Rod-Like LiBC Anode with High Specific Capacity in Li-Ion Batteries

As a well-known graphite-like material in superconductivity, lithium borocarbide (LiBC) can also be utilized as an electrode material in Li-ion batteries with a high specific capacity, which is assigned to the B–B bond produced through the aqueous reaction or the initial charge process. In this work, a rod-like LiBC sample (Ti-LiBC) is synthesized with the precursors of LiH + B + graphite in a sealed Ti tube through high-temperature sintering. Compared with the normal SUS-LiBC sintered in a sealed SUS304 tube, the Ti-LiBC possesses a lot of B–B bonds and a strong EPR signal, and it delivers a higher specific capacity (ca. 500 mAh g–1 at a mean discharge and charge potentials of 0.85 and 1.89 V, respectively) with excellent rate and cycle performances. Actually, the Ti metal can react with the H2 gas to produce the TiH2 phase at a high temperature, of which the extent determines the morphology of LiBC product, and the substitution of Li metal for LiH as the precursor can also result in the rod-like structure and the high specific capacity. Therefore, a hydrogen-free atmosphere is the key to synthesizing rodlike LiBC with excellent electrochemical properties, and this strategy might be extended to other graphite-like materials.