Preparation And Electrochemical Performance Of Organic Salts Derived Porous Carbon

Compared with conventional capacitors, the specific energy of supercapacitors is several orders of magnitude higher. Supercapacitors also have a higher specific power than most batteries, but their specific energy is somewhat lower. Many efforts, such asstudy of electrode materials and electrolyte, have been devoted to improve the specific energy density. Porous carbon materials with high surface area, a range of pore size distributions, as well as high electrical conductivity are being constantly developed and tested as potential supercapacitor electrodes.Therefore, the preparation of nitrogen-doped porous carbon with excellent performance has become the focus of the current. It has been a common trend in the word to prepare nitrogen-doped-carbon/ carbon electrode materialswith excellent properties. In addrion, the introduction of redox-active species to electrolytes has emerged as a new strategy to improve the specific capacitance of supercapacitors. The combination of the specific energydensity of supercapacitors with thatprovided by the redox reaction of electrodes/electrolytes interface likely increases the overall capacitance. This paper presents a simple synthesis of porous carbon and nitrogen-doped porous carbonmaterials via the carbonization of organic salts in inert atmosphere without any activation.And the relationship between the microstructure and the electrochemical properties of carbon electrode materials was investigated in detail.The effect of electrochemical-active species on the capacitance performance of the super capacitor was investigated.Mainly includes the following three aspects:(1) Preparation and electrochemical performances of nitrogen-doped porous carbon:We report a simple synthesis of nitrogen-doped porous carbon materials with higher nitrogen content(5.08 at.%)by direct carbonization of pure monosodium glutamate in inert atmosphere.The nitrogen-doped porous carbon obtained at a carbonization temperature of 800 ℃ and carbonizationtime of 2 h possesses a higher surface area(1873 m2/g), pore volume(1.10 cm3 /g), exhibits high capacitance(205 F/g), and cycledurability in 6 M KOH aqueous electrolytes.(2) Preparation and electrochemical performances ofporous carbon materials: The use of stearate salts(K, Na) as precursors, the direct synthesis of porous carbon materials with different microstructures via the carbonization precursors. The porous carbonmaterial derived from potassium stearate has a high specific surface area of576.4 m2/g, as well as good the pore volume of 0.26 cm3/g, respectively. It can also delivera highspecific capacitance(208 F/g for stearate salts),smaller impedance characteristics and good cycle stability.In addition, thecarbonization temperature and time are very important forthe carbon structures and their electrochemical performancein supercapacitors.(3) Study on electrochemical performance of KI–KOH electrolytes:KI is introducedto pure KOH electrolytes with different concentrations. The optimumelectrochemical performance of the porous carbonmaterial derived frompotassium stearate in 3.5 M KI + 1 M KOH was also obtained. The specific capacitance of the porous carbon material derived from potassium stearate in 3.5 M KI + 1 M KOH electrolytes increased by 91.15% compared with that in 1 M KOH electrolytes.Results show that 3.5 M KI + 1 M KOH electrolytes can deliver a good rate capability, and excellent cycling stability, and low resistance.