A worm-like mesoporous structured iron-based fluoride (Fe1.9F4.75 center dot 0.95H(2)O) is successfully synthesized for the first time by a rapid microwave irradiation heating route using ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BmimBF(4)) as fluorine source and iron (III) nitrate nonahydrate (Fe(NO3)(3)center dot 9H(2)O) as iron source. By controlling the amount of ionic liquid, a series of nanostructured iron-based fluoride materials with different morphologies are obtained. A possible formation mechanism related to the role of the ionic liquid is proposed. The electrochemical performances of the worm-like mesoporous structured iron-based fluoride as cathodes for rechargeable lithium batteries are investigated. A high discharge plateau around 2.7 V at the first cycle, a reversible discharge capacity as high as 145 mAh g(-1) at a current density of 14 mA g(-1) and a good rate performance with a high rate capacity of 125 mAh g(-1) even at 71 mA g(-1) are obtained. (C) 2013 Elsevier B.V. All rights reserved.