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Abstract

Micro-crystallite carbon ( CC) was synthesized by KOH activation of carbonized petroleum coke precursors. The porous properties structure and crystallite structure were characterized by N2 adsorption-desorption, X-ray diffraction ( XRD) measurements. The capacitive behavior of CC was investigated in the electrolyte of Et4NBF4 /PC,Et4NBF4 /AN,Bu4NBF4 /PC and Bu4NBF4 /AN,respectively. Results showed that the lower potential of electric field activation ( EFA) was obtained in the solvent of AN than in PC,which was ascribed to the fact that smaller solvated ions dimension in AN facilitating the intercalation of the solvated ions into micro-crystallite interlayer. The extent of EFA was more remarkable in AN under the same operating voltage due to its lower EFA potential; and consequently,produced the higher specific capacitance. With regarding to the Bu4NBF4 and Et4NBF4,little effect of cations size on the EFA process was observed,compared with that of solvent. After charge-discharged,micro-crystallite interlayer of CC swelled,indicating that the ion intercalation occurred during the EFA. And the interlayer expansion increased to a greater extent when the dimension of intercalated-ion was larger.

Keywords

micro-crystallite carbon, electric field activation, organic electrolyte

Publication Date

2010-05-28

Online Available Date

2010-05-28

Revised Date

2010-05-28

Received Date

2010-05-28

References

[1]Frackowia E.Carbon material for supercapacitor applica-tion[J].Physical Chemistry Chemical Physics,2007,9:1774-1785.
[2]Pandolfo A G,Hollenkamp A F.Carbon properties and their role in supercapacitors[J].Journal of Power Sources,2006,157:11-27.
[3]Raymundo Pin~ero E,Leroux F,Béguin F.A high-per-formance carbon for supercapacitors obtained by carbon-ization of a seaweed biopolymer[J].Advanced Materi-als,2006,18:1877-1882.
[4]Takeuch M,Koike K,Maruyama T,et al.Electrochemi-cal intercalation of tetraethylammonium tetrafluoroborate into the KOH-treated carbons consist of multi-graphene sheets for electric double-layer capacitor[J].Electro-chemistry,1998,66(12):1311-1317.
[5]Mitani S,Lee S I,Mochida I,et al.Contrast structure and EDLC performances of activated spherical carbons with medium and large surface areas[J].Electrochimica Acta,2006,51(25):5487-5493.
[6]Lee S I,Mitani S,Yoon S H,et al.Preparation of spheri-cal activated carbon with high electric double-layer ca-pacitance[J].Carbon,2004,42(11):2332-2334.
[7]Zhu C Y,Xu M,Cao G P,et al.Effect of petroleum coke on the structure and performance of crystallite carbon[J].Functional Materials,2007,38:677-680.
[8]Shi Z Q(时志强),Chen M M(陈明鸣),Zhao S(赵朔),et al.Structure and electrochemical capacitive be-havior of novel crystallite carbon[J].Acta Physico-Chimica Sinica(物理化学学报),2008,24(2):237-242.
[9]Bok H K,Seung M O.Electrochemical activation of ex-panded graphite electrode for electrochemical capacitor[J].Journal of Electrochemical Society,2008,155(9):A685-A692.
[10]Lin R,Taberna P L,Chmiola J,et al.Microelectrode study of pore size,ion size,and solvent effects on the charge/discharge behavior of microporous carbons for electrical double-layer capacitors[J].Journal of the Electrochemical Society,2009,156(1):A7-A12.
[11]Chmiola J,Largeot C,Taberna P L,et al.Desolvation of ions in subnanometer pores and its effect on capaci-tance and double-layer theory[J].Angew Chem Int Ed,2008,47:3392-3395.
[12]Chmiola J,Yushin G,Gogotsi Y,et al.Anomalous in-crease in carbon capacitance at pore sizes less than1nanometer[J].Science,2006,313:1760-1763.

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