New lithium-air cell could make car recharging obsolete
July 27, 2009
Could new technology out of Japan's science and technology research institute give Better Place's battery swapping plan a new option?
Two Japanese researchers said they’ve developed a new type of large capacity, lithium-air cell that holds promise in car batteries.
The plan from the Japanese researchers calls for an electric car driver to exchange one type of electrolyte in a battery cell for a new air electrode when the battery runs low. The person wouldn't have to wait for the batteries to be recharged, much like a plan being touted by Better Place that would allow drivers to swap out batteries at filling stations (see Hawaii becomes next stop for Better Place).
A battery, which converts chemical energy to electrical energy, is made of voltaic cells. Each voltaic cell consists of cells connected by a conductive electrolyte that contains anions (negatively-charged ions) and cations (positively-charged ions).
The researchers note that one current problem with lithium-ion batteries is that a solid reaction product (Li2O or Li2O2), which is not soluble in an organic electrolyte, clogs on the air electrode in the discharge process.
According to the study, an organic electrolyte was used on the negative electrode side and an aqueous electrolyte was used on the cathode (air) side. The two electrolytes were separated by a solid state electrolyte, so that the two electrolytic solutions didn’t mix.
Lithium ions only passed through the solid electrolyte, and the battery reactions occurred smoothly in the study. At the cathode, the reaction product in the discharge process was water soluble, and no solid substances were produced.
The team was researchers Yonggang Wang and Haoshen Zhou. Zhou is the chief researcher of Tsukuba, Japan-based Energy Interface Technology Group and the Energy Technology Research Institute of the National Institute of Advanced Industrial Science and Technology.
The study's results were first presented at an Electrochemical Society of Japan meeting held in Kyoto in March.
The Japanese team, however, isn’t the first to be exploring the air-cell concept. Funded by the Engineering and Physical Sciences Research Council, researchers at the Scotland’s University of St. Andrews with partners at Strathclyde and Newcastle are developing a new type of air-fueled battery that could give up to 10 times the energy storage of designs currently available.
In January, Staefa, Switzerland-based ReVolt Technology raised an additional $13.1 million toward its Series B funding to develop rechargeable zinc-air batteries (see ReVolt plans for zinc-air battery to trump Li-ion with $13M in funding). The company said its rechargeable batteries avoid problems in lithium-ion batteries of thermal runway, in which batteries can become overheated and combust.
cleantech.com |
