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標題: 電動效應電池性能之實驗探討
Experimental Study of Electrokinetic Cell Performance
作者: 葉力熒
Yeh, Li-Ying
關鍵字: nanoscale;奈米尺寸;electrokinetic energy conversion;I-V curve;streaming potential;energy conversion efficiency;電動能量轉換;電流-電位曲線;流動電位;電動電池效率
出版社: 機械工程學系所
引用: 【1】W.B. Russel, D.A. Saville, W.R. Schowalter, “Colloidal dispersions, Cambridge monographs on mechanics and applied mathematics,” Cambridge University Press, Cambridge, 1989. 【2】R.J. Hunter, “Zeta potential in colloid science: principles and applications,” Academic press, New York, 1981. 【3】J. Yang, F. Lu, L.W. Kostiuk, D.Y. Kwok, “Electrokinetic mircochannel battery by means of electrokinetic and microfluidic phenomena,” J. Micromech. Microeng. 13 (2003) 963-970. 【4】H. Daiguji, P. Yang, A.J. Szeri, A. Majumdar, “Electrochemomechanical energy conversion in nanofluidic channels,” Nano lett. 4(12) (2004) 2315-2321. 【5】J. Yang, F. Lu, L.W. Kostiuk, D.Y. Kwok, “Electrokinetic power via streaming potentials in microchannels: a mobile-ion-drain method to increase streaming potentials,” The 2004 Int. Conf. on MEMS, NANO and Smart Systems (Banff, Alberta-Canada) pp 675-9 【6】M.C. Lu, S. Satyanarayana, R. Karnik, A. Majumdar, C.C. Wang, “A mechanical-electrokinetic battery using a nano-porous membrane,” J. Micromech. Microeng. 16 (2006) 667-675. 【7】F.H.J. van der Heyden, D.J. Bonthuis, D. Stein, C. Meyer, C. Dekker, “Power generation by pressure-driven transport of ions in nanofluidic channels,” Nano lett. 7(4) (2007) 1022-1025. 【8】F.A. Morrison, J.F. Osterle, J. Chem, “Electrokinetic energy conversion in ultrafine capillaries,” J. Chemical Physics 43 (1965) 2111-2115 【9】X. Xuan, D. Li, “Thermodynamic analysis of electrokinetic energy conversion,” J. Power Sources 156 (2006) 677-684. 【10】J.Y. Min, E.F. Hasselbrink, S.J. Kim, “On the efficiency of electrokinetic pumping of liquids through nanoscale channels,” Sensor and Actuators B 98 (2004) 368-377. 【11】C.H. Chen, J.G. Santiago, “A planar electroosmotic micropump,” J. MEMS. 11 (2002) 672-683. 【12】Q. Li, L. Dong, R. Jia, X. Chen, Z. Hu, B.T. Fan, “Development of a quantitative structure-property relationship model for predicting the electrophoretic mobilities,” Computers and Chemistry 26 (2002) 245-251. 【13】F.H J. van der Heyden, D.J. Bonthuis, D. Stein, C. Meyer, C. Dekker, “Electrokinetic energy conversion efficiency in nanofluidic channels”. Nano lett. 6(10) (2006) 2232-2237. 【14】Y.F. Chen, M.C. Li, W.J. Chang, C.C. Wang, C.P. Chen, “Electroosmotic pumping using porous anodic alumina membranes,” 2008 Micro/Nanoscale Heat Transfer Internation Conference Tainan Taiwan. 【15】Y. Xie, X. Wang, J. Xue, K. Jin, L. Chen, Y. Wang, “Electric energy generation in single track-etched nanopores,” Applied Physics Letters 93(2008), 163116. 【16】P. Wang, Z. Chen, H.C. Chang, “A new electro-osmotic pump based on silica monoliths”. Sensors and Actuators B 113 (2006) 500-509.
在本研究中,利用實驗分析探討其電解質溶液通過具有奈米孔隙之帶電薄膜時,因電雙層內離子相互作用產生電動效應而作為能量轉換之電動電池,且量測其電流-電位曲線(I-V Curves),估算其發電效率。實驗方面,薄膜材質為氧化鋁,孔徑大小為20nm,其管道表面與電解液接觸時帶有正電帶,並使用三種不同的電解質KCl、H2SO4、HCOOH作為工作流體,其中KCl為強電解質在水中可完全解離成K+及Cl-離子,H2SO4為強酸,且可解離成H+及SO4-2離子,而HCOOH則是弱酸,其解離度較低,屬弱電解質,在水中可以解離為H+及HCOOH-離子,25°C時,解離常數為1.8x10-4。三種電解液在流量分別為4ml/min、2ml/min、1ml/min下進行實驗。
實驗結果發現電動電池能量轉換之最大效率與流量及壓力無關,大約為0.04%~0.05%之間。在溶液濃度為10-4M~10-6 M時,因各電解液之無因次Debye length,a/λD 小於1,因此ηmax較濃度為10-1M~10-2M之a/λD >1時高,可知當EDL發生重疊時可獲得較高的能量轉換效率。濃度為10-4M時,HCOOH之a/λD <1,而KCl及H2SO4皆大於1,因此HCOOH之最大效率大於KCl與H2SO4。

In this study, electrokinetic energy conversion in power generation mode is experimentally investigated. An alumina membrane with nanoscale pore size of 20nm density of 1011 per cm2 is employed as the substrate in the electrokinetic energy conversion unit design. Aqueous solutions of potassium chloride (KCl), sulfuric acid and formic acid (HCOOH) with bulk concentrations ranging from 10-6 to 10-1M are employed as the working electrolytes.
In the experiment, the electric current-voltage curves (I-V curves) were measured under various flow rates. Using the measured I-V curves, the energy conversion efficiency is computed. The results show that for all the flow rates and electrolytes used, maximum efficiency can be found when the voltage is approximately equal to half of the maximum streaming potential. The maximum efficiency strongly depends on the concentration of the electrolyte. Using dimensionless Debye length as the parameter, it was found that higher maximum efficiency can be found when dimensionless Debye length is less than 1. That is, higher efficiency can be resulted as the electrical double layer is overlapped. Among the three types of electrolytes, the HCOOH has the best performance because of low counterion (HCOO-) concentration as the HCOOH is dissolved in the water. As the H2SO4 electrolyte is used, poor conversion efficiency is resulted due to lesser amount of counterions (SO42-) present in the electric double layer.
其他識別: U0005-2108200910515100
Appears in Collections:機械工程學系所

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