液相法合成磷酸铁锂正极材料

Synthesis of Lithium Iron Phosphate Cathode Material by Liquid State Method

液相合成法具有传热、传质快,材料粒径、形貌可控等优点,被广泛应用于各类材料制备领域。本文综述了共沉淀法、溶剂热法、sol-gel法合成磷酸铁锂正极材料的过程、原理和研究进展,并进行了对比和总结:纳米化、高比表面积、碳包覆,可以解决电子电导率低和锂离子扩散速率慢所导致的倍率性能差的问题,是液相法合成的基本要求。共沉淀法有利于合成密堆积的球形形貌,获得高振实密度的材料,可以提高材料的能量密度。溶剂热法有利于合成大(010)面的材料,缩短锂离子扩散的距离,提高材料的倍率性能。Solgel法可以达到分子级别的混合,有利于制备成分均匀、原位碳包覆的材料。使用高电子电导率和离子电导率的材料,可以提高Li Fe PO4的倍率性能。相对固相法,寻找合成时间短、流程短、成本低的产业化方法,推动液相法在原理、工艺上的发展和进步是研究的方向。

The liquid state method has the advantages of fast heat and mass transfer, controlled particle size and shape of materials, so it is widely used in the preparation of various types of materials. In this paper, the process, principle and research progress of co-precipitation method, solvothermal method and sol-gel method for the synthesis of lithium iron phosphate are compared and summarized： the basic requirement of liquid phase synthesis is nano particle size, high specific surface area and carbon coating,which can solve the problem of low electron conductivity and slow lithium ion diffusion rate, accordingly improve the rate performance of materials. The co-precipitation method has advantage in synthesizing the densely packed spherical morphology materials to obtain high tap density and improve the energy density of materials. Solvothermal method is beneficial to synthesize large （010） surface materials, shorten the distance of lithium ion diffusion, and improve the rate performance of the material. Sol-gel can achieve molecular level mixing, which is favorable for the preparation of homogeneous and in situ carbon coated materials. Scientists introduce materials of high electronic conductivity and ionic conductivity to improve conductivity of LiFePO4. Compared with the solid phase method, to investigate a fast, facile process, low cost and easily-industrialized method, and to promote the development and progress of liquid state method in principle and technology is the research direction.