Investigation the electrochemical performance of layered cathode material Li1.2Ni0.2Mn0.6O2 coated with Li4Ti5O12

• Li1.2Ni0.2Mn0.6O2 powders are synthesized and coated by Li4Ti5O12.
• The middle voltage value and rate capacity of Li1.2Ni0.2Mn0.6O2 are enhanced after coating.
• The shrinkage of parameters and lower ohmic and charge transfer resistance are responsible for the improved performance.

Layered cathode material Li1.2Ni0.2Mn0.6O2 has been synthesized and coated with different content of Li4Ti5O12 (1, 3, 5 wt%) by a sol–gel method. The effect of Li4Ti5O12 coating on the physical and electrochemical properties of Li1.2Ni0.2Mn0.6O2 material has been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electrochemical impedance spectroscopy (EIS), cycling and rate performance tests. The XRD, SEM and TEM results show that the Li1.2Ni0.2Mn0.6O2 has been coated with the Li4Ti5O12 particles effectively. The electrochemical performance results indicate that the 3 wt% Li4Ti5O12-coated sample has the best electrochemical performance, showing initial discharge capacity of 258.5 mA h g−1 at 0.1 C, capacity retention of 98.7% after 50 cycles at 0.2 C, and a high discharge capacity of 110.8 mA h g−1 at 10 C. The voltage decay of Li1.2Ni0.2Mn0.6O2 is mitigated remarkably after 3 wt% Li4Ti5O12 coating. EIS results show that the Rct of Li1.2Ni0.2Mn0.6O2 electrode decreases after coating, which is responsible for superior rate capability. As a result, the surface coating of Li1.2Ni0.2Mn0.6O2 with Li4Ti5O12 is a beneficial way to improve the electrochemical performances of Li1.2Ni0.2Mn0.6O2, which is due to Li4Ti5O12 layer acts as a relatively stable protective barrier as well as an excellent lithium-ion conductor.

The Li1.2Ni0.2Mn0.6O2 (A) has been synthesized and coated by Li4Ti5O12 (B). The voltage decay of pristine Li1.2Ni0.2Mn0.6O2 has been mitigated (C). And the rate capability has been improved effectively after coating (D).Figure optionsDownload as PowerPoint slide