Lithium-sulfur dioxide cell

Lithium-silicates, 12 577 15 142 22 452 in adhesives and binders, 22 472 solutions of, 22 465 Lithium soap greases, 15 243 Lithium sulfate, 15 142 Lithium-sulfur dioxide cells, 3 464-466 characteristics, 3 462t speciality for military and medical use, 3 430t... 

Lithium—sulfur dioxide cells also use a liquid cathode construction. The SO2 is dissolved in an organic solvent such as PC or acetonitrile. Alternatively, SO2 is pressurized at several bars to use it in the liquid state. The cell reaction is similar to that depicted in Figure 18, with electronically insulating... 

Liquid Cathode Cells. Liquid cathode cells include lithium-sulfur dioxide cells and lithium-thionyl chloride cells. 

Li/S02 Cells Lithium/sulfur dioxide cells (Li/SC>2) are perhaps one of the most advanced lithium battery systems. They belong to the soluble cathode cells category. Liquid SO2 is used as cathode a lithium foil is used as anode, and lithium bromide dissolved in acetonitrile is used as electrolyte. The active cathode material is held on an aluminum mesh with... 

Lithium Primary Cells, Liquid Cathodes, Fig. 1 Lithium/sulfur dioxide cell... 

When discussing cathodes for primary cells, it is important to make a distinction between solid materials, mentioned above, and those in which the cathode electrochemical component is not in the physical electrode structure, but rather exist in a liquid or gas state. Examples include zinc air cells, lithium thionyl chloride cells, and lithium sulfur dioxide cells. In each case, the physical cathode stmcture serves as a catalytic reaction... 

Figure 18.20 Retention of capacity of lithium/sulfur dioxide cells during storage at various temperatures (Duracell).

Figure 18.22 Pressure drop in lithium/sulfur dioxide cells during discharge at various temperatures (from P. Bro).

Leclanche or dry cell Alkaline Cell Silver-Zinc Reuben Cell Zinc-Air Fuel Cell Lithium Iodine Lithium-Sulfur Dioxide Lithium-Thionyl Chloride Lithium-Manganese Dioxide Lithium-Carbon Monofluoride... 

Both the lithium sulfur dioxide (Li-SO and lithium thionyl chloride (Li-SOCy cells may be classified as liquid cathode systems. In these systems, S02 and SOCl2 function as solvents for the electrolyte, and as the active materials at the cathode to provide voltage and ampere capacity. As liquids, these solvents permeate the porous carbon cathode material. Lithium metal serves as the anode, and a polymer-bonded porous carbon is the cathode current collector in both systems. Both cells use a Teflon-bonded acetylene black cathode structure with metallic lithium as the anode. The Li-S02 is used in a spirally wound, jelly-roll construction to increase the surface area and improve... 

The BA5590 consists of 10 lithium sulfur dioxide (Li/SOa) D cells wired in a cardboard container which also contains diodes, electrical and thermal fuses, a connector, and a resistor with a manual switch to fully discharge the battery prior to disposal. When flesh, each battery contains the following materials ... 

The cells of lithium-sulfur dioxide system are largely similar to thionyl chloride-lithium cells. Similar to thionyl chloride, liquefied SO2 can simultaneously play the role of an oxidant and a solvent. However, the vapor pressure over liquefied SO2 is much higher than the vapor pressure over thionyl chloride, and dielectric permeability of SO2 is, on the contrary, lower than that of thionyl chloride. It is for this reason that the solvent used is not pure SO2, but its mixture with acetonitrile or acetonitrile and propylene carbonate. The lithium salt used is commonly bromide and, in some variants, chloroaluminate, perchlorate, tetrafluoroborate, orhexafluoroarsenate. 

The main current-producing reaction is described by Equation (11.11). The product of this reaction is lithium dithionite that is insoluble in the electrolyte. Therefore, a reasonable porous cathode structure is of great importance for provision of high capacity and power characteristics of sulfur dioxide-lithium cells. The cathodes in such cells are similar to cathodes of thionyl chloride-lithium cells. The cells of the "lithium-sulfur dioxide" system are also produced using the rammed and wound coil designs. Porous polypropylene is applied as a separator. 

Batteries for implantable medical devices are hermetically sealed. Hermetic seals have long been used for certain cell types, like lithium-sulfur dioxide and lithium-thionyl chloride, where long shelf life is important, or exposure to corrosive and toxic materials could result if the cell leaks. 

Experiments to develop this type of cell began in the 1960s and led to the Lithium-sulfur dioxide... 

Lithium primary batteries with liquid cathodes are a relatively mature technology. Incremental improvements in capacity and performance may occur through design modifications and the use of new materials such as improved carbons in the passive cathode. The U.S. Army is adopting Lithium/Manganese Dioxide replacements for some of the Lithium/Sulfur Dioxide Batteries listed in Table 1 in certain applications. These replacements provide higher capacity and energy at room temperature but not at lower temperature. See the chapter on Lithium Primary Cells Solid Cathodes in this work. 

The present situation is made easier by the comparably low turnover of lithium batteries. Partly batteries are disposed of as harmless in normal sanitary landfills (like primary lithium/manganese dioxide cells), partly more active systems are brought to special landfills (like lithium/sulfur dioxide together with neutralizing amounts of limestone), and partly batteries are burned in special ovens in combination with oil (like lithium/thionylchloride batteries). 

The Jet Propulsion Laboratory (Pasadena, CA) has evaluated several types of lithium primary batteries to determine their ability to operate planetary probes at temperatures of -80°C and below. Individual cells were evaluated by discharge tests and Electrochemical Impedance Spectroscopy. Of the five types considered (Li/SOCl2, Li/S02, Li/Mn02, Li-BCX and Li-CFn), lithium-thionyl chloride and lithium-sulfur dioxide were found to provide the best performance at -SOT. Lowering the electrolyte salt to ca. 0.5 molar was found to improve performance with these systems at very low temperatures. In the case of D-size Li/ SOCI2 batteries, lowering the LiAlCl4 concentration from 1.5 to 0.5 molar led to a 60% increase in capacity on a baseline load of 118 ohms with periodic one-minute pulses at 5.1 ohms at -85 C. 

TABLE 14.9 Typical Lithium/Sulfur Dioxide Cylindrical Cells (SAFT American, Inc.). ... 

This section focuses on four of the most commercially important cells of both classes of Li primaries two of the most common sohd cathode types,lithium manganese dioxide (Li-Mn02) and lithium carbon monoflouride (Li-(CF) ), and two of the most common liquid cathode types, lithium thionyl chloride (Li-SOCh) and lithium sulfur dioxide (Li-S02). 

These researches opened the door to the fabrication and commercialization of varieties of primary hthium batteries since the late l%0s nonaqueous hthium cells, especially the 3-V primary systems, have been developed. These systems include lithium-sulfur dioxide (Li//S02) cehs, lithium-polycarbon monofluoride (Li//(CF t) ) cells introduced by Matsuschita in 1973, lithium-manganese oxide (Li//Mn02) cells commercialized by Sanyo in 1975, lithium-copper oxide (Li//CuO) cells, lithium-iodine (Li//(P2VP)1J cells. During the same period, molten salt systems (LiCl-KCl eutecticum) using a Li-Al alloy anode and a FeS cathode were introduced [1]. The lithium-iodine battery has been used to power more than four million cardiac pacemakers since its introduction in 1972. During this time the lithium-iodine system has established a record of reliability and performance unsurpassed by any other electrochemical power source [18]. 

Sulfur dioxide is soluble in the electrolyte. Sulfur is soluble up to about 1 mol dm 3, but it precipitates in the cathode pores near the end of discharge. Lithium chloride is essentially insoluble and precipitates on the surfaces of the pores of the carbon cathode, forming an insulating layer which terminates the operation of cathode-limited cells [37],... 

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