Stability of superdense lithium graphite compounds Original Research Article

We have calculated total energies for LiC2 and LiC3, superdense lithium graphite compounds, and have compared the equilibrium parameters with the measured data. Both theory and experiment agree that LiC2 is metastable at ambient pressure. Furthermore, the calculations predict the existence of a stable phase for LiC3 with lattice constants a and c in excellent agreement with the measured values within 2.6% and 1.2%, respectively. However, the calculations cannot reproduce the ±0.4 Å vertical offset of Li atoms from the plane halfway between the carbon layers.