We studied the influence of the anion of lithium: salts dissolved in a solution based on propylene carbonate (PC), ethylene carbonate (EC) and dimethyl carbonate (DMC) on the electrochemical properties of a petroleum coke (LONZA) and on the petroleum coke/electrolyte interface. We explored a correlation between the electrochemical properties and the surface chemistry of this coke using infrared spectroscopy, Rutherford backscattering spectrometry, fluoride selective electrode and standard electrochemical techniques. The different techniques show that LiF is a major product of the reduction of LiAsF6 and LiBF4 and a minor product of the reduction of LiCF3SO3 and LiTFSI. Alkyl carbonates are generated by reductions of the carbonate solvents to an extent which is independent of the anion of the lithium salt. Electrochemical behaviour of the coke is discussed with regard to the composition of the passivating layer. We found better cycling behaviour and greater lithium stability with LiCF3SO3 and LiTFSI.