锂离子电池正极补锂材料Li_(5)FeO_(4)的制备及电化学性能  

Preparation and electrochemical properties of Li_(5)FeO_(4) cathode prelithiation material in lithium ion batteries

作　　者：曾林勇 梁锦记 蒋世用 詹世英 胡海玲 施志聪[1] ZENG Linyong;LIANG Jinji;JIANG Shiyong;ZHAN Shiying;HU Hailing;SHI Zhicong(School of Materials and Energy,Guangdong University of Technology,Guangzhou 510006,China;School of Electrical Engineering,Chongqing University,Chongqing 400044,China;Gree Altairnano New Energy Co.,Ltd.,Zhuhai 519090,Guangdong,China)

机构地区：[1]广东工业大学材料与能源学院,广州510006 [2]重庆大学电气工程学院,重庆400044 [3]格力钛新能源股份有限公司,广东珠海519090

出　　处：《材料工程》2023年第5期120-128,共9页Journal of Materials Engineering

基　　金：广东省科技厅国际合作项目(2019A050510043);珠海市产学研合作项目(ZH22017001200059PWC)。

摘　　要：为开发高能量密度的锂离子电池,补锂技术受到广泛的关注。以LiNO_(3)-LiOH混合锂盐为反应介质和锂源、纳米Fe_(2)O_(3)为铁源,通过熔盐法成功制备出正极补锂材料Li_(5)FeO_(4),采用正交实验法优化Li_(5)FeO_(4)的合成工艺条件,讨论合成条件对材料电化学性能的影响。将Li_(5)FeO_(4)添加到LiFePO_(4)正极极片表面,并与石墨负极组装成全电池,研究其对全电池电化学性能的影响,以及降低锂离子电池初始容量损失的机制。结果表明,使用熔盐法可制备出纯度高、粒径小且电化学性能好的Li_(5)FeO_(4)正极补锂材料,在0.05 C倍率下具有672.8 mAh·g^(-1)的脱锂比容量;当添加2.8%(质量分数)的Li_(5)FeO_(4)(基于活性物质质量的占比),LiFePO_(4)/石墨全电池在0.05 C倍率下的首周放电比容量为150 mAh·g^(-1),相较于未添加的高出8.5%,在0.2 C的倍率下循环100周次后,容量依旧有7.1%的提升,体系的不可逆容量得到恢复。In order to develop lithium-ion batteries with high energy density,prelithium technology has attracted extensive attention.Li_(5)FeO_(4) was successfully prepared by molten salt method with LiNO_(3)-LiOH mixed lithium salt as reaction medium and lithium source,and nano Fe_(2)O_(3) as iron source in this work.Li_(5)FeO_(4) as cathode prelithiation additive is applied to lithium-ion batteries.The synthesis conditions of Li_(5)FeO_(4) were optimized by orthogonal experiment,and the effect of synthesis conditions on the electrochemical properties of the material was discussed.Li_(5)FeO_(4) was added to the surface of LiFePO_(4) positive electrode and assembled with graphite negative electrode to form a full cell.Its effect on the electrochemical performance of the full cells and the mechanism of reducing the initial capacity loss of lithium-ion batteries were studied.The results show that Li_(5)FeO_(4) cathode prelithiation additives with high purity,small particle size and outstanding electrochemical performance can be prepared by molten salt method.When Li_(5)FeO_(4) with a mass fraction of_(2).8%(based on the percentage of active materials mass)was added,the discharge specific capacity of first cycle for the LiFePO_(4)/graphite full cell was 150 mAh·g^(-1) at 0.05 C,which was 8.5%higher than that without adding,after 100 cycles at 0.2 C.the capacity still increased by 7.1%,and the irreversible capacity of the svstem was restored.

关 键 词：锂离子电池 熔盐法 Li_(5)FeO_(4) 正极补锂 

分 类 号：TQ152[化学工程—电化学工业]