ZHANG Zhiqiang, ZHENG Shengquan, WANG Qiliang, et al. Effects of Cr-doping on structure and electrochemical performance of lithiumand manganese-rich cathode materials Li1.2Ni0.2Mn0.6O2[J]. CIESC Journal, 2017, (1): 398-407. DOI: 10.11949/j.issn.0438-1157.20160875.
ZHANG Zhiqiang, ZHENG Shengquan, WANG Qiliang, et al. Effects of Cr-doping on structure and electrochemical performance of lithiumand manganese-rich cathode materials Li1.2Ni0.2Mn0.6O2[J]. CIESC Journal, 2017, (1): 398-407. DOI: 10.11949/j.issn.0438-1157.20160875.DOI:
0.12) were synthesized by co-precipitation and high temperature solid state reaction.The structure
morphology and electrochemical properties of cathode material
which was doped with different amounts of Cr
were characterized by X-ray diffraction(XRD)
scanning electron microscopy(SEM)
galvanostatic charge-discharge testing and electrochemical impedance spectroscopy(EIS).The results show that the cathode materials Li1.2Ni0.2Mn0.2-x/2Mn0.6-x/2CrxO2 display the layered structure of solid solution.Cr-doping does not change the material structure
and stabilizes the host layered structure by prohibiting the speed of spinel structure formation during cycling.Li1.2Ni0.16Mn0.56Cr0.08O2 has the best electrochemical properties.The first discharge specific capacity of Li1.2Ni0.16Mn0.56Cr0.08O2 is 246.6 mA·h·g-1at 0.1C
while Li1.2Ni0.2Mn0.6O2 is 230.4 mA·h·g-1.The capacity retaining ratio is improved from 93.5% to 95.36% after 50 cycles at 0.2C.The discharge capacity of Li1.2Ni0.16Mn0.56Cr0.08O2 is 104.2 mA·h·g-1 at 5C
while that of pristine is about 91.5 mA·h·g-1.EIS results show that Li1.2Ni0.16Mn0.56Cr0.08O2 has the lowest charge transfer impedance.