Study On The Controllable Preparation And Electrochemical Properties Of Functional Heteroatomic Doped Carbon Microsperes

As one of the most important storage devices,the supercapacitors,especially the carbon supercapacitors are widely studied for their advantages such as fast charging and discharging rate,good rate capability,high chemical stability,excellent temperature stability and environmentally friendly.It is a simple and effective method to promote their capacity by introducing heteroatoms doping in carbon materials,among which the doping of nitrogen atoms in carbon material can effectively improve the specific capacity without affecting the intrinsic properties of carbon materials.This paper focuses on the synthesis of high performance nitrogen doped carbon materials.The nitrogen doped carbon microsphere electrode materials were successfully prepared by using simple preparation methods,and the relationships between the chemical states of doping nitrogen atoms and electrochemical performance were studied.Specific content as follows:1.Based on the feeding amounts by molar ratio of polymer monomer?nitrogen/fluorine=7:1?3:1?1:1 and 1:3?,different nitrogen doped carbon microsphere electrode materials were successfully prepared by simple one step hydrothermal synthesis and heat treatment at a certain temperature,the control of chemical states and contents of doped nitrogen was achieved,and the effect on electrochemical performance was also studied.The XPS test shows that the nitrogen doped carbon materials derived from F-APF with N/F molar ratio of 3:1 contain pyridinic N and pyrrolic N only,and the total effective nitrogen content is the highest.The doped N effectively promoted the capacitance properties of carbon materials,as to achieve the maximum of its quality specific capacity,it has a high specific capacity of 250 F g^-1 in a charge-discharge test with a current density of 0.5 A g^-1.2.The effect of carbonation temperature on electrochemical properties were investigated by the heat treatment at different temperatures?600 ^oC?700 ^oC?800 ^oC?900^oC and 1000 ^oC,respectively?on the precursors of the above optimized carbon materials.Tests show that,the activated nitrogen doped carbon microspheres?a-NCMs?800??carbonized at 800 ^oC show the highest quality specific capacity in 6 M KOH solution(250F g^-1 at a current density of 0.5 A g^-1)and long cycle stability(the capacity retention rate was 82.50%after 150 thousand cycles at a current density of 10 A g^-1).