Study on the First-Principles Calculations of Graphite Intercalated by Alkali Metal (Li, Na, K)

First-principles calculations of formation energy and energy barrier were done to examine the energetics of alkali metal graphite intercalation compounds (AM-GICs). The results showed that Li, K can be intercalated into the graphite layer under the high intercalated density, while Na was hardly intercalated into it, which was due to the energetic instability of Na-GICs. In addition, the ion jumps between sites in the graphite presented that Na can hardly move in ordered graphite layers, while K can move smoothly. Therefore, it can be expected that K-GICs will be an advantaged alternative as the battery anode material in theory.