The graphite electrode is a key component of the EAF, an essential part of steel manufacturing that accounts for over half of the cost. The EAF steelmaking industry would benefit greatly from any technological advancements that could reduce costs and prolong the lifespan of critical components.
Graphite has a high electrical conductivity that allows for efficient passage of current, reducing power losses and ensuring optimal performance. Graphite has a high thermal conductivity that prevents overheating of the electrode and increases its longevity. Its low density also makes it easy to machine in different shapes and sizes, depending on the processing requirements.
In LIBs, anodes are composed of graphite, and cathodes are based on lithium metal oxides. These include lithium cobalt (LiCoO2) or lithium nickel (LiNiO2) oxides, lithium iron (LiFePO4) oxides, or LiNi1y-zCoyMnzO4(NCA). NCA has the main advantage over other LIB anode material in that it can easily be manufactured using Li-ion production methods. NCA has a cycle stability and coulombic efficiencies that are below expectations. These factors prevent the material from being applied in large-scale energy storage applications.
The present study aims at improving the cycling stability of NCA by surface engineering of the graphite and its interaction with electrolyte additives. To achieve this, characterization of electrodes with various analytes was performed, including sodium tartrate (salt), glucose, and milktose. For each analyte, different voltammetric spikes were observed. This indicates the graphite exhibits different electrochemical behavior.
To address the above problems, a new modification of carbon paste electrodes was developed with the help of nonionic poly(2-amino-5-mercapto-thiadiazole) films (PAT). The graphite electrodes with PAT coating demonstrated good reproducibility and high detectability limits. In addition, they showed resistance to fouling even though they did not exhibit strong adsorption to the analytes.
The electrodes produced were formed by mixing Hexagon graphite, unpurified or thermally pure, with a thick paste of petroleum tar pitch. The paste is then extruded with a NAmLab proprietary extruder mixer, resulting in elongated rods of uniform diameter. After calcination to 2,800deg C, the dry weight of the electrodes was determined. The electrodes then were inserted in the EAF, to perform LIB tests. After the experiment was completed, the conductivity and resistance of the electrodes were measured and compared against the control. The more flake-graphite added to formulation, the better conductivity of electrodes. At 5% addition of flake graphite, the electrodes showed much lower resistivity as compared to the control. This is a significant finding that Hexagon’s Performance+ additive can significantly improve the performance graphite electrodes. The results suggest that further development of this additive may be a promising way to increase the efficiency of graphite electrodes for LIB.
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