Now that's what I call a really cool idea, an air-fuelled battery for the ever popular iPhone. Actually, it is more than an idea, this is a development with legs. University researchers in the UK, funded by the Engineering and Physical Sciences Research Council (EPSRC) have designed something called the STAIR cell.
The STAIR, short for St Andrews Air (the University of St Andrews is the lead researcher on the project) battery uses oxygen drawn from thin air to produce a reaction within porous carbon to create the electrical charge.
The good news being that this pretty green and clean device can theoretically last around ten times as long as current battery technologies. According to the boffins at EPSRC the new design has the potential to "improve the performance of portable electronic products and give a major boost to the renewable energy industry" mainly because it can "enable a constant electrical output from sources such as wind or solar, which stop generating when the weather changes or night falls."
Even better news, the STAIR cell should be cheaper than current rechargeable batteries as the main new component is constructed from porous carbon which is much less expensive that lithium cobalt oxide which it replaces in current battery designs. The University of St Andrews design replaces the lithium cobalt oxide electrode with a porous carbon electrode and allows Li+ and e- in the cell to react with oxygen from the air. Initial results from the project found a capacity to weight ratio of 1,000 milli-amp / hours per gram of carbon (mA/hours/g), while recent work has obtained results of up to 4,000 mA/hours/g.
The research project has been running for two years, and has another two to run. It builds on the discovery that the particular carbon component’s interaction with air can be repeated, creating a cycle of charge and discharge.
Principal investigator on the project, Professor Peter Bruce of the Chemistry Department at the University of St Andrews, told us "Our target is to get a five to ten fold increase in storage capacity, which is beyond the horizon of current lithium batteries. Our results so far are very encouraging and have far exceeded our expectations."
The STAIR cell should be available commercially within five years, and the first products will be aimed at small applications such as the iPhone. Certainly it should be a lot cooler than an iPhone battery which sets fire to your pants!