Graphite Cathode
A graphite cathode is an important element in the primary battery that stores electrochemical energy. It is thermally and electrically conductive, chemically passive (corrosion-resistant), and lighter than aluminum. It is used in a wide range of applications including electric vehicles, fuel cells, solar cells, and semiconductors.
Graphite is a metastable allotrope of carbon, a naturally occurring substance that is characterized by its crystalline structure and low thermal expansion. It is widely used in the industry, especially in battery electrodes.
Intercalation of reagents into graphite has played a significant role in the development of rechargeable batteries since Schaffautl first attempted to do so in 1840. It has since been utilized in a wide variety of battery applications, including superconducting materials and catalysts, hydrogen storage, and Li-ion batteries.
Co-intercalation of solvated guest ions into graphite has become an important strategy for improving battery performance. However, the high redox potentials of the co-intercalation reactions generally lead to unsatisfactory energy densities.
To decrease the redox potentials of co-intercalation and thus increase the energy densities, various electrolytes have been designed. Among them, linear ether-based electrolytes are typically applied to the Na, Li, K, and Mg co-intercalation reactions in graphite.
A co-intercalation graphite electrode with an ether-amine electrolyte system was investigated by using the methylene blue technique and X-ray diffraction. The results showed that the reversible capacity was significantly enhanced compared with that of a pure ether-based electrolyte system. In addition, a high rate capability was also achieved by utilizing 12-crown-4-ether solvents.
