Cathode reaction mechanism on the h-BN/Ni (111) heterostructure for the lithium-oxygen battery

Abstract

In this study, the heterostructure of h-BN and Ni (111) is adopted as effective cathode catalysts for the Li-O₂ battery using first-principles calculations. It was determined that h-BN/Ni (111) thermodynamically prefers a 2e⁻ pathway despite the large adsorption energy of O₂, even larger than Pt (111), and dissociation of O₂ at the formation of the oxygen reduction reaction (ORR) intermediates of the Li-O₂ battery on h-BN/Ni (111). In this respect, the result of h-BN/Ni (111) does not accord with previous studies that found that strong adsorption and dissociation of O₂ indicate a reaction to proceed via the 4e⁻ pathway. The reason for this behavior is identified as being adsorption of the ORR intermediates mainly conducted by strong ionic bonds between the B atoms of h-BN and the O atoms of the intermediates, while the Li atoms do not participate in the bonds. The electrochemical performance of h-BN/Ni (111) is remarkable with a maximum discharge potential of 1.93 V and a minimum charge potential of 3.83 V, comparable to noble metal based catalysts.