Also, 96.5% retention of capacitance after 5000 cycles was attained for the composite which is higher compared to Co2CuS4 advising that the electrochemical stability of the metal sulfide is amplified after forming the composite with NG and exhibited in The same group developed the 3D encapsulated Fe3O4 nanosphere anchored over Ndoped graphene sheet (Co-Fe3O4NS@NG) hybrid using solvothermal technique and got the high specific capacitance of 775 F g -1 at1 A g -1 in 3 M KOH and 97.1% capacitance retention after 10000 cycles . The composite (Co-Fe3O4NS@NG) was produced by mixing the desired molar ratios of aqueous solution of suitable metal salts precursors in ethylene glycol solution and urea with GO dispersion and sodium citrate as a surfactant at 200 °C for 11 h in a Teflon-lined stainless-steel autoclave. The specific capacitance determined from the CD profile for Fe3O4 NS@NG hybrid and NG at 1 A g -1 are found to be 478 and 315 F g -1 , respectively.