Study On The Preparation Of Porous Carbon By Aluminum Based Mof And Its Electrochemical Performance

The widespread application of new energy in the society and the continuous development of electronic equipment and electric vehicles have put forward high requirements for energy storage systems and batteries.In order to solve the problems of low capacity of supercapacitors,high cost of electrode active materials and the slow speed of charge-discharge,we proposed the development of a new type of electrode material in this dissertation.Metal-organic framework(MOF)materials have the advantages of self-regulation,high porosity,structural order,large specific surface area,and easy synthesis.Additionally,the structure and inherent characteristics of MOF during the carbonization process do not change.So MOF materials have become the best material for the preparation of porous carbon.In this dissertation,Al-based MOF is chosen as the precursor to prepare a 3D carbon material with a new rugby-shaped mesoporous and microporous heterogeneity.The obtained porous carbon materials have large specific surface area,high thermal stability,and low production cost.Therefore,the electrochemical performance of the Al-MOF derived porous carbon is superior to other carbon materials.The main content of this paper is as follows:1?Al(NO3)3 and trimellitic acid(H3BTC)were used to hydrothermally synthesize Al-BTC,and then porous carbon was prepared by high-temperature carbonization of Al-BTC precursor.The results of Scanning electron microscopy(SEM),BET adsorption isothermal test(BET),X-ray diffraction(XRD),and galvanostatic charge-discharge tests have shown that the optimal conditions for the preparation of porous carbon from Al-BTC precursors were to synthesize Al-BTC precursors at 120 ? for 9 h,and to calcine them at 800 O for 2 h.The galvanostatic charge-discharge test was used to characterize the electrochemical performance.The results indicate that the prepared porous carbon has a specific capacitance of 306.4 F g-1 at the current density of 1 A g-1.When the current density increases to 100 A g-1,the specific capacitance decreases to 190.4 F g-1.After 50000 cycles at the current density of 50 A g-1,the specific capacitance only decreases by about 5.0%.2?Based on the above porous carbon,the effects of activation of KOH and HNO3 on the electrochemical performance were studied.The optimum KOH activation condition is at 825 ? for 1 h.After activation,the electrochemical performance is improved.When the current density is 1 A g-1,the specific capacitance is 321.6 F g-1 for the activated porous carbon material,which is 6.77%higher than that of the porous carbon without KOH treatment.The optimal condition for HNO3 activation is 5 M HNO3.The activated material has a specific capacitance of 326.6 F g-1 at 1 Ag-1.3?Finally,on the basis of the Al-BTC precursor,the effects of different nitrogen source and doped proportion on the performance the porous carbon materials were studied.The results show that the nitrogen-doped porous carbon with melamine as a doping nitrogen source with mass ratio of 8:1 has the best electrochemical performance.The specific capacitance of the prepared nitrogen-doped porous carbon reaches 331.1 F g-1 at 1 A g-1 and the capacitance attenuation is only 4.8%after 50,000 cycles.