Lithium-carbon monofluoride cell

The lithium/carbon monofluoride cell possesses very high theoretical (2260 Wh/ kg) and practical energy densities [26], The cathode material is made by the reaction of carbon with fluorine. The overall reaction is... 

The design principle of lithium/carbon monofluoride cells is comparable to that of the LiMn02 cells. The cathode however uses as its active material the said carbon monofluoride. The reaction scheme... 

Lithium carbon monofluoride cells are manufactured as button cells, also as ultra-thin discs, as round cells, or as small pins . Such pins (e.g. with a diameter of 2.2 mm, a length of 115 mm) are used for fishing line floats. The round cells are mostly designed as bobbin cells for low rate applications. 

Figure 18.11 Discharge graphs of lithium/carbon monofluoride cells (C size) depending on the load (Matsushita).

Table 9.11 Characteristics cf lithium. -carbon monofluoride cells ...

Lithium-carbon monofluoride cells are available in capacities below lAh although attempts arc now in progress to produce larger cells. 

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... 

Linden, D. 1995. Lithium/carbon monofluoride [(Li/(CF)J cells. In Handbook of batteries fuel cells, 2nd ed. D. Linden (Ed.). New York McGraw-Hill. 14.59. 

The semiconductive properties and tunnel structure of sulfide and transition-metal oxides led to the use of these materials in lithium power sources (Table 2.5). Several lithium-based chemistries were successfully applied to replace the prior system Zn/AgO and later the lithium-iodine batteries in implantable medical devices [59-61]. For example, Li//CuO, Li//V205, Li//CF and more recently Li// Ag2V40ii couples have been adopted to power cardiac pacemakers requiring less that 200 pW [62,63]. The lithium/carbon monofluoride (Li//CFJ primary cells are very attractive in several applications because of the double energy density with respect to the state-of-the-art LiZ/MnOa primary batteries (theoretically 2203 against 847 Wh kg ). 

Some of the earliest concepts came from Japan, where Matsuchita developed the Li/(CF) battery that was used, for example, in fishing floats. Lithium fluoride and carbon are the final reaction products, but the cell potential of 2.8—3.0 V suggests a different electrochemical reaction. It was proposed that lithium initially intercalates the carbon monofluoride lattice and subsequently the lithium fluoride is formedF Li + (CF)n — L CF)n C + LiF. Although much work... 

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. 

The active components of the cell are lithium for the anode and polycarbon monofluoride (CF) for the cathode. The value of is typically 0.9 to 1.2. Carbon monofluoride is an interstitial compound, formed by the reaction between carbon powder and fluorine gas. While electrochemically active, the material is chemically stable in the organic electrolyte and does not thermally decompose up to 400" C, resulting in a long storage life. Different electrolytes have been used typical electrolytes are lithium hexafluorarsenate (LiAsFg) in S-butyrolactone (GBL) or lithium tetrafluoroborate (LiBFJ in propylene carbonate (PC) and dimethoxyethane (DME). 

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