Lithium carbon monofluoride battery

The lithium carbon monofluoride battery ( lithium graphite fluoride battery ) is a non-rechargeable lithium battery with lithium as the anode (negative pole in batteries) and graphite fluoride as the cathode (positive pole). It is used, for example, in cardiac pacemakers.

Since pure carbon monofluoride conducts electricity poorly, some soot is added; a few percent of a styrene-butadiene rubber serve as a binder. As electrolyte , a mixture of is propylene carbonate and dimethoxyethane with lithium tetrafluoroborate , LiBF ₄ , lithium perchlorate LiClO ₄ , or lithium hexafluorophosphate LiPF ₆ used as a conducting salt.

properties

The open circuit voltage of the battery is 3.0 V and the typical load voltage is 2.6 V. The practical energy density for button cells is approx. 400 mWh / cm ³ and for cylindrical round cells 450–500 mWh / cm ³ . It is particularly suitable for devices with low power requirements and long periods of use. The capacity of the battery depends on the degree of fluorination of the cathode. In practice, 100% fluorination is not aimed for, because graphite fluoride would then be an insulator.

Since the self-discharge is small, the battery can be stored for a long time.

Electrochemistry

During the discharge process, lithium is anodically oxidized to lithium ions (Li ⁺ ), releasing electrons . Graphite fluoride serves as an acceptor half-cell . The lithium ions formed are embedded in the graphite fluoride lattice. The overall equation can be formulated as follows:

${\displaystyle \mathrm {n\ Li+(CF)_{n}\rightarrow (CLiF)_{n}} }$

The end products are formed through decomposition of the intercalation compound lithium fluoride and carbon .

Historical

The lithium carbon monofluoride battery was developed by a Japanese company ( Matsushita Electric Industrial Co. , now known as Panasonic ), which received a patent for it in 1970. Since 1976 the battery has been used in space travel. The application in pacemakers was developed in the 1990s and came onto the market in the following decade.

Individual evidence

1. ^ MS Whittingham, Lithium Batteries and Cathode Materials, Chem. Rev. 104 (2004) 4273
2. ↑ N. Watanabe, M. Fukuda, U.S. Patent 3,536,532, Primary Cell for Electric Batteries
3. ^ W. Greatbatch, CF Holmes, ES Takeuchi, SJ Ebel, Lithium / carbon monofluoride (Li / CFx): a new pacemaker battery, Pacing Clin. Electrophysiol. 19 (11) (1996) 1836-1840
4. ↑ EaglePicher Medical Power Announces New Li / CFx Battery Technology ( Memento of the original from September 24, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 

literature

• Günter Eichinger, Günter Semrau: Lithium batteries II - discharge reactions and complete cells . In Chemie in our time 24, No. 2, ISSN  0009-2851 , 1990, pp. 90-96

Web links

• PatentDE: Batteries with organic electrolytes