Surfactant Assisted To Enhance The Rate Performance Of Supercapacitor Electrode Materials Derived From Melamine Resin Carbon

Energy shortage and environmental pollution hinder the sustainable development of human beings.In order to use energy effectively,researchers have great interest in supercapacitor storage technology for high-efficiency and low-cost.To obtain the electrode material with better performance,it has dual requirment for the choice of matrix material.In situ carbonization of nitrogen-rich organics to obtain high nitrogen content and mesoporous pores has been proved to be an effective strategy.Melamine formaldehyde resin?MF?stands out in the numerous materials,which because that its high bond energy?-C=N-?endows material with high nitrogen heteroatom retention?15 at.%above?after carbonization.It is eable to ensure that the wettability of the material in contact with the electrolyte interface and fast reversible redox reaction.What is more,the mesoporous pore structure can be obtained during carbonization,which can accelerate the transfer rate of electrolyte ions and increase the accumulated charge.In summary,MF has excellent comprehensive performance and prominent advantages as matrix material.It has been shown that polymer-based carbon materials prepared with the regulation and controlling of surfactants can improve the wettability of electrode materials to obtain good electrolyte penetration,which maximizes charge accumulation at the electrode/electrolyte interface.Besides,mesoporous pore structure was produced,synergistically improving the rate performance and capacitance performance of electrode material.Therefore,it is very desirable to improve the rate and capacitance properties of electrode materials by regulating the type and amount of surfactant.The main work of this paper is carried out from the following three aspects:1.Applying melamine resin for matrix carbon material,cationic surfactant cetyltrimethylammonium bromide?CTAB?was introduced into to synthesize was introduced into through a simple one-step method.And we explored systematically the influence factors on electrochemical properties,such as water bath temperature?30,40and 50 ^oC?,the amount of CTAB?0.05?0.2 g?and the reaction time?6?30 min?.Moreover,the optional experimental conditions were obtained by a series of tests,and the C_sp of the best sample MFC-0.2CTAB attain 255 F g^-1 at the current density of 0.5A g^-1.Importantly,the sample demonstrates good rate performance of 77%that the C_spup to 190 F g^-1 at 10 A g^-1.The above results show that CTAB can validly improve the capacitance and rate property of melamine resin based carbon materials with a green and mild method,which has great practical application value.2.Empolying melamine resin as matrix carbon material,anionic surfactant sodium dodecyl sulfate?SDS?was introduced to prepare was introduced into by one-step water bath method.The influences of different experimental conditions on electrochemical properties were systematically explored,such as carbonization temperature?700?800 ^oC?,the amount of SDS?0.05?0.2 g?and water bath temperature?30?50 ^oC?.After a series of tests,the sample of the MFC-0.1SDS with the most excellent electrochemical performance was prepared under the optional experimental conditions.At the current density of 0.5 A g^-1,the C_sp is 309 F g^-1,and the C_sp of 216 F g^-1 at 10 A g^-1 remained 78%of that at 1 A g^-1,showing a high rate performance.Furthmore,the final C_spof samples with high cycle stability can still maintain 103%of the original capacitance after 10000 cycles of constant current charge and discharge at10 A g^-1.These results exhibit an efficient strategy that SDS can assist in enhancing the rate performance of melamine resin based carbon materials,which was convenient,environmentally friendly,and practical.3.Adopting melamine resin as matrix carbon material,a simple one-step method was executed to synthesize melamine resin based derivative carbon material by introducing nonionic surfactant triblock copolymer Pluronic F127?F127?.We explored systematically the influences of the amount of F127?0.05?0.2 g?and the reaction time?4?30 min?on electrochemical properties,and the best sample preparation method was determined via a series of tests ultimately.Besides,the as-prepared sample of MFC-0.1F127 has specific surface area of 246 m² g^-1 and rich N,O heteroatom atoms content,which respectively up to 22 at.%and 5.3 at.%.It shows excellent capacitance and rate performance that the C_sp is 313 F g^-1 when at the current density of 0.5 A g^-1,and it can still maintain 228 F g^-1 at 10 A g^-1,retaining 85%of that of 1 A g^-1.In addition,MFC-0.1F127 with high cycle stability carried out 10000 cycles of constant current charge and discharge at 10 A g^-1,which can still maintain 105%of the original capacitance.The maximum energy density of symmetrical supercapacitors is 29 W h kg^-1 when the power density is 900 W kg^-1,and the energy density still achieved 13 W h kg^-1 at 18000 W kg^-1.The above results show that F127 can improve the performance of melamine resin based carbon materials with obvious advantages and great development potential.It is interesting to note that F127 as the template in the synthesis process of MF,polymer microspheres were converted from disorderly microspheres with different sizes without surfactant into uniform distribution,monodisperse microspheres.Furthermore,after carbonization at 750 ^oC,not only specific surface area had a markedly improvement from 68 m² g^-1 to 246.5 m² g^-1,but also the nitrogen content of MFC-0.1F127 increased from 15.1 at.%to 24.0 at.%.These results illustrate that the surfactants have played an important role in regulating morphology,as well as participated in the polymerization process.And the polymerization mechanism is still in further exploration.