Preparation Of Hyper-crosslinked Polymers-derived Porous Carbon Matrix Composites And Their Capacitive Properties

Porous organic polymers,as emerging porous materials,are receiving more and more attention in academic and industrial fields and are one of the representative carbon precursors.There are abundant types of porous organic polymers,among which hyper-crosslinked polymers are a class of organic materials with pore structures formed by dense crosslinking to prevent the close stacking of polymer chains.Hyper-crosslinked polymers are generally constructed by Friedel-Crafts alkylation reaction,coupling reaction,phenolic condensation reaction,and Schiff base condensation reaction,etc.The many types of reactions make the preparation of hyper-crosslinked polymers easier and more flexible.In this paper,the hyper-crosslinked polymers were prepared by the solvothermal method and used as carbon precursors to prepare the derived porous carbon materials by high-temperature carbonization-chemical activation.To address the drawback of low energy density of carbon-based materials as supercapacitor electrode materials,the derived porous carbon is compounded with transition metal sulfide to prepare derived porous carbon composite transition metal sulfide materials.The main research works are as follows:（1）A hyper-crosslinked polymer was prepared by a combination of phenolic condensation reaction and Schiff base condensation reaction using a solvothermal method as the carbon precursor PNO,and the derived porous carbon PNOC-T-y was prepared by high-temperature charring and chemical activation in an argon atmosphere.the effects of different char-base ratios and charring temperatures on the microstructure and electrochemical properties of the derived porous carbon were investigated.The results showed that the derived porous carbon PNOC-800-3 has a three-dimensional porous structure with abundant internal micropores and mesopores,a specific surface area of 3094.51 m² g^-1 and an average pore size of 1.89 nm.The specific capacitance of the derived porous carbon PNOC-800-3 was 247.3 F g^-1 at a current density of 1 A g^-1.to 10 A g^-1,the specific capacitance decay rate is 20.68%.The assembled symmetric double-layer supercapacitor based on the derived porous carbon PNOC-800-3 as the electrode material has a capacitance retention rate of 87.79%and a Coulomb efficiency of about100%after 5000 cycles of charging and discharging at a current density of 1 A g^-1,and an energy density of 8.47 Wh kg^-1 at a power density of 500 W kg^-1.The excellent electrochemical performance and good cycling stability of PNOC-800-3 indicate that hyper-crosslinked polymer-derived porous carbon is a potential electrode material for supercapacitors.（2）The composite PNOC-800-3@Ni S-a-T was prepared by hydrothermal method using hyper-crosslinked polymer-derived porous carbon PNOC-800-3 as the substrate and thiourea as the sulfur source,and the effects of different nickel-sulfur ratios and synthesis temperatures on the electrochemical properties of the composites were investigated.The results show that the composite PNOC-800-3@Ni S-2-180 is a three-dimensional porous structure with a specific surface area of 1006.31 m² g^-1 and an average pore size of 1.86 nm.The specific capacitance of the composite PNOC-800-3@Ni S-2-180 is 1051.2 F g^-1 at a current density of 1 A g^-1.When the current density is increased from 1 A g^-1 to 10 A g^-1,the decay rate is 49.58%.The asymmetric supercapacitor based on composite PNOC-800-3@Ni S-2-180 as the positive electrode and derived porous carbon PNOC-800-3 as the negative electrode was assembled,and the capacitance retention was 72.63%after 5000 cycles of charging and discharging at a current density of 1 A g^-1,and the energy density was 20.98 Wh kg^-1 at 700 W kg^-1 power density.This study provides a reference for the preparation of porous carbon materials with composite transition metal sulfides.