Improved electrochemical performance of LiCoO2 surface treated with Li4Ti5O12

The LiCoO2 cathode material was surface treated with the Li4Ti5O12 particles by a simple mechano-thermal process, followed by calcination at 723 K for 10 h in air. The X-ray diffractometer (XRD) patterns showed a single-phase hexagonal α-NaFeO2-type structure for the surface treated LiCoO2 without any structure modification and new phase formation. The transmission electron microscope (TEM) image exposed a uniform layer Li4Ti5O12 particulate over the surface of the LiCoO2 particles that had an average thickness of ~20 nm. The electrochemical performance studies indicated that a 1.0 wt.% Li4Ti5O12 coated LiCoO2 sample heated at 723 K for 10 h in air exhibited an initial discharge capacity of 171 mAh g−1 and excellent cycle stability of about 148 cycles for a cut-off voltage of 80% when cycled between 2.75 and 4.40 V. The differential capacity plots for LiCoO2 surface treated with Li4Ti5O12 confirmed that the enhanced performance can be attributed to slower impedance growth and increased resistance to Co dissolution into the electrolyte during the (de)intercalation processes.