News Picks : Storage capacitors made from hemp fibers
BBC: David Mitlin of Clarkson University in New York and his colleagues have made supercapacitors—energy storage devices that can charge and discharge quickly—from an unlikely material: the fibrous inner bark of hemp plants. Hemp, which lacks the hallucinogenic properties of its cousin, cannabis, is grown worldwide as a textile crop. The inner bark is usually discarded during milling. Mitlin found, however, that the bark's fibers can be processed to create thin, carbon-rich layers that function as efficient cathodes. When combined with an electrolyte, the hemp-based cathodes form capacitors that can sustain power densities up to 20 kW/kg.