Posted on 03/03/2014 9:55:59 PM PST by neverdem
Rechargeable, energy-dense bio-batteries running on sugar might be powering our electronic gadgets in as little as three years, according to a US team of scientists. The battery, created by the group of Percival Zhang, an associate professor of biological systems engineering at Virginia Tech, can convert all the potential chemical energy stored in a sugar into electricity.
The prototype is similar in size to a typical AA battery and has an energy storage density of 596 amp hours per kilogram – roughly one order of magnitude greater than a smartphone’s lithium-ion battery. This means that the battery could last at least twice as long as conventional lithium-ion batteries on a weight-for-weight basis.
An enzyme cascade strips electrons from glucose and turns it into electricity that could be used to power a mobile phone © NPG
Sugar is an excellent source of energy. Most living cells generate their energy from glucose by passing it down an enzymatic chain that converts it into different sugars. This enzymatic cascade provides the necessary energy to create an electrochemical gradient. This, in turn, can be used to power an enzyme that synthesises adenosine triphosphate (ATP) – the universal biological energy currency. However, extracting this energy from a sugar if you’re not a biological organism is tricky – short of combustion, which is impractical to power handheld electronics.
To fuel their battery the team used maltodextrin – a polymer made up of glucose subunits. They then created an entirely new synthetic enzymatic pathway to extract energy from the sugar. Using 13 different enzymes they were able to strip, on average, 24 electrons from a single glucose molecule, which can then be harnessed to power an electrical device.
In contrast to natural catabolic pathways for cellular glucose oxidation, the team’s artificial pathway does not rely on ATP as an energy carrier. Instead, the researchers used two redox enzymes to oxidise glucose, generating reduced nicotinamide adenine dinucleotide (NADH) as the sugar is broken down. Another 10 enzymes further breakdown the sugars and feed them back to the redox enzymes to produce more NADH, with water and carbon dioxide the only by-product. NADH is a reducing agent and author Zhiguang Zhu describes it as ‘an electron shuttle that carries electrons in living cells from one molecule to another’.
In the battery, NADH first transfers the electrons stripped from the glucose to a mediator with the help of an enzyme. The mediator then delivers these electrons to the battery’s electrode, ready to power an electronic device. In this way, the battery mimics the way a living cell transfers electrons from one molecule to another to generate power.
According to the team, the battery already has a number of advantages compared with lithium-ion batteries: the bio-battery runs on renewable sugars, has a high-energy storage density, and it can be easily and quickly recharged by simply topping it up with more sugar solution. Also, while lithium is a limited resource, sugar is abundant and totally safe to use.
The cost could also be an appealing factor. The enzymes are much cheaper than the metals used in conventional batteries. And the bio-battery is also fully biodegradable, says Zhang. But for the battery to get onto the market, the researchers must now tackle two other challenges: increasing power density and lifetime, he adds.
Plamen Atanassov, a bioelectrochemist at the University of New Mexico, US, who was not involved in the study, says the research provides a viable alternative to combustion to directly generate electricity from biofuels. ‘It is the link between biotechnology and biofuels with fuel cells and electrochemical energy technology,’ he says.
Z Zhu et al, Nat. Commun., 2014, DOI:10.1038/ncomms4026
Good point. Though....
...lithium is about half the density of water.
Assuming that the sugar is in a water solution (don’t know for sure), that means that the same size sugar battery would contain 5 times the energy of lithium ion.
CO2?? Aaaah! They're going to kill the planet!! /s
It might operate like a lead-acid battery. One electrode is connected to the implantee’s butt...where the lead is located; and the other to his gut, where the acid is produced. It’s elementary, Watson.
I just hope it doesn’t attract ants....
I wonder how far away we are from bio implanted computers that can run off of the implanted person’s metabolism?
To recharge your phone you just slide these pre-formed sugar sticks in the hole in the side of your phone and, presto, full charge. ;)
If only they could design one to work off body fat I’d never have to buy another battery.
Especially after the author called 'amp-hours' the 'energy storage density'. Without knowing the voltage, amp-hours is doesn't tell you anything about energy. In fact, it doesn't tell you much about anything.
Reading about magic batteries is almost as fun as reading about perpetual motion machines.
There is no known process that is 100% efficient.
Not if it's water vapor. Although temperature conditions might seem to be an issue. Condensation, freezing and all that.
Environmentalists will want it banned.
One order of magnitude...in the binary system = 2. Et voilà!
Biological process based fuel cell-runs as long as you feed it. Combine with self mobility and behavior to forage for sustenance, could become autonomous. Add intelligence and ability to duplicate or self repair and achieve “Replicators”. Piss them off...
Good point - I missed that.
It’s sad that a supposedly Science site is so science illiterate. Seems that science like everything else has gotten so PC, that they’ll sacrifice accuracy for the green agenda.
Once again sci/fi starts to become reality.
A new twist on “putting sugar in the gas tank.”
Certainly sounds like an engineering groaner. They might be plucking random factoids from different experiments in the same general family.
I’d think the kicker is, yes, voltage. It’s probably millivolts from the sugar, versus many volts from inorganic chemistry. Therefore more cells are needed, and the provision for that will eat up some of your capacity.
Bump for later.
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