新能源汽车动力型锂离子电池锰酸锂正极材料循环性能的改性  

Modification of lithium manganese oxide cathode material cycling performance for new energy vehicle lithium-ion battery

作　　者：蔚敬斌 梁卫强 YU Jingbin;LIANG Weiqiang(College of Automotive Engineering,Shanxi Vocational University of Engineering Science and technology,Jinzhong 030619;College of Mechanical Engineering,Taiyuan University of science and technology,Taiyuan 030024)

机构地区：[1]山西工程科技职业大学汽车工程学院,山西晋中030619 [2]太原科技大学机械工程学院,山西太原030024

出　　处：《粉末冶金工业》2023年第5期106-112,共7页Powder Metallurgy Industry

基　　金：山西省交通运输厅科技项目资助(2019-1-12)。

摘　　要：在目前主流的锂离子正极材料中,尖晶石锰酸锂(LiMn_(2)O_(4))具有成本低廉与安全性能高的优势,因此在小型新能源汽车领域有广泛的应用。目前锰酸锂正极材料发展与应用的主要障碍在于锰元素的溶解。锰的溶解将导致循环性能的迅速衰退,在高温循环中尤为显著。在实验中,以氟化锂作为包覆物质,将其包覆于锰酸锂正极材料表面,从而将锰酸锂与电解液隔绝,起到抑制锰溶解的目的。X射线衍射表明,氟化锂与锰酸锂的共烧结过程中未发生氟掺杂,因此未引起锰酸锂的结构变化。通过对不同氟化锂包覆量电化学阻抗谱的研究,能够确定最合适的氟化锂包覆量。相比原始锰酸锂样品,经氟化锂包覆的锰酸锂正极材料与金属锂和石墨组成的软包电池均表现出了更加优异的电化学性能。其中,软包全电池能量密度达到183 Wh/Kg,1C条件下常温与高温循环1000圈后容量保持率可达90.3%与75.7%。Among the current mainstream lithium-ion cathode materials,spinel lithium manganese oxide(LiMn_(2)O_(4))has been widely applied in mini-type new energy vehicles due to its advantages of low cost and high safety.At present,the main obstacle for the development and application of lithium manganate cathode materials is manganese dissolution.The dissolution of manganese will lead to a rapid deterioration of cycle performance,especially in high temperature cycles.In this study,lithium fluoride was used as the coating material to be coated on the surface of lithium manganate oxide cathode material,in order to isolate the lithium manganate oxide from the electrolyte and inhibit the dissolution of manganese.X-ray diffraction shows that there is no fluorine doping in the cosintering process of lithium fluoride and lithium manganate oxide.Hence,there is no structural change of lithium manganate oxide.The optimum lithium fluoride coating amount is determined by studying the electrochemical impedance spectroscopy of different lithium fluoride coating amount.Compared with the original lithium manganate oxide,the lithium manganate oxide that is coated with lithium fluoride shows better electrochemical performances.Among them,the energy density of the pouch battery is 183 Wh/Kg,and the room/high temperature capacity retention after 1000 cycles are 90.3%and 75.7%.

关 键 词：锂离子电池 正极材料 锰酸锂 循环 

分 类 号：TM912[电气工程—电力电子与电力传动] U465[一般工业技术—材料科学与工程]