The Application Of Photothermal Treatment In Electrode Nanomaterials Processing

The photothermal process,transfer photo-energy absorbed by nanomaterialsto heat energy by non-irradiative relaxation,can be used to modify nanomaterials.Based on inherent property of light and the size effect of nanomaterials,the heat generated by non-irradiative relaxation will be trapped in the individual nanostructure.This phenomenon will lead to a sharp rise in local temperature,which can be used to modify nanomaterials quickly,controllably,safely,flexibly,and without pollution.Firstly,Polyaniline(PANI)nanowires were selected as a model material to study the flash photothermal process.The effect of flash distance and flash numbers on the physical and chemical properities of PANI nanowires was investigated.The experimental results demonstrate that the morphology,doping status,surface roughness and electrochemical propertiesof PANI nanowires can be modified by photothermal treatment feasibly and controllably.After an appropriate photothermal treatment,the PANI nanowires can partially melt and form a conductive network,which can reduce electron transfer resistance and improve the utilization of electrode active materials.As well as that,this unique structure can avoid the structural damage or peeling of PANI nanowires caused by continuous volume expansion/contraction during the electrochemical process,and thus improve the cycle stability of PANI materials.Secondly,PANI-gel conductive network electrode with high specific surface area,good conductivity,stability,and electrochemical activity was prepared by flash photothermal treatment.The experimental results demonstrate that,a combination with new biredox electrolyte of 3-(2,2,6,6-tetramethyl-piperidiynl-1-oxyl)-1-methylylimidazoliumbromide,the PANI-gel conductive network electrode obtained by flash photothermal treatment improves the mass specific capacitance to 721 F g^-1,and alleviat the self-discharge of capacitors greatly.As well as that,the energy density,power density and stability of the supercapacitor was also significantly enhanced.This method paves the road to pursue for high energy density meanwhile maintains good power density of supercapacitor.Thirdly,the flash photothermal process was used to modify grapheneunder room temperature.Under the extremely high temperature induced by flash photothermal process,chemical bonds between carbon atoms were broken and unsaturated carbon reacted with ammonia in the atmosphere,thus the nitrogen doped graphene(NG)was quickly and safely prepared.The nitrogen atoms introduced by this method are mainly concentrated at the surface of the graphene electrode,making the electrodes exhibit excellent electrocatalytic and energy storage performance.The hydrogen peroxide reduction potential at the NG electrode was 200 m V positive shift and the peak current increased 15 times compare to bare glassy carbon electrode.As well as that,the specific capacitance of supercapacitor assembled by NG was as high as 350 F g^-1,while the supercapacitor possesses well cyclic stability and rate capability.