LiVPO4F/Li3V2(PO4)3-CNFs复合纳米材料高效电子/离子传输网络的构建及储锂性能

In order to improve the electronic conductivity and lithium ion diffusion of LiVPO4F, in this project, we introduce electrospinning method to synthesize novel LiVPO4F/Li3V2(PO4)3-CNFs nano-composite. Li3V2(PO4)3/CNFs is employed to construct effective three-dimensional mixed conducting networks, and thus to take effect of the modification of LiVPO4F. Firstly, CNFs is functioned as three-dimensional mixed conducting networks, ensuring the high-speed transmission of electron and ion in the composite. Secondly, the synergistic effect of Li3V2(PO4)3 and LiVPO4F can improve the electrochemical properties of the prepared composite. On the one hand, the mutual doping of Li3V2(PO4)3 and LiVPO4F will increase the electronic conductivity of the composite. On the other hand, Li3V2(PO4)3 possesses three-dimensional lithium ion channel, which can enhance the Li+ transmission in the composite. The law on associated regulation among the component, micromorphology, lithium storage mechanism and interface stability of composite material is studied. This project is aimed to reveal the influence of three-dimensional mixed conducting networks (Li3V2(PO4)3/CNFs) on lithium ion transmission and electronic conductivity, and the mechanism of the mutual doping of Li3V2(PO4)3 and LiVPO4F. All these are expected to provide new ideas for the research of other electrode materials for lithium ion battery.

针对LiVPO4F较低的电子电导率和锂离子扩散速率，本课题采用静电纺丝可控技术合成LiVPO4F/Li3V2(PO4)3-CNFs复合纳米材料，通过Li3V2(PO4)3/CNFs构建高效电子/离子传输网络对LiVPO4F进行改性，达到如下目标：①CNFs纳米碳纤维材料可起到三维混合导电网络的作用，实现电子和离子的快速传输；②Li3V2(PO4)3和LiVPO4F复合将起到协同导电效应：具有三维锂离子通道的Li3V2(PO4)3快离子导体可提高锂离子扩散速率，二者相互掺杂可提高电子电导率，从而更好地实现电子和离子的快速传输。项目研究了复合材料的组成、微观形貌与储锂机制及界面稳定性的关联调控规律，揭示Li3V2(PO4)3/CNFs三维混合导电网络对锂离子传输特性、电子电导率的作用机理，以及Li3V2(PO4)3和LiVPO4F相互掺杂的作用机理，从而为其它新型电极材料的研究开发提供新思路。

本项目针对LiVPO4F较低的电子电导率和锂离子扩散速率，通过复合Li3V2(PO4)3快离子导体，并构建Li3V2(PO4)3/CNFs高效电子/离子传输网络对LiVPO4F进行改性。研究表明：Li3V2(PO4)3和LiVPO4F复合产生了协同导电效应，具有三维锂离子通道的Li3V2(PO4)3快离子导体提高了材料的锂离子扩散速率，两者的相互掺杂有效提高了材料的电子电导率； CNFs纳米碳纤维材料可起到三维混合导电网络的作用，实现了电子和离子的快速传输。本项目研究了复合材料的组成、微观形貌与储锂机制及界面稳定性的关联调控规律，揭示了Li3V2(PO4)3/CNFs三维混合导电网络对锂离子传输特性、电子电导率的作用机理，以及Li3V2(PO4)3和LiVPO4F相互掺杂的作用机理，为其它新型电极材极材料的研究提供新思路。最终获得新型的LiVPO4F-Li3V2(PO4)3/CNFs复合正极材料，该材料在0.1C下的首次放电比容量约148 mAh/g，并且具有良好的倍率性能和循环性能。