{"id":4951,"date":"2011-11-26T21:44:23","date_gmt":"2011-11-27T04:44:23","guid":{"rendered":"http:\/\/cafe.foundation\/blog\/?p=4951"},"modified":"2014-02-12T15:01:34","modified_gmt":"2014-02-12T22:01:34","slug":"better-batteries-fluoride-not-just-for-toothpaste-anymore","status":"publish","type":"post","link":"http:\/\/cafe.foundation\/blog\/better-batteries-fluoride-not-just-for-toothpaste-anymore\/","title":{"rendered":"Better Batteries: Fluoride \u2013 Not Just for Toothpaste Anymore"},"content":{"rendered":"

At Germany\u2019s Karlsruhe Institute of Technology (KIT),\u00a0researchers have developed a new concept for rechargeable batteries. \u00a0Based on a fluoride shuttle \u2013 the transfer of\u00a0fluoride anions between the electrodes \u2013 it promises to enhance the storage\u00a0capacity reached by lithium-ion batteries by several factors. \u00a0Operational safety is also increased, as it\u00a0can be done without lithium. The fluoride-ion battery is presented for the\u00a0first time in a paper <\/a>in the Journal of Materials Chemistry<\/em> by Dr. Maximilian\u00a0Fichtner, Head of the Energy Storage Systems Group, and Dr. Munnangi Anji Reddy.<\/p>\n

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Showing "shuttle" of cations, anions between electrodes in fluoride battery. Courtesy KIT.<\/p><\/div>\n

\u201cIn search of new\u00a0concepts to build batteries with high energy densities, electrochemical cells based on metal fluorides may be promising. Herein, we report the demonstration\u00a0of secondary battery cells based on fluoride shuttle. \u00a0In fluoride ion batteries, [a] fluoride anion\u00a0<\/a>(negatively-charged ions moving toward the positive electrode) acts as charge\u00a0transfer ion between a metal\/metal fluoride pair where it will react with metal\u00a0or evolve from metal fluoride depending on the flow of current.\u201d<\/p>\n

Presenting on day\u00a0two of the Detroit Battery Show<\/a>, the researchers gave promise to\u00a0the concept of a radically lighter, more powerful cell type.<\/p>\n

The researchers noted that \u201cLithium-ion batteries are applied\u00a0widely, but their storage capacity is limited. \u201c\u00a0 Future mobile systems (airplanes, for\u00a0 instance), will need lighter, more energy dense batteries to be viable.<\/p>\n

KIT\u2019s press release explains further.\u00a0 \u201cMetal fluorides may be applied as conversion\u00a0materials in lithium-ion batteries. They also allow for lithium-free batteries\u00a0with a fluoride-containing electrolyte, a metal anode, and metal fluoride\u00a0cathode, which reach a much better storage capacity and possess improved safety\u00a0properties. Instead of the lithium cation <\/a>(positively-charged ions moving\u00a0toward the negative electrode), the fluoride anion takes over charge transfer.\u00a0\u00a0At the cathode and anode, a metal fluoride is formed or reduced. \u00a0\u2018As several electrons per metal atom can be\u00a0transferred, this concept allows to reach extraordinarily high energy densities\u00a0\u2013 up to ten times as high as those of conventional lithium-ion batteries,\u2019 [says] Dr. Fichtner.<\/p>\n

\u201cThe KIT researchers\u00a0are now working on the further development of material design and battery\u00a0architecture in order to improve the initial capacity and cyclic stability of\u00a0the fluoride-ion battery. Another challenge lies in the further development of\u00a0the electrolyte: The solid electrolyte applied so far is suited for applications\u00a0at elevated temperatures only. It is therefore aimed at finding a liquid electrolyte that is suited for use at room temperature.\u201d<\/p>\n

Supporting data for\u00a0KIT’s findings can be found here<\/a>.<\/p>\n

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