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Preparation Of Biomass Derived Porous Carbon And Its Electrochemical Energy Storage Properties

Posted on:2019-03-02Degree:MasterType:Thesis
Country:ChinaCandidate:S Y SongFull Text:PDF
GTID:2321330569978235Subject:Chemical Engineering
Abstract/Summary:PDF Full Text Request
In recent years,due to the large-scale development and utilization of traditional fossil fuels,energy has dried up and environmental pollution and other issues have intensified,causing agreat concern.Therefore,the development and utilization of new types of storage materials and devices have become urgent problems that countries need to solve.Supercapacitors as a passive new types of energy storage devices between conventional electrochemical cells and electrostatic capacitors.They combine the advantages of high energy density of traditional chemical batteries and high power density of electrostatic capacitors.They also have excellent cycle life and high charge and discharge.Efficiency,wide operating temperature range,and zero pollution to the environment.Electrode materials as a key component of supercapacitors have an important influence on their capacitive properties.Biomass,as a widely distributed,abundant and green carbon source,is also rich in heteroatom functional groups that are beneficial to the performance of capacitors.attention.In this paper,biomass carbon electrodes with excellent capacitance performance were prepared by using two different carbonization methods with different biomass as the carbon source.The main research results are as follows:1.Onion leaf is used as biomass carbon source,KOH is used as chemical activator,and onion leaf carbon material with different activation temperature and different activator concentration is prepared by high temperature pyrolysis activation method.The specific surface area has a high specific surface area of about 1640 m2 g-1.At the same time,in 6 mol KOH aqueous electrolyte,the specific capacitance as high as 280 F g-1 at a current density of0.5 A g-1,and good cycle stability,after 5000 cycles of charge and discharge Its capacitance retention rate is as high as 90.3%.2.In-situ nitrogen doping of black garlic based carbon materials with different activation temperatures of hydrothermal-assisted carbonization and the effect on capacitor performance when applied to supercapacitors were investigated.The experimental results show that the hydrothermal auxiliary carbonization method has the best nitrogen doping effect at the carbonization temperature of 800°C,and the specific surface area of the carbon material obtained is about 2186 m2 g-1;at 6 mol/L KOH electrolysis The current density of 1 A g-1 in the liquid showed an excellent specific capacitance value of about 331 F g-1;the capacitance attenuation after only 5000 cycles was only 12.99%with good stability.3.Using kelp as a biomass carbon source,a kelp-based carbon material with an ultra-high specific surface area(3179 m2 g-1)was prepared by hydrothermal assisted carbonization method.In a 6mol/L KOH electrolyte solution,1 A g-1 was obtained.At the current density,the specific capacitance value is as high as 314 F g-1,and after 5000charge-discharge cycles,the retention rate of the capacitance of the kelp-based carbon material is as high as 82.8%,exhibiting excellent cycle stability.
Keywords/Search Tags:supercapacitor, biomass carbon, nitrogen doping, specific surface area, capacitance performance
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