Rambutan-Like FeCO3 Hollow Microspheres: Facile Preparation and Superior Lithium Storage Performances

Rambutan-like FeCO3 hollow microspheres were prepared via a facile and economic one-step hydrothermal method. The structure and morphology evolution mechanism was disclosed through time-dependent experiments. After undergoing the symmetric inside-out Ostwald ripening, the resultants formed microporous/nanoporous constructions composed of numerous one-dimensional (1D) nanofiber building blocks. Tested as anode materials of Li-ion batteries, FeCO3 hollow microspheres presented attractive electrochemical performances. The capacities were over 1000 mAh g(-1) for initial charge, similar to 880 mAh g(-1) after 100 cycles at 50 mA g(-1), and similar to 710 mAh g(-1) after 200 cycles at 200 mA g(-1). The 1D nanofiber assembly and hollow interior endow this material efficient contact with electrolyte, short Li+ diffusion paths, and sufficient void spaces to accommodate large volume variation. The cost-efficient FeCO3 with rationally designed nanostructures is a promising anode candidate for Li-ion batteries.