Abstract: A method of making copper sulfide electrode material comprising steps of: 1) stirring and dissolving copper(ii) nitrate hydrate (Cu(NO3)2.3H2O) and Thiourea (CH4N2S) in a mixed solution consisting of ethylene glycol and deionized water; 2) adding hexadecyl trimethyl ammonium bromide (C19H42N.Br) to mixture A; 3) placing the mixture B into a roaster, raising a temperature of the roaster to 100° C. to 180° C. for 10 hours to 18 hours; 4) washing the crude CuS by using a mixed fluid of ethanol absolute (C2H6O) and deionized water to be cooled in a room temperature, placing the crude CuS in the roaster and raising a temperature of the roaster to 50° C. to 80° C.; 5) producing cathode electrode of asymmetric capacitive deionization module by using the copper sulfide electrode material; 6) producing anode electrode of asymmetric capacitive deionization module by using activated carbon electrode material.