Electrochemistry in Ionic Liquids (eBook)

Dr. Angel A. J. Torriero is a Lecturer of Chemistry and Electrochemistry at Deakin University, Melbourne, Australia. He has published more than 50-refereed papers (h-index = 18; Scopus, November 2014), six book chapters, several patents, and one book, Electrochemical Properties and Applications of Ionic Liquids in 2011. Dr. Torriero has a broad interest in both fundamental and applied electrochemistry and has made significant contributions in a number of fields, including analytical electrochemistry, biosensor, bioelectrochemistry, organic and organometallic electrochemistry, and most recently internal reference systems for ionic liquids.

Preface for First Volume 6
Preface for Second Volume 8
Contents 10
Contributors 14
About the Editor 18
Chapter 1: Introduction 19
References 21
Part I: Fundamental Concepts of Electrochemistry in Ionic Liquids 22
Chapter 2: Electrode–Electrolyte Interfacial Processes in Ionic Liquids and Sensor Applications 23
2.1 Introduction 23
2.2 Fundamentals of Electrode/Electrolyte Interfacial Processes 24
2.2.1 Adsorption 26
2.2.2 Electrical Double Layer 27
2.2.3 Chemical Reactions 28
2.3 Techniques for Studying Interfacial Properties in ILs 29
2.3.1 Cyclic Voltammetry 31
2.3.1.1 Electrochemical Stability (Electrochemical Potential Window) 31
2.3.1.2 Mass Transport 33
2.3.1.3 Charging Current in CV 34
2.3.1.4 Scan Rate Effects on the IL Double-Layer Charging Currents 34
2.3.1.5 Electrolyte Conductivity 36
2.3.2 Potential-Step Methods (Chronoamperometry) 37
2.3.2.1 Kinetics Study for Electrochemical Process 37
2.3.2.2 Faradaic Current Determination 38
2.3.3 Electrochemical Impedance Spectroscopy 39
2.3.3.1 Randles Circuit 40
2.3.3.2 Proposed Equivalent Circuit in ILs 41
2.3.3.3 EIS Measurement in IL 41
2.3.4 Infrared Spectroscopy 41
2.3.4.1 IR Signal from IL 42
2.3.4.2 Effects on Dissolved Analytes (Peak Position and Width) 44
2.3.4.3 Interface Signal 44
2.3.5 In Situ EQCM Methods 45
2.3.6 In Situ Electrochemical–Scanning Probe Microscopy 49
2.4 New Approaches for Sensor Development Using IL Interface 52
2.4.1 ILs as Electrolytes for Electrochemical Sensors 53
2.4.2 Sensory Design Based on the Potentiometry 54
2.4.2.1 Sensing Based on the Liquid Junction Potentials 54
2.4.2.2 Ion-Selective Electrodes with ILs 55
2.4.2.3 Nonclassical Potentiometry 58
2.4.2.4 Sensing Based on Voltammetry 59
2.4.2.5 IL Redox Chemistry Enabled Reliable Voltammetric Sensing 61
2.4.3 Electrified IL/Electrode Interface and Related Sensor Based on Impedance Technique 62
2.4.4 IL Electrochemical Microarrays 65
2.4.4.1 Microarray Fabrication 66
2.4.5 IL as Component for New Electrode Materials 67
2.4.5.1 Electrodes Modified with IL Droplets or IL Films 68
2.4.5.2 Carbon Paste Electrodes with IL as Binder 69
2.4.6 Adsorption and Absorption-Based Chemical Sensing Using IL Thin Films 70
2.4.6.1 IL-Based QCM Mass Sensor 71
2.4.6.2 IL-Thin Film Formation 72
2.4.6.3 IL High Temperature Sensor 74
2.4.6.4 IL Solvation and Other Sensing Platform 74
2.4.6.5 Detection of Explosives and Chemical Warfare Agents 76
2.5 Future Directions and Concluding Remarks 77
References 78
Chapter 3: Reference Systems for Voltammetric Measurements in Ionic Liquids 91
3.1 Introduction 91
3.2 Reference Electrodes 91
3.3 Internal Reference Redox Scales 99
3.3.1 Limitations in the Application of IRRS in Ionic Liquids 113
3.3.2 Selection of an Internal Reference Redox Scale for Voltammetric Measurements 115
3.4 Recommendations 122
References 123
Chapter 4: Ultramicroelectrode Voltammetry and Scanning Electrochemical Microscopy in Room Temperature Ionic Liquids 128
4.1 Introduction 128
4.2 Principles of Ultramicroelectrode Voltammetry 129
4.3 Principles of Scanning Electrochemical Microscopy 132
4.4 Instrumentation for Scanning Electrochemical Microscopy 135
4.5 Steady-State Voltammetry at Ultramicroelectrodes in RTILs 136
4.6 Scanning Electrochemical Microscopy in RTILs 140
4.7 Effects of Non-equal Diffusion Coefficients on Scanning Electrochemical Microscopy 145
4.8 Studying Electron Transfer in RTILs Using SECM 147
4.9 SECM Imaging in Ionic Liquids 152
4.10 Conclusions 152
References 154
Chapter 5: Electroanalytical Applications of Semiintegral and Convolution Voltammetry in Room-­Temperature Ionic Liquids 157
5.1 Introduction 157
5.2 Conventional Voltammetric Techniques 159
5.2.1 Steady-State Microelectrode Voltammetry 159
5.2.2 Rotating Disk Electrode Voltammetry 160
5.2.3 DC Cyclic Voltammetry 161
5.3 Convolution Voltammetry 163
5.3.1 Theory 163
5.3.2 Applications of Semiintegral Voltammetry 167
5.3.2.1 [Co(Cp)2]+/0 Process in [C8mim][PF6] 167
5.3.2.2 I?/I3?/I2 Processes in [C8mim][PF6] 168
5.3.2.3 Electro-oxidation of Iodide on a Glassy Carbon Electrode in [C2mim][N(Tf)2] 169
5.3.2.4 Electro-oxidation of Iodide on a Gold Electrode in [C2mim][N(Tf)2] 171
5.3.3 Applications of Convolution Voltammetry 172
5.3.3.1 Electro-oxidation of Iodide at a Platinum Microdisk Electrode 172
5.3.3.2 [Fe(Cp)2]0/+ Process in [C2mim][N(Tf)2]: Determination of D and nc 174
5.4 Conclusions 175
References 177
Chapter 6: Small-Angle X-Ray Scattering of Ionic Liquids 182
6.1 Introduction 182
6.2 General Theory 183
6.2.1 Elastic X-Ray Scattering 183
6.2.2 Data Reduction 184
6.2.3 Diffraction 185
6.2.4 Fundamental SAXS Theory 185
6.2.5 Scattering Inhomogeneities 187
6.3 SAXS Analysis 187
6.3.1 Common SAXS Assumptions 188
6.3.2 Indirect Fourier Transformation Analysis 189
6.3.3 Useful Approximations and Relationships 191
6.3.3.1 Guinier Approximation 191
6.3.3.2 Power-Law Decays 193
6.3.4 Unified Equations 197
6.3.5 Invariant 199
6.3.6 Composite Inhomogeneities, Form Factors, and Structure Factors 199
6.3.6.1 Size Distribution and Anisotropic Inhomogeneities 200
6.3.7 Aggregation 202
6.3.8 Microemulsions 203
6.3.9 Monte-Carlo Simulations 205
6.4 Experimental 207
6.4.1 Experimental Preparation 207
6.4.1.1 Energy Selection 207
6.5 Future of SAXS and XPCS 209
6.5.1 Theory 212
6.5.2 Examples 215
6.5.2.1 Example 1: Particle Dynamics 215
6.5.2.2 Example 2: Surface Dynamics of Capillary Wave 216
6.6 Conclusion and Outlook 218
References 219
Part II: Structure and Properties of Ionic Liquids Relevant to Electrochemistry 227
Chapter 7: Room-Temperature Molten Salts: Protic Ionic Liquids and Deep Eutectic Solvents as Media for Electrochemical Application 228
7.1 Introduction 228
7.2 Advances in Proton-Donor Room-Temperature Molten salts 229
7.2.1 Protic Ionic Liquids 229
7.2.2 Deep Eutectic Solvents 231
7.2.3 Natural Ionic Liquids 234
7.3 Physicochemical Properties of H-donor RTMS 235
7.3.1 Transport Properties and Ionicity Classification 236
7.3.1.1 Conductivity 236
7.3.1.2 Viscosity 237
7.3.1.3 Ionicity and Diffusion 239
7.3.2 Structural Properties and Application to Materials Chemistry 242
7.3.2.1 Self-Assembled Structures in PILs 242
7.3.2.2 Application of PILs Structuring Reductive Media to Nanoparticle Synthesis 244
7.3.3 Electrochemical Stability and Metal Protection Against Corrosion in RTMS 245
7.4 Application of H-Donor RTMS as Electrolytes in Energy Storage 248
7.4.1 Use of H-Bond Donor for Supercapacitors: Advantage and Limitations 248
7.4.1.1 Application of PILs as Electrolytes for Supercapacitors 249
7.4.1.2 Parameters Influencing the Storage Mechanism According to PILs 250
7.4.1.3 Specific Behavior of DESs as Electrolytes for Supercapacitors 251
7.4.2 Application of the PILs for Lithium Ion Batteries 252
7.4.2.1 Use of PILs as Electrolytes in Li-Ion Batteries 253
7.4.2.2 Use of DESs as Electrolytes in Li-Ion Batteries 254
7.5 Conclusion 255
References 256
Chapter 8: Task-Specific Ionic Liquids for Electrochemical Applications 264
8.1 Introduction 264
8.2 Ether/Thioether- and Hydroxyl/Thiol-Functionalized ILs 264
8.2.1 General Physical Properties 264
8.2.2 Electrochemical Properties 266
8.2.3 Electrochemical Applications 268
8.2.4 Thiol/Thioether Functionality (Also See Review [94]) 272
8.3 Carboxyl-Functionalized ILs 273
8.4 Amine-Functionalized ILs 275
8.5 Nitrile (or Cyano)-Functionalized ILs 276
8.6 Zwitterionic ILs 277
8.7 Polymerized ILs 277
8.8 Other Cation-Functionalized ILs 279
8.9 Anion-Functionalized ILs 281
8.10 Deep Eutectic Solvents 283
8.11 Summary 283
References 284
Chapter 9: Polymeric Ion Gels: Preparation Methods, Characterization, and Applications 293
9.1 Introduction 293
9.2 Gels: Basic Definition and Classifications 294
9.3 Preparation Methods of Polymeric Ion Gels 295
9.4 Properties of Ion Gels 298
9.4.1 Ionic Conductivity 299
9.4.2 Mechanical and Rheological Properties 299
9.4.3 Morphology 302
9.5 Applications 303
9.5.1 Batteries 304
9.5.2 Fuel Cells 306
9.5.3 Solar Cells 309
9.5.4 Supercapacitors 310
9.5.5 Actuators 313
9.5.6 Emerging Applications: Electrochemical Sensors, Optoelectronic Devices, Bioelectronics, Gas Separation Membranes, Catalytic Membranes, Drug Releases 315
9.6 Summary and Outlook 317
References 318
Chapter 10: Structural Aspect on Li Ion Solvation in Room-Temperature Ionic Liquids 326
10.1 Introduction 326
10.2 Liquid Structure of Neat ILs 327
10.3 Li Ion Solvation: Raman Spectroscopic Study 331
10.4 Atomistic Solvation Structure of Li Ion in ILs: HEXRD and MD Simulation Study 335
10.5 Conclusion 338
References 338
Symbols and Abbreviations 342
Ionic Liquid Abbreviations 342
Cations 342
Anions 344
Chemical Abbreviations 345
Abbreviations 346
Roman Symbols 349
Greek Symbols 352
Index for First Volume 353
Index for Second Volume 356