The Preparation Of Carbon Matrix Composites And Its Electrochemical Properties

Supercapacitors are energy storage devices that combine the advantages of batteries and capacitors to improve energy storage and conversion efficiency effectively.Carbon-based composite supercapacitors have become one of the hottest research directions due to their high specific power,capacity,safety and environmental protection.In this paper,the preparation of carbon-based composites is studied.The energy and power density are improved by improving the porous structure of carbon materials,doping,and introducing pseudocapacitance.Characterization of SEM,TEM,XRD,FTIR,XPS,Raman,BET,and electrochemical test was carried out to investigate the electrochemical energy storage performance of the composite materials structure and composition.The main results are as follows:1.Phosphorus doped porous carbon-based materials.P-doped porous carbon materials were synthesized by high temperature with phytic acid as phosphorus source,porous carbon prepared from wheat flour,potassium hydroxide and urea.The p-doped porous carbon framework?P-PCF?electrode materials with different proportions of phytic acid were studied.The test results show that 0.25 P-PCF performs optimally,reaching 112 F g-1(1 A g^-1).0.25 P-PCF as the electrode material has the smallest solution resistance?0.0647??,and at a current density of 2 A g^-1,0.25 P-PCF undergoes5,000 cycles charge-discharge cycles,and 0.25 P-PCF can still be maintained near 100%retention and about 92%coulomb efficiency,indicating good cycle life and storage capacity,showing good charge-discharge performance and rate performance at 10 A g^-1 compared with 83.9%retention of capacitance.2.PANI/porous carbon-based materials.PCF was used as the framework structure and nitric acid was used as the oxidant.Polyaniline?PANI?was successfully coated on APCF.Then,The hydroxylated porous carbon-polyaniline?APCF-PANI?composite was successfully prepared and used as the electrode material.PCF-PANI and APCF-PANI were tested and compared.It was found that APCF-PANI has better electrochemical properties as an electrode material.In the three-electrode test,the specific capacitance of APCF-PANI reached 279.13 F g^-1(1 A g^-1);in the asymmetric two-electrode test,its voltage reached 2 V of APCF//APCF-PANI in 1M Na₂SO₄.The specific capacitance of APCF//APCF-PANI and PCF//PCF-PANI is 61.619 F g^-1,59.635 F g^-1(1 A g^-1),respectively.The capacity density is 14.46,33.13 Wh kg^-1,respectively.The power density is 647 W kg^-1 and 1000W kg^-1,respectively.The APCF//APCF-PANI excellent coulombic efficiency is 100%after 200 cycles,and even84%after 9000 cycles,and the cycle performance is excellen.3.V_xO_y/carbon-based composite materials.Using V₂O₅ self-oxidation on its surface self-assembled PANI,high temperature heat treatment PANI to obtain vanadium oxide?V_xO_y?/carbon-based composite materials,V₂O₅,V_xO_y/carbon-based composite materials as electrode materials for electrochemical performance test.The results show that V_xO_y/carbon composites have superior electrochemical properties as electrode materials.And it has a specific capacity of 98.6 F g^-1(0.1A g^-1).For asymmetric two-electrode testing,its voltage reached 2V in 1M Na₂SO₄,the specific capacity of PCF//V_x O_y/carbon composite is 36.5 F g^-1(0.5A g^-1)with an energy density of 20.31 Wh kg^-1,and a power density of 1029.59 W kg^-1.Meanwhile,its specific capacitance of remained stable at 27 F g^-1 and the charge-discharge efficiency remained97%after 200 cycles,providing a method for preparing a supercapacitor electrode material with a high water system voltage window while increasing energy density and power density.