釩液流電池大多選用大面積、高導電且多孔結構的碳材作為電極，導電石墨氈即為符合此需求的材料之一。然而，石墨氈材料面臨電化學活性不足及可逆性較差等問題，嚴重影響全電池效率的表現。因此本實驗將以電極改質處理為出發，利用靜電紡織纖維添加電化學活性物質及二氧化碳活化處理石墨氈進行電極改質，期能藉由纖維表面處理提升反應面積和導入活性基團(OH-、COOH-)用來催化釩離子反應。同時親水端的活性基團能夠提升電極的親水性，使電解液能夠有效潤濕電極纖維，以此改善電極的電化學活性。
研究第一部分將利用聚丙烯腈溶於二甲基甲醯胺，並添加電化學活性物質，經由靜電紡織技術織出一層高分子混合纖維。透過控制添加物比例、纖維粗細、織構，孔隙率等，以提高電極整體官能基程度、表面親水性及增加反應活性點，提升電極材料電化學活性和增加釩液流電池的電池性能。第二部分利用二氧化碳輔助熱處理改質石墨氈電極，藉由改變熱處理參數與氣氛流量之調整，得到最適化處理條件。透過控制纖維表面孔洞缺陷大小與分布之各項製程參數製備一系列電極，研究其製備參數、形貌結構與應用在釩液流電池中所表現的效能之關聯性。

Carbon-based materials with large surface area, high conductivity, and porous structure are used as the electrode in vanadium redox flow battery (VRFB). According to these criteria, the graphite felt is suitable to be the electrode in VRFB. However, the graphite felt has a low energy efficiency problem due to its insufficient electrochemical activity and poor reversibility. In order to solve this problem, we focus on the electrode modification to increase the surface area and oxygen-containing functional groups on the surface of GF fibers, which is known to be electrochemically more active sites for vanadium redox reaction.
In the first part, we try to modify the morphology of carbon nanofibers by adding some electrochemical additives and using the electrospinning method, in which its radius, size, length, and texture of carbon nanofiber can be modified by the electrospinning process. In the second part, we plan to improve the energy storage efficiency of graphite felt by using activation process with CO2 gas. By controlling the process parameters, the correlation between the electrode, the morphology, the physical characteristics, the electrochemical behavior, and its application for vanadium redox flow battery can be established.

[1] Grid scale energy storage systems. Copyright © Woodbank Communications Ltd 2005.
[2] T.U. Daim, X. Li, J. Kim, S. Simms, Evaluation of energy storage technologies for integration with renewable electricity: Quantifying expert opinions. Environmental Innovation and Societal Transitions, 3 (2012) 29-49.
[3] C.J. Rydh, Environmental assessment of vanadium redox and lead-acid batteries for stationary energy storage. J. Power Sources, 80 (1999) 21-29.
[4] 馬振基, 謝曉峰, 江仁吉, 蕭閔謙, 楊士賢, 張立學. 全釩液流電池的原理與發展現況. 化學, 第七十卷 (2012) 第三期 237-246.
[5] W. DC, Flow cell development and demonstration project. NASA TM-97067, (1979).
[6] E. Sum, M. Rychcik, M. Skyllas-Kazacos, Investigation of the V(V)/V(IV) system for use in the positive half-cell of a redox battery. J. Power Sources, 16 (1985) 85-95.
[7] E. Sum, M. Skyllas-Kazacos, A study of the V(II)/V(III) redox couple for redox flow cell applications. J. Power Sources, 15 (1985) 179-190.
[8] P. Alotto, M. Guarnieri, F. Moro, Redox flow batteries for the storage of renewable energy: A review. Renew. Sust. Energ. Rev., 29 (2014) 325-335.
[9] J.H. Chen, Z.Q. Xu, B. Li, Research on the characteristics of the vanadium redox-flow battery in power systems applications. J. Power Sources, 241 (2013) 396-399.
[10] C. Fabjan, J. Garche, B. Harrer, L. Jörissen, C. Kolbeck, F. Philippi, G. Tomazic, F. Wagner, The vanadium redox-battery: an efficient storage unit for photovoltaic systems. Electrochim. Acta, 47 (2001) 825-831.
[11] M. Vijayakumar, S.D. Burton, C. Huang, L. Li, Z. Yang, G.L. Graff, J. Liu, J. Hu, M. Skyllas-Kazacos, Nuclear magnetic resonance studies on vanadium(IV) electrolyte solutions for vanadium redox flow battery. J. Power Sources, 195 (2010) 7709-7717.
[12] M. Gattrell, J. Qian, C. Stewart, P. Graham, B. MacDougall, The electrochemical reduction of VO2+ in acidic solution at high overpotentials. Electrochim. Acta, 51 (2005) 395-407.
[13] X. Qiu, T. A. Nguyen, J. D. Guggenberger, A field validated model of a vanadium redox flow battery for microgrids. IEEE Transactions on smart grid, 4 (2014) 1592-1601.
[14] H. Chen, T.N. Cong, W. Yang, C. Tan, Y. Li, Y. Ding, Progress in electrical energy storage system: A critical review. Science, 19 (2009) 291-312.
[15] C. Ding, H. Zhang, X. Li, T. Liu, F. Xing, Vanadium flow battery for energy storage: Prospects and Challenges. J. Phys. Chem. Lett. , 4 (2013) 1281-1294.
[16] M. Skyllas‐Kazacos, C. Menictas, M. Kazacos, Thermal stability of concentrated V(V) electrolytes in the vanadium redox cell. J. Electrochem. Soc., 143 (1996) 86-88.
[17] F. Rahman, M. Skyllas-Kazacos, Solubility of vanadyl sulfate in concentrated sulfuric acid solutions. J. Power Sources, 72 (1998) 105-110.
[18] G. Oriji, Y. Katayama, T. Miura, Investigation on V(IV)/V(V) species in a vanadium redox flow battery. Electrochim. Acta, 49 (2004) 3091-3095.
[19] B. Dunn, H. Kamath, J.-M. Tarascon, Electrical energy storage for the Grid: A battery of choices. Science, 334 (2011) 928-935.
[20] H.M. Tsai, S.Y. Yang, C.C.M. Ma, X. Xie, Preparation and electrochemical properties of graphene-modified electrodes for all-vanadium redox flow batteries. Electroanalysis, 23 (2011) 2139-2143.
[21] H.M. Tsai, S.J. Yang, C.C.M. Ma, X. Xie, Preparation and electrochemical activities of iridium-decorated graphene as the electrode for all-vanadium redox flow batteries. Electrochim. Acta, 77 (2012) 232-236.
[22] T.M. Tseng, R.H. Huang, C.Y. Huang, C.C. Liu, K.L. Hsueh, F.S. Shieu, Carbon felt coated with titanium dioxide/carbon black composite as negative electrode for vanadium redox flow battery. J. Electrochem. Soc., 161 (2014) 1132-1138.
[23] T.C. Chang, J.P. Zhang, Y.K. Fuh, Electrical, mechanical and morphological properties of compressed carbon felt electrodes in vanadium redox flow battery. J. Power Sources, 245 (2014) 66-75.
[24] J.Z. Chen, W.Y. Liao, W.Y. Hsieh, C.C. Hsu, Y.S. Chen, All-vanadium redox flow batteries with graphite felt electrodes treated by atmospheric pressure plasma jets. J. Power Sources, 274 (2015) 894-898.
[25] D. Chen, M.A. Hickner, E. Agar, E.C. Kumbur, Optimized Anion Exchange Membranes for Vanadium Redox Flow Batteries. ACS Appl. Mater. Interfaces, 5 (2013) 7559-7566.
[26] A. Parasuraman, T.M. Lim, C. Menictas, M. Skyllas-Kazacos, Review of material research and development for vanadium redox flow battery applications. Electrochim. Acta, 101 (2013) 27-40.
[27] C. Yao, H. Zhang, T. Liu, X. Li, Z. Liu, Carbon paper coated with supported tungsten trioxide as novel electrode for all-vanadium flow battery. J. Power Sources, 218 (2012) 455-461.
[28] Y. Shen, H. Xu, P. Xu, X. Wu, Y. Dong, L. Lu, Electrochemical catalytic activity of tungsten trioxide- modified graphite felt toward VO2+/VO2+ redox reaction. Electrochim. Acta, 132 (2014) 37-41.
[29] X. Wu, H. Xu, L. Lu, H. Zhao, J. Fu, Y. Shen, P. Xu, Y. Dong, PbO2-modified graphite felt as the positive electrode for an all-vanadium redox flow battery. J. Power Sources, 250 (2014) 274-278.
[30] Z. González, A. Sánchez, C. Blanco, M. Granda, R. Menéndez, R. Santamaría, Enhanced performance of a Bi-modified graphite felt as the positive electrode of a vanadium redox flow battery. Electrochem. Commun., 13 (2011) 1379-1382.
[31] B. Sun, M. Skyllas-Kazakos, Chemical modification and electrochemical behaviour of graphite fibre in acidic vanadium solution. Electrochim. Acta, 36 (1991) 513-517.
[32] W.H. Wang, X.D. Wang, Investigation of Ir-modified carbon felt as the positive electrode of an all-vanadium redox flow battery. Electrochim. Acta, 52 (2007) 6755-6762.
[33] B. Li, M. Gu, Z. Nie, X. L. Wei, C. M. Wang, V. Sprenkle, W. Wang. Nanorod niobium oxide as powerful catalysts for an all vanadium redox flow battery. Nano Lett, 14 (2014) 158-165.
[34] H.T. Thu Pham, C. Jo, J. Lee, Y. Kwon, MoO2 nanocrystals interconnected on mesocellular carbon foam as a powerful catalyst for vanadium redox flow battery. RSC Adv., 6 (2016) 17574-17582.
[35] H.Q. Zhu, Y.M. Zhang, L. Yue, W.S. Li, G.L. Li, D. Shu, H.Y. Chen, Graphite–carbon nanotube composite electrodes for all vanadium redox flow battery. J. Power Sources, 184 (2008) 637-640.
[36] B.T. Sun, Skyllas-Kazacos, Chemical modification of graphite electrode materials for vanadium redox flow battery application-part II. acid treatments. Electrochim. Acta, 37 (1992) 2459-2465.
[37] A. Di Blasi, O. Di Blasi, N. Briguglio, A.S. Aricò, D. Sebastián, M.J. Lázaro, G. Monforte, V. Antonucci, Investigation of several graphite-based electrodes for vanadium redox flow cell. J. Power Sources, 227 (2013) 15-23.
[38] L. Yue, W. Li, F. Sun, L. Zhao, L. Xing, Highly hydroxylated carbon fibres as electrode materials of all-vanadium redox flow battery. Carbon, 48 (2010) 3079-3090.
[39] W. Li, J. Liu, C. Yan, Graphite–graphite oxide composite electrode for vanadium redox flow battery. Electrochim. Acta, 56 (2011) 5290-5294.
[40] X. Wu, H. Xu, P. Xu, Y. Shen, L. Lu, J. Shi, J. Fu, H. Zhao, Microwave-treated graphite felt as the positive electrode for all-vanadium redox flow battery. J. Power Sources, 263 (2014) 104-109.
[41] K.J. Kim, S.W. Lee, T. Yim, J.G. Kim, J.W. Choi, J.H. Kim, M.S. Park, Y.J. Kim, A new strategy for integrating abundant oxygen functional groups into carbon felt electrode for vanadium redox flow batteries. Sci Rep, 4 (2014) 6906.
[42] X. Wang, X. Li, L. Zhang, Y. Yoon, P.K. Weber, H. Wang, J. Guo, H. Dai, N-doping of graphene through electrothermal reactions with ammonia. Science, 324 (2009) 768-771.
[43] A.L.M. Reddy, A. Srivastava, S.R. Gowda, H. Gullapalli, M. Dubey, P.M. Ajayan, Synthesis of nitrogen-doped graphene films for lithium battery application. ACS Nano, 4 (2010) 6337-6342.
[44] Y. Wang, Y. Shao, D.W. Matson, J. Li, Y. Lin, Nitrogen-doped graphene and its application in electrochemical biosensing. ACS Nano, 4 (2010) 1790-1798.
[45] V. Nallathambi, J.W. Lee, S.P. Kumaraguru, G. Wu, B.N. Popov, Development of high performance carbon composite catalyst for oxygen reduction reaction in PEM Proton Exchange Membrane fuel cells. J. Power Sources, 183 (2008) 34-42.
[46] S. Maldonado, K.J. Stevenson, Influence of nitrogen doping on oxygen reduction electrocatalysis at carbon nanofiber electrodes. J. Phys. Chem. B, 109 (2005) 4707-4716.
[47] Y. Shao, J. Sui, G. Yin, Y. Gao, Nitrogen-doped carbon nanostructures and their composites as catalytic materials for proton exchange membrane fuel cell. Appl. Catal. B: Environ., 79 (2008) 89-99.
[48] K. Gong, F. Du, Z. Xia, M. Durstock, L. Dai, Nitrogen-doped carbon nanotube arrays with high electrocatalytic activity for oxygen reduction. Science, 323 (2009) 760-764.
[49] R.A. Sidik, A.B. Anderson, N.P. Subramanian, S.P. Kumaraguru, B.N. Popov, O2 reduction on graphite and nitrogen-doped graphite:  Experiment and Theory. J. Phys. Chem. B, 110 (2006) 1787-1793.
[50] G. Wu, D. Li, C. Dai, D. Wang, N. Li, Well-dispersed high-loading Pt nanoparticles supported by shell−core nanostructured carbon for methanol electrooxidation. Langmuir, 24 (2008) 3566-3575.
[51] J.I. Ozaki, S.I. Tanifuji, A. Furuichi, K. Yabutsuka, Enhancement of oxygen reduction activity of nanoshell carbons by introducing nitrogen atoms from metal phthalocyanines. Electrochim. Acta, 55 (2010) 1864-1871.
[52] C. Médard, M. Lefèvre, J.P. Dodelet, F. Jaouen, G. Lindbergh, Oxygen reduction by Fe-based catalysts in PEM fuel cell conditions: Activity and selectivity of the catalysts obtained with two Fe precursors and various carbon supports. Electrochim. Acta, 51 (2006) 3202-3213.
[53] C.H. Wang, S.T. Chang, H.C. Hsu, H.Y. Du, J.C.S. Wu, L.C. Chen, K.H. Chen, Oxygen reducing activity of methanol-tolerant catalysts by high-temperature pyrolysis. Diamond Relat. Mater., 20 (2011) 322-329.
[54] C.H. Wang, H.C. Hsu, S.T. Chang, H.Y. Du, C.P. Chen, J.C.S. Wu, H.C. Shih, L.C. Chen, K.H. Chen, Platinum nanoparticles embedded in pyrolyzed nitrogen-containing cobalt complexes for high methanol-tolerant oxygen reduction activity. J. Mater. Chem., 20 (2010) 7551-7557.
[55] F. Jaouen, S. Marcotte, J.P. Dodelet, G. Lindbergh, Oxygen reduction catalysts for polymer electrolyte fuel cells from the pyrolysis of iron acetate adsorbed on various carbon supports. J. Phys. Chem. B, 107 (2003) 1376-1386.
[56] D. Villers, X. Jacques-Bedard, J.P. Dodelet, Fe-based catalysts for oxygen reduction in PEM fuel cells pretreatment of the carbon support. J. Electrochem. Soc., 151 (2004) 1507-1515.
[57] Y. Shao, X. Wang, M. Engelhard, C. Wang, S. Dai, J. Liu, Z. Yang, Y. Lin, Nitrogen-doped mesoporous carbon for energy storage in vanadium redox flow batteries. J. Power Sources, 195 (2010) 4375-4379.
[58] L.G. Cançado, A. Jorio, E.H.M. Ferreira, F. Stavale, C.A. Achete, R.B. Capaz, M.V.O. Moutinho, A. Lombardo, T.S. Kulmala, A.C. Ferrari, Quantifying defects in graphene via raman spectroscopy at different excitation energies. Nano Lett., 11 (2011) 3190-3196.
[59] W.Y. Li, J.G. Liu, C.W. Yan, Multi-walled carbon nanotubes used as an electrode reaction catalyst for VO2+/VO2+ for a vanadium redox flow battery. Carbon, 49 (2011) 3463-3470.
[60] W.Y. Li, J.G. Liu, C.W. Yan, Modified multiwalled carbon nanotubes as an electrode reaction catalyst for an all vanadium redox flow battery. J Solid State Electr, 17 (2013) 1369-1376.
[61] M. Park, Y.J. Jung, J. Kim, H. Lee, J. Cho, Synergistic effect of carbon nanofiber/nanotube composite catalyst on carbon felt electrode for high-performance all-vanadium redox flow battery. Nano Lett, 13 (2013) 4833-4839.
[62] O. Di Blasi, N. Briguglio, C. Busacca, M. Ferraro, V. Antonucci, A. Di Blasi, Electrochemical investigation of thermically treated graphene oxides as electrode materials for vanadium redox flow battery. Appl. Energy, 147 (2015) 74-81.
[63] T.J. Sill, H.A. von Recum, Electrospinning: Applications in drug delivery and tissue engineering. Biomaterials, 29 (2008) 1989-2006.
[64] X. Zhang, Y. Wang, D. Guo, Y. Wang, The morphology of the hollow PAN fibers through electrospinning. AASRI Procedia, 3 (2012) 236-241.
[65] J.M. Deitzel, W. Kosik, S.H. McKnight, N.C. Beck Tan, J.M. DeSimone, S. Crette, Electrospinning of polymer nanofibers with specific surface chemistry. Polymer, 43 (2002) 1025-1029.
[66] C. Santos, C.J. Silva, Z. Büttel, R. Guimarães, S.B. Pereira, P. Tamagnini, A. Zille, Preparation and characterization of polysaccharides/PVA blend nanofibrous membranes by electrospinning method. Carbohydr. Polym., 99 (2014) 584-592.
[67] R. Padmavathi, D. Sangeetha, Synthesis and characterization of electrospun carbon nanofiber supported Pt catalyst for fuel cells. Electrochim. Acta, 112 (2013) 1-13.
[68] W. Yang, Y. Zhang, C. Liu, J. Jia, Dual-doped carbon composite for efficient oxygen reduction via electrospinning and incipient impregnation. J. Power Sources, 274 (2015) 595-603.
[69] M. Gizdavic-Nikolaidis, S. Ray, J.R. Bennett, A.J. Easteal,
R.P. Cooney, Electrospun functionalized polyaniline copolymer-based nanofibers with potential application in tissue engineering. Macromol Biosci, 10 (2010) 1424-1431.
[70] S. Pirani, H.M.N. Abushammala, R. Hashaikeh, Preparation and characterization of electrospun PLA/nanocrystalline cellulose-based composites. J. Appl. Polym. Sci., 130 (2013) 3345-3354.
[71] C. Tekmen, Y. Tsunekawa, H. Nakanishi, Electrospinning of carbon nanofiber supported Fe/Co/Ni ternary alloy nanoparticles. J. Mater. Process. Technol., 210 (2010) 451-455.
[72] Q. Shi, N. Vitchuli, J. Nowak, J.M. Caldwell, F. Breidt, M. Bourham, X. Zhang, M. McCord, Durable antibacterial Ag/polyacrylonitrile (Ag/PAN) hybrid nanofibers prepared by atmospheric plasma treatment and electrospinning. Eur. Polym. J., 47 (2011) 1402-1409.
[73] S. Fang, W. Wang, X. Yu, H. Xu, Y. Zhong, X. Sui, L. Zhang, Z. Mao, Preparation of ZnO:(Al, La)/polyacrylonitrile (PAN) nonwovens with low infrared emissivity via electrospinning. Mater. Lett., 143 (2015) 120-123.
[74] C. Su, J. Liu, C. Shao, Y. Liu, Controlled synthesis of PAN/Ag2S composites nanofibers via electrospinning-assisted hydro(solvo)thermal method. J. Non-Cryst. Solids, 357 (2011) 1488-1493.
[75] C. Prahsarn, W. Klinsukhon, N. Roungpaisan, Electrospinning of PAN/DMF/H2O containing TiO2 and photocatalytic activity of their webs. Mater. Lett., 65 (2011) 2498-2501.
[76] C. Wang, C. Shao, L. Wang, L. Zhang, X. Li, Y. Liu, Electrospinning preparation, characterization and photocatalytic properties of Bi2O3 nanofibers. J. Colloid Interface Sci., 333 (2009) 242-248.
[77] F.E. Ahmed, B.S. Lalia, R. Hashaikeh, A review on electrospinning for membrane fabrication: Challenges and applications. Desalination, 356 (2015) 15-30.
[78] G. Wei, X. Fan, J. Liu, C. Yan, Electrospun carbon nanofibers/electrocatalyst hybrids as asymmetric electrodes for vanadium redox flow battery. J. Power Sources, 281 (2015) 1-6.
[79] C.H. Wang, H.C. Hsu, J.H. Hu, High-energy asymmetric supercapacitor based on petal-shaped MnO2 nanosheet and carbon nanotube-embedded polyacrylonitrile-based carbon nanofiber working at 2 V in aqueous neutral electrolyte. J. Power Sources, 249 (2014) 1-8.
[80] P. Han, Y. Yue, Z. Liu, W. Xu, L. Zhang, H. Xu, S. Dong, G. Cui, Graphene oxide nanosheets/multi-walled carbon nanotubes hybrid as an excellent electrocatalytic material towards VO2+/VO2+ redox couples for vanadium redox flow batteries. Energy Eviron. Sci., 4 (2011) 4710-4717.
[81] G. Wei, M. Jing, X. Fan, J. Liu, C. Yan, A new electrocatalyst and its application method for vanadium redox flow battery. J. Power Sources, 287 (2015) 81-86.
[82] Interagency Working Group on Nanoscience, Engineering and Technology (IWGN). Nanotechnology Research Directions:IWGN Workshop Report. 9 (1999).
[83] Y. Wang, Y.Y. Shao, D.W. Matson, J.H. Li, Y.H. Lin. Nitrogen-doped graphene and its application in electrochemical biosensing. ACS Nano, 4 (2010) 1790-1798.
[84] Z. Zhou, X.F. Wu, High-performance porous electrodes for pseudosupercapacitors based on graphene-beaded carbon nanofibers surface-coated with nanostructured conducting polymers. J. Power Sources, 262 (2014) 44-49.
[85] S.R. Dhakate, A. Gupta, A. Chaudhari, J. Tawale, R.B. Mathur, Morphology and thermal properties of PAN copolymer based electrospun nanofibers. Synth. Met., 161 (2011) 411-419.
[86] B.H. Kim, K.S. Yang, Structure and electrochemical properties of electrospun carbon fiber composites containing graphene. J. Ind. and Eng. Chem., 20 (2014) 3474-3479.
[87] A. Bara, E. Chitanu, C. Banciu, V. Marinescu, V. Tsakiris. Polyacrylonitrile-based Electrospun Fibers. IEEE, 9 (2015). .
[88] P. Raghavan, D.-H. Lim, J.H. Ahn, C. Nah, D.C. Sherrington, H.S. Ryu, H.J. Ahn, Electrospun polymer nanofibers: The booming cutting edge technology. React. Funct. Polym., 72 (2012) 915-930.
[89] H.C. Hsu, C.H. Wang, Y.C. Chang, J.H. Hu, B.Y. Yao, C.Y. Lin, Graphene oxides and carbon nanotubes embedded in polyacrylonitrile-based carbon nanofibers used as electrodes for supercapacitor. J. Phys. Chem. Solids, 85 (2015) 62-68.
[90] Z. González, C. Botas, P. Álvarez, S. Roldán, C. Blanco, R. Santamaría, M. Granda, R. Menéndez, Thermally reduced graphite oxide as positive electrode in Vanadium Redox Flow Batteries. Carbon, 50 (2012) 828-834.
[91] G. Wei, C. Jia, J. Liu, C. Yan, Carbon felt supported carbon nanotubes catalysts composite electrode for vanadium redox flow battery application. J. Power Sources, 220 (2012) 185-192.
[92] H. Hou, J.J. Ge, J. Zeng, Q. Li, D.H. Reneker, A. Greiner, S.Z.D. Cheng, Electrospun polyacrylonitrile nanofibers containing a high concentration of well-aligned multiwall carbon nanotubes. Chem. Mater., 17 (2005) 967-973.
[93] 近藤精一, 石川達雄, 安部郁夫. 吸附科学. ISBN7-621-04843-0.
[94] M. Kruk, M. Jaroniec, Gas adsorption characterization of ordered organic-inorganic nanocomposite materials. Chem. Mater. 13 (2001) 3169-3183.
[95] J. F. Delon, O. Lietard, J. M. Cases, J. Yvon. Determinaton of porosity of platy materials using slit-shaped and becelled pores. Clay Minerals, 21 (1986) 361-375.
[96] A. Arami-Niya, W.M.A.W. Daud, F.S. Mjalli, Comparative study of the textural characteristics of oil palm shell activated carbon produced by chemical and physical activation for methane adsorption. Chem. Eng. Res. Des., 89 (2011) 657-664.
[97] S. Guo, J. Peng, W. Li, K. Yang, L. Zhang, S. Zhang, H. Xia, Effects of CO2 activation on porous structures of coconut shell-based activated carbons. Appl. Surf. Sci., 255 (2009) 8443-8449.
[98] S.G. Herawan, M.A. Ahmad, A. Putra, A.A. Yusof, Effect of CO2 flow rate on the Pinang frond-based activated carbon for methylene blue removal. Sci. World J., 2013 (2013) 545948.
[99] F. Nestler, L. Burhenne, M.J. Amtenbrink, T. Aicher, Catalytic decomposition of biomass tars: The impact of wood char surface characteristics on the catalytic performance for naphthalene removal. Fuel Process. Technol., 145 (2016) 31-41.
[100] J. Guo, A.C. Lua. Preparation of activated carbons from oil-palm-stone chars by microwave-induced carbon dioxide activation. Carbon 38 (2000) 1985–1993.
[101] B.H. Hameed, I.A. Tan, A.L. Ahmad, Preparation of oil palm empty fruit bunch-based activated carbon for removal of 2,4,6-trichlorophenol: Optimization using response surface methodology. J Hazard Mater, 164 (2009) 1316-1324.
[102] A.C. Lua, J. Guo. Microporous oil-palm-shell activated carbon prepared by physical activation for gas-phase adsorption. Langmuir, 17 (2001) 7112-7117.
[103] F. Rodriguez-Reinoso, M. Molina-Sabio and M.T. Gonzalez. The use of steam and CO2 as actvating agents in the preparaton of actvated carbons. Carbon, 33 (1995) 15-23.
[104] T. Zhang, W. Walawender, L. Fan, M. Fan, D. Daugaard, R. Brown, Preparation of activated carbon from forest and agricultural residues through CO activation. Chem. Eng. J., 105 (2004) 53-59.
[105] W. Zhang, J. Xi, Z. Li, H. Zhou, L. Liu, Z. Wu, X. Qiu, Electrochemical activation of graphite felt electrode for VO2+/VO2+ redox couple application. Electrochim. Acta, 89 (2013) 429-435.
[106] K.J. Kim, M.S. Park, Y.J. Kim, J.H. Kim, S.X. Dou, M. Skyllas-Kazacos, A technology review of electrodes and reaction mechanisms in vanadium redox flow batteries. J. Mater. Chem. A, 3 (2015) 16913-16933.
[107] Bard A. J., Faulkner L.R., Electrochemical Methods - Fundamentals and Application. ISBN 0-471-04372-9.
[108] G. Wei, J. Liu, H. Zhao, C. Yan, Electrospun carbon nanofibres as electrode materials toward VO2+/VO2+ redox couple for vanadium flow battery. J. Power Sources, 241 (2013) 709-717.
[109] N. Li, M. Suzuki, Y.o Abe, H. Itoh, T. Suzuki, M. Kawamuraa, K. Sasaki, Effects of substrate temperature on the ion conductivity of hydrated ZrO2 thin films prepared by reactive sputtering in H2O atmosphere. Sol. Energ. Mat. Sol. Cells, 99 (2012) 160–165.
[110] J. Guo, A.C. Lua, Experimental and kinetic studies on pore development during CO2 activation of oil-palm-shell char. J. Porous Mater, 8 (2001) 149–157.
[111] T. Yang, A.C. Lua, Characteristics of activated carbons prepared from pistachio-nut shells by physical activation. J. Colloid Interface Sci., 267 (2003) 408-417.
[112] Y. Huang, B. Jin, Z. Zhong, W. Zhong, R. Xiao, Characteristic and mercury adsorption of activated carbon produced by CO2 of chicken waste. J. Environ. Sci., 20 (2008) 291-296.
[113] K.J. Kim, Y.J. Kim, J.H. Kim, M.S. Park, The effects of surface modification on carbon felt electrodes for use in vanadium redox flow batteries. Mater. Chem. Phys., 131 (2011) 547-553.
[114] J. Liu, Z.A. Wang, X.W. Wu, X.H. Yuan, J.P. Hu, Q.M. Zhou, Z.H. Liu, Y.P. Wu, Porous carbon derived from disposable shaddock peel as an excellent catalyst toward VO2+/VO2+ couple for vanadium redox battery. J. Power Sources, 299 (2015) 301-308.
[115] L. Roldan, I. Santos, S. Armenise, J.M. Fraile, E. García-Bordejé, The formation of a hydrothermal carbon coating on graphite microfiber felts for using as structured acid catalyst. Carbon, 50 (2011) 1363-1372.
[116] Y. Wang, Y. Liu, K. Wang, S. Song, P. Tsiakaras, H. Liu, Preparation and characterization of a novel KOH activated graphite felt cathode for the electro-Fenton process. Appl. Catal. B: Environ., 165 (2015) 360-368.
[117] L. Zhang, Z.-G. Shao, X. Wang, H. Yu, S. Liu, B. Yi, The characterization of graphite felt electrode with surface modification for H2/Br2 fuel cell. J. Power Sources, 242 (2013) 15-22.
[118] W. Li, J. Liu, C. Yan, Multi-walled carbon nanotubes used as an electrode reaction catalyst for VO2+/VO2+ for a vanadium redox flow battery. Carbon, 49 (2011) 3463-3470.
[119] Z. González, P. Álvarez, C. Blanco, S. Vega-Díaz, F. Tristán-López, L.P. Rajukumar, R. Cruz-Silva, A.L. Elías, M. Terrones, R. Menéndez, The influence of carbon nanotubes characteristics in their performance as positive electrodes in vanadium redox flow batteries. Sustainable Energy Technologies and Assessments, 9 (2015) 105-110.
[120] S. Jeong, S. An, J. Jeong, J. Lee, Y. Kwon, Effect of mesocelluar carbon foam electrode material on performance of vanadium redox flow battery. J. Power Sources, 278 (2015) 245-254.
[121] G. Wei, X. Fan, J. Liu, C. Yan, Investigation of the electrospun carbon web as the catalyst layer for vanadium redox flow battery. J. Power Sources, 270 (2014) 634-645.
[122] P.H. Wang. Aspects on prestretching of PAN precursor shrinkage and and thermal behavior. J. Appl Polym Sci., 67 (1998) 1185-1190.
[123] C.I. Su, Y.X. Huang, J.W. Wong, C.H. Lu, C.M. Wang, PAN-based carbon nanofiber absorbents prepared using electrospinning. Fibers and Polymers, 13 (2012) 436-442.