Biochar obtained by carbonization of spent coffee grounds and its application in the construction of an energy storage device
Tatiana Santos Andrade, John Vakros, Dionissios Mantzavinos, Panagiotis Lianos
Abstract
Biochar has been made by carbonization of spent coffee grounds without further activation and has been characterized by several techniques revealing a material with a satisfactory balance of microporosity with meso and macroporosity. The material was fairly pure with 96% of its mass made of carbon and oxygen, 2.2% of K and the rest of unidentified minerals. This biochar was used to make a supercapacitor electrode combined with a photocatalytic fuel cell as an electric power source. It has been shown that the present biochar does apply as material to make a supercapacitor with specific capacitance mounting up to 200 Fg−1. Its combination with a photocatalytic fuel cell can be designed into a very simple system which provides several functions in one single device: solar energy conversion, photocatalytic degradation of an organic substance and storing of electric energy in a supercapacitor.