Electrolytes
Electrolytes are substances that conduct electricity when dissolved in water or melted. They are made up of ions, which are electrically charged particles. In solution, electrolytes can carry an electric current, making them essential for various biological and chemical processes, including nerve signaling and muscle contractions.
5 Key excerpts on "Electrolytes"
eBook - ePubElectrical and Electronic Devices, Circuits and Materials
Design and Applications
- Suman Lata Tripathi, Parvej Ahmad Alvi, Umashankar Subramaniam(Authors)
- 2021(Publication Date)
- CRC Press(Publisher)
...Diverse kinds of Electrolytes have been developed which can significantly advance with the electrochemical evolution of supercapacitor appliance. The electrolyte is a medium that conducts the electricity produced by the dissolution of the salt in an adequate ionizing solvent such as water. Typically, electrolyte exists within the separator and inside the active material layers. The electrolyte plays an important function in the development of the electrical double layer for EDLCs and redox reactions for a pseudocapacitor. Further, the electrolyte is an indispensable and extensive component in supercapacitors and play an incredibly vital function in transporting as well as compensating charges among the two electrodes. The key factors for an electrolyte are wide potential window to attain high energy density, higher ionic concentrations, small ohmic resistance, and small viscosities, which affect the power densities of the SCDs. Therefore, the electrolyte has a unique importance in SCDs as the energy and power density normally rely on the operating potential window of supercapacitor, which is determined by the electrolyte. A good quality electrolyte is described by an extensive voltage window, concentration of ions, low solvated ionic radii, small volatility, temperature coefficient, low resistivity, low viscosity, less toxicity, high electrochemical stability, and low cost [ 19 ]. In general, Electrolytes are classified into three groups, viz., liquid electrolyte, solid-state electrolyte, and redox-active electrolyte [ 28 ]. Each electrolyte has its own merits and disadvantages. Among these, the liquid electrolyte can be further classified into two types, namely, aqueous Electrolytes and non-aqueous Electrolytes, of which the aqueous one is the most extensively employed in the literature because of its high ionic conductivity and excellent safety properties...
eBook - ePub- Orjan G. Martinsen, Sverre Grimnes(Authors)
- 2014(Publication Date)
- Academic Press(Publisher)
...When the exchangeable ions do start to emerge from the end of the column, the column has become completely saturated. The column may be regenerated by passing through it a solution of the ions that it originally contained. 2.3.2. Special Electrolytes Some substances are completely ionized in water (strong acids) whereas others are only partly ionized (e.g., weak acids). Water is often necessary for the ionization or molecule split; for example, pure HCl liquid is an insulator. Many substances dissolved in water are not ionized at all; therefore, they do not contribute to electric conductivity. They are true nonElectrolytes, such as sugar/glucose. The molecules of such substances are not split up (ionized, dissociated) by water. Some may have a symmetrical distribution of charges, with the center of positive and negative charge coinciding. However, many molecules have centers not coinciding, forming permanent dipoles with zero net charge—such substances are called polar. Water itself is polar, and a substance must actually be polar to be soluble in water. NaCl as a dry salt at room temperature is not an electrolyte. The DC conductance is negligible; still, the Na and Cl atoms are ionized, but they are “frozen” so that they cannot migrate. NaCl dissolved in water is the true electrolyte, and the Na + and Cl – are split and free. Even if NaCl is the true electrolyte, the whole electrolyte solution is often also called just the electrolyte. Electrolyte Classification In a solution with colloidal particles, a charged double layer will surround each particle, and the particle may be regarded as a macro-ion. The colloidal particles free to migrate contribute to the solution's electrical DC conductance, and they may be regarded as a colloidal electrolyte. Particles are called colloidal when two of the dimensions are in the range of 1 nm to 1 μm (the third dimension does not have this constraint; e.g., a very thin string). A solid electrolyte is also possible...
eBook - ePubEnergy Storage
A New Approach
- Ralph Zito, Haleh Ardebili(Authors)
- 2019(Publication Date)
- Wiley-Scrivener(Publisher)
...Liquid Electrolytes can be either aqueous or non-aqueous. Solid Electrolytes are usually either polymers or ceramics. Figure 10.1 Electrolyte classification. In this chapter, we will focus mainly on the Electrolytes associated with three main electrochemical energy storage systems, specifically, batteries, supercapacitors and fuel cells. Although there are many common aspects about the ESMs used in these three devices, there are also several differences including their specific chemistry, ionic species, and morphology that will be addressed in later discussions. Before we start an in-depth discussion of electrolyte types for specific energy storage devices, let us take a look at two important and basic electrolyte properties, namely, ion conductivity and the transference number. 10.2 Ionic Conductivity Ionic conductivity is arguably one of the most important properties of an electrolyte. In simple terms, it represents how fast and how much of the charged ions can pass through the material. Fundamentally, ion conductivity, σ, can be expressed as (10.1) where n i is the concentration of ionic species (m -3), z i is the charge of the ions (C), and m i is the mobility of the ions (m 2 s –1 volt –1). The ion conductivity in SI units is represented in Siemens per meter (S/m). Siemens (S) is the reciprocal of ohm, which is the unit of resistance or impedance. In the past, conductivity was represented in terms of “mho” (ohm spelled backward). A quick verification of the final unit from Equation 10.1, reveals the resulting units based on the individual parameters as coulomb sec -1 volt -1 meter -1, which simplifies to its equivalent, ampere volt -1 meter -1 or ohm -1 meter -1, and finally, represented as S/m. 10.2.1 Measurement Techniques Ionic conductivity can be determined through several methods. If the mobility and concentration of the specific ions are known or can be directly measured, then the ionic conductivity can be determined through Equation 10.1...
- Jung-Ki Park, Jung-Ki Park(Authors)
- 2012(Publication Date)
- Wiley-VCH(Publisher)
...3.3 Electrolytes An electrolyte acts as a medium for the movement of ions and commonly consists of a solvent and salt. Molten Electrolytes are also possible. Liquid Electrolytes are formed from organic solvents and solid Electrolytes are derived from inorganic compounds or polymers, while polymer Electrolytes are prepared from polymers and salts. PolyElectrolytes are also considered polymer Electrolytes. In general, the term “electrolyte solution” is used to refer to liquid Electrolytes. The electrodes of lithium ion batteries use materials capable of lithium intercalation/deintercalation and are separated by a membrane before being immersed in a liquid electrolyte. The liquid electrolyte transports lithium ions from anode to cathode during charging, and vice versa. Porous electrodes with a transition metal oxide and carbon as an active material are used for the cathode and anode of lithium secondary batteries. As such, the electrolyte not only supplies lithium ions by permeating into the micropores but also exchanges lithium ions at the surface of active materials. The working voltage and energy density of lithium secondary batteries are determined by the cathode and anode materials. The choice of electrolyte is also important since high ionic conductivity between electrodes is essential for high-performance batteries. Table 3.5 shows the characteristics of Electrolytes in lithium secondary batteries. (1) Liquid Electrolytes with lithium salt dissolved in an organic solvent have been widely used since the 1970s when lithium primary batteries were first developed. Most lithium secondary batteries available today use organic Electrolytes. (2) Ionic liquid Electrolytes are comprised of molten salts with a melting point below room temperature and used together with lithium salts. Due to the absence of a combustible and flammable organic solvent, they are known to produce safer batteries...
- Mary Anna Thrall, Glade Weiser, Robin W. Allison, Terry W. Campbell, Mary Anna Thrall, Glade Weiser, Robin W. Allison, Terry W. Campbell(Authors)
- 2022(Publication Date)
- Wiley-Blackwell(Publisher)
...25 Laboratory Evaluation of Electrolytes Andrea A. Bohn Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA Evaluation of electrolyte concentrations is often used to assess severity of disease and guide treatment but can also aid in the diagnosis of disorders. Electrolytes are present in all intracellular and extracellular body fluids, but we typically measure their concentration in blood, plasma, or serum. The serum electrolyte concentration may not accurately reflect the balance of that particular electrolyte within the whole body, especially for Electrolytes that are predominantly intracellular. Sodium and chloride are the Electrolytes whose concentrations are greatest in extracellular fluid (ECF). The concentration of potassium, calcium, phosphorus, and magnesium are highest in intracellular fluid (ICF). Maintaining the intra‐ and extracellular concentration of each electrolyte within narrow limits is essential to life. Intake of all of the Electrolytes is via the oral route. The common organs that are important in maintaining all serum electrolyte levels are the gastrointestinal (GI) system and the kidneys. Additional regulatory mechanisms as well as the consequences and causes of imbalances for each individual electrolyte will be covered when each electrolyte is discussed in more detail. Sodium Sodium has many important functions, including maintaining normal blood pressure and volume and maintaining normal function of muscles and nerves. These functions are dependent on keeping plasma sodium concentrations within a narrow range. The concentration of sodium in the blood is predominantly a balance between what is consumed in food and drink and what is excreted in urine...
