We adopted an effective route to prepare the particle size controllable core-shell structure carbon-coated LiFePO4 from different sized FePO4 precursors, varying from 80 nm, 200 nm and 1 μm by an in situ polymerization method integrated with a surface modification technology. The discharge capacities of the three sized LiFePO4/C are, respectively, 162 mAh·g-1, 142 mAh·g-1 and 92 mAh·g-1 at 0.1C rate. The nano-sized LiFePO4-a/C (80 nm) delivers a discharge capacity as large as 100 mAh·g-1 even at 30C, while the macroscopic LiFePO4-c/C (1 μm) exhibits a much poorer discharge capacity of 54 mAh·g-1 under the same current density. The carbon coated LiFePO4 (LiFePO4/C) also shows good chemical stability after the exposure to air atmosphere, in which the uniform carbon layer could prevent the LiFePO4 from reacting with H2O and O2.
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