Two-dimensional phosphorus supercapacitors

•Electrochemical properties of different phases of 2D phosphorus were investigated here for the first time.•We have shown here that the 2D phosphorus is promising candidate for being electrodes of supercapacitor.•Band structure, quantum capacitance and total capacitance of black, blue and green 2D phosphorous are obtained here by utilizing JDFT.•We have shown that the area-normalized capacitances of these 2D phosphorous structures are higher than that of graphene.