Liquid cathodes

Liquid Cathode Cells. Liquid cathode cells were discovered at almost the same time as the successful soHd cathode cells. A strongly oxidising hquid such as SO2, was deterrnined to be suitable for direct contact with the strongly reducing lithium, because an excellent passivating film forms... 

An inspection of Tables 1 and 2 shows that appropriate solvents for lithium batteries mainly belong to classes 6 and 7 and include cyclic (EC, PC) and open-chain (DMC, MEC, DEC, MPC) esters and ethers (DIOX, DME, THF) as well as inorganic sulfur compounds (S02, SOCl2). These sulfur compounds are mainly used as liquid cathode materials, simultaneously serving as solvents (S02C12, SOCl2) or cosolvents (S02) in primary or secondary lithium batteries. Recent developments of solvents include... 

Liquid cathode lithium cells, 3 464-466 Liquid chromatography, 4 618—620 6 375, 440-468 14 233. See also High performance liquid chromatography Ion chromatography applications, 4 625-626 6 457-465 brief overview, 6 384-388 column switching, 6 446-447 columns, 4 623 derivatization, 6 447—448 detectors, 4 622-623 6 386-387, 448 52... 

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... 

The energy density of liquid cathode lithium cells can be further enhanced to over 500 Wh/kg (1000 Wh/dm3) by the use of halogen additives. BrCl, added to lithium-thionyl chloride cells, boosts the OCV to 3.9 V and prevents the formation of sulphur in the early stages of discharge. D-sized cells are manufactured, Addition of chlorine to lithium-sulphur yl chloride cells increases the energy density and improves the temperature-dependent electrical characteristics. 

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

One variant of the liquid cathode reserve battery is the lithium-water cell in which water serves as both the liquid cathode and the electrolyte. A certain amount of corrosion occurs, but sufficient lithium is provided to compensate. These cells are mostly used in the marine environment where water is available or compatible with the cell reaction product. Common applications are lor torpedo propulsiuu and to puwer sonobuoys and submersihles. 

The lithium sulfur dioxide and the lithium thionyl chloride systems are specialty batteries. Both have liquid cathode reactants where the electrolyte solvent is the cathode-active material. Both use polymer-bonded carbon cathode constructions. The Li-S02 is a military battery, and the Li-SOCl2 system is used to power automatic meter readers and for down-hole oil well logging. The lithium primary battery market is estimated to be about 1.5 billion in 2007. 

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... 

Oxyhalide solvents include solvents such as thionylchloride (SOCl2), sulfurile chloride (S02C12), and POCl3, which are also utilized as liquid cathodes in primary Li batteries. The basic reduction process of thionyl chloride may be illustrated as... 

Table 2 lists oxyhalide solvents that may all be utilized as liquid cathodes for Li, Ca, or Mg primary batteries, along with some of their physical properties. 

Table 2 Representative List of Oxyhalide and Thiohalide Solvents and Some of Their Physical Properties (interesting as liquid cathodes and solvents for primary Li, Ca and Mg batteries)... 

S02 is used both as a liquid cathode for Li batteries [52] and as a nonaqueous solvent for the study of electrochemical reactions. Bard et al. made an extensive study of the electrochemical reactions in S02-based solutions at low temperature and under critical conditions [53,54], The basic cathodic reaction of this solvent is... 

The most used liquid metal pool electrode is the aluminum cathode (m.p. 660°C) in the Hall-Heroult aluminum extraction cell. Alkali metals and alkaline-earth metals are also used as liquid cathodes in their molten salt extraction processes. 

Commercial Cells with Liquid Cathodic Materials. 91... 

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