Large-scale synthesis of ultrafine Fe3C nanoparticles embedded in mesoporous carbon nanosheets for high-rate lithium storage.

ABSTRACT

Fe3C modified by the incorporation of carbon materials offers excellent electrical conductivity and interfacial lithium storage, making it attractive as an anode material in lithium-ion batteries. In this work, we describe a time- and energy-saving approach for the large-scale preparation of Fe3C nanoparticles embedded in mesoporous carbon nanosheets (Fe3C-NPs@MCNSs) by solution combustion synthesis and subsequent carbothermal reduction. Fe3C nanoparticles with a diameter of ∼5 nm were highly crystallized and compactly dispersed in mesoporous carbon nanosheets with a pore-size distribution of 3-5 nm. Fe3C-NPs@MCNSs exhibited remarkable high-rate lithium storage performance with discharge specific capacities of 731, 647, 481, 402 and 363 mA h g-1 at current densities of 0.1, 1, 2, 5 and 10 A g-1, respectively, and when the current density reduced back to 0.1 A g-1 after 45 cycles, the discharge specific capacity could perfectly recover to 737 mA h g-1 without any loss. The unique structure could promote electron and Li-ion transfer, create highly accessible multi-channel reaction sites and buffer volume variation for enhanced cycling and good high-rate lithium storage performance.