钴基MOFs/石墨烯微纳结构电极材料的制备及其电容性能的研究

Preparationof Co-MOFs/rGO electrode with micro-nano structure and its supercapacitance performance

以氧化石墨烯为前驱体、Co(NO_3)_2·6H_2O为钴源、对苯二甲酸(H_2BDC)为配体、三乙胺为添加剂、N,N-二甲基甲酰胺(DMF)为溶剂,通过一步溶剂热法制备了具有微纳结构Co_2(OH)2_BDC/rGO复合电极材料。Co_2(OH)_2BDC/rGO复合材料是由微米级的Co-MOF颗粒直接锚定式生长在还原氧化石墨烯表面形成的,而Co_2(OH)_2BDC是由定向排列的纳米棒自组装形成的类球形颗粒。研究结果表明:不同的GO的浓度对复合材料的物相结构、形貌及电化学性能有很大的影响。当GO的浓度为2 mg/ml时,在110℃,24 h溶剂热合成得到的Co_2(OH)_2BDC/rGO复合材料在电解液为1M KOH,5 mV/s下比电容为225 F/g。在恒流充放电测试中,当电流密度从3 A/g增加到10 A/g时,Co_2(OH)_2BDC/rGO的电容保持率为83.5%。在3 A/g下经过500次充放电循环后电容的保持率为93.9%。

The Co2(0H)2BDC/rG0electrode materials with micro-nano structure have been obtained using a facile synergistic self-assembly solvothermal route.The desired control of coordination between1,4-DBC with cobalt ions enables the macroscopic self-as-sembly of crystal orientation-ordered Co2(〇H)2BDC nanorod-bundles to be tailored into round and elongated micron-sized parti-cles.As the electrode materials for supercapacitor,it exhibited large specific capacitance,high rate capability and good cycling sta-bility.The GO loading are important factors in determining the phase,morphology and electrochemical property of as-prepared Co2(0H)2BDC/rG0composites.The optimum condition was achieved by the synthesis temperature of110,reaction time24h and2mg/ml of graphene oxide addition.Co2(0H)2BDC/rG0composite deliver a large specific capacitance of225F/g at a scan rate of5mV/s in1M KOH electrolyte,superior rate capability with a stable capacity of83.5%when the current density increase from3A/g to10A/g.Also,it displays good electrochemical stability with93.9%of the initial capacitance over consecutive500cycles at3A/g.