Three-dimensional self-supported CuCo2O4 nanowires@NiO nanosheets core/shell arrays as an oxygen electrode catalyst for Li–O2 batteries

Abstract

Developing rechargeable Li–O₂ batteries is an effective way to relieve current energy stress and electricity shortage. Designing an oxygen electrode catalyst with superior bifunctional catalytic activity can significantly improve the performance of Li–O₂ batteries. In this study, unique CuCo₂O₄ nanowires@NiO nanosheets core/shell arrays are directly synthesized on carbon cloth (CC) through a facile hydrothermal and electrochemical deposition. The one-dimensional CuCo₂O₄ nanowires have good electrical conductivity and a short transmission path to overcome sluggish kinetic processes. The two-dimensional NiO nanosheets can promote the easier formation and decomposition of Li₂O₂. The CuCo₂O₄@NiO/CC electrode can run 181 cycles with the capacity limit of 500 mA h g⁻¹ at 0.2 mA cm⁻², much higher than the CuCo₂O₄ electrode (107 cycles) and can exhibit the discharge capacity of 10 843 mA h g⁻¹ at 0.1 mA cm⁻², as well as better rate performance than CuCo₂O₄ electrode. Thus, the three-dimensional self-supported CuCo₂O₄ nanowires@NiO nanosheets core/shell arrays can take full advantage of each chemical component, provide more effective space for Li⁺ and O₂ diffusion and Li₂O₂ storage, and possess better electrical conductivity.