Co_3O_4/氮掺杂三维石墨烯材料制备及电容性能

Preparation of Co_3O_4/nitrogen doped three-dimensional graphene composite and its supercapacitor properties

通过两步法制备Co_3O_4/氮掺杂三维石墨烯,先使用不同pH的NH_3-NH_4^+缓冲溶液制得前驱体,之后煅烧前驱体制得复合材料。电化学测试结果表明,在pH=9.75时制备的复合材料电化学性能最好,在电流密度为1 A/g下的比电容值为630.6 F/g,电流密度增大到2 A/g时,电容保持率为87%,经过1 000次充放电测试后,电容保持率仍高达87%,且材料内阻小于1Ω。XRD和SEM测试表明,复合材料为非晶形材料且呈蜂窝状结构。

The materials of Co3O4 and N-doped three-dimensional graphene were prepared by a simple and feasible two-step method.The precursors were prepared at different pH values of NH3-NH4+ buffer solution.And then the precursors were calcined to obtain the composite material.The results of electrochemical tests show that the composite prepared at pH=9.75 has the best electrochemical performance with a specific capacitance of 630.6 F/g at a current density of 1 A/g.and when the current density is 2 A/g,the capacitance retention is up to 87%.After 1 000 charge-discharge tests,the capacitance retention is as high as 87%and the material internal resistance is less than 1Ω.XRD and SEM tests show that the composites are amorphous and have a honeycomb structure.