中国科学技术大学：《物理化学》课程教学资源（课件讲稿）Physical Chemistry III Chapter 7 交流阻抗谱技术 AC Impedance Spectroscopy

第九章交流阻抗谱技术 ●Introduction o Basic elements in an electric circuit Nyquist and Bode plots Data analysis and software ●Examples

第九章 交流阻抗谱技术  Introduction  Basic elements in an electric circuit Basic elements in an electric circuit  Nyquist and Bode plots Nyquist and Bode plots  Data analysis and software  Examples

What should you know? ●阻抗谱的原理 ●如何看懂阻抗谱？ ●如何解析阻抗谱？（常用软件） ●阻抗谱的常见错误

What should you know?  阻抗谱的原理  如何看懂阻抗谱？  如何解析阻抗谱？（常用软件）  阻抗谱的常见错误

Introduction Terminology: ● AC Impedance Spectroscopy (IS) ● Electrochemical Impedance Spectroscopy (EIS) ● Complex Impedance Spectroscopy(CIS) References: ● J.R.MacDonald,Impedance Spectroscopy,Chapel Hill,North Carolina,1987.(John-Wiley,2005?) ● 史美伦，交流阻抗谱原理及应用，国防工业出 版社，2001 曹楚南，张鉴清，电化学阻抗谱导论，科学出版 社，2002

Introduction Terminology: • AC Impedance Spectroscopy (IS) AC Impedance Spectroscopy (IS) • Electrochemical Impedance Spectroscopy (EIS) • Complex Impedance Spectroscopy (CIS) Complex Impedance Spectroscopy (CIS) References: • J.R. MacDonald, Impedance Spectroscopy, Chapel Hill N h C li 1987 (J h Hill, North Carolina, 1987. (John-Wil 2005?) Wiley, 2005?) • 史美伦，交流阻抗谱原理及应用，国防工业出 版社，2001. • 曹楚南, 张鉴清，电化学阻抗谱导论，科学出版 社，2002

Introduction ●暂态与稳态：This is a transient technique,but one that requires a general steady state condition. ●可测性质：can be used for determining both: Interfacial parameters(界面参数 a)reaction rates b)rate constants c)capacitance/charge storage abilities d)diffusion coefficients e)adsorption rate constants f)reaction mechanisms And aterial parameters(材料参数 a)conductivity b)dielectric constants c)bulk generation-recombination reaction rates d)charge mobilities e)film thickness f)equilibrium conc.of charged species g)presence of pores and cracks

Introduction  暂态与稳态: This is a transient technique, but one that requires a general steady state condition.  可测性质: can be used for determining both: Interfacial parameters ( Interfacial parameters (界面参数) a) reaction rates b) rate constants c) capacitance/charge storage abilities d) diffusion coefficients e) adsorption rate constants f) reaction mechanisms And Material parameters (材料参数) a) conductivity a) conductivity b) dielectric constants b) dielectric constants c) bulk generation-recombination reaction rates d) charge mobilities e) film thickness f) equilibrium conc. of charged species g) presence of pores and cracks

General concept -like other spectroscopy experiments,we apply an excitation to the system under study and observe its response (generally as a function of frequency) 一般 光吸收 恒压测量 厂留人 -in EIS,we apply a potential perturbation (usually a Sine wave) and observe the current response,which is a sine wave at the same frequency,but with a different amplitude and phase than the potential signal. Cell

General concept - like other spectroscopy experiments, we apply an excitation to the system under study and observe its response (generally as a f nction of freq enc ) a function of frequency) 一般 光吸收 恒压测量 - in EIS, we apply a potential perturbation (usually a Sine wave) and observe the current response which is a sine wave at the same 恒压测量 and observe the current response, which is a sine wave at the same frequency, but with a different amplitude and phase than the p g otential signal

Advantageous features of EIS -measurements are made under steady state conditions -all electrical parameters of the system can be determined in a single experiment -a simple measurement,easy to automate -characterize bulk and interfacial properties of all sorts of materials(conductors,semiconductors,ionic transport media, dielectrics(insulators)) -can be used to help verify mechanistic models -works even in low conductivity electrolyte solutions -signal can be averaged over long periods to achieve high precision -non-destructive Caution:Because it is easy to do,it is also easy to collect large amounts of meaningless data!(无效数据/错误数据)

Advantageous features of EIS - measurements are made under steady state conditions - all electrical parameters of the system can be determined in a single e periment single e xperiment - a simple measurement, easy to automate - characterize bulk and interfacial properties of all sorts of characterize bulk and interfacial properties of all sorts of materials (conductors, semiconductors, ionic transport media, dielectrics (insulators)) - can be used to help verify mechanistic models - works even in low conductivity electrolyte solutions - signal can be averaged over long periods to achieve high signal can be averaged over long periods to achieve high precision - non -destructive Caution: Because it is easy to do, it is also easy to collect large amounts of il d ! f mean ing less data!（无效数据 /错误数据）

Basis of EIS:Ohm's law Ohm's law:current is approximately proportional to electric field for most materials. I= R or V=IR or R= I R The complex generalization of resistance is impedance, usually denoted with Z. Im V=I.Z X 2 Z-Z+7i Re Real R Imaginary part part Z

Basis of EIS: Ohm’s law Ohm’s law: current is approximately proportional to electric field for most materials electric field for most materials . V V IR R V I  or  or  Th l li ti f i t i i d I V IR R R I  or  or  The comp lex generalization o f res i s tance is impe dance, usually denoted with Z . V  I  Z Z’’ Z Z Z j ' ''   Real part Imaginary part Z’

R:Resistance in AC ◆Resistance circuit Applied electric energy is consumed as heat P=VI=I2R=V2/R V=IR (Ohm's Law) the identical phase between resistance and applied voltage 布e班 VR Vrusinot V V助 R sinat VR -1 RuSin ot

R: Resistance in AC

R:Resistance in AC 欧拉(Euler)公式： e=cos(x)+isin(x) (另一个Euler公式：凸多面体F+V=E+2) V=Vo(cos(@t)+jsin(@t))=Ve R ∴.Impedance: V Zg==R(cos(0)+jsin(0))=R

R: Resistance in AC 欧拉（Euler）公式： e cos(x) isin(x) ix   （另 个一 Euler公式： 凸多面体F+V=E+2 F+V=E+2） j t V V t j t V e  0   0  0 (cos( )  jsin( ))  0 ( ( ) ( )) V j t I 0 jt e R I 0    Impedance: R j R V ZR   R(cos(0)  jsin(0))  R I ZR (cos(0)  sin(0))

R:Resistance in AC e证=1+x+ +++++++ 21 311 4!51 61 7列 =1+ic- x2 ix3 xi ix5 x6 ix7 x8 2-31+4+5-6-71+8+. =(-豆+-+萄）+(-+罗-员+.） =c0sx十&simx

R: Resistance in AC