Lithium-oxygen (Li-O 2 ) battery is one of the most promising batteries due to its high theoretical energy density. However, the poor catalytic performance of its air-cathode impeded its commercialization.
Recently, a joint research group led by Prof. BAO Xinhe and Prof. WU Zhongshuai from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has fabricated two-dimensional (2D) Mn 3 O 4 nanosheets with dominant crystal planes on graphene (Mn 3 O 4 NS/G) as efficient oxygen catalysts for Li-O 2 batteries, achieving ultrahigh capacity and long-term stability.
This study was published in ACS Catalysis on Oct. 7.
Designing oxygen catalysts with well-defined shapes and high-activity crystal facets can effectively regulate the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the three-phase interfaces, but it is still remains challenging.
The researchers indicated that the Mn 3 O 4 NS/G with the (101) facets and enriched oxygen vacancies offered a lower charge overpotential of 0.86 V than that of Mn 3 O 4 nanoparticles on graphene (1.15 V).
Moreover, Mn 3 O 4 NS/G cathode exhibited long-term stability over 1,300 hours and ultrahigh specific capacity up to 35,583 mAh/g at 200 mA/g, outperforming most Mn-based oxides for Li-O 2 batteries reported.
Both the experimental and theoretical results proved the lower adsorption energy of Mn 3 O 4 (101) for the discharge product Li 2 O 2 in comparison with Mn 3 O 4 (211), manifesting the easier decomposition of Li 2 O 2 during the charging process.
"This work may provide clues for engineering Mn-based materials with defined crystal facet for high-performance Li-O 2 batteries," said Prof. WU.
The above work was supported by the National Natural Science Foundation of China and Dalian National Laboratory for Clean Energy of CAS.
ACS Catalysis
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Two-Dimensional Mn3O4 Nanosheets with Dominant (101) Crystal Planes on Graphene as Efficient Oxygen Catalysts for Ultrahigh Capacity and Long-Life Li–O2 Batteries
7-Oct-2022