In situ multifunctional surface design for high-performance 4.6 V LiCoO2

Lithium cobalt oxide (LCO) cathode materials could deliver about 220 mAh/g when operated at 4.6 V. However, high-voltage LCO materials still endure detrimental interfacial side reactions and serious structural degradation, leading to severe performance deterioration. Herein, we have proposed a facile strategy that utilizes good-wettability LiPO 3 and ionically conductive Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) to successfully construct a highly stable Li 3 PO 4 layer and a well-matched transition layer (such as Co 2 TiO 4 and LiCoPO 4 ) on the surface of LCO material. The designed multifunctional coating can not only suppress the oxygen release and electrolyte decomposition but also facilitate Li + diffusion kinetics. As a result, the modified LCO exhibits superior cycling stability over 200 cycles at 4.6 V, with excellent capacity retentions of 79.24 % at room temperature and 79.45 % at high temperature of 45 ℃. Besides, the modified LCO realizes a reversible discharge capacity of 178.42 mAh/g at 3C (1C = 200 mA/g) over 300 cycles. This work provides a practical reference for mass-production of high-voltage LCO with long lifespan and high-rate capability.