超级电容器用CeO_2-MnO/3D石墨烯复合材料的制备

以西瓜瓜瓤为碳源,采用两步碳化法制备三维石墨烯(3D-Fiberbased Graphene,3D G)材料,并使用水热法制备了CeO_2-MnO/3DG复合材料,以期获得比电容高,循环寿命好的石墨烯超级电容器电极材料。结果表明:3DG材料具有较高比表面积,最高可达到332m~2·g~(-1)。CeO_2-MnO/3DG复合材料具有三维导电网络结构,金属氧化物颗粒在石墨烯片层间生长均匀,粒径在10nm左右。电化学测试结果显示:在0.5 mol·L~(-1)的Na_2SO_4溶液中,电流密度1A·g~(-1),当摩尔比MnO∶CeO_2=4∶1,复合负载量在80%时得到的CeO_2-MnO/3D G复合材料拥有最高比电容,达308.5F·g~(-1),经过1 000次循环充放电测试比电容保持率为95.5%。CeO_2-MnO/3DG复合材料电化学性能的提高主要是因为两种金属氧化物复合负载与石墨烯的协同作用。

Synthesis of CeO2-MnO/3D graphene composite for supercapacitors

In order to obtain supercapacitor materials with high specific capacitance and good cycle life,The 3D-Fiberbased graphene(3D G)was prepared with a two-step carbonation by watermeon flesh as carbon source.At last CeO2-MnO/3D G composite was prepared with the Hydrothermal method.The results show thatthe 3D G exhibits an excellent BET-surface area of 332 m2 ·g-1 due to the good spatial structure.CeO2-MnO/3D G composite are featured with a 3D conductive network structure,and metal oxide particles between the graphene sheets grow evenly,with about 10 nm in diameter.The electrochemical testing results show that the CeO2-MnO/3D G composite exhibit an excellent capacitance of 308.5 F·g-1 with the current density of 1 A·g-1 ,MnO∶CeO2=4∶1 and composite load at 80% in 0.5 mol·L-1 Na2 SO4 solution.Meanwhile,the CeO2-MnO/3D G composite also show outstanding cycling stability with 95.5% of the capacitance retention after 1000 cycles of charge/discharge.The high electrochemical properties of the CeO2-MnO/3D G composite is mainly attributed to the synergy of two metal oxide composite load with graphene.