Research Progress in High Performance Lithium Manganese Phosphate Cathode Materials
LI Junhao1, FENG Sitong1, ZHANG Shengjie1, ZHENG Yuying1, XU Jianbo2, DANG Dai1, LIU Quanbing1
1 School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006 2 Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China
Abstract: Lithium-ion batteries have many advantages such as high energy density, good cycle performance, no memory effectand so on. They are widely used in many fields such as electronic products, electric traffic, and energy storage system, which have greatly improved the modern human's life. Lithium iron phosphate (LiFePO4), as a cathode electrode material, possesses high safety, excellent cycle performance and thermal stability, and it is widely used in lithium-ion power battery. However, its energy density is low, which restricts its further development and application. Lithium manganese phosphate (LiMnPO4) has high safety and stability similar to LiFePO4, and its theoretical energy density is 21% higher than that of the latter, so it is considered to be the most promising cathode material for next-generation power lithium-ion power battery. However, the olivine-structured LiMnPO4 still has some inherent defects that restrict its development and application: (1) the ionic conductivity and electronic conductivity of the material are very low, which make it's difficult to make full use of the material capacity; (2) LiMnPO4 reacts with the electrolyte to produce the product Li4P2O7, etc. which will result in the activity will gradually lose as charge and discharge process;(3) the manganese phosphate (MnPO4) formed after delithiation will be affected by the Jahn-Teller effect, the crystal structure will change from octahedron to cubic phase, and the channel of lithium-ion decompression is compressed, causing structural irreversible changes; (4) part of manganese ions are dissolved in the disproportionation reaction that occurs in the electrolyte causes the material to cycle poorly. A lot of work has been done to overcome these problems. In order to improve the electrochemical performance of LiMnPO4, the researchers have made continuous attempts in the preparation and modification of materials:(1) nanocrystallization, shortening the solid-state diffusion path of lithium-ion, and increasing the reaction area of the electrode, thereby increasing the ionic conductivity of the material in macro; (2) selection control of planes, increasing the area of the crystal plane for rapid migration of lithium ions, thereby increasing the ionic conductivity of the material in micro; (3) body doping, in-situ substitution of heteroatoms or formation of solid solution to stabilize the crystal structure and improve ionic/electronic conductivity, thereby improving the cyclic and rate performance of the material;(4) surface coating, by coating conductive carbon, metal oxide layer, etc. on the surface of the material to improve the ionic/electronic conductivity of the material and prevent LiMnPO4 from directly contacting the electrolyte. Since now, LiMnPO4 has been developed from the original almost playno specific capacity, and developed to a theoretical value at a low rate. In this paper, the research progress on the preparation and modification of high performance LiMnPO4 is summarized. The approaches to improve the material properties are analyzed from the aspects of material structure, surface interface properties and electrode reaction kinetics. Finally, we believe that the crystal surface control and surface coating modification on the basis of element doping and nanocrystallization is the most effective way to maximize the material properties, thus promoting its commercialization process.
作者简介: 李俊豪,2017年6月毕业于广州大学,获得学士学位。现为广东工业大学硕士研究生,在刘全兵副教授的指导下进行研究。目前主要研究方向为锂离子电池磷酸锰锂正极材料和过渡金属氧化物负极材料。 刘全兵,副教授、硕士研究生导师。2007年7月本科毕业于武汉工程大学,2012年7月在华南理工大学应用化学专业取得博士学位,2012/7—2016/10年分别在中国电子科技集团公司第十八研究所和珠海光宇电池有限公司从事锂离子电池研发工作。2016年11月以“青年百人”人才引进加入广东工业大学,先后入选第五批珠海市“优秀青年人才”和第八批广州市“珠江科技新星”。目前主要从事新能源材料与器件方面的研究,包括锂离子电池、锂硫电池、超级电容器、燃料电池等。近年来,在该领域发表SCI论文20余篇,包括Advanced Energy Materials、Small、Journal of Materials Chemistry A和Journal of Power Source等。
引用本文:
李俊豪,冯斯桐,张圣洁,郑育英,徐建波,党岱,刘全兵. 高性能磷酸锰锂正极材料的研究进展[J]. 材料导报, 2019, 33(17): 2854-2861.
LI Junhao, FENG Sitong, ZHANG Shengjie, ZHENG Yuying, XU Jianbo, DANG Dai, LIU Quanbing. Research Progress in High Performance Lithium Manganese Phosphate Cathode Materials. Materials Reports, 2019, 33(17): 2854-2861.
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2019, Vol. 33 
