Electrochemical Aspects of Ionic Liquids E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 666

Veröffentlichungsjahr: 2011

Beschreibung

The second edition is based on the original book, which has been revised, updated and expanded in order to cover the latest information on this rapidly growing field. The book begins with a description of general and electrochemical properties of ionic liquids and continues with a discussion of applications in biochemistry, ionic devices, functional design and polymeric ionic liquids.

The new edition includes new chapters on Li ion Batteries and Actuators, as well as a revision of existing chapters to include a discussion on purification and the effects of impurities, adsorption of ionic liquids on interfaces and on the electrochemical double layer, among other topics.

Leseprobe

Table of Contents

Cover

Table of Contents

Title page

Copyright page

PREFACE TO THE SECOND EDITION

PREFACE TO THE FIRST EDITION

ACKNOWLEDGMENTS FOR THE SECOND EDITION

CONTRIBUTORS

1 IMPORTANCE AND POSSIBILITY OF IONIC LIQUIDS

1.1 IONIC LIQUIDS

1.2 IMPORTANCE OF IONIC LIQUIDS

1.3 POTENTIAL OF IONIC LIQUIDS

2 PHYSICAL CHEMISTRY OF IONIC LIQUIDS: INORGANIC AND ORGANIC AS WELL AS PROTIC AND APROTIC

2.1 CLASSES OF IONIC LIQUIDS

2.2 LOW-TEMPERATURE LIQUID BEHAVIOR OF IONIC MELTS

2.3 MELTING POINTS AND THE LATTICE ENERGY

2.4 RELATION BETWEEN ELECTRICAL CONDUCTIVITY AND LOW VAPOR PRESSURE

2.5 COHESION AND FLUIDITY: THE TRADE-OFF

2.6 PROTON TRANSFER IONIC LIQUIDS AS NOVEL FUEL CELL ELECTROLYTES

2.7 IONICITY AND ACIDITY OF PILS: THE PROTON FREE ENERGY LEVEL DIAGRAM

2.8 COMPARISON OF HIGHEST-CONDUCTING ORGANIC AND INORGANIC IONIC LIQUIDS

2.9 CONCLUDING REMARKS

ACKNOWLEDGMENTS

Part I: BASIC ELECTROCHEMISTRY

3 GENERAL TECHNIQUES

3.1 EQUIPMENT

3.2 PREPARATION OF ELECTROLYTES

3.3 WORKING ELECTRODES

3.4 REFERENCE ELECTRODES

4 ELECTROCHEMICAL WINDOWS OF ROOM-TEMPERATURE IONIC LIQUIDS (RTILs)

4.1 INTRODUCTION

4.2 EFFECTS OF THE MEASUREMENT CONDITIONS ON THE VOLTAMMETRY IN THE RTILS

4.3 MUTUAL COMPARISONS OF ELECTROCHEMICAL WINDOWS OF RTILS

4.4 CONCLUSION

5 DIFFUSION IN IONIC LIQUIDS AND CORRELATION WITH IONIC TRANSPORT BEHAVIOR

5.1 DIFFUSION AND DIFFUSIVITY—FUNDAMENTAL ASPECTS

5.2 THE PROCESSES OF DIFFUSION IN LIQUIDS

5.3 SELF-DIFFUSION AND IONIC TRANSPORT IN IONIC LIQUIDS

5.4 PULSED-GRADIENT SPIN-ECHO (PGSE)-NMR FOR MEASUREMENTS OF SELF-DIFFUSION COEFFICIENTS

5.5 IONIC LIQUIDS FOR DIFFUSION STUDIES AND IONIC TRANSPORT BEHAVIOR

5.6 SELF-DIFFUSION COEFFICIENT AND ITS CORRELATION WITH VISCOSITY

5.7 MOLAR CONDUCTIVITY AND ITS CORRELATION WITH DIFFUSION COEFFICIENT

5.8 CONCLUSIONS

ACKNOWLEDGMENTS

6 IONIC CONDUCTIVITY

7 OPTICAL WAVEGUIDE SPECTROSCOPY

7.1 INTRODUCTION

7.2 ANALYSIS OF REDOX REACTIONS IN IONIC LIQUID

8 ELECTROLYTIC REACTIONS

8.1 CELL DESIGN

8.2 ELECTROLYTIC METHOD

8.3 SELECTIVE ANODIC FLUORINATION

8.4 ELECTROCHEMICAL POLYMERIZATION

8.5 ELECTROCHEMICAL FIXATION OF CO2

8.6 ELECTROREDUCTION OF CARBONYL COMPOUNDS

8.7 ELECTROREDUCTIVE COUPLING USING METAL COMPLEX CATALYSTS

8.8 ANODIC OXIDATION OF ALCOHOLS AND AROMATIC COMPOUNDS

8.9 OTHER DEVELOPMENTS

8.10 CONCLUSION

9 ELECTRODEPOSITION OF METALS IN IONIC LIQUIDS

9.1 CHLOROALUMINATE IONIC LIQUIDS

9.2 NONCHLOROALUMINATE IONIC LIQUIDS

Part II: BIOELECTROCHEMISTRY

10 ENZYMATIC REACTIONS

10.1 GEOTRICHUM CANDIDUM-CATALYZED SYNTHESIS OF OPTICALLY ACTIVE ALCOHOLS IN AN IONIC LIQUID

10.2 OPTICAL RESOLUTION BY BIOCATALYTIC OXIDATION

10.3 DERACEMIZATION OF RACEMIC SECONDARY ALCOHOLS WITH CHEMOENZYMATIC METHOD

10.4 IMPROVEMENT OF FLUORINATION REACTION WITH IMMOBILIZED FLUORINASE

11 MOLECULAR SELF-ASSEMBLY IN IONIC LIQUIDS

11.1 MOLECULAR SELF-ASSEMBLIES IN AQUEOUS AND IN ORGANIC MEDIA

11.2 EARLY STUDIES OF THE FORMATION OF MICELLES AND LIQUID CRYSTALS IN IONIC LIQUIDS

11.3 SUGAR-PHILIC IONIC LIQUIDS: DISSOLUTION OF CARBOHYDRATES AND FORMATION OF GLYCOLIPID BILAYER MEMBRANES, IONOGELS

11.4 CHARGED BILAYER MEMBRANES IN IONIC LIQUIDS

11.5 CONTROL OF IONOPHILIC–IONOPHOBIC INTERACTIONS AND GENERALIZATION OF MOLECULAR SELF-ASSEMBLIES IN IONIC LIQUIDS

11.6 SUMMARY, UPDATES AND OUTLOOK

12 SOLUBILIZATION OF BIOMATERIALS INTO IONIC LIQUIDS

12.1 POLAR IONIC LIQUIDS AS SOLVENTS FOR CELLULOSE

12.2 NOVEL SOLVENT FOR DISSOLUTION OF NATIVE PROTEIN: HYDRATED IL

12.3 SOLUBILIZATION METHOD OF PROTEINS IN IL: POLYETHER MODIFICATION

12.4 NONAQUEOUS BIOFUEL CELLS

13 REDOX REACTION OF PROTEINS

13.1 PEO MODIFIED PROTEIN

13.2 NATIVE PROTEIN IN HYDRATED IL

Part III: IONIC DEVICES

14 LI BATTERIES

14.1 INTRODUCTION

14.2 SAFETY ASPECTS OF LI-ION BATTERY CONCERNING THE ADVANTAGE OF USE OF IONIC LIQUIDS

14.3 SOME EXAMPLES FOR APPLICATION TO LI-ION BATTERIES

14.4 RECENT TOPICS AFTER THE FIRST EDITION PUBLISHED

14.5 SUMMARY AND FUTURE VIEW

15 PHOTOELECTROCHEMICAL CELLS

15.1 INTRODUCTION

15.2 PARAMETERS FOR THE PERFORMANCE EVALUATION OF PEC CELLS

15.3 IONIC LIQUIDS USED AS AN IN-VOLATILE SOLVENT

15.4 QUASI SOLID-STATE DSSC SYSTEM USING RTILS BASED ON IODIDE

15.5 RECENT PROGRESS

15.6 SUMMARY

16 FUEL CELLS

17 DOUBLE-LAYER CAPACITORS

17.1 INTRODUCTION

17.2 OUTLINE OF DOUBLE-LAYER CAPACITORS

17.3 REQUIREMENTS FOR ELECTROLYTE MATERIALS

17.4 FUNDAMENTAL PROPERTIES OF IONIC LIQUIDS

17.5 PERFORMANCES OF IONIC LIQUIDS IN DOUBLE-LAYER CAPACITORS

17.6 RECENT PROGRESS

17.7 CONCLUDING REMARKS

18 ACTUATORS

Part IV: FUNCTIONAL DESIGN

19 NOVEL FLUOROANION SALTS

20 NEUTRALIZED AMINES

20.1 REQUIREMENT OF EASY PREPARATION

20.2 NEUTRALIZATION METHOD

20.3 EFFECT OF ION SPECIES ON THE PROPERTIES OF NEUTRALIZED AMINES

20.4 IONIC CONDUCTIVITY

20.5 MODEL SYSTEMS FOR ORDINARY QUATERNIZED ONIUM SALTS

20.6 CONCLUSION

21 ZWITTERIONIC LIQUIDS

22 ALKALI METAL IONIC LIQUIDS

22.1 ALKALI METAL IONIC LIQUID

22.2 GELATION OF ALKALI METAL IONIC LIQUID

22.3 TRIPLE ION-TYPE IMIDAZOLIUM SALT

22.4 CONCLUSION

23 POLYETHER/SALT HYBRIDS

23.1 ANOTHER IONIC LIQUID

23.2 DESIGN OF POLYETHER/SALT HYBRIDS

23.3 IMPROVEMENT OF IONIC CONDUCTIVITY

23.4 POLYMERIZED PEO/SALT HYBRIDS

23.5 POLYETHER/ALMINATE OR BORATE SALT HYBRIDS

23.6 ANION CONDUCTIVE POLYETHER/SALT HYBRID

23.7 CONCLUSION

24 ELECTRIC CONDUCTIVITY AND MAGNETIC IONIC LIQUIDS

24.1 NEUTRAL DA CHARGE TRANSFER COMPLEX

24.2 CATION RADICAL SALTS WITH LOW MELTING POINT

24.3 TCNQ ANION RADICAL SALTS WITH LOW MELTING POINT

24.4 EMI SALTS CONTAINING COMPLEXES WITH PARAMAGNETIC METALS

Part V: IONIC LIQUIDS IN ORDERED STRUCTURES

25 ION CONDUCTION IN ORGANIC IONIC PLASTIC CRYSTALS

25.1 INTRODUCTION

25.2 PLASTIC CRYSTAL PHASES—BACKGROUND

25.3 SYNTHESIS AND THERMAL PROPERTIES OF IONIC PLASTIC CRYSTAL ELECTROLYTES

25.4 CONDUCTIVITY IN ORGANIC IONIC PLASTIC CRYSTALS

25.5 TRANSPORT MECHANISMS IN PLASTIC CRYSTAL PHASES

25.6 DEVELOPING AREAS OF RESEARCH

25.7 CONCLUDING REMARKS

26 LIQUID CRYSTALLINE IONIC LIQUIDS

26.1 LIQUID CRYSTALLINE IONIC LIQUIDS BY THE CHEMICAL MODIFICATION OF IONIC LIQUIDS

26.2 SELF-ASSEMBLY OF IONIC LIQUIDS WITH LIQUID CRYSTAL MOLECULES

26.3 ANISOTROPIC IONIC CONDUCTIVITIES OF IONIC LIQUID CRYSTALS

26.4 RELATED MATERIALS

26.5 SUMMARY

Part VI: GEL-TYPE POLYMER ELECTROLYTES

27 IONIC LIQUID GELS

27.1 GELATION OF IONIC LIQUIDS BY LOW MOLECULAR WEIGHT GELATORS

27.2 CONDUCTIVITY OF IONIC LIQUID GELS

27.3 POLYMER GELS OF IONIC LIQUIDS

28 ZWITTERIONIC LIQUID/POLYMER GELS

29 IONIC LIQUIDIZED DNA

29.1 DNA

29.2 IONIC LIQUIDIZED DNA

29.3 REDOX REACTION OF DYE MOLECULES IN THE IONIC LIQUIDIZED DNA

Part VII: POLYMERIZED IONIC LIQUIDS

30 ION CONDUCTIVE POLYMERS

30.1 POLYCATIONS

30.2 POLYANIONS

31 AMPHOTERIC POLYMERS

31.1 COPOLYMERS

31.2 POLY(ZWITTERIONIC LIQUID)S

32 POLYMER BRUSHES

Part VIII: CONCLUSION

33 FUTURE PROSPECTS

APPENDIX: STRUCTURES OF ZWITTERIONS

Index

Copyright © 2011 by John Wiley & Sons, Inc. All rights reserved

Published by John Wiley & Sons, Inc., Hoboken, New Jersey

Published simultaneously in Canada

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Library of Congress Cataloging-in-Publication Data:

Electrochemical aspects of ionic liquids / edited by Hiroyuki Ohno.

p. cm.

 Includes bibliographical references and index.

 ISBN 978-0-470-64781-3 (cloth); ISBN 978-1-118-00334-3 (ePub)

 1. Ionic solutions. 2. Electrochemistry. 3. Polymerization. I. Ohno, Hiroyuki, 1953–

 QD562.I65E38 2011

 541′.372–dc22

2010034796

PREFACE TO THE SECOND EDITION

The first edition of this book was published in 2005 as the first book on the basic study and application of the ionic liquids for electrochemical aspects. At this time, there is increasing interest in ionic liquids as an electrolyte solution substituent. In particular, interests are focused on the safety of the organic ion conductive liquids. Despite the safety of ionic liquids, there is still hesitation in using these ionic liquids as an electrolyte solution. This might be caused by two major reasons, one is cost, and the other is the great possibility of the development of better ionic liquids. The former is actually important for industry, but it should also be a matter of demand. Larger demand lowers the price. The second reason is a bit serious, because there is always the possibility of finding or developing new and better ionic liquids. There should be a kind of hesitation in deciding on the industrial use of current ionic liquids, because no one can deny that there is the possibility that better ones will emerge. In any case, it should be most important to develop ionic liquids having sufficient properties for practical use. Understanding of the latest in ionic liquid science is important to provide motivation for researchers to use them.

In the second edition, we considerably updated the content to catch up with the fast changes in ionic liquid science. Also, interesting new chapters have been added. In every chapter, we tried to add the latest information while keeping the number of pages as low as possible. It will be one of our great pleasures if readers find some interesting point regarding ionic liquid science that aids in their research.

HIROYUKI OHNO

PREFACE TO THE FIRST EDITION

This book introduces some basic and advanced studies on ionic liquids in the electrochemical field. Although ionic liquids are known by only a few scientists and engineers, their applications’ potential in future technologies is unlimited. There are already many reports of basic and applied studies of ionic liquids as reaction solvents, but the reaction solvent is not the only brilliant future of the ionic liquids. Electrochemistry has become a big field covering several key ideas such as energy, environment, nanotechnology, and analysis. It is hoped that the contributions on ionic liquids in this book will open other areas of study as well as to inspire future aspects in the electrochemical field. The applications of ionic liquids in this book have been narrowed to the latest results of electrochemistry. For this reason only the results on room-temperature ionic liquids are presented, and not on high-temperature melts.

The reader of this book should have some basic knowledge of electrochemistry. Those who are engaged in work or study of electrochemistry will get to know the great advantages of using ionic liquids. Some readers may find the functionally designed ionic liquids to be helpful in developing novel materials not only in electrochemistry but also in other scientific fields. This book covers a wide range of subjects involving electrochemistry. Subjects such as the solubilization of biomolecules may not seem to be necessary for electrochemistry concerning ionic liquids, but some readers will recognize the significance of solubility control of functional molecules in ionic liquids even in an electrochemical field. Many more examples and topics on ionic liquids as solvents have been summarized and published elsewhere, and the interested reader will benefit from studying the references that are provided at the end of each chapter.

HIROYUKI OHNO

ACKNOWLEDGMENTS FOR THE SECOND EDITION

First of all, I would like to express my sincere thanks to all the contributors for the second edition. All authors kindly agreed to reuse their chapters and made an effort to put the latest information in every chapter. A new chapter has been added in the second edition for better reviewing in electrochemistry.

Next an acknowledgment should be given to Dr. Naomi Nishimura of the Department of Biotechnology, Tokyo University of Agriculture and Technology. Naomi worked hard to help me to edit manuscripts. She was so systematic that there were no serious problems in the editing of the manuscript. Without her energetic contribution, this book would not be published by the due date.

Finally I would like to thank Dr. Arza Seidel of John Wiley and Sons, Inc. for her kind support and encouragement.

HIROYUKI OHNO

CONTRIBUTORS

C. Austen Angell, Department of Chemistry and Biochemistry, Arizona State University

Younes Ansari, Department of Chemistry and Biochemistry, Arizona State University

Kinji Asaka, National Institute of Advanced Industrial Science and Technology (AIST)

Jean-Philippe Belieres, Department of Chemistry and Biochemistry, Arizona State University

Maria Forsyth, Department of Materials Engineering, Monash University

Toshio Fuchigami, Department of Electronic Chemistry, Tokyo Institute of Technology

Kyoko Fujita, Department of Biotechnology, Tokyo University of Agriculture and Technology

Masahiro Yoshizawa-Fujita, Department of Materials and Life Sciences, Sophia University

Yukinobu Fukaya, Department of Biotechnology, Tokyo University of Agriculture and Technology

Dominic Gervasio, Center for Applied Nanobioscience in the BioDesign Institute and School of Materials, Arizona State University

Rika Hagiwara, Department of Fundamental Energy Science, Kyoto University

Kenji Hanabusa, Graduate School of Science and Technology, Shinshu University

Akitoshi Hayashi, Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University

Shinsuke Inagi, Department of Electronic Chemistry, Tokyo Institute of Technology

Noritaka Iwai, Department of Bioengineering, Tokyo Institute of Technology

Yasushi Katayama, Department of Applied Chemistry, Faculty of Science and Technology, Keio University

Takashi Kato, Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo

Nobuo Kimizuka, Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University

Tomoya Kitazume, Department of Bioengineering, Tokyo Institute of Technology

Pierre Lucas, Department of Chemistry and Biochemistry, Arizona State University

Douglas R. MacFarlane, School of Chemistry, Monash University

Hajime Matsumoto, Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Industrial Science and Technology (AIST)

Kazuhiko Matsumoto, Graduate School of Energy Science, Kyoto University

Tomonobu Mizumo, Department of Applied Chemistry, Hiroshima University

Takuya Nakashima, Graduate School of Materials Science, Nara Institute of Science and Technology

Asako Narita, Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University

Naomi Nishimura, Department of Biotechnology, Tokyo University of Agriculture and Technology

Akihiro Noda, Honda R & D Co., Ltd.

Wataru Ogihara, Nissan Motor Co., Ltd.

Hiroyuki Ohno, Department of Biotechnology, Tokyo University of Agriculture and Technology

Jennifer M. Pringle, Department of Materials Engineering and School of Chemistry, Monash University

Gunzi Saito, Research Institute, Meijo University

Hikari Sakaebe, Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Industrial Science and Technology (AIST)

Md. Abu Bin Hasan Susan, Department of Chemistry, University of Dhaka

Jeffery Thomson, Center for Applied Nanobioscience in the BioDesign Institute and School of Materials, Arizona State University

Makoto Ue, Fellow, Mitsubishi Chemical Corporation

Kazuhide Ueno, Department of Chemistry and Biochemistry, Arizona State University

Marcelo Videa, Department of Chemistry and Biochemistry, Arizona State University

Masayoshi Watanabe, Department of Chemistry and Biotechnology, Yokohama National University

Xu Wu, Department of Chemistry and Biochemistry, Arizona State University

Masafumi Yoshio, Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo

Zuofeng Zhao, Department of Chemistry and Biochemistry, Arizona State University

1

IMPORTANCE AND POSSIBILITY OF IONIC LIQUIDS

HIROYUKI OHNO

1.1 IONIC LIQUIDS

Ionic liquids are salts with a very low melting temperature. Ionic liquids have been of great interest recently because of their unusual properties as liquids. Because these unique properties of ionic liquids have been mentioned in a few other books, we will not repeat them here but will summarize them in Table 1.1. Note that these are entirely different properties from those of ordinary molecular liquids. Also, every ionic liquid does not always show these properties. For electrochemical usage, the most important properties should be both nonvolatility and high ion conductivity. These are essentially the properties of advanced (and safe) electrolyte solutions that are critical to energy devices put in outdoor use.

TABLE 1.1. Basic and Possible Characteristics of Organic Ionic Liquids

Low melting point• Treated as liquid at ambient temperature • Wide usable temperature rangeNonvolatility• Thermal stability • Flame retardancyComposed by ions• High ion density • High ion conductivityOrganic ions• Various kinds of salts • Designable • Unlimited combinations

Safety is a more important issue than performance these days, and it has been taken into account in the materials developed for practical use. Thus, more developments in ionic liquids are expected in the future. The nonvolatile electrolyte solution will change the shape and performance of electronic and ionic devices. These devices will become safer and have longer operational lives. They are composed of organic ions, and these organic compounds have unlimited structural variations because of the easy preparation of many different components. So there are unlimited possibilities open to the new field of ionic liquids. The most compelling idea is that ionic liquids are “designable” or “fine-tunable.” Therefore, we can easily expect explosive developments in fields using these remarkable materials.

1.2 IMPORTANCE OF IONIC LIQUIDS

Ionic liquids are salts that melt at ambient temperature. The principles of physical chemistry involved in the great difference between solution properties of molecular solvents and molten salts have already been introduced and summarized in several books. Thousands of papers have already been published on their outstanding characteristics and effectiveness for a variety of fields. Thus, as mentioned, in this book, we take the most important point that these salts are composed of organic ions and explore the unlimited possibility of creating extraordinary materials using molten salts.

Because ionic liquids are composed of only ions, they usually show very high ionic conductivity, nonvolatility, and flame retardancy. The organic liquids with both high ionic conductivity and flame retardancy are practical materials for use in electrochemistry. At the same time, the flame retardancy based on nonvolatility inherent in ion conductive liquids opens new possibilities in other fields as well. Because most energy devices can accidentally explode or ignite, for motor vehicles there is plenty of incentive to seek safe materials. Ionic liquids are being developed for energy devices. It is therefore important to have an understanding of the basic properties of these interesting materials. The ionic liquids are multipurpose materials, so there should be considerable (and unexpected) applications. In this book we, however, will not venture into too many other areas. Our concern will be to assess the possible uses of ionic liquids in electrochemistry and allied research areas.

1.3 POTENTIAL OF IONIC LIQUIDS

At present, most interest in ionic liquids is centered on the design of new solvents. Although the development of “new solvents” has led the development of possible applications for ionic liquids, there is more potential for development of electrochemical applications.

Electrochemistry basically needs two materials: electroconductive materials and ion conductive materials. Ionic liquids open the possibility of improving ion conductive materials. The aqueous salt solution is one of the best electrolyte solutions for electrochemical studies. However, because water is volatile, it is impossible to use this at a wide temperature range or on a very small scale. Many other organic polar solvents have been used instead of water to prepare electrolyte solutions. They, however, have more or less the same drawback, depending on the characteristics. The material known to be a nonvolatile ion conductor is the polymer electrolyte. Polymers do not vaporize but decompose at higher temperatures; the vapor pressure at ambient temperature is zero. Polymer electrolytes are considered a top class of electrolytes except for the one drawback: relatively low ionic conductivity.

One remarkable propertie of ionic liquids is the proton conduction at a temperature higher than 100 °C. Water-based proton conductors cannot be operated at such a high temperature because of vaporization of water. As mentioned in a later chapter, proton-conductive ionic liquids are the most expected materials.

Some literature has included statements that the ionic liquids are thermally stable and never decompose. This kind of statement has led to a misunderstanding that the ionic liquids are never vaporized and are stable even when on fire. Are the ionic liquids indestructable? The answer is “no.” However, although inorganic salts are entirely stable, the thermal stability of organic salts depends largely on their structure. Because ionic liquids are organic compounds, their degradation begins at the weakest covalent bond by heating. Nevertheless, ionic liquids are stable enough at temperatures of 200 °C to 300 °C. This upper limit is high enough for ordinary use.

Does it need more energy or cost to decompose ionic liquids after finishing their role? It is not difficult to design novel ionic liquids that can be decomposed at a certain temperature or by a certain trigger. It also is possible to design unique catalysts (or catalytic systems) that can decompose target ionic liquids. Some catalysts such as metal oxides or metal complexes have the potential to become excellent catalysts for the decomposition of certain ionic liquids under mild conditions. The post-treatment technologies of ionic liquids should therefore be developed along with the work on the design of ionic liquids.

At the present time there has been little progress in this area. Although post-treatment technologies are beyond the scope of this book, we do attempt to give ideas on the various future developments in ionic liquid technologies as well as in electrochemistry. This book is dedicated to introducing, analyzing, and discussing ionic liquids as nonvolatile and highly ion conductive electrolyte solutions. The astute reader will find the future prospects for ionic liquids between the lines in all chapters of this book.