If you\u2019ve been following the long-standing competition between electric and fuel-powered cars, you\u2019ll know the basics. That electric motors have better efficiency than internal combustion engines, but electric cars have short ranges because batteries lack the energy density of liquid fuels, are heavy, and expensive, and take a long time to re-charge.<\/p>\n
The current favorite among advanced battery technologies is the lithium-ion battery, which can produce a real-world range just north of 200 miles for a Tesla S sedan, but the Tesla S checks in at 4.600-4.900 pounds, and costs between $70,000 and $100,000.<\/p>\n
So, we have a ways to go before all-electrics dominate car sales.<\/p>\n
One battery technology that may prove a game-changer is a lithium-air battery. Going back to the theory of the battery, you get electron current flow because at the positive end of a battery you are creating free electrons through reduction, and they are flowing out of the negative end through oxidation. No need to go through the specifics \u2014 just focus on oxidation, meaning you need oxygen, which batteries usually are loaded with. And oxygen adds weight.<\/p>\n
Hence the lithium-air battery. Acts in many ways like a Li-ion battery, only it draws its oxygen from the air. Hence it weighs less, and is more efficient. Up to 3X what a Li-ion battery can achieve \u2014 that\u2019s the promise seen in the labs.<\/p>\n
The biobased angle in this? Bio is solving three daunting challenges in making lithium-air a reality \u2014 stability, rate of discharge and recharge, and the cost of manufacturing.<\/p>\n
The technology employed is not entirely unlike the process by which an sea-based organism builds a shell. From clams to abalone, they have a metabolic process by which they extract calcium from seawater, and use the calcium to accumulate a pattered structure.<\/p>\n
A team led by Angela Belcher at MIT \u2014 who had a previous technological breakthrough that is currently at the heart of Siluria\u2019s technology, to mention one \u2014 uses a modified virus known as M13, which extracts manganese from water and accumulates manganese oxide into an 80 nanomater-wide structure known as a nanowire, which can carry a current.<\/p>\n
As you know, shells have a rough texture on the outside and a large surface area because of that texture, and M13\u2019s nanowires have the same qualities. Bottom line, that dramatically increases the charge and discharge rate \u2014 and M13 works under normal room tempetature conditions. Plus, they are more stable than nanowires produced through chemical instead of an organic process.<\/p>\n
Far beyond what lithium-air batteries can achieve, there are the efficiencies possible with fuel cells. Now, the typical fuel cell uses stored hydrogen, and in the process of mixing it with oxygen drawn from the air, produces water and an electron flow. It\u2019s just about Nirvana when it comes to engine efficiency and green appeal, because you have electric motor efficiencies and the only emission is water.<\/p>\n
But there\u2019s the problem of hydrogen. It\u2019s difficult to store very much of it in a confined space, it\u2019s explosive, and it\u2019s generally produced at economical rates only from petroleum. Whoops, there goes range, stability and green appeal. But help is on the way.<\/p>\n
The solution is the organic world\u2019s favorite energy source. You guessed it, sugar. Yes, glucose. It\u2019s far more energy dense than hydrogen on a joules\/cc basis, it\u2019s stable, widely available and green.<\/p>\n
Now, how do you get electric flow from sugar? That\u2019s where fuel cell technology comes in.<\/p>\n