Carbon layers with microporous structures fine-modulated by naphthalene (NAP) were prepared to coat on LiFePO 4 , aiming to enhance the Li + diffusion coefficient for Li-ion batteries. Characterized by BET, XRD, TEM, EIS, etc., it is indicated that in the presence of NAP, the carbon-coated LiFePO 4 /C-NAP composites have the enlarged micropore size of 1.66 nm and the enhanced Li + diffusion coefficient of 2.83 ×10 ? 12 cm 2 s ? 1 , which is about five times higher than that of LiFePO 4 /C prepared in the absence of NAP. At a high rate of 20 C, the discharge capacity of the LiFePO 4 /C-NAP is up to 120.1 mA h g ? 1 and maintains a good retention rate of 93.2％ after 400 cycles. It is suggested that the NAP-modulated car- bon coating is a promising route to accelerate the Li-ion diffusion rate and enhance the electrochemical performance for lithium ion batteries.