{"id":8418,"date":"2013-11-05T11:45:43","date_gmt":"2013-11-05T18:45:43","guid":{"rendered":"http:\/\/cafe.foundation\/blog\/?p=8418"},"modified":"2013-11-05T11:49:23","modified_gmt":"2013-11-05T18:49:23","slug":"corncobs-as-a-source-of-supercapacitors","status":"publish","type":"post","link":"http:\/\/cafe.foundation\/blog\/corncobs-as-a-source-of-supercapacitors\/","title":{"rendered":"Corncobs as a Source of Supercapacitors?"},"content":{"rendered":"

Researchers at the Illinois Sustainable Technology Center<\/a>\u00a0at the University of Illinois report, \u201cthat wood-biochar\u00a0supercapacitors can produce as much power as today\u2019s activated-carbon supercapacitors at a fraction of the cost \u2013 and with environmentally friendly byproducts.\u201d<\/p>\n

Junhua Jiang, senior research engineer at the Center, has been reducing wood and cellulose products such as corncobs to biochar by heating the fibers in a reduced oxygen environment.\u00a0 This pyrolysis process creates a \u00a0porous, black substance that can be used as electrodes in supercapacitors.\u00a0 While other researchers use carbon black or more advanced forms of carbon such as nanotubes, this more humble approach yields equal or better performance at a fraction of the cost of the more labor-intensive methods.\u00a0 Many of the alternatives obtain their carbon from fossil-fuels, making biochar the environmental option.<\/p>\n

\"Biochar<\/a>

Biochar as electrode: corncobs have an internal structure that lends them to rapid ion transfer<\/p><\/div>\n

Jiang notes, \u201cSupercapacitors are ideal for applications needing instant power and can even provide constant power \u2013 like batteries, but at lower cost,\u201d adding that they are useful in transportation, electronics and solar- and wind-power energy storage and distribution.<\/p>\n

Most carbon exploitation involves \u201ccostly and complicated procedures\u201d to grow a pore network and increase the surface area on the electrode.\u00a0 This helps it capture and release energy quickly.\u00a0 The biochar method eliminates a great deal of the complications.\u00a0 Wood already has a nice pore structure that stays in place when burnt, especially in low-oxygen surroundings.<\/p>\n

Biochar reduces or eliminates the toxic chemicals used in processing other carbon electrodes.\u00a0 The team washed impurities such as calcium carbonate and potassium carbonate from their biochar with mild nitric acid.\u00a0 The resulting solution can be used as fertilizer.<\/p>\n

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Researchers note that “Any kind of wood can be made into biochar by heating in a low-oxygen chamber. Some types of wood work better than others.” Left to right, white birch, white pine and red cedar. | Photo by L. Brian Stauffer<\/p><\/div>\n

Icing the cake, \u201cThe material costs of producing wood-biochar supercapacitors are five to 10 times lower than those associated with activated carbon,\u201d Jiang said.<\/p>\n

Jiang concludes,\u00a0\u201cThe performance of our biochar materials is comparable to the performance of today\u2019s advanced carbon materials, including carbon nanotubes and graphenes. We can achieve comparable performance with much less cost and probably much lower environmental costs.\u201d<\/p>\n

Adding the cherry on top, when biochar supercapacitor are done producing power thousands of cycles in the future, \u201cthe electrodes can be crushed and used as an organic soil amendment that increases fertility.\u201d<\/p>\n

U of Illinois soil scientists report<\/a>, \u201cBiochar can be used as a fuel or as a soil amendment. When used as a soil amendment, biochar can boost soil fertility, prevent soil erosion, and improve soil quality by raising soil pH, trapping moisture, attracting more beneficial fungi and microbes, improving cation exchange capacity, and helping the soil hold nutrient. Moreover, biochar is a more stable nutrient source than compost and manure. Therefore, biochar as a soil amendment can increase crop yields, reduce the need for chemical fertilizers, and minimize the adverse environmental effects of agrochemicals on the environment.\u201d<\/p>\n

Biochar helps sequester the carbon that would otherwise be released into the atmosphere, according to University researchers.<\/p>\n