Bifunctional Catalytic Co₂VO₄ Nanoarray Grown on Carbon Nanofiber for Free-Standing Lithium-Air Battery Cathode

In recent research on cathode for LABs, systematic investigations have been conducted to develop rational catalysts with diverse morphologies. Studies have shown increased exposure to the high-activity surface leads to improved cycle life and cell performance. In particular, spinel cobalt oxide (Co₃O₄) draw attention due to Co²⁺/Co³⁺ bifunctional catalytic activity and electrochemical stability in electrocatalys. Nevertheless, the efficacy of these applications was hindered due to the inherent constraints associated with their poor intrinsic electrical conductivity and comparatively low catalytic activity. To address these limitations, we have designed cobalt vanadium oxide uniformly decorated on the carbon nanofiber (Co₂VO₄@CNF) <i>via </i>hydrothermal synthesis as a free-standing cathode for LABs. By substituting vanadium for the octahedron site of Co₃O₄, vanadium atoms can offer an electron pathway and facilitate high electrical conductivity. In addition, the substitution of vanadium improves oxygen reduction reaction (ORR) performance through proper electron configuration of Co²⁺. The oxide catalyst grown on the CNF facilitates the maximization of active catalytic sites and stable formation/dissociation of Li₂O₂, enabling greater capacity and longer cyclability. The findings indicate that the formation/dissociation process of Li₂O₂ is influenced by the presence of an appropriate catalyst and the surface chemistry. The air cathode structure composed of rational nanostructures and catalysts is expected to improve LAB performance in capacity and cyclability.