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Nanowire technology doubles capacity of rechargeable batteries

A research team working out of the Materials and Surface Science Institute located at the University of Limerick, Ireland, believe they have found a way to double the capacity of lithium-ion rechargeable batteries. The key to this capacity boost is a new nanowire anode made of germanium.

Existing lithium-ion batteries rely on graphite (although silicon is becoming more common now as it provides up to 20 per cent higher capacity), and while it performs well, graphite limits the capacity of such batteries. So the research team, lead by Dr. Kevin Ryan, set about replacing graphite with a new element.

They ended up focusing on germanium, a gray-white metalloid that's similar to tin and silicon. The problem with germanium is it doesn't handle charging very well–it expands significantly and after only a few charging cycles it falls apart completely. This may account for why we haven't heard of its use before. However, Ryan and his team managed to overcome these issues with the help of nanotechnology.

They set about restructuring germanium using nanowires to create a porous material that remains stable during charging. In fact, not only is it stable, it also extends the life of any lithium-ion battery using it to over 1,000 cycles. Today's batteries are typically rated at hundreds of cycles.

The good news doesn't end there, though. As well as producing a much higher capacity battery that lasts longer, the process of producing the new germanium anode is highly scalable, cheap, and requires very little energy. In a world where the use of such batteries is growing quickly, that's going to be a major plus for both manufacturers and the environment.

When these new batteries make it to market, they can be used in anything from a smartphone right up to an electric car. All we need to know now is when that's actually going to happen.