α-LiAlO2包覆LiLi0.2Mn0.54Co0.13Ni0.13O2的性能

摘要

Co-precipitation method was used to synthesize the solid solution cathode material Li[Li0.2Mn0.54Co0.i3Ni0.13]O2 and the performance of this material coated with lithium aluminate (a-LiAlO2) was studied.XRD and field-emission scanning electron microscopy (FESEM) test showed that both the materials before and after coating belonged to a-NaFeO2 hexagonal layered structure with R3m space group, the thick inhomogeneous floccus layers were coated on the surface of particle. The better performance was achieved by sample with coating amount of 3% : when cycled in 2.0-4.8 V at a low current (0.05 C) ,the specific discharge capacity was 273.0 mAh/g,when the current increased to 1.00 C,the specific discharge capacity reached to 173.2 mAh/g.The rate capability was benefitted from the lower surface impedance and reaction impedance as indicated by the electrochemical impedance spectroscopy(EIS) test result.%用共沉淀法制备了固溶体正极材料Li[Li0.2Mn0.54Co0.13Ni0.13]O2,并用偏铝酸锂(α-LiAlO2)进行包覆改性.XRD和场发射扫描电子显微镜(FESEM)测试表明:包覆前后的材料均属于α-NaFeO2六方层状结构,R3m空间群；包覆后的样品颗粒表面形成了一层不均匀絮状包覆物α-LiAlO2.包覆量为3％的样品性能较好:以低电流(0.05 C)在2.0～4.8 V循环,首次放电比容量达273.0 mAh/g;当电流提高到1.00C时,放电比容量为173.2 mAh/g.倍率性能的提高,得益于包覆样品具有的较低的界面电阻与反应电阻,电化学阻抗谱(EIS)测试结果证明了这一点.