Ab initio analysis of Li-B-C structure stability

Prediction of high-Tc superconductivity in hole-doped Li_xBC two decades ago has brought about an extensive effort to synthesize new materials with honeycomb B-C layers but the thermodynamic stability of Li-B-C compounds remains largely unexplored. In this study, we use density functional theory to characterize well-established and recently reported Li-B-C phases. Our calculation of the Li chemical potential in Li_xBC helps estimate the (T,P) conditions required for delithiation of the LiBC parent material, while examination of B-C phases helps rationalize the observation of metastable BC₃ polymorphs. At the same time, some of the previously reported crystal structure phases appear to be thermodynamically and kinetically inaccessible.