯包覆无定形磷酸铁正极材料。系统研究该正极材料的微观结构和电化学性能，从而理解超高氮掺杂多孔石墨烯包覆结构与电化学性能的内在关联性，阐明超高氮掺杂多孔石墨烯包覆无定形磷酸铁正极材料的储钠机理。从技术和理论上建立一套完善的超高氮掺杂多孔石墨烯包覆钠离子电池正极材料的可控制备技术，为新型钠离子电池正极材料设计与制备提供理论指导。

氮掺杂多孔石墨烯在电池材料中具有重要应用，但高含量氮掺杂多孔石墨烯包覆钠离子电池正极材料的研究薄弱，特别是超高氮掺杂多孔石墨烯(N>20wt%)包覆钠离子电池正极材料是亟需系统研究的重要课题。超高氮掺杂多孔石墨烯包覆结构与电化学性能的关联性及储钠性能是钠离子电池发展亟需解决的重要科学问题。本项目系统研究该钠离子电池正极材料的微观结构和电化学性能，从而理解钠离子电池正极材料结构与电化学性能的内在关联性，阐明超高氮掺杂正极材料的储钠机理。改性后的Na3V2(PO4)2F3/NSC展现了优异的电化学性能，0.5C下经过100次循环后容量保持率为93.6%，同时首次放电比容量达到109 mAh g-1，在5C和10C超高倍率下循环500圈容量保持率依然高达92.1%和87.6%，在10C下容量依然可以达到83 mAh g-1。从技术和理论上建立一套完善的超高氮掺杂多孔石墨烯包覆钠离子电池正极材料的可控制备技术，为新型钠离子电池正极材料设计与制备提供理论指导。