Minute holes could dramatically improve battery performance

Poking tiny holes in batteries could both extend their life and speed up charging time according to a newly-published research.

This isn’t a case of taking a skewer to a AA (which GeeksAreSexy does not recommend), but rather it involves the material of the moment, graphene. The technique takes advantage of the fact that the lithium ions are stored between two sheets of graphene (a layer of carbon that is one atom thick) and must slide about between these sheets as part of the recharging process. Layers of carbon then lie between the sheets of graphene for structural support.

Northwestern University researchers led by Professor Harold Kung have made two changes to the design that can improve performance. The first is to replace some of the carbon layers with silicon, which works more efficiently with lithium ions. While silicon used in such a context has previously been problematic because it expands too much, this isn’t so much of an issue thanks to the graphene layer being particularly malleable. The result is that the lithium ions can be packed into the battery in a higher density, increasing battery life up to ten-fold.

The second big change is to build holes of around 20 to 40 nanometers wide into the graphene sheets: the holes are “drilled” via oxidation. These holes appear to act a little like the pits on a solitaire board, making it easier for ions to find the right location and stay there. The result is much more efficient and thus allows faster recharging.

According to the researchers, a commercial model of this technology could be ready in three to five years. It could mean a cellphone battery lasting a week between charges could recharge in 15 minutes.

As things stand it could only keep this performance up for around 150 charges before dropping off: after this it would still perform better than today’s batteries. Of course, if the one-week charging cycle proved possible with top-end smartphones, 150 charges would be plenty for users who regularly upgrade their handsets.

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