Dramatically Accelerated Formation of Graphite Intercalation Compounds Catalyzed by Sodium.

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. We have discovered that Na has a catalytic property that dramatically accelerates the formation of GICs. We demonstrate that LiC 6 n (n = 1, 2), KC 8 , KC 12 n (n = 2, 3, 4), and NaC x are synthesized simply by mixing alkali metals and graphite powder with Na at room temperature (∼25°C), and A E C 6 (A E = Ca, Sr, Ba) are synthesized by heating Na-added reagents at 250°C only for a few hours. The NaC x , 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. This article is protected by copyright. All rights reserved.