Highly fluorinated graphites have been synthesized by using elemental fluorine under pressure and high oxidation state complex fluoride, K2NiF6 or KAgF4 in anhydrous hydrogen fluoride. Their electrochemical discharge as a cathode of primary lithium battery has been investigated in organic electrolyte solution. Main products were stage 1 compounds or the stage 1 involving stage 2 and 3 phases as minor components with approximate compositions of C1.6F. X-ray photoelectron spectra indicated the existence of nearly semi-ionic C-F bonds. Electrochemical studies demonstrated that the CxF samples prepared using KAgF4 and elemental fluorine exhibited high and flat discharge potentials of 3.2 V versus Li/Li+ and discharge capacities of similar to 500 mA h g(-1) at cut-off potential 1.5 V. (C) 2000 Elsevier Science Ltd. All rights reserved.