Under funding from the Pennsylvania Infrastructure Technology Alliance (PITA) and Blaschak Anthracite Corp. (Blaschak), the Energy Research Center (ERC) worked on the development of a promising anthracite-base electrode material for high-performing supercapacitor applications. The Lehigh team included Drs. Jonas Baltrusaitis, Kai Landskron, and Carlos Romero, and Mr. Zheng Yao along with graduate student Guanrong Song. This is the third study sponsored by Blaschak focused on investigating non-energy uses of anthracite.
Previous studies included recovery of rare earth elements (REEs) from anthracite, and anthracite activation for production of sorbent to be used for mercury capture from flue gases. Blaschak participants included Gregory Driscoll, Boyd Kreglow, Tom Lowe and Dr. Harold Schobert.
Anthracite-based porous carbons underwent a multi-stage carbonization, and physical and chemical activation at temperatures in the 650-900°C range under steam flow conditions, and impregnation with potassium hydroxide (KOH). A series of instrumentation equipment was used to fully characterize the activated materials, which included a Brunauer Emmett and Teller (BET) machine, a contact angle goniometer, X-ray diffraction (XRD), scanning electron microscopy (SEM), and a custom-built X-ray photoelectron spectrometer (XPS). Anthracite-based carbons were compared to a generic activated carbon by Calgon Carbon Corp. Larger specific surface areas and porosity volume at appropriate pore size was achieved by the anthracite-activated carbons. These carbons also displayed two broad diffraction peaks at 2θ centered at around 26° and 43°, representing a highly amorphous carbon structure embedded with a partially graphitic structure.
The electrochemical performance of the anthracite-derived activated carbons was evaluated in a three-electrode testing system. Multiple electrolyte concentrations were utilized, including 1M sulfuric acid (H2SO4), and 1M and 6M KOH solutions. The anthracite materials were characterized by their largest wettability and superior conductivity and achieved excellent electrochemical performance. The wettability of carbon with the electrolyte is essential for its use as an electrode material in supercapacitors. An optimized anthracite material exhibited a specific capacitance of 288.52 F/g at 0.5A/g and a remarkable cycling stability of 95.4% capacitance retention after 1,000 cycles, which is superior to the benchmark commercial grade supercapacitor carbon.