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She was apparently “playing around” in the lab when she coated a gold nanowire in a manganese dioxide shell and encased the whole thing in a Plexiglas-like gel electrolyte. This combination, it seems, somehow strengthens the nanowires and makes them many many times more resistant to failure.

“She discovered that just by using this gel, she could cycle it hundreds of thousands of times without losing any capacity,” explains Reginald Penner, chair of UCI’s chemistry department. “That was crazy, because these things typically die in dramatic fashion after 5,000 or 6,000 or 7,000 cycles at most.”

So how much more resilient was Le Thai’s creation? After putting her battery through 200,000 recharge cycles over the course of three months, the researchers still couldn’t detect “any loss of capacity or power.”

No, this is a real thing. The biggest problem we have right now with portable batteries is plate degradation during the recharging process. Basically every time you charge the battery, you damage it a little, even when you're doing it exactly the right way. This damage accumulates over time, showing up as reduced capacity, and possibly ending in catastrophic failure. ("battery ballooning" usually)

A battery's ability to store power is directly proportional to the surface area of the plates, where they are exposed to the electrolyte and can store a differential in (somewhat of a static) charge. Roughing up the surface texture of a plate is one way to increase total surface area, a bit like how there are cilia in our intestines to greatly increase the absorption surface area of our intestines. It works the same way with batteries. But when you reduce it to a thin wire, the charge is spread out and isn't very strong in any one particular spot. But because of the enormous increase in area, it more than makes up for it in capacity.

This "soft" charge over a wide area is helpful because when batteries discharge deeply, some of the plate dissolves. When it's recharged, the plate material precipitates out of the electrolyte and back onto the plate... somewhere. Over many cycles of uneven redeposit, structures build up that resemble crystals, which grow toward each other and eventually can make contact with neighboring plates, causing a short. They can also puncture the insulating membrane between electrolyte areas of different potential, and that's where you get ballooning. The softer charging and discharging of nanowires still does this dissolve/deposit, but to a much smaller degree, and on a much smaller scale. This makes the charge and discharge processes far less destructive to the plates.

But this also means you aren't storing as strong (deep) of a charge in any one area, so you need to find a way to manufacture the wires densely enough without making them too delicate, and get them to combine electrically gradually to the external contacts, so the battery has a large total capacity. (a very dense storage battery isn't very useful if it's the size of a poppy seed and cost $10,000 to produce) If you can figure that out, you can create a very durable battery. This is where we're at right now. We know what the problem is, and how to avoid it, but we're still working out how to manufacture it efficiently and on a larger scale. It's a bit like carbon nanotubes and buckyballs. We need to start making more breakthroughs in nano-scale manufacturing. We've got the drill down for photolithography of chips, but that's about the only place where we've made any serious progress.


I work for the Department of Redundancy Department