Yuexing Jiang

Spinel MnCo2O4 nanospheres as an effective cathode electrocatalyst for rechargeable lithium–oxygen batteries

The air cathode is vital for lithium–oxygen batteries (LOBs) to achieve high performance, which will facilitate the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) during the discharge and charge processes. In this paper, MnCo2O4 nanospheres prepared through the hydroxide co-precipitation method are investigated as an effective electrocatalyst for the ORR and OER in non-aqueous LOBs. The results show that a non-aqueous LOB with the electrocatalyst exhibits an excellent discharge capacity of 8518 mA h gcathode−1 with a narrow voltage gap of 0.85 V between the discharge and charge plateaus at a current density 100 mA gcathode−1, and can deliver cycling stability over 20 cycles. This study shows that MnCo2O4 nanospheres can be a promising cathode electrocatalyst in rechargeable lithium–oxygen batteries due to its enhanced catalytic activity towards the ORR and OER.

Aprotic Lithium–Air Batteries Tested in Ambient Air with a High‐Performance and Low‐Cost Bifunctional Perovskite Catalyst

Aprotic lithium–air batteries (LABs) with remarkably high energy density are facing some challenges, including insufficient cycle stability, high‐cost for applications, and unclear understanding about the mechanism. Seeking high‐performance and low‐cost catalysts is one of the effective solutions to resolve these problems. Perovskite oxide La0.6Sr0.4CoO3 (LSC) together with Fe and Mn doped materials La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) and La0.6Sr0.4Co0.2Mn0.8O3 (LSCM) are prepared and applied as catalysts for LABs, which have been previously studied mostly in a pure oxygen atmosphere and rarely in ambient air. The results show that these catalysts are effective for LABs, and LSCF can improve the capacity and cycle number to 6027 mA h g−1 and 156 at current density of 400 mA g−1 in ambient air. The reasons for performance degradation of LABs tested in ambient air are discussed by EIS spectra and products analysis, which also clarifies the reason for improvement of the LSCF catalyst.

Ceria Microspheres Decorated Graphene Foam as Flexible Cathode for Foldable Lithium-Air Batteries

Foldable lithium‐air batteries with a high theoretical specific energy show wide applications in portable electronic devices, and the flexible cathodes play the most important role. In this work, CeO2 microspheres are grown in situ on 3 D interconnected graphene foam by hydrothermal treatment as the flexible cathode for lithium‐air batteries. With the assistance of a macroporous framework for rapid O2 diffusion and CeO2 distributed uniformly for enhanced catalytic activity towards the oxygen reduction reaction, the lightweight flexible cathodes show a large discharge capacity of 3250 mA h g−1 at a current density of 200 mA g−1 (based on the whole cathode) and can cycle steadily for 80 times with a capacity limitation of 600 mA h g−1. The flexible lithium‐air battery based on the new cathode also shows a stable discharge/charge potential platform during bending and good electrochemical reversibility after bending for at least 1000 times in ambient air. The study reveals that the high‐catalytic‐activity flexible cathode would be suitable for foldable lithium‐air batteries.