电化学阻抗谱课件

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,2005-10-12,*,*,实验电化学,电化学阻抗、微分电容技术(II）,2005 秋季,2005-10-12,0,实验电化学电化学阻抗、微分电容技术(II）2005 秋季20,Principles of (EIS) measurement,2005-10-12,1,Principles of (EIS) measuremen,Impedance is a complex quantity,Z,re,Z,im,2005-10-12,2,Impedance is a complex quantit,The Digital Correlation Technique,2005-10-12,3,The Digital Correlation Techni,Schematic of a Frequency Response Analyzer,2005-10-12,4,Schematic of a Frequency Respo,纯电阻元件,I=I,0,sint,V,R,V,V=V,0,sint,I,V和I相位相同,Z与频率无关,2005-10-12,5,纯电阻元件I=I0sintVRVV=V0sintIV和I,纯电容元件,只有当电位发生变化时才有电流流过,V,C,| |,V,I,t,V和I的频率仍然相同，但是电流超前/2,2005-10-12,6,纯电容元件只有当电位发生变化时才有电流流过VC| |VItV,Impedance of a capacitor,V,I,t,2005-10-12,7,Impedance of a capacitorVIt200,V,L,I,V,t,Inductor L,2005-10-12,8,VLIVtInductor L2005-10-128,Impedance of L,I,V,t,V和I的频率仍然相同，但是电流滞后/2,2005-10-12,9,Impedance of LIVtV和I的频率仍然相同，但是,串联阻抗,Z,1,Z,2,Z,R和C串联,R,C,| |,Z,2005-10-12,10,串联阻抗Z1Z2ZR和C串联RC| |Z2005-10-12,2005-10-12,11,2005-10-1211,并联阻抗,Z,Z,2,Z,1,Z,R,C,| |,2005-10-12,12,并联阻抗ZZ2Z1ZRC| |2005-10-1212,Z”,Z,R,=1/RC,2005-10-12,13,Z”ZR=1/RC2005-10-1213,Z”,Z,R,ct,+R,s,R,s,=1/R,ct,C,dl,R,s,R,ct,C,dl,a,2005-10-12,14,Z”ZRct+RsRs=1/RctCdlRsRctCdl,Z,L,R,出现电感的可能原因,2005-10-12,15,ZLR出现电感的可能原因2005-10-1215,Diffusion related elements, W and O,2005-10-12,16,Diffusion related elements, W,Constant phase element,Constant phase element (CPE),Dispersion effect,An alternative way of modelling the dispersion of time constants is a transmission line,Depressed semicircle in Nyquist plot,inhomogeneity of the surface and charge distribution,Parameters, Y,0,and n, 1n0,Dimension of Y,0,-1,cm,-2,s,n,2005-10-12,17,Constant phase elementConstant,Effect of a CPE replacing capacitor in parallel with a resistor,CPE,R,2005-10-12,18,Effect of a CPE replacing capa,增大,Z”,Z,Schematic Nyquist plot of Randle circuit with capacitor replaced by CPE,R,l,R,ct,C,dl,R,l,R,ct,CPE,a,b,Equivalent circuit to describe Diagram of Randle circuit (a), and modified Randle circuit (b),2005-10-12,19,增大Z”ZSchematic Nyquist plot,Effect of n of CPE on the high frequency semicircle and slope and low frequency tail in Nyquist plot of simulated circuit R(RWQ),2005-10-12,20,Effect of n of CPE on the high,How to calculate capacity from CPE,max,represents the frequency of the maximum on the -,Z, vs. dependence and is independent of,2005-10-12,21,How to calculate capacity from,Presentation of impedance data: Bode and Nyquist plots,2005-10-12,22,Presentation of impedance data,Nyquist plotcomplex plane plot,每个,下的Z()的虚部对实部作图，得到 Nyquist 图,making it easy to see the effects of ohmic resistance,emphasizing circuit components that are in series,R,s,R,s,R,ct,Z,-Z”,2005-10-12,23,Nyquist plotcomplex plane plo,Bode plot,lg|Z|lgf & phase shift vs. lgf,2005-10-12,24,Bode plotlg|Z|lgf & phase shi,Advantages of Bode plot,Providing a clearer description of systems frequency-dependent behavior,Avoiding the longer measurement times associated with low frequency R,p,determinations,The log |Z| vs. log w plot sometimes allowing a more effective extrapolation of data from higher frequencies,Showing the magnitude ( | Z | ) on a log axis so that you can easily plot wide impedance ranges on the same set of axes,2005-10-12,25,Advantages of Bode plotProvidi,Time constant and relaxation,Time constant,Time required for a system to reach a new steady state after a excitation,Time constant for (RC),2005-10-12,26,Time constant and relaxationTi,Configuration of Electrochemical cells for EIS measurement,For study of ion transport through the membrane,For investigations of electrolyte properties,2005-10-12,27,Configuration of Electrochemic,Parameters setting for EIS measurement,Mode:,Potentiostatic, more popular,Galvanostatic, electrodeposition, battery research,DC bias,2005-10-12,28,Parameters setting for EIS mea,Parameters setting for EIS measurement (II),Frequency range,10,7,10,-5,Hz,Amplitude,Signal to noise ratio,Linearity condition,Frequency distribution,linear,Square root,Logarithmic,2005-10-12,29,Parameters setting for EIS mea,Equivalent circuit fitting,Described by circuit description elements: R1(Q1R2W1),2005-10-12,30,Equivalent circuit fittingDesc,Effect of R,s,from 75.9 to 10,R1(Q1R2W1), R1(R,s,)=75.9,Q: Y,0,=3.138e-4, n=0.8762,R2(R,ct,)=283, W=1.626e-3,2005-10-12,31,Effect of Rs from 75.9 to 10 ,Effect of O_diffusion resistance with finite length, Y,0,=1.610,-3, B=0.1,2005-10-12,32,Effect of O_diffusion resistan,Effect of R,ct,from 283 to 1000,2005-10-12,33,Effect of Rct from 283 to 1000,Effect of Warburg resistance, 1.626,10,-3,to 1.626,10,-2,2005-10-12,34,Effect of Warburg resistance,Effect of Q(C,dl,) from 3.13810,-6,to 3.13810,-5,2005-10-12,35,Effect of Q(Cdl) from 3.13810,Limitation of equivalent circuit method on interpreting impedance data,An impedance spectroscopy can be described by more than one equivalent circuit,The physical meaning of some elements is ambiguous,2005-10-12,36,Limitation of equivalent circu,2005-10-12,37,2005-10-1237,2005-10-12,38,2005-10-1238,Application of EIS: Evaluating the performance of coating,The data obtained from EIS measurements can be correlated directly to allow analysis of the following phenomena:,blister formation,water permeation,swelling, of the coating,loss of adhesion, including delamination.,corrosion,2005-10-12,39,Application of EIS: Evaluating,Cautions taken in setting parameters,Increasing Exposure area with increasing thickness,Area(cm,2,)0.4d(,m),Larger ac amplitude (100 mV) is possible to be used,2005-10-12,40,Cautions taken in setting para,General equivalent circuit model for polymer coated metals,R,s,2005-10-12,41,General equivalent circuit mod,Significance of elements,R,s,Electrolyte/solution resistance,A measuring of ionic film resistance,C,c,Coating capacitance,Volume of water absorbed by coating:,2005-10-12,42,Significance of elementsRsVolu,Phase 1, penetration/adsorption process begins,Phase 2, the coating becomes saturated,Phase 3, further accumulation of water normally at the polymer-metal interface indicating adhesion loss and the possible on-set of corrosion,2005-10-12,43,Phase 1, penetration/adsorptio,R,c,Pore resistance resulting from the penetration of electrolyte through real pores or regions of low crosslinking,C,d,a measure of the area over which the coating has disbonded,A measure of electroactive area,2005-10-12,44,Rc2005-10-1244,2005-10-12,45,2005-10-1245,结合电化学其它实验技术，利用EIS研究在稀HNO,3,中不锈钢的电化学活性，也可以选择你感兴趣的电化学溶液/电极体系。,欲开展此实验的同学请和胡融刚博士联系如何使用教研室现有的仪器。Rongganghu,阻抗实验设计,2005-10-12,46,结合电化学其它实验技术，利用EIS研究在稀HNO3 中不锈钢,