以皮胶原纤维为模板制备碳/过渡金属氧化物核壳型纳米纤维束高性能锂离子电池负极材料

Transition metal oxides featured with high theatrical Li-ion storage are ideal candidates for the anode materials of high-performances Li-ion batteries. However, transition metal oxides usually have poor electrical and ionic conductivity, as well as huge volumeric changes during the charge-discharge process. As a result, these anode materials usually suffer from poor rate capability and cycling instability. To address the above issues, skin collagen fiber, a natural biomass with well-defined 3 dimensional (3D) nanostrucutre, will be used as biotemplate to prepare the anode material of carbon/transition metal oxides core shell composite nanofiber bundle. The main contents investigated in this project include: (1) The influences of pretreatment to skin collagen fiber on the formation of nanofiber bundle morphology, the shell thickness of transition metal oxide layer, the specific surface area and the porosity; (2)The effects of thermal treatment to the crystallinity of transition metal oxide and the quality of carbon nanofiber bundle; (3) The dependent relationships between the nanostructure of anode materials and their battery performances, including charge-discharge capacity, cycling stability and rate capability. In summary, the implementation of the present project is feasible to develop high-performances anode materials with large charge-discharge capacity, high cycling stability and good rate capablity, which may also explore a new field for the resource utilization of skin collagen fiber.

过渡金属氧化物的理论储锂容量大，是制备高性能锂离子电池理想的负极材料。然而，过渡金属氧化物的电导率和离子传导性较差，且充/放电过程中体积变化显著，因而其倍率性能和循环稳定性较差。为解决上述问题，本申请项目拟以皮胶原纤维这类具有规整3维纳米结构的天然生物质为模板，制备碳/过渡金属氧化物核壳型纳米纤维束负极材料。项目的主要研究内容包括：（1）皮胶原纤维预处理对电极材料的纳米纤维束形貌、金属氧化物壳层厚度、比表面积及孔隙率的影响；（2）热处理条件对过渡金属氧化物结晶度和碳纳米纤维束品质的影响；（3）电极材料的纳米结构对其充-放电容量、循环稳定性、倍率性能等的影响，并揭示其结构与性能间的构效关系。本项目的实施有望制备出充-放电容量大、循环稳定性好和倍率性能优良的高性能锂离子电池负极材料，同时也为皮胶原纤维的资源化利用拓展新的应用领域。

高性能锂离子电池的开发依赖于新一代电极材料的发展。过渡金属氧化物基于转化反应机制存储锂离子，因此其质量能量密度较插层反应原理存储锂离子的传统石墨负极材料更高，是目前最有潜力的高性能负极材料之一。然而，过渡金属氧化物的电子传导性差，且在存储和脱出锂离子时伴随着显著的体积膨胀和体积收缩，显著的体积效应进一步导致了金属氧化物电极材料循环稳定性差的问题。为开发高性能过渡金属氧化物锂离子电池负极材料，本项目以具有规整3维纳米结构的皮胶原为模板制备了多种核壳型和三明治型三维纳米纤维束锂离子电池负极材料，包括：具有高循环稳定性的核壳型C@Fe3O4三维纳米纤维束，可进行大电流活化的C@NiFe2O4三维纳米纤维束、具有高质量能量密度的C@SnO2@C三维复合纳米纤维束、兼有高质量能量密度和体积能量密度的C@Sn@C三维复合纳米纤维束、具有C-Al2O3复合包覆层的C@Co3O4@COAl三维复合纳米纤维束高性能锂离子电池负极材料。成功发展了核壳型和三明治型三维复合纳米纤维束电极材料简便合成策略，揭示了三维纳米纤维束结构在适应显著体积效应和强化电子传输和离子扩散动力学方面的重要作用。研究结果发表第一作者及通讯作者SCI论文13篇，申请专利2项。