Fabrication And Properties Of Nitrogen-doped Carbon-based Supercapacitor Electrode Materials

Supercapacitor is a novel electrochemical energy storage device due to the advantages such as:high power density,wide operating temperature range,and stable cycle life.The choice of electrode material has a decisive effect on the performance of supercapacitors.Therefore,this wotk starts with a nitrogen-doped carbon-based electrode material,two functional types of nitrogen-doped carbon-based supercapacitor electrode materials for porous biomass charcoal derived from chicken tree leaves and NiO@N-C double-shell hollow nanotubes were prepared by various methods including high-temperature pyrolysis,activated pore forming,sacrificial template,anionic polymerization and chemical bath deposition.The morphological characterization and structural composition analysis of the prepared composite electrode materials were performed by means of Scanning electron microscope?SEM?,transmission electron microscope?TEM?,Fourier infrared spectroscopy?FT-IR?,X-ray powder diffractometer?XRD?,Raman spectroscopy?Raman?and X-ray photoelectron spectroscopy?XPS?.The specific surface area and pore size distribution of the material were obtained by N₂adsorption-desorption test.Finally,the cyclic voltammetry?CV?,galvanostatic charge/discharge?GCD?and electrochemical impedance spectroscopy?EIS?tests were used to investigate the electrochemical performance of the composite electrode materials,the specific research content is as follows:1?N,O co-doped porous biomass carbon?HGPC-XY?was prepared as acarbon precursor by high temperature carbonization and KOH activated pore forming methods.The effects of different activator dosages and activation temperatures on the electrochemical performance of porous biomass charcoal,and HGPC-5-600 was obtained as the optimal activator dosage and activation temperature.According to the EIS and GCD test,the charge transfer resistance?Rct?of the HGPC-5-600 was 2.86?,and its specific capacitance is as high as 612.8 F/g at a current density of 0.5 A/g,meanwhile,it has a capacitance retention rate of 96.02%after 10,000 cycles of the charge and discharge tests.In addition,when assembled into a symmetrical supercapacitor,the device has an energy density of 25.6 Wh/kg and a power density of up to 450 W/kg.2?Using MoO₃nanorods as the template and polypyrrole?PPy?as carbonprecursors,NiO@N-C double-shell hollow nanotube electrode material was prepared by continuous coating method.According to the EIS test,the charge transfer resistance?Rct?of the electrode material was 2.21?.Further GCD test was performed on this electrode material,and the specific capacitance value of NiO@N-C composite material was as high as 782 F/g at a current density of 0.5 A/g,after2000 cycles of the GCD test,the capacitance retention rate of the composite electrode material was as high as 89.8%.The above research results show that NiO significantly increases the specific capacitance of carbon-based electrode materials,and the hollow tubular structure prepared by the template method is beneficial for electrolyte penetration and charge transport.