钠离子电池二维锑烯负极材料的可控制备及储能机理研究

Antimonene is a kind of two-dimensional material consisted of buckled structure of interlinked ruffled hexagonal rings. Theoretical calculations show that anitmonene presents outstanding physical and chemical properties such as high carrier mobility, novel optical limiting properties and superior thermal conductivity. Despite these theoretical achievements, there are only a few experimental studies on the fabrication, characterization, physicochemical property, and application of antimonene. In particular, there are few studies on the size-controllable preparation of two-dimensional antimonene plane. In this project, stable two-dimensional few-layer antimonene with high quality will be fabricated through electrochemically cathodic polarization followed by liquid phase sonication treatments. To realize the conversion from metallic antimony to two-dimensional antimonene, the influences of the synthesis conditions and the formation mechanism will be investigated. The electrochemical characteristics of sodium storage and the key factors affecting sodium storage will be examined. The structure, valence state, phase change during the process of sodiation and desodiation and the sodium storage mechanism for the two-dimensional antimonene will be investigated. Based on these, the antimonene/graphene composites will be constructed and the inner connections between the interfaces structure of the composites and electrochemical performances will be illustrated. Finally, two-dimensional antimonene/two-dimensional graphene composites with best electrochemical sodium storage performances will be abstracted, providing theoretical and technical guidance for better sodium-ion batteries.

锑烯是一种新型的呈蜂窝状排列的具有非平面原子结构的二维材料。理论计算说明其具有良好的载流子迁移率，新奇的光学性能，优异的热导性等一系列新奇的物理化学性质。然而，当前其制备方法、表征、物理化学性质及应用等相关实验研究皆处于起步阶段。尤其是锑烯二维平面尺度可控制备方面，鲜有研究。本项目拟采用电化学阴极极化法辅以后续超声处理以金属锑为原材料制备高质量化学性质稳定的二维材料锑烯，优化合成条件，揭示合成过程反应机制，实现对二维锑烯制备过程的有效调控。探索二维锑烯电化学储钠特征并解析影响储钠性能的关键因素，研究钠化、去钠化过程中的结构、价态及物相变化，揭示二维锑烯储钠机制。在上述基础上，构建具有稳定界面结构的二维锑烯/二维石墨烯复合材料，阐明锑烯与石墨烯的界面结构与电化学性能之间的内在联系，为开发高性能钠离子电池材料提供理论技术支持。

锑烯是一种呈蜂窝状排列的具有非平面原子结构的二维材料。由于其具有独特的物理化学性质，自2015年被发现以来在光电子、能源存储、电催化及癌症治疗等领域引起了广泛关注。为了实现其应用目前发展了外延生长、液相剥离、机械剥离及电化学剥离等方法。其中，电化学剥离法具有可控性好、成本低、高效、设备简单等优势。本项目探索了不同电解液中的锑电化学剥离行为，发现锑块在四甲基氢氧化铵和四乙基氢氧化铵水溶液中恒定电势阴极剥离可分别获得多孔锑烯以及锑烯纳米片。进一步地以添加得有乙二醇的硫酸钠作水溶液作为电解液，阴极剥离锑块获得了锑烯/碳复合材料，该材料作为钠离子电池负极材料比容量为520.5 mAh/g，150次循环后比容量高达489.4 mAh/g。在较高的电流密度5000 mA/g下，其比容量可达到334.5 mAh/g。此外，在含有表面活性剂及石墨烯的季铵盐有机溶液中，电化学阴极剥离可获得结晶性良好的Sb/石墨烯复合材料，并采用原位XRD证明了脱嵌钠机制为多步合金-去合金机制：Sb→NaSb→Na3Sb→NaSb→Sb。该项目为开发高容量、倍率性能及循环性能良好的钠离子电池负极材料提供有效方法，对推动钠离子电池在能源存储领域的应用具有重要的科学意义。