The electrochemical performance of two electrolytes, containing 1 mol L −1 spiro structure quaternary ammonium salts, spiro-(1,1′)-bipyrrolidinium tetrafluoroborate (SBP-BF 4 ) and piperidine-1-spiro-1′-pyrrolidinium (PSP-BF 4 ), in acetonitrile (AN), are investigated in commercial 7500F electric double layer capacitors (EDLC). Compared with conventional tetraethylammonium tetrafluoroborate (TEA-BF 4 ) electrolyte in AN, the cell using SBP-BF 4 /AN electrolyte have a larger capacitance and an equivalent equivalent series resistance (ESR). The cells with electrolytes containing spiro structure quaternary ammonium salts have great advantages in capacitance and ESR remained in floating test at 70°C and 2.85 V.