Spherical, flower-like MnCo2O4 with a hollow structure as the cathode for efficient Li-CO2 batteries

Abstract

Global warming and climate change caused by the emission of carbon dioxide (CO₂) have induced unprecedented threats to the natural environment. Efficient utilization of CO₂ is a highly desirable approach to neutralizing CO₂ emissions. Li-CO₂ batteries can store electrochemical energy. They have received considerable attention due to their ability to “fix” and convert CO₂. However, their application suffers from poor reversibility as well as short cycle stability without the use of effective catalysts. We demonstrated that a flower-like MnCo₂O₄ sphere with a hollow structure could be introduced as the cathode to enhance the electrochemical performance of Li-CO₂ batteries. The flower-like, hollow, spherical structure could facilitate the transport and accessibility of CO₂. Moreover, it could relieve the accumulation of insoluble Li₂CO₃ on the electrode to further sweep the pathway of CO₂. After 100 charge-and-discharge cycles, the corresponding overpotential was ∼1.41 V at a current density of 100 mA g⁻¹. MnCo₂O₄ as a cathode provided an efficient electrocatalytic activity to enhance the reduction and evolution of CO₂. These features could promote the development of other binary transition-metal oxides in Li-CO₂ batteries.