Reported Li–B–C compounds and calculated phase diagram establishing conditions required for LiBC delithiation.

LiB, a predicted layered compound analogous to the MgB2 superconductor, has been recently synthesized via cold compression and quenched to ambient pressure, yet its superconducting properties have not been measured. According to prior isotropic superconductivity calculations, the critical temperature (Tc) was expected to be only 10−15 K. Using the anisotropic Migdal-Eliashberg formalism, we show that the Tc may actually exceed 32 K. Our analysis of the contribution from different electronic states helps explain the detrimental effect of pressure and doping on the compound's superconducting properties. In the search for related superconductors, we screened Li-Mg-B binary and ternary layered materials and found metastable phases with Tc close to or even 10−20% above the record 39 K value in MgB2. Our reexamination of the Li-B binary phase stability reveals a possible route to synthesize the LiB superconductor at lower pressures readily achievable in multianvil cells.