摘要
在镍钴铝酸锂正极材料Li[Ni_(0.8)Co_(0.15)Al_(0.05)]O_(2)(NCA)制备过程中表面遗留的碱性物质会严重影响其循环稳定性能,针对这一难题,提出使用Y(PO_(3))_(3)对其进行表面包覆改性,利用Y(PO_(3))_(3)与表面残留的LiOH反应消除表面残碱,并探讨包覆改性对NCA整体性能的影响机制。测试分析结果表明,在低温煅烧过程中前驱体表面会形成均匀致密的Y(PO_(3))_(3)和LiPO_(3)包覆层,LiPO_(3)有较高的离子电导率,双包覆层能够防止活性物质在电化学循环过程中与电解液相互接触时发生有害副反应,提高电极材料的循环稳定性。其中Y(PO_(3))_(3)包覆量(质量分数)为1%的样品在0.1C下的首次库仑效率从未改性样品的78.65%提高到88.50%,在1C下循环150圈后容量保持率从59.38%提高到85.33%,相比于未改性样品具有更高的首次库仑效率和更优异的循环性能。
Aiming at the difficulty that the alkaline substances left on the surface of Li[Ni_(0.8)Co_(0.15)Al_(0.05)]O_(2)(NCA)precursor preparation and lithium preparation sintering process can seriously affect its cycling stability performance,a proposal was made to employ Y(PO_(3))_(3)for surface coating modification.This modification involves utilizing Y(PO_(3))_(3to)react with the surface residual Li OH to eliminate surface residual alkali and investigate the impact mechanism of coating modification on the overall performance of NCA.The thickness of the cladding layer was not affected by the residual alkali content on the surface.Test analysis results demonstrate that during low-temperature calcination,a uniform and dense coating layer of Y(PO_(3))_(3)and LiPO_(3)formed on the precursor's surface.LiPO_(3)exhibited higher ionic conductivity,and the dual coating layer can prevent harmful side reactions between the active material and the electrolyte during the electrochemical cycling process,enhancing the cycling stability of the electrode material.Specifically,for samples with a mass fraction of 1%Y(PO_(3))_(3)coating,at 0.1C,the initial Coulombic efficiency increased from 78.65%for unmodified samples to 88.50%.After 150 cycles at 1C,the capacity retention rate increased from59.38%to 85.33%.Compared to unmodified samples,it showed higher initial Coulombic efficiency and superior cycling performance.
作者
李泓漪
吴爱民
赵刘洋
刘新朋
陈凤琴
李爱魁
黄昊
LI Hongyi;WU Aimin;ZHAO Liuyang;LIU Xinpeng;CHEN Fengqin;LI Aikui;HUANG Hao(Key Laboratory of Energy Materials and Device(Liaoning Province),School of Materials Science and Engineering,Dalian University of Technology,Dalian,Liaoning 116024,China;Shaanxi Coal Chemical Industry Technology Research Institute Co.,Ltd.,Xi’an 710065,China;School of Electrical Engineering,Dalian University of Technology,Dalian,Liaoning 116024,China)
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2024年第7期1320-1328,共9页
Chinese Journal of Inorganic Chemistry
基金
陕煤-秦岭基础科学研究五年行动计划资助。
关键词
电化学
高镍正极材料
磷酸盐
表面涂层
循环稳定
electrochemistry
high nickel cathode material
phosphate
surface coating
cyclic stability
