GM claims fuel cell breadkthrough

this is probably in the wrong section. Perhaps it belongs in environmental discussion for electricity generation.

Its GE not GM, and Solid oxide methane fuel cells not PEM hydrogen, which means it wouldn't work in the 10,000 psi car fuel cell family that might help things like the mirai and clarity.

 

Actually I like it here because it is one of the forums I like to monitor. Since I used to work for GE (and now draw a pension from them,) I'm happy to see this type of work. There was a time when GE was run by 'an idiot' but we'll take that discussion to FoP.

What I found interesting was another link from that page:
http://www.nature.com/nature/journal/v520/n7547/full/nature14340.html

I have long been an advocate of Aluminum-air batteries as a high energy density, primary cell. The next best being Iron-air. But here the clever team has figured out how to solve the 'density change' problem of aluminum to make a rechargable cell. This would make electric aircraft practical:

. . . Here we present a rechargeable aluminium battery with high-rate capability that uses an aluminium metal anode and a three-dimensional graphitic-foam cathode. The battery operates through the electrochemical deposition and dissolution of aluminium at the anode, and intercalation/de-intercalation of chloroaluminate anions in the graphite, using a non-flammable ionic liquid electrolyte. The cell exhibits well-defined discharge voltage plateaus near 2 volts, a specific capacity of about 70 mA h g–1 and a Coulombic efficiency of approximately 98 per cent. The cathode was found to enable fast anion diffusion and intercalation, affording charging times of around one minute with a current density of ~4,000 mA g–1 (equivalent to ~3,000 W kg–1), and to withstand more than 7,500 cycles without capacity decay.​

This is awesome work.

'Density change' is one of the harder problems of new battery chemistry. As the ions/molecules change to take on or release a charge, the new compound has a different density. Seen under a microscope, it looks like the electrodes have exploded or eroded away. Aluminum being trivalent has at least three variations it can form . . . especially challenging. So often batteries appear to have a surface effect versus volume. This aluminum rechargable battery sounds especially interesting.

Bob Wilson