The present invention provides a process for the production of perfluoroalkylsulphonyl fluorides of the formula C.sub.n F.sub.2n+1 SO.sub.2 F with n=6-10 by electrochemical fluorination of alkylsulphonyl halides of the general formula C.sub.n H.sub.2n+1 SO.sub.2 X with n=6-10 and X=F, Cl, Br or I in hydrogen fluoride, which process is characterised in that electrodes are used which consist of nickel with a columnar structure or which are coated with nickel with a columnar structure as shown in FIG. 1.The invention also provides electrodes for the production of perfluoroalkylsulphonyl fluorides from the corresponding alkylsulphonyl halides by electrochemical fluorination in hydrogen fluoride, which electrodes are characterised in that they consist of nickel with a columnar structure or are coated with nickel with a columnar structure.