In this study, we tried to evaluate the application of defected silicene as an electrode in supercapacitors using density functional theory calculations. Researchers have focused on single and double-vacancy silicene. In this work, we investigated six types of vacancies, namely the structures of mono vacancy (MV), double vacancy (DV), triple vacancy (TV), quadruple vacancy (QV), five vacancy (FV) and six vacancy (SV). The density of state, the integrated quantum capacitance, and stored charge plots for the pristine and the vacancy-modified defected silicene structures were investigated. Our results showed that using the vacancy-modified defected structures in the voltage range of -0.50 to 0.50 V provides more quantum capacities than using the pristine silicene. The vacancies MV, TV, QV, FV, and SV can be used as negative and positive electrodes, and they are p-type semiconductors. According to our calculations, the charge stored in at the vacancy-modified defected structures is higher than the charge stored in the pristine silicene at 0 to 0.5 V. The values of the charge stored in all of the vacancy-modified defected structures are similar to those in the pristine silicene. According to our results, the defected silicene is considered as a promising material in high-efficiency supercapacitors.