A Portable Battery That Runs on Saltwater – or Urine

MetalCell MetalCell gives gives soldiers a charge anywhere. All they need is a little saltwater – or in a pinch, some urine.

If you've got an electronic device, you need power either in the form of a cable or a battery. If you've got a battery, you still need a means of charging it. And if you're in the military, you know that you never have exactly what you need exactly when you need it. Which is why South Korean battery makers have created the MetalCell, a magnesium battery based on 2,000-year-old technology that can be charged with saltwater or, barring that, urine.

MetalCell was designed with militaries in mind; on the modern battlefield, soldiers rely on a growing array of electronics to execute their missions, but when operating in remote areas or cut off from support, those devices can run out of juice at inopportune moments. But MetalCell can sit in the back of a Humvee, in a remote bunker, or in a locker at a forward operating base for years, waiting to power up electrical devices in a pinch.