Synthesis Of Co₃O₄/rGO By Hydrothermal Method For High-performance Supercapacitors

In this parper,Co₃O₄/rGO composites successfully self-assembled through the hydrothermal method.The effects of the hydrothermal reaction parameters on Co₃O₄/rGO composites’structure and electrochemical performances were discussed,including temperature and time.Subsequently,MMT and CNTs were used to fabricate3D porous graphene doped with GO,the phase characteristics of composites under different doping ratios were discussed to obtain electrode materials for Co₃O₄/rGO supercapacitors with better electrochemical performance.The results show that the crystal structure of Co₃O₄was changed from one-dimensional nanowires to high-dimensional nanoparticles,and the agglomeration phenomenon was weakened after loaded on graphene.Under the optimal hydrothermal conditions at 150 ℃ for 12 h,Co₃O₄/rGO has the most excellent electrochemical performance,with a specific capacitance of 1362.1 F/g at 1A/g,Co₃O₄and rGO has a good synergistic effect.The graphene layers were expanded by doping GO with MMT and CNTs.When the mass doping ratio of GO and MMT was1:5,the GO layers were obviously expanded and intersected with the MMT plates.CNTs were added to maintain the stability of large amounts of GO in the water system.When the mass rate of composite materials was GO（10%）/MMT/CNTs（50%）,A CMG-2 sample with an excellent conductive grading frame was obtained.MRC-2 and CMRC-2 composites were obtained by loading Co₃O₄onto 3D graphene,respectively.CMRC-2 had a reinforced concrete structure,and Co₃O₄was distributed in the highly oriented layer structure.There were abundant ion transport channels and micro-capacitors in the structure,which made CMRC-2 have higher electrochemical stability.When the current density was increased from 1A/g to 10 A/g,the specific capacitance values of MRC-2 and CMRC-2 were 65%and 72%of the original values,respectively.The CV test of CMRC-2 composites was carried out under the temperature condition of 0 to 50 ℃ at a speed of 10 m V/s.All the CV curves had a pair of REDOX peaks,and the curves basically coincide,indicating that CMRC-2composites could meet the working environment of low,medium and high temperature,which has certain practical significance.The composite materials were assembled into asymmetric capacitors,the specific capacitance of CMRC-2 was 98%of the original value after 5000 cycles of GCD test at 1A/g,and the power density and energy density were 751.7 W/kg and 43.84 Wh/kg,respectively.When the current density was increased to 5 A/g,it still had an impressive power density of 3750 W/kg and an energy density of 21.87 Wh/kg,which is better than other modified graphene-based composite button capacitors.It shows that CMRC-2 has good practical value.There are 61 pictures,4tables,and 115 references in this paper.