Graphite fluorides obtained by fluorination of graphite at room temperature and after a subsequent re-fluorination treatment were characterised by X-ray diffraction and 19F MAS NMR. Their electrochemical performances as cathode materials in magnesium batteries have been investigated. Four different electrolytes (0.5 or 1M 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°C was also studied.