Just about everything that’s considered a “gadget” these days—from your phone to your laptop to the wireless earbuds Apple’s forcing you to buy—runs on lithium-ion batteries. They’re cheap, powerful for their weight, and can go through a few thousand charge cycles before wearing down, properties which have earned them their title as the champion workhorses of the portable digital age. New and better technologies are always on the horizon, though: lithium-oxygen batteries promise to be the next big thing, with the potential to store fifteen times the energy of their lithium-ion counterparts. There are still some kinks that need to be ironed out before the technology is viable, but scientists may have just overcome one of the biggest hurdles between us and this exciting new tech. The discovery comes from a ubiquitous but surprising source: red blood cells.
Lithium-oxygen batteries have the potential to carry almost as much energy as gasoline per kilogram of weight. This fact gives the technology enormous potential importance—if it lives up to its promise, Li-oxygen could drastically reshape the energy infrastructure of the future, accelerating our transition away from gas-powered automobiles and making home energy storage affordable for more people. For that to happen, though, there are some engineering challenges that need to be surmounted.
Foremost among these challenges is the undesired formation of lithium peroxide, which creates a crust on the battery’s interior cathode during use. This isn’t a problem for the first few charge cycles—the crust is shaken off during the recharging process—but after about five uses, the peroxide reaches concentrations that interfere with the battery’s operation, effectively clogging it up.
To prevent this, scientists have been looking for the right kind of chemical to tear apart the lithium and oxygen atoms, a quest that led Yale scientist Andre Taylor to experiment with heme: the molecule that’s responsible for picking up oxygen in your lungs and transporting it throughout your body. Taylor’s lab published results last week in Nature Communications indicating that heme may be the catalyst they’ve been looking for.
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| Heme is part of hemoglobin, which is the protein responsible for both the bright red color and the oxygen-binding capabilities of blood. Image Credit: Blood–Stock at Deviantart |
In order for a discovery to find real applications in the market, though, it has to be scaleable: batteries play a huge role in the modern world, and that role is only going to grow in coming years. If a molecule is expensive or difficult to synthesize in the lab—as heme unfortunately is—its usefulness can be severely limited. However, this isn’t a problem, as long as you’re not squeamish about a piece of your gadget having come from a living thing: heme can easily be refined from whole blood.
If that sounds creepy—like it could be the premise of a robot apocalypse movie—not to worry: there’s no shortage of blood. In fact, we’ve got so much to spare that it’s a problem; when animals are slaughtered for meat, the resulting blood has to be treated as a biohazard, requiring special disposal procedures to ensure that it doesn’t contaminate the environment. If another industry could make use of this byproduct at an industrial scale, it could be a beneficial arrangement for both parties. And there may be options for the vegan crowd as well: while heme is most abundant in the hemoglobin of animal blood, it’s also found at lower concentrations in the roots of legumes, meaning that you probably won’t be forced to choose between your ethics and your electronics.
I LOVE this work, but not just for the obvious reasons. Sure, I’m excited for the prospect of a phone that doesn’t need to be charged daily, but to me the most intriguing aspect of this story is the notion that blood is chemically useful.
See, I’m fascinated with old science. And when I say “old”, I’m not talking enlightenment-era, I’m talking “so old most people wouldn’t consider it science”—think 1000 AD. Their record-keeping wasn’t as rigorous, and their understanding relied far more heavily on heuristics than modern science, but the alchemists and physicians of old still relied on a system of hypothesis, experiment, and observation to reach their conclusions about the workings of the world. Yes, a lot of ancient medicine was likely superstition or the placebo effect, but by and large the scientists of old aren’t given nearly their due credit by people in the modern day.
To wit: a year or so ago, some scientists fished up a recipe for an eye salve out of an ancient Anglo-Saxon medical text, Bald’s Leechbook. Following its instructions, they boiled together some garlic and onions in wine, tossed in a bit of cow bile and a strip of brass (the instructions insisted on a brass vessel) and—voila—found themselves with an antibiotic that can take out MRSA, one of the deadlier “superbugs” currently plaguing our healthcare system. To me, that’s incredible. The recipe was likely arrived at through trial and error, but that doesn’t change the fact that they were doing some pretty sophisticated chemistry, using a metal as a catalyst in the synthesis of an early pharmaceutical.
So, keeping in mind that the alchemists of old weren’t that different from the chemists of today, and knowing as we do now that blood components can be a useful tool in oxygen-dependent reactions, we come to a surprising conclusion: a potential factual basis for “blood magic”.
That means there’s a genuine chance that, at some point in history, a man dressed as a wizard has cut his hand to bleed into a cauldron as an actual, necessary step in the process of whipping up some subtle poison or lifesaving medicine. It’s wild speculation, of course, but the very fact that it’s a theoretical possibility has me tickled to no end.
—Stephen Skolnick
P.S. I mentioned earlier that heme can be found in legumes—it turns out that a company called Impossible Foods is using plant-sourced heme to create veggie burgers “so real they bleed”. Phrased that way, it sounds creepy, but it seems that heme is a crucial part of actual meat’s flavor profile, and that adding it in makes for a more authentic stand-in. Here’s to chemistry, old and new!