Operating electrolyte used for an aluminum electrolyte capacitor contains ethylene glycol and a cinnamic acid-substituted salt

Operating electrolyte contains 70-99 (preferably 90-99) wt.% ethylene glycol and 1-20 (preferably 1-10) wt.% of a substance selected from cinnamic acid substituted on the phenyl ring and its ammonium salts, cinnamic acid and the corresponding ammonium salt, alpha -methyl cinnamic acid and its ammonium salt and trans-4-phenyl-3-butenoic acid and its ammonium salt. An Independent claim is also included for an aluminum electrolyte capacitor comprising a capacitor coil with a separator layer (3) arranged between an anode layer (1) and a cathode layer (2). The anode and cathode layers each have an oxide layer (4, 5) on the side facing the separating layer.