S-doped graphene oxide hybrid nanosheets are prepared by a facile in situ-polymerization method. The electrochemical performance is evaluated using cyclic voltammetry, galvanostatic charge/discharge techniques and impedance spectroscopy in 2 M KOH. As an electroactive material, it exhibits good capacitive performance in alkali aqueous electrolyte, high specific capacitance (up to 296 F g−1) at a current density of 0.3 A g−1, which is calculated via charge/discharge curve in three electrode systems. The electrical conductivity is also measured. More importantly, over 91.86% of the long-term stability is retained after repeating the galvanostatic charge/discharge over 4000 cycles. Furthermore, larger energy density (up to 148 W h kg−1 at a power density of 41.6 W kg−1) of the GO-TB-based three-electrode device is obtained with alkali aqueous electrolytes.