May
27
A Better Cheaper SuperCapacitor
May 27, 2011 | Leave a Comment
There was a temptation to headline with the word ‘natural’ as Dr. Woo Lee, the George Meade Bond Professor of Chemical Engineering and Materials Science at the Stevens Institute of Technology and his senior design team of Rachel Kenion, Liana Vaccari, and Katie Van Strander has designed biochar electrodes for supercapacitors.
Today supercapacitors are used in solar panels and hydrogen fuel cells and electric vehicle car batteries, but the material the capacitors use to store energy, activated carbon, is unsustainable and expensive. Biochar, on the other hand, represents a cheap, green, and natural alternative.
The team designed, fabricated, and tested a prototype supercapacitor electrode. The group demonstrated biochar’s feasibility as an alternative to activated carbon for electrodes targeted for use in hybrid electric automobile batteries or home energy storage in solar panels.
Dr. Lee said in the press release, “While the team’s findings are preliminary, the approach taken by us represents a small, but potentially very important step in realizing sustainable energy future over the next few decades.”
With EEStor still out of the market the current technology continues to be refined. Biochar is viewed as a green solution to the activated carbon currently used in supercapacitor electrodes. Unlike activated carbon, biochar is the byproduct of the pyrolysis process used to produce biofuels. That is, biochar comes from the burning of organic matter. As the use of biofuels increases, biochar production increases as well.
Liana Vaccari said, “With our process, we are able to take that biochar and put it to good use in supercapacitors. Our supply comes from goldenrod crop, and through an intellectual property protected process, most organics, metals, and other impurities are removed. It is a more sustainable method of production than activated carbon.” Another significant advantage is biochar isn’t toxic and will not pollute the soil when it is tossed out. The team estimates that biochar costs almost half as much as activated carbon, and is more sustainable because it reuses the waste from biofuel production, a process with sustainable intentions to begin with.
There is direct application to savings right now. The main concern for solar panel production today is the raw cost of manufacturing supercapacitors. Current photovoltaic arrays rely on supercapacitors to store the energy that is harnessed from the sun. While the growth rate of supercapacitors is advancing at 20 percent a year, their cost is still very high partly because they require activated carbon. Biochar, on the other hand, is cheaper and readily available as a byproduct of a process already used in energy production.
Katie Van Strander said, “My favorite part of this project was seeing the creation of the prototype. It was cool to be able to hold it in my hand and test it and say that I made this. Using this technology, we can reduce the cost of manufacturing supercapacitors by lowering the cost of the electrodes. Our goal is eventually to manufacture these electrodes and sell them to a company that already makes supercapacitors. Once supercapacitors become cheaper, they will become more common and be integrated into more and more devices.”
Ms Van Strander is right. The solar panel and electric vehicle battery markets are not the whole market. There are far more uses and many can use improvements today. The trick for the students is they need some more lab time to get to a production process and hard numbers for the values that biochar offers over the activated charcoal.
It’s also not so simple to just use any old waste biochar. There will likely be parameters to the pyrolysis process that yields the most effective biochar carbon. Some types of organic matter will be better than others, and the other ash components in the biochar will need consideration.
The students and the professor deserve a notice. From today’s simple motor start capacitors to the exotic devices of the future a better cheaper and more environmentally friendly capacitor will be a good thing. It would be great if the biochar design would have a much longer lifespan. The Stevens Institute team has a good idea and its working in a prototype, lets hope those in the business can help it along and make today’s expensive supercapacitor more affordable and more widely available.
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