富锰橄榄石型Li(MnyFe1-y)PO4正极材料具有工作电位比LiFePO4高，导电性比LiMnPO4好的优点，但较低的电子电导率和锂离子扩散速率、Mn的Jahn-Teller效应以及Mn在电解液中的溶解等问题制约了该材料的有效应用。本项目拟通过常温锂化-低温热处理法制备纳米Li(MnyFe1-y)PO4，采用快离子导体磷酸钒锂和纳米碳对其进行双重修饰改性提高电化学性能。利用材料纳米化和磷酸钒锂包覆提高锂离子扩散速率；利用内核和包覆层中Mn、Fe、V的相互掺杂以及磷酸钒锂和纳米碳的双重修饰提高电子电导率；利用磷酸钒锂和纳米碳双重包覆抑制锰的溶解。通过本项目的研究，揭示磷酸钒锂和纳米碳双重修饰对锂离子传输特性及电导率的影响规律，Mn、Fe、V相互掺杂及Jahn-Teller效应的抑制机理，Mn的溶解机制和抑制原理，从而为锂离子动力电池正极材料的开发应用提供新的思路和科学依据。

The olivine cathode material Li(MnyFe1-y)PO4 with high Mn-content possesses higher operating potential than LiFePO4, and better conductivity than LiMnPO4. However, the low electronic conductivity, low lithium diffusivity, Jahn-Teller effect, and dissolution of the Mn in electrolyte hinder the practical application of Li(MnyFe1-y)PO4. In this project, nanosized Li(MnyFe1-y)PO4 is made by a room temperature lithiation and low temperature heat treatment method, and the material is also double-modified using fast ion conducting Li3V2(PO4)3 and nano-carbon to improve the Li(MnyFe1-y)PO4 performance. Firstly, the lithium diffusivity can be enhanced owing to the nanorization of the material and the coating layer of fast ion conductor. Secondly, the mutual doping of Mn, Fe, and V, and the double-modification of Li3V2(PO4)3 and nano-carbon will increase the electronic conductivity of Li(MnyFe1-y)PO4. Moreover, the dissolution of Mn can be decreased due to the two coating layers. The study shows the law and mechanism how the Li3V2(PO4)3 and nano-carbon layers influence the lithium ion transport and electronic conductivity, how the Mn, Fe, and V enter into the lattices of shell or core, how the Jahn-Teller effect is restrained, why the Mn dissolution happens and how it is suppressed. These all can provide new ideas and theoretical guidance for the development and application of the cathode materials for lithium ion battery.