MOF衍生碳复合电极材料制备及电化学性能研究

Preparation and electrochemical performance of MOF-derived carbon composite electrode materials

针对活性炭比电容低的问题,利用金属有机骨架(MOFs)大的比表面积和丰富孔隙结构,研究了一种协同双电层机制与赝电容特性的MOFs衍生多孔碳与活性炭的杂化复合材料。通过设计不同的Zn/Co比和碳化温度,制备了N掺杂多孔碳复合材料。ZCPC@AC-800经三电极体系测试,以6 mol/L KOH为电解质,在0.5 A/g时,比电容为327.5 F/g,高于单金属原子生成的MOF衍生多孔碳复合材料,这是由于纳米复合材料中双金属MOF在热解过程中能提供更加多样的活性位点。此外,在电位窗口为0~1.5 V的3 mol/L KOH电解液中组装的对称超级电容器(ZCPC@AC-800∥ZCPC@AC-800)在375 W/kg的功率密度下,具有21 Wh/kg的能量密度。经循环测试,5 A/g时充放电5000次后,其初始比电容仍保持80%。

Aiming at the problem of low specific capacitance of activated carbon,utilizing the large specific surface area and abundant pore structure of metal organic frameworks(MOFs),a synergistic bilayer mechanism with pseudocapacitive properties of MOFs-derived porous carbon hybrid composites with activated carbon was investigated in this paper.N-doped porous carbon composites were prepared by designing different Zn/Co ratios and carbonization temperatures.ZCPC@AC-800 was tested in a three-electrode system and showed a specific capacitance of 327.5 F/g at 0.5 A/g,which was higher than that of the MOF-derived porous carbon composites generated from monometallic atoms,due to the fact that the bimetallic MOFs in the nanocomposites could provide a more diverse range of active sites during pyrolysis.In addition,symmetric supercapacitors(ZCPC@AC-800∥ZCPC@AC-800)assembled in a 3 mol/L KOH electrolyte with a potential window of 0-1.5 V have an energy density of 21 Wh/kg at a power density of 375 W/kg.After cycling test,its initial specific capacitance remained 80%after 5000 times of charging and discharging at 5 A/g.