A delicate structure of graphitic carbon-encapsulated alpha-Fe2O3 nanocomposite is in situ constructed via "Absorption-Catalytic graphitization-Oxidation" strategy, taking use of biomass matter of degreasing cotton as carbon precursor and solution reservoir. With the assistance of the catalytic graphitization effect of iron core, onion-like graphitic carbon (GC) shell is made directly from the biomass at low temperature (650 degrees C). The nanosized alpha-Fe2O3 particles would effectively mitigate volumetric strain and shorten Li+ transport path during charge/discharge process. The graphitic carbon shells may promote charge transfer and protect active particles from directly exposing to electrolyte to maintain interfacial stability. As a result, the as-prepared alpha-Fe2O3@ GC composite displays an outstanding cycle performance with a reversible capacity of 1070 mA h g(-1) after 430 cycles at 0.2C, as well as a good rate capability of similar to 950 mA h g(-1) after 100 cycles at 1C and similar to 850 mA h g(-1) even up to 200 cycles at a 2C rate. (C) 2015 Elsevier Ltd. All rights reserved.