Electrolyte Overview

Electrolytes play an important role in overall ES performance. They exert critical effects on the development of the double-layer and accessibility of pores to electrolyte ions. Normally, electrolyte-electrode interactions and the ionic conductivity of the electrolyte play a significant role in internal resistance. Poor electrolyte stability at different cell operating temperatures and poor chemical stability at high rates can further increase resistances within an ES and reduce cycle life. 

Basic Properties of Available Organic and Aqueous Solvents for ESs 

Solvent Melting Point (°C) Viscosity (Pa-si) Dielectric Constant (s) 

Source Inagaki, M., H. Koimo, and O. Tanaike. 2010. Journal of Power Sources, 195, 7880-7903. With permission. 

Electrolyte Resistances and Voltages of Various Electrolyte Solutions at Room Temperature 

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Encyclopedia of Electrochemical Power Sources, Vol. 5, K. Xu, Secondary batteries—Lithium recharagable systems Electrolytes Overview, in G. Jurgen (Ed.), pp. 51-70, Copyright 2009, with permission from Elsevier.)... 

A logical division is made for the adsorption of nonelectrolytes according to whether they are in dilute or concentrated solution. In dilute solutions, the treatment is very similar to that for gas adsorption, whereas in concentrated binary mixtures the role of the solvent becomes more explicit. An important class of adsorbed materials, self-assembling monolayers, are briefly reviewed along with an overview of the essential features of polymer adsorption. The adsorption of electrolytes is treated briefly, mainly in terms of the exchange of components in an electrical double layer. 

By the time the next overview of electrical properties of polymers was published (Blythe 1979), besides a detailed treatment of dielectric properties it included a chapter on conduction, both ionic and electronic. To take ionic conduction first, ion-exchange membranes as separation tools for electrolytes go back a long way historically, to the beginning of the twentieth century a polymeric membrane semipermeable to ions was first used in 1950 for the desalination of water (Jusa and McRae 1950). This kind of membrane is surveyed in detail by Strathmann (1994). Much more recently, highly developed polymeric membranes began to be used as electrolytes for experimental rechargeable batteries and, with particular success, for fuel cells. This important use is further discussed in Chapter 11. 

The composition of body fluids remains relatively constant despite the many demands placed on the body each day. On occasion, these demands cannot be met, and electrolytes and fluids must be given in an attempt to restore equilibrium. The solutions used in the management of body fluids discussed in this chapter include blood plasma, plasma protein fractions, protein substrates, energy substrates, plasma proteins, electrolytes, and miscellaneous replacement fluids. Electrolytes are electrically charged particles (ions) that are essential for normal cell function and are involved in various metabolic activities. This chapter discusses the use of electrolytes to replace one or more electrolytes that may be lost by the body. The last section of this chapter gives a brief overview of total parenteral nutrition (TPN). 

The influence of interfaeial potentials (diffusion or liquid junction potentials) established at the boundary between two different electrolyte solutions (based on e.g. aqueous and nonaqueous solvents) has been investigated frequently, for a thorough overview see Jakuszewski and Woszezak [68Jak2]. Concerning the usage of absolute and international Volt see preceding chapter. 

Sol-gel techniques have been widely used to prepare ceramic or glass materials with controlled microstructures. Applications of the sol-gel method in fabrication of high-temperature fuel cells are steadily reported. Modification of electrodes, electrolytes or electrolyte/electrode interface of the fuel cell has been also performed to produce components with improved microstructures. Recently, the sol-gel method has expanded into inorganic-organic hybrid membranes for low-temperature fuel cells. This paper presents an overview concerning current applications of sol-gel techniques in fabrication of fuel cell components. 

An overview about more than 10 years of R D activities on solid electrolyte interphase (SEI) film forming electrolyte additives and solvents at Graz University of Technology is presented. The different requirements on the electrolyte and on the SEI formation process in the presence of various anode materials (metallic lithium, graphitic carbons, and lithium storage metals/alloys are particularly highlighted. 

H. J. Santner, M. R. Wagner, G. Fauler, P. Raimann, C. Veit, K. C. Moller, J. O. Besenhard, M. Winter (2003). An Overview on SEI Formation Processes of Lithium Battery Anodes in Organic Solvent Based Electrolytes, Taipei Power Forum and Exhibition (TPF2003), December 1-3, 2003, Taipei (Taiwan) Invited lecture. 

Several companies now market readily assembled parallel-plate electrolytic devices. The sizes range from 16 to 21 m2 of flat-plate electrodes. An excellent modern overview on ... 

In addition to the overview of models that are used for adsorption at the oxide-electrolyte interface, examples for the application of these models were discussed. It has been stated that there is a great deal of uncertainty associated with models of the oxide-electrolyte interface, and, in the opinion of the author, it is better to cast uncertainty in terms of a simple model than in terms of a complex model. 

There are fewer studies devoted to the electrochemistry of silicon in alkaline electrolytes than is the case for HF. This can partly be ascribed to the fact that pore formation is not observed in alkaline electrolytes, which limits the field of applications. This section gives a brief overview of the characteristic features of I-V curves of silicon electrodes in alkaline electrolytes. 

Fig. 17.6 (a) Overview of processes and typical time constants under working conditions (1 sun) in a Ru-dye-sensitized solar cell with iodide/triiodide electrolyte. Recombination processes are indicated by red arrows. Reprinted with permission from [30]. Copyright 2010, American Chemical Society. Electron transport across nanostructured semiconductor films (b) in the absence and (c) in the presence of a nanotube support architecture. Reprinted with permission from [38]. Copyright 2007, American Chemical Society. 

The objective of this chapter is to study some essential practical aspects, which have to be considered. First, as necessary background information, the different alternatives for electrochemical cell operation are discussed in general. Then follows an overview of properties of electrode materials, electrolyte components, and cell separators. Finally, examples of cell constructions are shown. 

In addition to the function as reaction medium - as in all chemical reactions - in electrochemical processes, the electrolyte has to provide the transport of ions between the electrodes. An optimal combination of solvent and supporting electrolyte has to be found, considering the reaction conditions and the properties of reactants, products, and electrodes. A short overview of usual electrolytes - and some examples of unconventional electrolytes as thought-provoking impulse for research - is given... 

Polymer electrolyte fuel cells (PEFC) deliver high power density, which offers low weight, cost, and volume. The immobilized electrolyte membrane simplifies sealing in the production process, reduces corrosion, and provides for longer cell and stack life. PEFCs operate at low temperature, allowing for faster startups and immediate response to changes in the demand for power. The PEFC system is seen as the system of choice for vehicular power applications, but is also being developed for smaller scale stationary power. For more detailed technical information, there are excellent overviews of the PEFC (1,2). 

This chapter reviews the underlying principles of ion chromatography and its application in pharmaceutical analysis. It provides an overview of eluent systems, applications of gradients, electrolytic eluent generation, suppressors, and stationary phases. Applications of ion chromatography to the confirmation of counter ions, active ingredient analysis, competitive analysis and development work are discussed. 

The purpose of the present review is to summarize the current status of fundamental models for fuel cell engineering and indicate where this burgeoning field is heading. By choice, this review is limited to hydrogen/air polymer electrolyte fuel cells (PEFCs), direct methanol fuel cells (DMFCs), and solid oxide fuel cells (SOFCs). Also, the review does not include microscopic, first-principle modeling of fuel cell materials, such as proton conducting membranes and catalyst surfaces. For good overviews of the latter fields, the reader can turn to Kreuer, Paddison, and Koper, for example. 

Abiotic transformation of contaminants in subsurface natural waters result mainly from hydrolysis or redox reactions and, to lesser extent, from photolysis reactions. Complexation with natnral or anthropogenic ligands, as well as differential volatilization of organic compounds from multicomponent hquids or mixing with toxic electrolyte aqueous solutions, may also lead to changes in contaminant properties and their environmental effects. Before presenting an overview of the reactions involved in contaminant transformations, we discuss the main chemical and environmental factors that control these processes. 

Polar organic solvents with electrolytes such as sodium p-toluenesulfonate are compatible with capillary electrophoresis. Background electrolyte need not be an aqueous solution. [P. B. Wright, A. S. Lister, and J. G. Dorsey, Behavior and Use of Nonaqueous Media Without Supporting Electrolyte in Capillary Electrophoresis and Capillary Electrochromatography, Anal. Chem. 1997, 69, 3251 I. E. Valko, H. Siren, and M.-L. Riekkola, Capillary Electrophoresis in Nonaqueous Media An Overview, LCGC 1997, 15, 560.]... 

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