The rational design of carbon coated Fe 2 (MoO 4 ) 3 nanosheets for lithium-ion storage with high initial coulombic efficiency and long cycle life.

Binary metal oxides are potential anode materials for lithium-ion storage due to their high theoretical specific capacities. However, the practical applications of metal oxides are limited due to their large volume changes and sluggish reaction kinetics. Herein, carbon coated Fe 2 (MoO 4 ) 3 nanosheets are prepared via a simple method, adopting urea as the template and carbon source. The carbon coating on the surface helps to elevate the conductivity of the active material and maintain structural integrity during the lithium storage process. Combining this with a catalytic effect from the generated Fe, leading to the reversible formation of a solid electrolyte interface layer, a high initial coulombic efficiency (>87%) can be obtained. Based on this, the carbon coated Fe 2 (MoO 4 ) 3 nanosheets show excellent rate capability (a reversible discharge capacity of 983 mA h g -1 at 5 A g -1 ) and stable cycling performance (1376 mA h g -1 after 250 cycles at 0.5 A g -1 and 864 mA h g -1 after 500 cycles at 2 A g -1 ). This simple in situ carbonization and template method using urea provides a facile way to optimize electrode materials for next-generation energy storage devices.