Enhancement of electrochemical performance of Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]O_2 by surface modification with Li_4Ti_5O_(12)

摘要

Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]O_2 was prepared using a coprecipitation method and modified with Li_4Ti_5O_(12). The sample coated with 3 wt% Li_4Ti_5O_(12) exhibited the best cyclability and mean coulombic efficiency in the voltage range of 2.0-4.75 V. These improvements are attributed to the effective Li_4Ti_5O_(12) 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 10 wt% Li_4Ti_5O_(12), in the larger potential window of 1.5-4.75 V. It was confirmed that the irreversible capacity loss decreased with increasing Li_4Ti_5O_(12) content; this is because Li_4Ti_5O_(12) offers a larger number of available sites for insertion of extracted lithium.