I just had a paper published in The Journal of Materials Chemistry A about some research done at Brookhaven National Lab. It’s cool and new because it uses extremely high-power X-rays that can penetrate thick materials, even metals. The technique was developed to find points of strain inside high-performance materials like turbine blades. We use it to do the same thing, but inside batteries. And not just small batteries, but very thick ones, like D-cell batteries, which are an inch or two across.
Inside the battery, the X-rays bounce off crystal faces of the materials, and because of that you can know things about how far apart the atoms are. A D-cell has zinc at its center (anode) and manganese dioxide around its outside (cathode). The lines in the image above are like fingerprints of these materials. (And the numbers like (002) refer to the crystal faces themselves.)
Another cool thing about this technique is that it is very fast. You can scan the battery in a few minutes. This means that as it’s charging and discharging you can watch the materials changing in real time, inside the sealed battery. Basically this is what we do in the paper, seeing some things no one has ever been able to see before (except by cracking a battery open after cycling it, which can sometimes be effective, but not always). Brookhaven (on Long Island, in New York) is one of the only places in the world you can do this.
We took the data for this paper during a couple of intense sessions at Brookhaven. One was almost a year ago during a snowstorm, and another was a 20-hour block of borrowed time that ended with a fire alarm.
Occasionally I do this when I need battery materials: Crack open a D cell battery and pull out the anode.
The anode is a gooey cylinder at the center of the battery. In the second picture I’ve peeled off one layer of cellophane and one layer of paper from the anode. Inside it’s just a shiny jelly of zinc particles. Zinc is a high energy material, so by dissolving it you can get power. That’s how a battery works, basically.
There’s a cathode too, which is made of manganese oxide. It’s a black powder caked around the inside of the cell. You can also see the nail or pin sticking up at the center. This is the electrical contact to the zinc jelly.
Karl Kordesch, the chemist who invented the alkaline battery, died in 2011.
This is a promotional video from Energy.gov about the CUNY Energy Institute, where I work. It was shown at the 2012 ARPA-E Energy Innovation Summit in Washington DC (where I just was for about 42 hours, all in the convention center). The video features my boss, the extremely dapper Distinguished Professor Banerjee, and fellow Science Tumblr Dan.
A research grade cadmium-manganese dioxide rechargeable battery we exhibited at the ARPA-E Energy Innovation Summit. Our project is to make advanced, rechargeable zinc-manganese dioxide batteries. The need is for a high-performance battery, like the ones in your laptops and cell phones, except on a very large scale. Large enough for the battery to power houses, buildings, and utilities.
Zinc and manganese dioxide are extremely inexpensive battery materials, which would make these massive batteries feasible. Zinc and manganese dioxide are the same materials in a standard “alkaline” battery, like a AA. The hard part is to get them to recharge many times (say 1000).
This particular battery is cadmium-manganese dioxide because cadmium is a well-understood battery electrode (in Ni-Cd or NiCad batteries). A good way to approach a complicated system like a battery is to separate the zinc and manganese dioxide electrodes and study them paired with well-understood electrodes first.