MOFs衍生多孔碳/MnO_2复合材料及其在超级电容器中的应用

Porous carbon materials/MnO_2 composites derived from MOFs and their application in supercapacitors

利用高比表面积、大孔隙率金属有机骨架材料(metal-organic frameworks, MOFs)作为牺牲模板,制备了MOFs(ZIF-8)衍生多孔碳材料(PCs),以其作为导电基底,在表面生长金属氧化物MnO_2,获得MnO_2/PCs复合材料并将其应用在超级电容器中.制备的复合材料具有良好的电化学电容性能,在三电极体系中,1 A·g^(-1)的电流密度下比电容可达199 F·g^(-1),经过2 000次充放电循环后,比电容仍能保持初始值的80%.使用MnO_2/PCs复合材料作为正极,PCs作为负极,组成的非对称型电容器MnO_2/PCs//PCs具有优异的电化学储能性能,在950 W·kg^(-1)的功率密度下,能量密度高达10.16 Wh·kg^(-1);而且当功率密度上升为9 500 W·kg^(-1)时,能量密度仍可以保持4.48 Wh·kg^(-1).

In this paper,MOFs-derived porous carbon materials (PCs) are prepared by serving metal-organic frameworks(MOFs) with high specific surface area and large porosity as sacrificial templates,and then the resultant PCs is used as conductive substrate to grow metal oxide MnO2 on its surface to form MnO2/PCs composite for electrode materials of supercapacitors.The as-prepared composite shows good electrochemical capacitance performances.The experimental results show that under the three-electrode system,the specific capacitance can reach 199 F ·g^-1 at a current density of 1 A ·g^-1 .After 2 000 charge and discharge cycles,the specific capacitance can still maintain 80% of the initial value.We use MnO2/PCs composite as positive electrode and PCs as negative electrode to assemble an asymmetric capacitor MnO2/PCs//PCs.The resulting device (MnO2/PCs//PCs) achieves an energy density of 10.16 Wh ·kg^-1 at a power density of 950 W ·kg^-1 and it still retains a value of 4.48 Wh ·kg^-1 at 9 500 W ·kg^-1 .