K-doped layered LiNi0.5Co0.2Mn0.3O2 cathode material: towards the superior rate capability and cycling performance
RIS ID
111506
Abstract
K-doped LiNi0.5Co0.2Mn0.3O2 is successfully synthesized by introducing larger K ions into the Li slabs of the layered material through a substitution of Li source method. Structural and morphological characterizations reveal that the substitution of K ions on the Li site could enlarge the Li layer spacing and decrease the degree of Li+/Ni2+ cation mixing in the hexagonal layered LiNi0.5Co0.2Mn0.3O2. Compared with the LiNi0.5Co0.2Mn0.3O2, the K-doped Li0.97K0.03Ni0.5Co0.2Mn0.3O2 electrode material demonstrates larger reversible discharge capacity (176.5 mAh g−1), higher initial coulombic efficiency (88.45%), and greatly improved rate capability (123.4 mAh g−1, 5 C). The Li0.97K0.03Ni0.5Co0.2Mn0.3O2 electrode also exhibits excellent cycle stability with capacity retention of 93.17% and 86.42% in cell tests at 25 °C and 55 °C after 100 cycles at 1 C. The improved electrochemical performances of Li0.97K0.03Ni0.5Co0.2Mn0.3O2 are attributed to the enlarged interlayer space of O-Li-O, the decreased degree of cation mixing and enhanced structural stability induced by the potassium substitution.
Publication Details
Yang, Z., Guo, X., Xiang, W., Hua, W., Zhang, J., He, F., Wang, K., Xiao, Y. & Zhong, B. (2017). K-doped layered LiNi0.5Co0.2Mn0.3O2 cathode material: towards the superior rate capability and cycling performance. Journal of Alloys and Compounds, 699 358-365.