Synergistic Effect of CuGeO₃/Graphene Composites for Efficient Oxygen–Electrode Electrocatalysts in Li–O₂ Batteries

Hybridized 1D/2D CuGeO₃/graphene composites are applied as the oxygen–electrode electrocatalysts for Li–O₂ batteries. The CuGeO₃/graphene composites are synthesized by the crystallographic alignment of CuGeO₃ nanowires on graphene, rendering strong heteroepitaxial coupling between the 1D oxide nanostructures and the 2D electrically conducting graphene. The inherited excellent electrocatalytic activity of the CuGeO₃/graphene composites leads to lower overpotentials and more stable cycling performance of Li–O₂ cells than CuGeO₃ nanowires and graphene. The relationships between CuGeO₃ nanowires and graphene are studied for the oxygen reduction and oxygen evolution activity in both aqueous and nonaqueous solutions, and the electrocatalytic activity is improved by manipulating the redox pair and sp3/sp2 via surface chemical modification.