A Novel Cr2O3/MnO2-x Electrode for Lithium-Oxygen Batteries with Low Charge Voltage and High Energy Efficiency

• Published in: Frontiers in chemistry Vol. 9; p. 646218
• Main Authors: Wei, Zhaohuan, Zhang, Zhiyuan, Ren, Yaqi, Zhao, Hong
• Format: Journal Article
• Language: English
• Published: Frontiers Media S.A 01-02-2021
• Subjects: charge voltage; Chemistry; Cr2O3; Energy efficiency; lithium-oxygen battery; MnO2-x
• ISSN: 2296-2646; 2296-2646
• DOI: 10.3389/fchem.2021.646218

A high energy efficiency, low charging voltage cathode is of great significance for the development of non-aqueous lithium-oxygen batteries. Non-stoichiometric manganese dioxide (MnO
2-x
) and chromium trioxide (Cr
2
O
3
) are known to have good catalytic activities for the discharging and charging processes, respectively. In this work, we prepared a cathode based on Cr
2
O
3
decorated MnO
2-x
nanosheets via a simple anodic electrodeposition-electrostatic adsorption-calcination process. This combined fabrication process allowed the simultaneous introduction of abundant oxygen vacancies and trivalent manganese into the MnO
2-x
nanosheets, with a uniform load of a small amount of Cr
2
O
3
on the surface of the MnO
2-x
nanosheets. Therefore, the Cr
2
O
3
/MnO
2-x
electrode exhibited a high catalytic effect for both discharging and charging, while providing high energy efficiency and low charge voltage. Experimental results show that the as-prepared Cr
2
O
3
/MnO
2-x
cathode could provide a specific capacity of 6,779 mA·h·g
−1
with a terminal charge voltage of 3.84 V, and energy efficiency of 78%, at a current density of 200 mA·g
−1
. The Cr
2
O
3
/MnO
2-x
electrode also showed good rate capability and cycle stability. All the results suggest that the as-prepared Cr
2
O
3
/MnO
2-x
nanosheet electrode has great prospects in non-aqueous lithium-oxygen batteries.