Electrochemical Performance And Application Of Carbon Materials From Waste Recovery

With the rapid development of industrialization,the problem of solid waste comes one after another.The traditional treatment method for solid waste has been unable to fulfill the current requirements.Most solid waste contains an extremely high carbon content,which can be easily converted into"high value-added"carbon materials.Such measures can not only effectively alleviate the environmental crisis caused by solid waste but also improve our economic development to some extent,which is in line with the sustainable development strategy.Based on this,in this thesis,the wastes were carbonized into carbon materials by a simple"one-pot method",and their energy storage performances were explored.The main research contents and results include:（1）The porous carbon material（PCN）prepared by thermal oxidation and carbonization using waste agricultural plastic film as a carbon source and potassium citrate as a template showed a porous nanostructure.The whole experiment process does not use any strong acids or bases,in line with green chemistry.At 0.5 A g^-1,the capacitance of PCN-700 can reach276.3 F g^-1.The symmetric supercapacitor based on PCN-700 exhibits fast charge and discharge dynamics and ideal capacitance behavior.After 10000 cycles at 5 A g^-1,the capacity retention rate was 88.9%.In addition,the practical application of PCN was tested.（2）Using waste corn bract fiber as a carbon source,aniline monomer was in situ polymerized into fiber material under an ice water bath to form polyaniline-corn bract fiber composite materials（PANI-CBF）.Electrochemical analysis proved that PANI-CBF-1 showed the best performance when the concentration ratio of aniline monomer to sulfuric acid was1:10.The carbon fiber materials（N-C）were formed by high-temperature carbonization of this composite material as a carbon source and presented a coral-like structure.At 0.5 A g^-1,the specific capacitance of N-C-800 can reach 220.7 F g^-1.These results demonstrated the possibility of N-C as an electrode material for supercapacitors.（3）Using waste corn bracts as carbon sources,S and N atoms were introduced into carbon materials by adding thiourea.After high-temperature carbonization,S and N-codoped porous carbon materials（SNPC-x）displayed an obvious three-dimensional porous tubular structure.The electrochemical analysis of SNPC-x indicated that SNPC-800 presented the best capacitance.At 0.5 A g^-1,the specific capacitance was 268.9 F g^-1.When the power density is 5186.3 W/kg,the energy density of the assembled symmetric supercapacitor is 29.4Wh/kg.At 5 A g^-1,after 11,000 long cycles,the capacity retention rate is 91.3%.Additionally,aqueous zinc-ion capacitors（AZICs）were assembled,and the most suitable electrolyte was found.It is proven that carbonization temperature and doping can affect the properties of AZICs.