Graphite fluorides obtained by fluorination of graphite at room temperature and after a subsequent re-fluorination treatment were characterised by X-ray diffraction and F-19 MAS NMR. Their electrochemical performances as cathode materials in magnesium batteries have been investigated. Four different electrolytes (0.5 or 1 M Mg(ClO4)(2) in ACN, DMSO, PC and THF) were used for these tests. The specific energy and power densities were estimated for all media. A comparison of the performances between lithium and magnesium batteries was realised. The effect, on the electrochemical performances, of a re-fluorination treatment at 250 degrees C was also studied. (C) 2007 Elsevier B.V. All rights reserved.