Battery technology active materials

Redox flow batteries, under development since the early 1970s, are stUl of interest primarily for utility load leveling applications (77). Such a battery is shown schematically in Figure 5. Unlike other batteries, the active materials are not contained within the battery itself but are stored in separate tanks. The reactants each flow into a half-ceU separated one from the other by a selective membrane. An oxidation and reduction electrochemical reaction occurs in each half-ceU to generate current. Examples of this technology include the iron—chromium, Fe—Cr, battery (79) and the vanadium redox cell (80). 

Practically every battery system uses carbon in one form or another. The purity, morphology and physical form are very important factors in its effective use in all these applications. Its use in lithium-ion batteries (Li-Ion), fuel cells and other battery systems has been reviewed previously [1 -8]. Two recent applications in alkaline cells and Li-Ion cells will be discussed in more detail. Table 1 contains a partial listing of the use of carbon materials in batteries that stretch across a wide spectrum of battery technologies and materials. Materials stretch from bituminous materials used to seal carbon-zinc and lead acid batteries to synthetic graphites used as active materials in lithium ion cells. 

The active material comprises the substances that constitute the charge-discharge reaction. In the positive electrode of lead-acid batteries, the active material in the charged state is lead dioxide (PbOj), which is converted into lead sulfate (PbS04) when the electrode is discharged. The active material is the most essential part of a battery, and battery technology has to aim at optimum constitution and performance for the expected application. This does not only concern the chemical composition but also the physical structure and its stability. Specialized methods have been developed to fulfill these requirements, and the primary products as well as the manufacturing process are usually specified by the individual battery manufacturer. 

These technologies have one point in common. Unlike the technologies presented hitherto, in these batteries, the electrodes are liquid and are separated by a solid membrane. In the operation of many batteries, the active material will not occupy the same volume in different states of charge. The successive charges and discharges impose mechanical stresses on the electrodes, which are one of the causes of degradation on the scale of the components and, consequently, aging of the element. With liquid electrodes, these phenomena of volumetric expansion/contraction disappear. 

Goodenough JB (2013) Battery components, active materials for. In Brodd RJ (ed) Batteries for sustainability selected entries from the encyclopedia of sustainability science and technology. Springer Sci, New York, NY, pp 51-92... 

A battery system closely related to Na—S is the Na—metal chloride cell (70). The cell design is similar to Na—S however, ia additioa to the P-alumiaa electrolyte, the cell also employs a sodium chloroalumiaate [7784-16-9J, NaAlCl, molten salt electrolyte. The positive electrode active material coasists of a transitioa metal chloride such as iroa(Il) chloride [7758-94-3] EeQ.25 or nickel chloride [7791-20-0J, NiQ.25 (71,72) in Heu of molten sulfur. This technology is in a younger state of development than the Na—S. 

Masset P, Guidotti RA (2008) Thermal activated ( thermal ) battery technology Part Ilia FeS2 cathode material. J Power Sources 177 595-609... 

Said subjects are being analyzed in this work. Also, the authors have attempted to show that in order to be suitable for lithium-ion applications, a carbon-based active material has to meet a complex number of physicochemical and electrochemical characteristics. A simple check of galvanostatic behavior, which is often used today to conclude about carbon s suitability for lithium-ion battery technology, is rarely enough for making an accurate assessment. 

Most battery systems employ carbon materials in one form or another, as noted in Table 10.1. The use of carbon materials in batteries stretches across a wide spectrum of battery technologies. The variety of carbon runs the gamut from bituminous materials, used to seal carbon-zinc and carbon black powders in lead acid batteries, to high performance synthetic graphites, used as active materials in lithium-ion cells. The largest use is as a conductive diluent to enhance the performance of cathode materials. In many instances, it is used as a conductive diluent for poorly conducting cathode materials where carbon blacks, such as acetylene black, are preferred. It is essential that... 

Within a given line of battery technology, energy and power density typically are inversely related. Increasing the energy density requires maximization of active electrode material mass per battery mass and thus requires minimization of the amount of additional components (such as current collector, conductive additives, or void space for optimizing electronic and ionic connectivity within an electrode material, see Section 3.5.5), most of which are beneficial for increased power densities. 

Nickel-hydrogen batteries (Ni/T ) were developed in 1970 for aerospace applications. These batteries are a combination of the Ni-Cd technology (Ni electrode) and the fuel-cell technology (H2 electrode). They use nickel hydroxide as cathode active material, a hydrogen electrode as anode, and an aqueous solution of potassium hydroxide as electrolyte. Asbestos (fuel-cell grade asbestos paper) and Zircar (untreated knit ZYK-15 Zircar cloth) are used... 

Both the anode and the cathode are composed of a coating of the electrochemically active material onto a current collector (copper or aluminum). Another key component of the battery is the separator that physically separates the two electrodes and prevents contact between them. In the case of a liquid technology battery, a polyolefin separator is typically used and a liquid electrolyte is used to transport the Li ions from one side of the porous separator to the other. In the case of a polymer Li ion battery, a polymer, such as PVDF, is used to form a porous structure, which is then swollen with a Li" " conducting liquid electro-lyte. " This results in a gel-type electrolyte, which plays the dual role of electrolyte and separator, with no free liquid present. 

The application of nanocrystalline metal oxides in sensor devices is now well-established, and should produce benefits in terms of improved sensitivity and speed of response. On a similar note, nanomaterials have become increasingly important in battery technology, particularly in the development of lithium solid-state batteries [106, 303, 304]. Nanocrystalline oxides offer many advantages in SOFCs, primarily by increasing the surface area of the materials and hence the catalytic activity [305, 306], and this is especially important for lowering the cell s operating temperature. Overall, however, it remains clear that further research into the... 

DSC and TG were used for quality control of the materials and the technological processes during battery manufacture, Matrakova and Pavlov presented the results of an investigation on lead-acid battery pastes and active materials, aimed to estimate the efficiency of the two thermal methods for the analysis and the control of the processes taking place during battery production and operation [190]. 

The capacity and cycle life of the battery depend greatly on the structure of the active materials. Hence, it was important to examine the structure of the two types of active masses and to elucidate how it was formed during the technological process of plate manufacture. 

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