钠离子电池纳米锡基负极材料的设计、制备与构效关系

Na-ion batteries are considered as one of the best candidates for replacing Li-ion batteries in the large scale energy storage, due to their advantages of abundant sodium-containing resources, low cost, relatively high specific capacity and efficiency. Developing the anode materials with high capacity and long lifetime is one of key factors for Na-ion batteries applications. In present project, the study focus on the Sn-based alloys of Sn–M (M=Fe, Co, Ni, Cu) systems. The sodium storage properties of Sn-based alloys are calculated and estimated by first principles methods to explore the potential high sodium storage capacity Sn-based anode alloys for Na-ion batteries. Nanosized Sn-bade anode materials are prepared by chemical liquid phase and their structures and electrochemical performance are investigated using material characterization and electrochemical testing techniques to determine the structure-property relationships between structure and sodium storage properties. The effects of synthesis methods on the microstructure and properties of nanosized anode materials are analyzed to find out the simple and efficient preparation schemes. Based on the results obtained by analyzing the kinetic behaviors and structure changes, the mechanisms of sodium ion insertion into/extraction out of the anode materials are clarified. The integrated use of methods such as alloying, nanocrystallization and carbon composite to improve the stability of the anode materials and develop nanosized Sn-based anode materials with excellent comprehensive properties for Na-ion batteries. The research findings obtained by completing this project can provide the significant theoretic guide and technical support to explore new electrode materials and to promote their practical process of Na-ion batteries.

钠离子电池具有资源丰富、成本低、比能量高、安全性好等优点，在大规模储能领域有望成为锂离子电池的替代品。目前，研发高容量长寿命负极材料已成为钠离子电池实用化的关键之一。本申请项目选择Sn-M (M=Fe, Co, Ni, Cu)体系锡基合金为研究对象，通过第一性原理计算预测锡基合金的储钠特性，挖掘出高储钠量的锡基合金。采用化学液相法制备纳米锡基负极材料，通过材料表征和电化学测试等技术研究材料的结构和储钠特性，构建材料结构与储钠性能的构效关系；考查制备方法与工艺对材料结构和储钠性能的影响，制定简单高效的制备方案；分析材料的嵌脱钠动力学行为和结构的变化，揭示材料的嵌脱钠机理。综合运用合金化、纳米化、碳复合等方法提高材料的稳定性，开发出综合性能优良的钠离子电池纳米锡基负极材料。本项目的研究将为开发新型电极材料及其储钠性能的改进，提供重要的理论指导和技术支持，并推动钠离子电池的实用化进程。

作为有前景的一类钠离子电池负极，具有高理论容量的Sn基合金面临着严重的体积膨胀问题，导致循环稳定性差，制约了其应用发展。针对这一问题，本项目基于Sn-M (M=Fe, Co, Ni, Cu)体系的相图和化合物晶体结构，利用第一原理计算，遴选出5种高比容量的合金（CoSn2，Cu6Sn5，FeSn，FeSn2，Ni3Sn4）。. 本项目系统研究了5种合金的纳米结构设计和构筑、电化学性能、脱嵌钠动力学机理以及性能调控机制，开发出3种综合性能优良的钠离子电池锡基负极材料（纳米Fe-Sn-Sb、Ni3Sn4/PNC和Cu6Sn5@SnO2@C），通过碳包覆、纳米结构、多孔结构和异质材料复合等途径，有效抑制了合金的体积膨胀，提升材料的电化学性能。本项目取得成果为开发新型合金负极材料提供了新思路和新方法，为实现高性能Sn基负极材料的应用提供了技术支撑和理论指导。. 值得指出的是，Fe-Sn-Sb纳米复合物在50 mAg-1的电流密度下，首次充电容量为905 mAhg-1，首次库伦效率大约为83%；Ni3Sn4@PNC在400 mA g-1电流下循环1000圈后容量保持率高达81.6%；双核壳结构Cu6Sn5@SnO2@C纳米复合材料在50 mAg-1电流密度下，首次可逆容量为463 mAhg-1，100 次循环后容量保持为86%。. 上述工作基础上，适当将研究内容扩展到Sb基负极材料、层状结构锰基氧化物正极材料和钒基磷酸盐正极材料，详细研究了电极材料的合成、结构与电化学性能，分析了材料的储钠机理，构建了材料性能与结构的构效关系。. 本项目截至结题时，共发表标注项目批准号（51661009）的SCI/EI学术论文17篇，其中，中科院JCR一区论文4篇；申请发明专利5项，获授权专利2项；获授权软件著作权2项；培养研究生7名，培养青年教师2名，圆满达到了计划书的预期成果考核指标要求。