Investigation of structural and electrochemical properties of biomass based activated carbon materials for energy storage applications

Köse, Kadir Özgün
Finding new energy sources and efficient ways for energy storage is one of the primary goals in both scientific and industrial research. To achieve this purpose, studies are concentrated on optimizing the characteristics of energy storage devices such as batteries, fuel cells and supercapacitors. Activated carbon (AC), beside its versatile application areas including wastewater and gas treatment, is used as electrodes in electrical double layer capacitors and as cathode in metal air batteries due to its high conductivity and high specific surface area (up to 3000 m2/g). In this thesis, AC is derived from biomass like pine cone, and its structural and electrochemical properties were characterized as an electrode material in supercapacitors. The porosity and conductivity of AC have a great influence on the electrochemical properties when used in EDLC applications; therefore, the production conditions of AC were arranged accordingly. As a result, surface area range of 1300 to 2700 m2/g was achieved. Furthermore, it is seen that electrical conductivity of AC is dependent on activation temperature with a 5 orders of magnitude greater value for high temperature treated ones. This dependence is linked to surface functional groups and structural order of the AC’s and they are characterized by FTIR and Raman spectroscopies. After the production and characterization of AC’s with various properties, they were used in the EDLC fabrication with two binders and two electrolytes. The effect of binders and electrolytes were investigated in EDLC performance; PSBR100 binder is found to be suitable for high power applications, whereas LA 132 binder is appropriate for high energy devices. The performance of TEA BF4 salt in acetonitrile was superior to TBA PF6 in acetonitrile. As a result, maximum power density of 72 kW/kg and energy density of 28 Wh/kg were achieved in EDLC’s fabricated.  
Citation Formats
K. Ö. Köse, “Investigation of structural and electrochemical properties of biomass based activated carbon materials for energy storage applications,” M.S. - Master of Science, Middle East Technical University, 2017.