Dramatically Accelerated Formation of Graphite Intercalation Compounds Catalyzed by Sodium

• Published in: Advanced materials (Weinheim) 2023-04, Vol.35 (15), p.e2209964-n/a
• Main Authors: Iyo, Akira, Ogino, Hiraku, Ishida, Shigeyuki, Eisaki, Hiroshi
• Format: Article
• Language: English
• Subjects: Alkali metals; BaC 6; CaC 6; catalysts; Chemical synthesis; Graphite; Intercalation; Intercalation compounds; K–graphite intercalation compounds; Materials science; R&D; Reaction intermediates; Reagents; Research & development; Room temperature; Sodium; SrC 6
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202209964

Graphite intercalation compounds (GICs) have a variety of functions due to their rich material variations, and thus, innovative methods for their synthesis are desired for practical applications. It is discovered that Na has a catalytic property that dramatically accelerates the formation of GICs. It is demonstrated that LiC6n (n = 1, 2), KC8, KC12n (n = 2, 3, 4), and NaCx are synthesized simply by mixing alkali metals and graphite powder with Na at room temperature (≈25 °C), and AEC6 (AE = Ca, Sr, Ba) are synthesized by heating Na‐added reagents at 250 °C only for a few hours. The NaCx, formed by the mixing of C and Na, is understood to act as a reaction intermediate for a catalyst, thereby accelerating the formation of GICs by lowering the activation energy of intercalation. The Na‐catalyzed method, which enables the rapid and mass synthesis of homogeneous GIC samples in a significantly simpler manner than conventional methods, is anticipated to stimulate research and development for GIC applications. Pellets of graphite intercalation compounds (GICs) are synthesized by the Na‐catalyzed method. AM–GICs (AM = Li, Na, K) are formed simply by mixing AM and graphite with Na at room temperature. A Ca‐GIC (CaC6) is formed by heating a mixture of Ca, graphite, and Na at 250 °C for only several hours.