Preparation And Supercapacitor Performance Of ZIF-8 Derived Carbonaceous Materials

In order to meet the demand for development of electric vehicle and wearable electronics industry,researchers have invested a great deal of effort in the fabrication of energy storage device with high power density or flexibility.Supercapacitors with high power density and long cycle life have been considered to be one of the most promising solution,however,relative low energy density limits its practical application.Therefore,ionic liquid based high voltage supercapacitors?ILSC?and lithium-ion capacitors?LIC?have attracted increasing interests due to their improved energy density.To date,the design and synthesis of high performance electrode materials for LIC anode or ILSC electrode still remain challenging.Herein,we prepared novel electrode materials for ILSC electrode and LIC anode,respectively,as shown below:1.We reported a novel hierarchically porous carbon/rGO material?HC-40-4?with tailored morphology and pore structure where MOFs derived hierarchically porous carbon polyhedrons are in situ anchored on the rGO layers uniformly.The HC-40-4 shows a synergistic effect of porous nanocarbon and rGO,and possesses ultrahigh specific surface area?2837 m²/g?,desired meso-/micropore distribution and nitrogen doping.After testing the electrochemical performance of as synthesized materials,we used HC-40-4 as electrode material to construct high voltage flexible supercapacitor with the aid of EMIMBF₄/PVDF-HFP gel polymer electrolyte.The flexible device demonstrates superior specific capacitance?201 F/g?,good rate/cycling performance and high energy/power density.The energy and power densities are estimated to be 86 Wh/kg at 438 W/kg and 61 Wh/kg at 17500 W/kg.Moreover,the flexible supercapacitor shows good capacity retention under various bending states,which represents the promising potential of HC-40-4 material for application in wearable electronics.2.We utilized ZnO nanoparticles,graphite oxide and organic ligands to prepare ZnO@ZIF-8/GO precursor,and the hollow porous carbon/rGO composite?HCZ-650?can be obtained after carbonization and acid washing process.The HCZ-650 exhibits high lithium storage performance because of its unique hollow structure and electron conductive network.The LIC composed of HCZ-650 anode and commercial activated carbon?YP-80?cathode possesses both high energy density and power density?76.6 Wh/kg at 29973 W/kg?.We also found that the weight ratio of active material of cathode to that of anode should be 3:1 to maximize the electrochemical performance of LIC.Besides,the LIC shows long cycle life and good rate capability,which shows the extensive application potentiality of HCZ-650 composite in LIC.