Preparation And Superelectric Properties Of Fluorophenol Modified Nitrogenous Resin Derived Carbon

Active functional group functionalized resin-derived carbon materials have become one of the most promising electrode materials for supercapacitors due to their wide source of precursors and good heteroatom inheritance.Both urea-formaldehyde resin and melamine resin contain a high proportion of nitrogen in their structures and are usually used as precursors of nitrogen-containing carbon materials.However,the transformation of non-conjugated cross-linked structure to conjugated carbon plane is involved in the process of carbonization at high temperature,resulting in the loss of a large number of carbon atoms and active heteroatoms,and the uncontrolled transformation of heteroatom configuration at high temperature often restricts the improvement of their performance and the study of energy storage mechanism.In order to further improve the properties of functional resin-derived carbon materials,the fluorophenol-urea-formaldehyde/melamine resin copolymer was obtained by adding3-fluorophenol into the synthesis process of resin.By low temperature dehalogenation carbonization and low temperature alkali activation,carbon materials with high residual carbon rate and high heteroatom retention rate were obtained,and their electrochemical properties were systematically studied.（1）Firstly,urea,formaldehyde and 3-fluorophenol were used as raw materials to obtain modified urea-formaldehyde resin by hydrothermal polymerization.Then,the modified urea-formaldehyde resin derived carbon material was obtained by low temperature carbonization and low temperature alkali activation.The content of heteroatoms was as high as 18.92 at%.At the current density of 1 A g^-1,the specific capacity of the material is 484 F g^-1,which is much higher than that of the traditional high temperature urea formaldehyde resin derived carbon material（175%of its specific capacity）.When the current density increases to 20 A g^-1,the specific capacity is 392 F g^-1and the capacity retention rate is 81%.After 10000 cycles of 10 A g^-1,the high specific capacity of 366.8 F g^-1 is still maintained,and the capacity retention rate is 90.4%.（2）In order to further improve the specific capacity of the material,melamine with higher nitrogen content was selected as the nitrogen source to synthesize the 3-fluorophenol-melamine-formaldehyde resin by copolymerization with formaldehyde and3-fluorophenol.The carbon electrode material prepared at low temperature had A heteroatomic content of 18.82 at.%,and the specific capacity of the material was up to 540F g^-1 under the current density of 1 A g^-1.Far more than the traditional high temperature urea formaldehyde resin derived carbon material（is 200%of its specific capacity）.When the current density increases to 20 A g^-1,the specific capacity is 424 F g^-1 and the capacity retention rate is 78.6%.After 20,000 cycles under 10 A g^-1,the high specific capacity of373.3 F g^-1 is still maintained,and the capacity retention rate is 92.75%.