Synergistic effects of microwave irradiation and CeF 3surface-coating of lithium titanate for stable, high-capacity, and high-rate lithium-ion batteries

Abstract

Lithium titanate (LTO) has continued to attract a lot of attention as an anode material for lithiumion batteries due to its high safety, long cycle life, fast charging capabilities, and affordability. The low theoretical specific capacity and rapid capacity degradation especially at long cycling have been the key challenges to the practical application of lithium titanate (Li 4 Ti 5 O 12 ) as anode material for stable high-energy and high-power densities lithium-ion batteries (LIBs). This study reports a novel strategy of the synergy of surface lattice plane engineering by microwave irradiation and CeF 3 -surface-coating to synthesize a high specific capacity, high-rate and durable LTO-CeF 3 -mw anode material for LIB. The innovative anode material shows outstanding specific capacity, rate capability and long-term cycle stability. It is of interest to note that the LTO-CeF 3 -mw anode material has specific capacities of 191.1 mAh g -1 at 175 mA g -1 (1 C) which is greater than the theoretical specific capacity of LTO (175 mAh g -1 ). Furthermore, LTO-CeF 3 -mw has specific capacities of 168.3 and 119.9 mAh g -1 at 875 mA g -1 (5 C) and 1750 mA g -1 (10 C)respectively. Remarkably, it shows a specific capacity of 166.5 mAh g -1 after 1000 cycles at 5 C, and a capacity retention of 98.9 %. This notable electrochemical performance of LTO-CeF 3 -mw is attributed to the synergy of surface lattice plane engineering by microwave irradiation and CeF 3surface-coating that transformed the surface lattice plane (111) of LTO to ( 220) and ( 311) in LTO-CeF 3 -mw having high surface area which significantly improved mass transport. Therefore, the unique structure of LTO-CeF 3 -mw anode material is a key development to safe and durable highenergy and high-power lithium-ion batteries and potential applications in large-scale energy storage.