Effect of grain size of single crystalline cathode material of LiNi0.65Co0.07Mn0.28O2 on its electrochemical performance

In this paper, single crystalline cathode materials LiNi0.65Co0.07Mn0.28O2 with different grain size are successfully prepared via controlling the key experimental parameters. Tap density, compact density, specific surface area, X-ray diffraction, scanning electron microscopy and transmission electron microscopy are performed to evaluate the effect of grain size on the physical property and electrochemical performance of single crystalline material. The electrochemical tests reveal excellent rate capability and cycle stability at the cut-off voltage of 4.5 V for the sample with grain size around 3 μm with a capacity retention of 83% while only 40% of initial capacity is retained for the sample in 9 μm. The inferior electrochemical performance of large-sized single crystalline material is attributed to the severe planar gliding, particle cracking and irreversible phase transition. A moderate grain size between 3 and 5 μm can achieve desirable physical property and electrochemical performance.