Bromophenyl moieties were attached to the carbon-coated LiFePO4 (LiFePO4/C) surface by spontaneous reduction of in-situ generated 4-bromobenzene diazonium ions in organic media. The presence of the surface organic species on the grafted LiFePO4/C powders was confirmed by X-ray photoelectron spectroscopy. Thermogravimetric analyses revealed a low loading (lower than 1 wt. %) of grafted molecules. The electrochemical characterization of the LiFePO4/C cathodes showed that a low loading of bromophenyl groups at the LiFePO4/C surface can enhance the rate of Li+ extraction, presumably due to the decrease of the LiFePO4/C agglomerate size and an increase of the wettability of the electrode. On the other hand, poor performances were obtained using the grafted cathode material with the highest loading of bromophenyl moieties.