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Redesigned Lithium Batteries Could Charge Ten Times Faster, Last Ten Times Longer

Pretty much everything nowadays uses a lithium-ion battery, and they seem to work alright, right? Well, a team of engineers from Northwestern University have put some effort into seeing if they could improve upon the norm. Miraculously enough, they seem to have stumbled upon a discovery that could not only allow lithium-ion batteries to charge ten times as fast as they do now, but also last up to ten times as long. Even after hundreds of charges, this new battery prototype remains at least five times faster than any brand new battery you could get today.

Current lithium-ion batteries, used in just about any mobile device you could get your hands on, work by sending lithium ions from one end of the battery to the other, moving them through an electrolyte in the process. If the battery is discharging and providing energy for one device or another, the ions go from the anode to the cathode. When it’s getting charged, it’s the other way around. Simple enough, right?

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It is pretty simple, but there are a few factors that are responsible for the charge time and capacity that is prevalent today. First of all, the anode — which is made of thin, but long, graphene sheets — can only hold one lithium ion per six molecules of carbon. Not bad, but not great. This limits the amount of “battery power” you can cram in there when the battery is charged. The researchers tried silicon because it can hold a whopping 4 lithium ions per one molecule of silicon, but the problem there is that silicon’s expansion and contraction during charging and discharging make for a pretty explosive battery. The other problem is that when the ions are heading into the anode (the battery is being charged) it takes them a long time to get down the long graphene sheets and settle in where they want to be. In other words, to charge.

The Northwestern engineers seemed to have solved both of these problems by inserting a bunch of silicon slices into the graphene sheets and poking some tiny holes in there as well. This allows at least part of the battery to benefit from that killer 4:1 lithium ion to anode-material ratio while still leaving enough graphene to keep the expansion and contracting in check, which increases the capacity. The holes do their part by giving the ions a shortcut into a sweet spot of the anode where they want to sit, decreasing the charge time.

The team expects that this technology might make it into the market within the next 2-5 years, which would be awesome. The only downside is that when it gets there, we might not be able to really appreciate some of the gains. Given the way that mobile devices are going — becoming more capable but requiring more energy — it’s possible that by the time these new lithium-ion batteries show up, device power consumption will be so high that these might not provide luxuriously long battery lives, but rather, normal ones. In any event, I am always for better battery life. That is of course, unless people could be making headway on wireless power. I think I’d prefer that.

(via Wired)

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