项目名称： 3D多孔结构LiMnPO4•LiVPO4F@石墨烯气凝胶复合物材料的构筑及电化学性能研究

项目编号： No.51502256

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 舒洪波

作者单位： 湘潭大学

项目金额： 21万元

中文摘要： LiMnPO4具有电压高和安全好等优点成为最具发展前景的高电压锂离子电池正极材料之一。然而，该材料差的导电性和结构不稳定导致其存在放电容量偏低、循环稳定性差、倍率性能不理想等关键问题，制约其规模化应用。本项目拟通过氮掺杂石墨烯气凝胶包裹LiMnPO4并交联，同时LiVPO4F掺杂，构筑3D多孔结构LiMnPO4•LiVPO4F@石墨烯气凝胶复合物材料。基于氮掺杂石墨烯气凝胶包裹改善导电性和表面结构稳定性，LiVPO4F掺杂稳定内部结构和改善本征导电性，两者耦合有效提高材料的导电性和稳定性，且LiMnPO4纳米晶和由氮掺杂石墨烯气凝胶交联构筑的3D多孔结构能缩短电子和Li+传输路径，从而改善其电化学性能。探讨材料组成、掺氮类型与电化学性能的内在关系，揭示3D多孔结构LiMnPO4•LiVPO4F@石墨烯气凝胶性能耦合及改善性能的机理，为高性能磷酸锰锂及其他正极材料发展提供新思路和技术依据。

中文关键词： 锂离子电池；正极材料；高电压；表面修饰；掺杂

英文摘要： LiMnPO4 has been recognized as one of the most promising high voltage cathode materials for lithium ion batteries, owing to its high voltage, excellent safety, etc. However, the poor conductivity and unstable structure of LiMnPO4, which result in low discharge capacity, poor cycling stability and unsatisfactory rate capacity is key to restricting its large-scale application. The project plans to construct 3D porous structures LiMnPO4•LiVPO4F@Graphene aerogel composites material via nitrogen doped grapheme aerogel wraping LiMnPO4 and corss-linking, and LiVPO4F doping. Based on the wraped nitrogen doped grapheme aerogel improves the conductivity and stability of surface structure, the dopping LiVPO4F stabilizes internal structure and increases the intrinsic conductivity, both coupling can obviously enhance the conductivity and stability of materials. Moreover, LiMnPO4 nanocrystal and 3D porous structure construct by cross-linked nitrogen doped grapheme aerogel is beneficial to shorten the distance of electron and Li+ transport. Therefore, it can improve the electrochemical properties. The internal relationship between composite of material, type of dopping nitrogen and electrochemical performance will be discussed. In addition, the performance coupling of 3D porous structures LiMnPO4•LiVPO4F@Graphene aerogel, mechanism of enhancing performance will be ascertained. Above works will provide new idea and technology support for the development of high electrochemical performance lithium manganese phosphate and other cathode material.

英文关键词： Lithium ion batteries;Cathode material;High voltage ;Surface modification;Dopping