Reports have been coming in of a new type of air-charged battery which could provide up to ten times the energy storage of a conventional lithium cobalt battery. Called the STAIR (‘St Andrews Air,’ where it was developed at Scotland’s University of St Andrews), it provides improved capacity via a porous carbon exchange cell lattice which they say is a chemical-free lightweight battery technology ideal for electric vehicles.
Oxygen exchange battery
It’s early days yet, but developers aim to get a ten-fold increase in storage capacity. A reagent in the battery draws oxygen from the air during the discharging phase and the carbon lattice interacts with the air to achieve an efficient charge/discharge cycle with little degradation over time, unlike what one would typically get in your regular chemical exchange systems.
Like all battery developments, it takes time to develop and trial the technology and another two years of development is expected, plus a further two or three years to commercialize (by which time some EVers may be ready for a swap-over from tired Thunderskys). Air heads – pardon the pun – are very optimistic about the STAIR Air Battery technology and, having fiddled with air capacitors (i.e., ‘electrostatic batteries’ (C=Q/V etc.)), I kind of appreciate where this is coming from – but unlike the closely-spaced plates/dielectric of a supercap giving a short-term storage*, the STAIR technology involves a tight porous lattice able to hold the charge for extended periods.
As you know, cobalt anode types have a graphite negative electrode. In the STAIR battery, Li is taken from the lattice intercalation oxide on charge and restored on discharge (intercalation being the reversible include of a molecule/group between two other molecules/groups) which means there is a reaction from the air as the carbon electrode is porous (but not the sort of chemical reaction seen in regular batteries). Manganese oxide is said to be the catalyst (or do they mean dioxide?); it’d have to be pure as naturally-occurring MnO/MnO2 has a fair amount of impurities so high production expense is expected (note also the sulfur battery link below). There’s a claimed capacity to weight ratio of some 1,000 mAh per gram of carbon allowing plenty of time to go for a country drive before recharging. Since degradation of constant cycling is reduced, one could almost drain the battery to completely flat without the type of disintegration seen in lithium phosphates below 30% charge.
More details here…
http://www.physorg.com/news161862319.html
plus an article on another type of battery utilizing sulfur waste…
http://tech.yahoo.com/blogs/null/142195
The electron race is on…
Meanwhile, a super fast-charge battery technology from Massachusetts is charging ahead. Scientists are fiddling with various electrode coatings and have come up with a crystalline array which allows fast transfer of Li for fast charging. Again, thermal runaway is the issue, so it’d be interesting to see how they deal with this without the embellishment of elaborate cooling methods. Hmm, wonder if they can integrate nanopeltier nodes with each array? I’m just dreaming of course. The downside with peltiers is that the hot side swaps over to the cool side given a temperature threshold and visa verse (that’s my limited knowledge of such things and I digress). Anyway, the guys at MIT are probably trialling the best throughput speed as possible but consider the amounts of current driven into the batteries in just a few seconds. It’d be massive, somewhere in excess of over 1200Amps @240v – ewww.
More here…
http://web.mit.edu/newsoffice/2009/battery-material-0311.html
*Regarding other battery developments, someone mentioned to me recently at the disappointing results of the CSIRO lead-acid supercap hybrid battery. Indeed the intent is clear now that the battery is designed only for hybrid cars as the charge/delivery is not great enough for pure EVs to make them economically/energy viable. I’ll find out more in due course.
Again, recyclability/land fill issues and many other factors need to be taken into account for all these batteries. Thundersky says their batteries are fully recyclable – we’ll see.
