Surface coating of LiNi0.8Co0.15Al0.05O2 with LiCoO2 by a molten salt method

An electro-active LiCoO2 layer is coated onto the surface of LiNi0.8Co0.15Al0.05O2 powders via a molten salt method. The effect of calcination temperature, calcination time, flux content and coating amount on the electrochemical properties of the sample is investigated. The X-ray diffraction (XRD) analyses show that the LiCoO2 coating does not change the structure of LiNi0.8Co0.15Al0.05O2. The transmission electron microscopy (TEM) and scanning electron microscopy (SEM) measurements indicate that a uniform layer LiCoO2 particulate is coated on the surface of the LiNi0.8Co0.15Al0.05O2 particles. The electrochemical performance studies demonstrate that the 3.0 wt.% LiCoO2-coated LiNi0.8Co0.15Al0.05O2 powders sintered at 800 °C for 4 h at weight ratio of KCl/LiNi0.8Co0.15Al0.05O2 = 2 exhibit the best electrochemical properties, with an initial discharge capacity of 196.2 mAh g− 1 and capacity retention of 98.7% after 50 cycles when cycled at a current density of 0.2 C between 2.8 and 4.3 V. Besides, these powders also show better rate capability and high-temperature performance than LiNi0.8Co0.15Al0.05O2.

► An electro-active LiCoO2 layer was coated onto the surface of LiNi0.8Co0.15Al0.05O2 powders via a molten salt method.
► The optimum coating condition of LiNi0.8Co0.15Al0.05O2 with LiCoO2 was obtained.
► The LiCoO2 coating didn't change the structure of LiNi0.8Co0.15Al0.05O2.
► The LiCoO2 coating improved further the electrochemical properties of LiNi0.8Co0.15Al0.05O2.