I’m not a big fan of Coke, unless it’s for cleaning metal. However, a student at St Martins College in London has designed a mobile phone battery that is powered by sugary fizzy drinks. The bio battery uses the glucose in drinks such as Coca Cola, which are then reduced to hydrogen molecules using enzymes. Passing them accross an anothode and cathode creates the power. The by product is plain old water.
As yet bio batteries do not have the power to actually allow the mobile to make a call, but developments in the techonolgy are rapidly improving and it should be possible to use the fuel within a few years.