Study of effects on LiNi0.8Co0.15Al0.05O2 cathode by LiNi1/3Co1/3Mn1/3O2 coating for lithium ion batteries

• LiNi1/3Co1/3Mn1/3O2 was firstly used as a coating layer for Li[Ni0.8Co0.15Al0.05]O2.
• The coating layer is composed of small particle with the size of 10–50 nm that grows into flocculent shape.
• The thickness of the layer is about 300 nm.
• Samples displaying good rate capability and cyclic stability.

Electrochemically active material, LiNi1/3Co1/3Mn1/3O2, was chosen to coat LiNi0.8Co0.15Al0.05O2 particle by a co-precipitation method with a weight ratio of 3:97. The thickness of coating layer is about 300 nm observed clearly by cross-section SEM photos. The coated material showed better electrochemical performance than that of the un-coated sample. At room temperature, the initial discharge capacity of the coated material was 188.2 mA h g−1 at 0.2C between 2.8 and 4.3 V and retained 96.2% after 100 cycles. Moreover, the discharge capacities of the coated cathode material at 50 °C could retain 163.2 mA h g−1 after 100 cycles. The composite also had a good rate performance with a capacity of about 146.3 mA h g−1 at 2C rate. Electrochemical impedance spectroscopy measurements showed that the coated material had a lower charge-transfer resistance.