Construction And Study On Energy Storage System Of Modified Porous Carbon Fiber Coupling With Organic Active Molecules

Supercapacitors have attracted tremendous attention due to their outstanding performance,such as high power density,long cycle life,safely and ultra-fast charge and discharge rate,making them the nextgeneration energy-storage systems for potential applications in the now hybrid vehicles,portable electronic devices,etc.Carbon-based materials are the most widely used materials for supercapacitor electrodes,but low capacitance limits their further development.For that reason,in this paper,the preparation of high capacitance carbon-based electrode materials and the construction of high voltage asymmetric supercapacitors(ASCs)were studied.This paper proposes a strategy for boosting the charge storage of carbon-based materials by combining surface modified carbon-based materials with redox active moieties.Typically,the porous carbon fiber(PC)is modified by electrochemically activation and boron-doping,respectively,followed combining with HQ molecules.The electrochemical activated PC(EAPC)can absorb HQ molecules and the EAPC@HQ electrode yields a high area capacitance(2700 m F/cm² at 5 m V/s).More interestingly,the surface modified PC obtained by boron-doping(BPC)can adsorb HQ molecules more efficiently,the BPC@HQ delivered an amazing electrochemical performance including high area specific capacity(2670 m F/cm² at 5 m V/s),good rate performance(1068 m F/cm² at 200 m V/s),and excellent long-term cycling stability(100%retention over 10000 cycles at 80 m A/cm²).In combination with the structure characterization and DFT theory analysis,the excellent performance is attributed to the stronger noncovalent?-?interactions between BCO₂ functional group and HQ molecules.And the closer distance is more beneficial to the electron conduction between HQ molecules and BCO₂functional groups,which improves the proton-coupled electron transfer reaction rate of HQ.In addition,to further demonstrate the feasibility of the BPC@HQ electrode at the device level,a 1.8 V asymmetric supercapacitor with BPC@HQ cathode and Ti₃C₂T_x anode is constructed.A high energy density of 12.2 m Wh/cm³ can be obtained at a power output of 230m W/cm³,while it still delivers an energy density of 7.7 m Wh/cm³ at a power density of 3683m W/cm³.The combination of surface modified carbon-based materials and redox active moieties provides an efficient strategy towards improving the energy density of the carbon-based supercapacitor without comprising the power capability.