A morphology, porosity and surface conductive layer optimized MnCo2O4 microsphere for compatible superior Li+ ion/air rechargeable battery electrode materials

Abstract

A porosity and morphology controlled MnCo ₂O ₄ microsphere for superior rechargeable Li ⁺ battery electrodes.

Abstract

Uniform surface conductive layers with porous morphology-conserved MnCo ₂O ₄ microspheres are successfully synthesized, and their electrochemical performances are thoroughly investigated. It is found that the microwave-assisted hydrothermally grown MnCo ₂O ₄ using citric acid as the carbon source shows a maximum Li ⁺ ion lithiation/delithiation capacity of 501 mA h g ⁻¹ at 500 mA g ⁻¹ with stable capacity retention. Besides, the given microsphere compounds are effectively activated as air cathode catalysts in Li–O ₂ batteries with reduced charge overpotentials and improved cycling performance. We believe that such an affordable enhanced performance results from the appropriate quasi-hollow nature of MnCo ₂O ₄ microspheres, which can effectively mitigate the large volume change of electrodes during Li ⁺ migration and/or enhance the surface transport of the LiO _x species in Li–air batteries. Thus, the rationally designed porous media for the improved Li ⁺ electrochemical reaction highlight the importance of the 3D macropores, the high specific area and uniformly overcoated conductive layer for the promising Li ⁺ redox reaction platforms.