Biochar is a type of charcoal that enhances soil health created under special conditions. The result of natural or human-made forces—such as forest fires or the 2,000 year-old practice of transforming agricultural waste into a soil-booster—biochar is a carbon-rich material that exhibits a high porosity and fine grain. It has been shown to improve nutrient-depleted soil, elevate water quality, and maintain soil vitality. In a laboratory setting, biochar can be made by heating wood or other plant-based materials in a low-oxygen chamber.
Scientists at the University of Illinois recently revealed another promising application for biochar, which they claim can be used in supercapacitors. Supercapacitors are similar to high-potency batteries, providing instant and constant energy for applications in electronics, transportation, and renewable power. They are typically made of activated carbon, which is derived from fossil fuels and requires expensive, chemically-intensive methods to ensure an optimized degree of porosity.
Based on preliminary tests, the researchers were able to produce a promising alternative using biochar, activating it with a mild nitric acid to remove impurities. Not only do the scientists claim the new material promises a five to 10-fold reduction in material costs, but also a greatly-improved environmental record, given the elimination of highly-corrosive chemicals and a reduction in embodied energy. "The performance of our biochar materials is comparable to the performance of today’s advanced carbon materials, including carbon nanotubes and graphenes," said engineer Junhua Jiang in
a University of Illinois press release. "We can achieve comparable performance with much less cost and probably much lower environmental costs."
Jiang and his colleagues' work reinforces a broadening trend involving the replacement of technically-sophisticated yet resource-intensive materials with widely-available natural substitutes. From biophotovoltaics replacing silicon PVs to mycological biocomposites replacing XPS insulation, the rediscovery and utilization of organic materials in advanced applications represents a retooling of global industrial processes, symbolizing the next step towards a carbohydrate economy.
Blaine Brownell, AIA, is a regularly featured columnist whose stories appear on this website each week. His views and conclusions are not necessarily those of ARCHITECT magazine nor of the American Institute of Architects.
Blaine Brownell, AIA, is an architect and materials researcher. The author of the three Transmaterial books (2006, 2008, 2010), he is the director of graduate studies in the school of
architecture at the University of Minnesota.