Solid-cathode lithium primary cells

Li2S204 being the SEI component at the Li anode and the solid discharge product at the carbon cathode. The Li—SOCI2 and Li—SO2 systems have excellent operational characteristics in a temperature range from —40 to 60 °C (SOCI2) or 80 °C (SO2). Typical applications are military, security, transponder, and car electronics. Primary lithium cells have also various medical uses. The lithium—silver—vanadium oxide system finds application in heart defibrillators. The lithium—iodine system with a lithium iodide solid electrolyte is the preferred pacemaker cell. 

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. 

Several types of primary batteries have been developed that use lithium-metal anodes and solid cathodes. This entry reviews the more common commercial systems, namely Li-FeS2, Li-MnOa, and Li-CFx- Readers are referred to the relevant sections for information on Li-V20s and Li-Ag2V40ii cells that are used for reserve and medical battery applications, respectively. There has been a wide range of cathodes developed in the laboratory and also marketed for specialty applications [1], but most have never been produced commercially. (Li-CuO cells were made for some military applications [2], but production was discontinued in the mid-1990s). Before going into details on the aforementioned three types mostly used in consumer applications, we will cover the main characteristics that they have in common. 

Lithium batteries use nonaqueous solvents for the electrolyte because of the reactivity of lithium in aqueous solutions. Organic solvents such as acetonitrile, propylene carbonate, and dimethoxyethane and inorganic solvents such as thionyl chloride are typically employed. A compatible solute is added to provide the necessary electrolyte conductivity. (Solid-state and molten-salt electrolytes are also used in some other primary and reserve lithium cells see Chaps. 15, 20, and 21.) Many different materials were considered for the active cathode material sulfur dioxide, manganese dioxide, iron disulfide, and carbon monofluoride are now in common use. The term lithium battery, therefore, applies to many different types of chemistries, each using lithium as the anode but differing in cathode material, electrolyte, and chemistry as well as in design and other physical and mechanical features. 

Solid Electrolytes. A protected Lithium anode is under development for both primary and secondary batteries that promise much larger capacities. This strategy is illustrated by the Li/seawater primary battery in which a Lithium anode is immersed in a nonaqueous electrolyte, the anolyte, that is separated from seawater contacting a cathode current collector by a Li -ion solid-electrolyte separator. The seawater acts as a liquid cathode. Except for contact with a negative post, the Lithium anode and its anolyte are sealed in a compartment containing a Li -ion solid-electrolyte wall that interfaces the seawater. The anolyte is chemically stable to both the Lithium and the solid electrolyte the solid electrolyte must not be reduced on contact with the Li anode. Moreover, eiflier the seal or the compartment must be compliant to allow for the change in volume of the Lithium on discharge. The seawater is not ccmtained in an open cell, it is contained within a battery in a closed cell. The LF ions from the anode react with water at the cathode current collector ... 

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... 

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