Preparation And Electrochemical Performance Of Petroleum Coke Based Activated Carbon For Electric Double Layer Capacitor

Activated carbon with high specific s ur face area and reasonable pore size distr ibution used for e lectric doub le layer capacitor?EDLC?were prepared with petrole um coke?PC?as raw mater ia l.The influe nces of types of petrole um coke,preparation process,types of mixed activator and ratio of mixed activator were thoroughly investigated.The relations hip between the electr oche mical perfor mance of activated carbon and pore structures were clar ified.The standard had been established to screening of high quality raw materia ls by discuss ing the relatio nship between the structure of PC and its reactivity with KOH.The influence of activation te mperature,the mass ratio of KOH/PC,heating rate and activatio n time on pore structure,specific surface area and electrochemica l character istics of activated carbon were studied and the best preparatio n process for preparing activated carbon for EDLC was obtained,as well.The feas ib ility o f preparing activated carbon by us ing mixed activator was investigated and a perfect reaction system of mixed activator was obtained.Activated carbon used for EDLC were prepared with daqing coke,fushun coke and dagang coke,respective ly.And the relations hip between pore structure,electrochemica l perfor ma nce and structure of PCs was in vestigated.Dagang coke with low crystallinity and fine mosaic structure shows the highest reactivity.Altho ugh the activated carbon,prepared by dagang coke,has the highest specific sur face area,best pore size d istr ibutio n,its e lectroche mical per forma nce is lower than activated carbon prepared by fushun coke due to the high ash content.High specific sur face area activated carbon with distinct pore structure was prepared with fus hun coke as raw mater ia l and KOH as activator by chemica l activatio n.The influences of the activation temperature,active agent amo unt,activatio n temperature,heating rate and activatio n time on pore structure and electrochemica l perfor mance of activated carbon were investigated.The specific area decreased with increase of act ivation te mperature,while the specific capacitance linked with organic electro lyte increased.At the temperature of 850?,both the pore structure and specific capacitance of activation carbon reach the top.The specific area and specific capacita nce increased firstly and decreased afterwards with increase of active agent amo unt.At a KOH/PC mass ratio of 3.5:1,the specific area and specific capacitance reach the top.The specific area decreased with increas ing o f heating rate,while the specific capacitance reach the top,at a heating rate of 2?/min.The specific area and specific capacitance have a little fluctuation with increas ing of activatio n time.The activated carbon shows excelle nt e lectr ochemica l perfor mance when the activation time is 1.5h and 2h.The activated carbon shows excelle nt perfor mance at a KOH/PC mass ratio of 3.5:1 and a te mperature of 850? with a heating rate of 2?/min for 2h.The BET sur face,ratio of V_meso/V_total and highest specific capacitance linked with organic electro lyte is 2824m²/g,20.3%and 169 F/g,respectively.With the discharge current rais ing fro m 1 mA/cm² to 50 mA/c m²,little attenuation is observed.Activated carbon used for EDLC were prepared with fushun coke as raw mater ial KOH as main activator and ZnCl₂,NaOH,Mg?OH?₂ and Ca?OH?₂ as co-activator.The influe nces of types of mixed activator on pore structure and elec trochemica l perfor mance of activated carbon were investigated.The results show that the add ition of ZnCl₂,NaOH and Ca?OH?₂ are aga inst to achieve activated carbon of s uitable pore structure and excellent e lectrochemica l perfor mance.The addition o f Mg?OH?₂ can be bene fic ial to achie ve activated carbon of high specific surface area,high micropore volume,high mesopore volume and high specific capacitance.The activated carbon shows excelle nt performa nce at a KOH/PC mass ratio of 4:1,a KOH/Mg?OH?₂ mass ratio of 3:1.The BET sur face,ratio of Vmeso/Vtota l and highest spec ific capacitance linked with organic e lectrolyte is 2730m²/g,19.2%and 170F/g,respectively,only a little attenuation is observed.