Israeli chemists have come up with the first rechargeable battery made from magnesium--a less expensive, more environmentally friendly and safer metal than those used in current systems. Better yet, the researchers expect that the magnesium battery's energy density could be made considerably higher than what is possible in common lead-acid and nickel-cadmium batteries. They describe their invention in today's issue of Nature.

The new battery from Doron Aurbach and his colleagues at Bar-Ilan University follows the same basic blueprint for any battery--including an anode, cathode and conducting electrolyte. The anode is made from magnesium, as is the case in some existing, one-life military batteries. But the other two elements represent the advance. Because of magnesium's particular chemistry, most electrolytes ruin the anode's surface, but Aurbach and his team use solutions based on magnesium organohaloaluminate salts that don't create the same surface films. And the cathode is made from MgxMo3S4 (where x is a number between zero and one), which unlike most other cathode materials can reversibly bind to the magnesium ions created when the anode reacts. It is this reversal that makes the battery system rechargeable.

In fact, the new battery can be recharged more than 2,000 times and produces up to 1.3 voltsan amount that the team hopes to pump up to 1.7 volts with further refinements. Aurbach predicts that the battery will be commercially available within a year, serving first as a means to supply uninterrupted power to computer networks during outages.