摘要
磷化铁(Fe_(2)P)作为磷酸铁锂生成过程中常见的副产物,其对磷酸铁锂(LiFePO_(4),LFP)电化学性能的影响到目前为止研究地还不够深入。通过球磨法在LFP中掺入不同比例的Fe_(2)P来探究其对LFP正极材料电化学性能的影响。结果表明:在掺入Fe_(2)P后,LFP材料的晶体结构无明显变化,颗粒形貌规整度较高,各主要元素分布均匀,并且LFP材料的离子电导率和电子电导率得到了不同程度的提升;尤其是当Fe_(2)P掺入量为0.5%(质量分数)时,在0.1C和0.5C倍率下首次放电比容量分别达到了158.2、148.5 mA·h/g,相比纯LFP分别提升了8.90%和7.2%;CV曲线中的氧化还原峰电位差值(ΔE)仅为0.264 V,说明Fe_(2)P的引入有利于改善LFP材料的极化,且前3次CV曲线的重合度高,表明材料具有高度的可逆性;电荷转移电阻(R_(ct))仅为41.56Ω,相比纯LFP降低了76.49%;锂离子扩散系数为8.20×10^(-9)cm^(2)/s,相比纯LFP提升了89.4%,同时对倍率性能和循环性能的改善效果显著。
Fe_(2)P is a common by-product during the generation of lithium iron phosphate(LiFePO_(4),LFP),and its effect on the electrochemical performance of LFP has not been thoroughly studied so far.The effect of adding different proportions of Fe_(2)P into LFP by ball milling method on the electrochemical performance of LFP cathode materials was explored.The results showed that after doping Fe_(2)P,the crystal structure of LFP material remained unchanged,the particle morphology was highly organized,and the distribution of major elements was uniform.Additionally,the ion and electron conductivity of LFP material were improved to varying degrees.Especially,when the Fe_(2)P doping amount was 0.5%(mass fraction),the first dis-charge specific capacity reached 158.2 mA·h/g and 148.5 mA·h/g at 0.1C and 0.5C magnification,which were 8.90%and 7.2%higher than pure LFP,respectively.The difference in redox peak potential in CV curve(ΔE)was only 0.264 V,indicating that the introduction of Fe_(2)P was beneficial for improving the polarization of LFP materials,and the high overlap of the first three CV curves indicated that the material had a high degree of reversibility.The charge transfer resistance(Rct)was only 41.56Ω,which was 76.49%lower than pure LFP.The diffusion coefficient of lithium ions was 8.20×10-9 cm2/s,which was 89.4%higher than pure LFP.At the same time,the improvement on rate capability and cycling performance was significant.
作者
屈恋
李越珠
李铭雅
王昭沛
陈燕玉
李意能
QU Lian;LI Yuezhu;LI Mingya;WANG Zhaopei;CHEN Yanyu;LI Yineng(Qujing Dynanonic Co.,Ltd.,Qujing 655000,China;Foshan Dynanonic Co.,Ltd.,Foshan 528500,China)
出处
《无机盐工业》
CAS
CSCD
北大核心
2023年第12期88-94,共7页
Inorganic Chemicals Industry
基金
云南省科技厅科技计划项目(202103AA080009)。
关键词
磷酸铁锂
磷化铁
阻抗
锂离子扩散系数
电化学性能
LiFePO_(4)
Fe_(2)P
EIS
Li diffusion coefficient
electrochemical performance
