List of Symbols ................................................ xi
Preface ....................................................... xxi
1 Electrolytes ................................................. 1
1.1 Liquid Electrolyte Solutions ............................ 1
1.2 Ionic Melts ............................................. 6
1.2.1 Alkali halide melts .............................. 6
1.2.2 Glass forming molten salts ....................... 7
1.2.3 Ionic liquids .................................... 8
1.3 Ionic Conductance in Polymers .......................... 10
1.3.1 Polymer electrolytes ............................ 10
1.3.2 Gel polymer electrolytes ........................ 12
1.3.3 Ion exchanging polymer electrolytes ............. 13
1.4 Ionic Conductance in Solids ............................ 13
1.4.1 Crystal defects ................................. 13
1.4.2 Intrinsic disorder .............................. 16
1.4.3 Extrinsic disorder .............................. 18
1.4.4 Disorder in sub-lattices ........................ 19
1.4.5 Transport by defects ............................ 23
1.4.6 Ion conducting glasses .......................... 23
1.4.7 Mixed ionic and electronic conductance .......... 24
2 Structure and Bonding ....................................... 27
2.1 Structure Factors ...................................... 27
2.2 Closed Packed Structures of Metals ..................... 28
2.3 Alloys with Closed Packed Structure .................... 29
2.4 Hume-Rothery Rules for Formation of Solid Solutions .... 30
2.5 Body Centered Cubic Structure .......................... 33
2.6 Hume-Rothery Phases .................................... 33
2.7 Ionic Structures ....................................... 35
2.8 Coordination Polyhedrons of Molecules .................. 38
2.9 The Band Model of Electrons in Solids .................. 41
2.9.1 Free electrons in a metal ....................... 41
2.9.2 Orbitals in solids .............................. 43
2.9.3 Density of states (DOS) ......................... 46
2.9.4 Filling up with electrons; Fermi energy ......... 47
2.9.5 Crystal orbital overlap population: the
formation of bonds .............................. 48
2.9.6 Extension to more dimensions .................... 49
2.9.7 Band structure of d-metals ...................... 52
2.9.8 Semiconductors: example TiO2 .................... 53
2.9.9 Peierls distortion .............................. 53
2.9.10 Energy bands in electrolytes .................... 55
2.10 Cohesion in Solids ..................................... 56
2.10.1 Lattice enthalpy ................................ 56
2.10.2 Sublimation enthalpy ............................ 57
2.10.3 Bond energies of metals ......................... 57
2.10.4 Bond energies of alloys ......................... 60
3 Electrode Potentials ........................................ 71
3.1 Pure Metals ............................................ 71
3.1.1 Equilibrium between a metal phase and an
electrolyte phase ............................... 71
3.1.2 Standard electrode potentials ................... 72
3.1.3 Standard electrode potentials of metal
complexes ....................................... 79
3.2 Alloys ................................................. 80
3.2.1 Partial molar Gibbs energies .................... 80
3.2.2 Electrochemical measurements of partial molar
functions ....................................... 83
3.2.3 AgTAuv—example of a solid solution .............. 85
3.2.4 Partial molar functions of component В .......... 89
3.2.5 From partial molar functions to integral
functions ....................................... 91
3.3 Intermetallic Phases and Compounds ..................... 92
3.3.1 Potential versus mole fraction diagrams ......... 92
3.3.2 Coulometric titration ........................... 94
3.3.3 Coulometric titration: the system LiAl .......... 94
3.3.4 Intermetallic compounds: the system LiSb ........ 97
3.3.5 Measurements at room temperatures: CuZn ........ 100
4 Ad-Atoms and Underpotential Deposition ..................... 101
4.1 The Thermodynamic Description of the Interphase ....... 101
4.1.1 The electrochemical double layer ............... 101
4.1.2 Ideally polarizable electrodes ................. 105
4.1.3 Electrocapillary curves ........................ 105
4.1.4 Adsorption isotherms ........................... 107
4.1.5 Reversible electrodes .......................... 109
4.1.6 Partial charge and electrosorption valency ..... 110
4.1.7 Thermodynamics of solid electrolyte
interfaces ..................................... 113
4.2 Principal Methods for the Investigation of the
Electrochemical Double Layer .......................... 114
4.2.1 Measurement of capacitance ..................... 114
4.2.2 Cyclic voltammetry and chronoamperometry ....... 118
4.2.3 Determination of the adsorbed mass ............. 119
4.2.4 Scanning tunneling microscopy and related
methods ........................................ 122
4.3 Ad-Atoms .............................................. 126
4.3.1 Adsorption and desorption of ad-atoms .......... 127
4.3.2 Equilibrium ad-atom concentration .............. 128
4.3.3 Surface diffusion of ad-atoms .................. 129
4.4 Underpotential Deposition ............................. 130
4.4.1 Lead on silver ................................. 130
4.4.2 Copper on Au
4.4.3 Underpotential deposition as two-dimensional
phase formation ................................ 137
4.4.4 Multiple steps of UPD film formation ........... 139
5 Mass Transport ............................................. 143
5.1 Stationary Diffusion .................................. 143
5.2 Non-Stationary Diffusion .............................. 147
5.2.1 Chronopotentiometry ............................ 147
5.2.2 Chronoamperometry, chronocoulometry ............ 148
5.2.3 Warburg impedance .............................. 150
5.2.4 Cyclic voltammetry ............................. 154
5.2.5 Microelectrodes ................................ 156
5.3 Diffusion in Solid Phases ............................. 157
5.3.1 Potentiostatic method .......................... 157
5.3.2 Galvanostatic method ........................... 160
5.4 Methods to Control Diffusion Overpotential ............ 161
5.4.1 Rotating-disc electrode ........................ 162
5.4.2 Rotating ring-disc electrodes .................. 165
5.4.3 Rotating-cylinder electrodes ................... 166
6 Charge Transfer ............................................ 169
6.1 Electron Transfer ..................................... 169
6.1.1 Butler-Volmer equation ......................... 170
6.1.2 Tafel lines .................................... 172
6.1.3 Charge transfer resistance ..................... 174
6.1.4 Theories of electron transfer .................. 175
6.2 Electrochemical Reaction Orders ....................... 178
6.2.1 Determination of electrochemical reaction
orders from Tafel lines ........................ 179
6.2.2 Determination of electrochemical reaction
orders from the charge transfer resistance ..... 180
6.3 Ion Transfer .......................................... 184
6.4 Charge Transfer and Mass Transport .................... 186
6.4.1 Elimination of diffusion overpotential with
a rotating disc electrode ...................... 188
6.4.2 Elimination of diffusion contribution to the
overpotential in chronoamperometry and
chronopotentiometry ............................ 190
6.4.3 Elimination of diffusion contributions to the
overpotential by impedance spectroscopy ........ 193
7 Nucleation and Growth of Metals ............................ 195
7.1 Nucleation ............................................ 195
7.1.1 Three-dimensional nucleation ................... 195
7.1.2 Two-dimensional nucleation ..................... 197
7.1.3 Rate of nucleation ............................. 198
7.1.4 Instantaneous and progressive nucleation ....... 200
7.2 Intermediate States of Electrodeposition .............. 203
7.2.1 Crystallization overpotential .................. 203
7.3 Surface Dynamics ...................................... 205
7.3.1 Residence time in kink site positions .......... 205
7.3.2 Calculation of the residence time .............. 207
7.4 Density of Kink Site Positions ........................ 209
7.4.1 Equilibrium conditions ......................... 209
7.4.2 Deposition conditions .......................... 209
7.5 Experimental Investigations of Electrodeposition ...... 212
7.5.1 Electrodeposition on amalgam electrodes ........ 212
7.5.2 Investigations on solid electrodes ............. 212
7.5.3 Applications of electrodeposition from aqueous
solvents ....................................... 215
7.5.4 Parallel reactions ............................. 217
7.6 Deposition From Non-Aqueous Solvents .................. 217
7.6.1 Aluminum deposition from a molten salt ......... 217
7.6.2 Aluminum deposition from an organic
electrolyte .................................... 218
7.6.3 Aluminum deposition from ionic liquids ......... 219
7.7 Additives ............................................. 220
7.7.1 Adsorption, the hard-soft concept .............. 221
7.7.2 Influence of additives on deposition at
different crystallographic faces ............... 222
7.7.3 Anodic stripping to study additive behavior .... 223
7.8 Optical Spectroscopy to Study Metal Deposition ........ 223
7.8.1 Raman spectroscopy on silver in cyanide
electrolytes ................................... 224
7.8.2 Raman spectroscopy of organic additives ........ 226
8 Deposition of Alloys ....................................... 231
8.1 Deposition Potential and Equilibrium Potential ........ 231
8.2 Alloy Nucleation and Growth: The Partial Current
Concept ............................................... 232
8.3 Brenner's Alloy Classification ........................ 233
8.4 Mixed Potential Theory ................................ 234
8.5 Surface Selectivity in Alloy Deposition ............... 235
8.5.1 Kink site positions of alloys .................. 235
8.5.2 Rate of separation and residence times ......... 236
8.5.3 Residence time and structure of alloys ......... 237
8.6 Markov Chain Theory; Definition of the Probability
Matrix ................................................ 238
8.6.1 Equilibrium of the crystallization process ..... 238
8.6.2 Rate controlled processes ...................... 240
8.6.3 Determination of selectivity constants ......... 241
8.6.4 Alloy characterization by selectivity
constants ...................................... 242
8.6.5 Selectivity constants and residence times in
kink site positions ............................ 243
8.7 Experimental Examples ................................. 243
8.7.1 The cobalt-iron alloy system ................... 243
8.7.2 Cobalt-nickel .................................. 247
8.7.3 Iron-nickel .................................... 249
8.7.4 Induced electrodeposition: the NiMo system ..... 251
8.8 Ternary Systems ....................................... 258
8.8.1 Kink site positions of ternary systems ......... 258
8.8.2 The Markov chain theory for ternary systems .... 259
8.8.3 Example: prediction of the composition of
CoFeNi alloys .................................. 260
9 Oxides and Semiconductors .................................. 263
9.1 Electrochemical Properties of a Semiconductor ......... 263
9.1.1 Band model of a semiconductor .................. 263
9.1.2 Semiconductor-electrolyte contact .............. 265
9.1.3 Gap states and surface states .................. 267
9.1.4 Current-potential curves ....................... 267
9.1.5 Space-charge capacitance ....................... 270
9.2 Photoelectrochemistry of Semiconductors ............... 271
9.2.1 Photocurrents .................................. 271
9.2.2 Intensity modulated photocurrent spectroscopy
(IMPS) ......................................... 275
9.2.3 Photopotentials and photopotential transients .. 276
9.3 Spectroscopic Methods ................................. 277
9.3.1 In situ spectroscopic methods .................. 277
9.3.2 In situ X-ray diffraction (XRD) and X-ray
absorption spectroscopy (XAS) .................. 278
9.3.3 In situ Mossbauer spectroscopy ................. 280
9.3.4 Ex situ methods ................................ 280
9.4 Microscopy ............................................ 280
9.5 Oxide Particles ....................................... 282
9.5.1 Batteries ...................................... 282
9.5.2 Lithium ion batteries .......................... 283
9.5.3 TiO2-based photovoltaic cells .................. 284
9.5.4 Catalytic activity of oxide particles .......... 285
9.6 Oxide Layers .......................................... 286
9.7 Electrochemical Deposition of Semiconductors .......... 287
10 Corrosion and Corrosion Protection ......................... 291
10.1 Corrosion ............................................. 291
10.1.1 Fundamental processes .......................... 292
10.1.2 Mechanism of metal dissolution ................. 295
10.1.3 Mechanisms of compensation reactions ........... 297
10.1.4 Iron and steel ................................. 298
10.1.5 Metallurgical aspects of iron and steel ........ 299
10.1.6 Copper ......................................... 300
10.1.7 Zinc ........................................... 301
10.1.8 Corrosion products ............................. 301
10.1.9 Corrosion of alloys ............................ 302
10.2 Corrosion Protection .................................. 305
10.2.1 Passivity ...................................... 307
10.2.2 Cathodic protection ............................ 316
10.2.3 Corrosion inhibition ........................... 316
10.2.4 Phosphatizing .................................. 318
10.2.5 Chromatizing ................................... 319
10.2.6 Corrosion protection by surface coatings ....... 319
11 Intrinsically Conducting Polymers .......................... 323
11.1 Chemical Synthesis .................................... 325
11.2 Electrochemical Synthesis and Surface Film Formation .. 326
11.3 Film Formation with Adhesion Promoters ................ 329
11.4 Ion Transport During Oxidation-Reduction .............. 330
11.4.1 Analyzing oxidation-reduction cycles using
QCMB ........................................... 331
11.5 Electrical and Optical Film Properties ................ 335
11.5.1 Impedance of conducting polymers ............... 335
11.5.2 Neutral state properties ....................... 338
11.5.3 Photoelectrochemical properties ................ 339
11.5.4 Polaron-bipolaron model of conducting
polymers ....................................... 339
11.5.5 Spectro-electrochemical methods ................ 343
11.6 Copolymerization ...................................... 343
11.6.1 Mechanism of copolymerization .................. 345
11.6.2 Structure analysis of copolymers ............... 349
11.6.3 Properties of copolymers ....................... 356
11.7 Corrosion Protection by Intrinsically Conducting
Polymers .............................................. 356
11.7.1 Film formation on non-noble metals ............. 357
11.7.2 Kinetic experiments of corrosion protection .... 357
11.7.3 Role of anions for a possible corrosion
protection of conducting polymers .............. 359
12 Nanoelectrochemistry ....................................... 365
12.1 Going to Atomic Dimensions ............................ 365
12.2 Co-Deposition ......................................... 365
12.2.1 Particle dispersions ........................... 367
12.2.2 Determination of the zeta potential ............ 367
12.2.3 Factors influencing zeta potential and
particle properties ............................ 370
12.2.4 Properties of the metal surface ................ 371
12.2.5 Process parameters influencing the
incorporation .................................. 372
12.2.6 Mechanistic models ............................. 372
12.2.7 General concepts for the development of
a model ........................................ 378
12.2.8 Examples ....................................... 382
12.3 Compositionally Modulated Multi-Layers ................ 383
12.3.1 Plating of multi-layers ........................ 383
12.3.2 Examples of multi-layers ....................... 384
12.4 Core-Shell Composites ................................. 384
12.4.1 Preparation procedure .......................... 386
12.4.2 Particle characterization: applications ........ 387
Index ......................................................... 389
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