Li[Li0.2Mn0.54Ni0.13Co0.13]O2 was prepared using a coprecipitation method and modified with Li4Ti5O12. The sample coated with 3wt% Li4Ti5O12 exhibited the best cyclability and mean coulombic efficiency in the voltage range of 2.0–4.75V. These improvements are attributed to the effective Li4Ti5O12 coating layer, which stabilizes the host structure, protects the electrode surface from electrolyte attack, and prevents the formation of a thick passive film on the electrode surface. The initial irreversible capacity loss was eliminated by blending with 10wt% Li4Ti5O12, in the larger potential window of 1.5–4.75V. It was confirmed that the irreversible capacity loss decreased with increasing Li4Ti5O12 content; this is because Li4Ti5O12 offers a larger number of available sites for insertion of extracted lithium.