Daniel: Building on the work of researchers at Singapore’s Institute of Bioengineering and Nanotechnology, Japanese company Aqua Power Systems have released a rechargeable battery that runs on any electrolyte-containing liquid including juice, beer, saliva and … urine. All pee-related jokes aside, this novel invention has great potential as an environmentally friendly replacement for current unfriendly mercury, cadmium etc power cells in everything from mp3 players to clock radios. Using a combination of magnesium and carbon separated by electrolyte-soaked paper the batteries produce around 500mAh (milli-amp hours) of power, on a par with existing zinc batteries, although less than alkaline at 1200-1700mAh. The Nopopo (No Pollution Power) is available in standard AA and AAA and the only downer is that they’re currently only available in Japan. So next time you go to the toilet you might want to check whether your batteries are charged up!