Li(Ni0.6Co0.2Mn0.2)O2 has been surface-modified by the lithium-ion conductor Li1.4Al0.4Ti1.6(PO4)3 via a facile mechanical fusion method. The annealing temperature during coating process shows a strong impact on the surface morphology and chemical composition of Li(Ni0.6Co0.2Mn0.2)O2. The 600-℃ annealed material exhibits the best cyclic stability at high charging cut-off voltage of 4.5 V (versus Li+/Li) with the capacity retention of 90.9% after 100 cycles, which is much higher than that of bare material (79%). Moreover, the rate capability and thermal stability are also improved by Li1.4Al0.4Ti1.6(PO4)3 coating. The enhanced performance can be attributed to the improved stability of interface between Li(Ni0.6Co0.2Mn0.2)O2 and electrolyte by Li1.4Al0.4Ti1.6(PO4)3 modification. The results of this work provide a possible method to design reliable cathode materials to achieve high energy density and long cycle life.
Project supported by the National Key Research and Development Program of China (Grant No. 2017YFB0102004), the National Natural Science Foundation of China (Grant No. 51822211), and the State Grid Technology Project, China (Grant No. DG71-17-010).
- Yi Wang, Bo-Nan Liu, Ge Zhou, Kai-Hui Nie, Jie-Nan Zhang, Xi-Qian Yu, Hong Li. Improved electrochemical performance of Li(Ni0.6Co0.2Mn0.2)O2 at high charging cut-off voltage with Li1.4Al0.4Ti1.6(PO4)3 surface coating[J]. Chin. Phys. B, 2019, 28(6): 068202.