期刊
JOULE
卷 5, 期 4, 页码 975-997出版社
CELL PRESS
DOI: 10.1016/j.joule.2021.02.004
关键词
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资金
- DOE Data, Artificial Intelligence, and Machine Learning at DOE Scientific User Facilities project
- ALS fellowship program
- DOE [DE-AC02-05CH11231]
- National Key R&D Program of China [2016YFB0100100, 2016YFB0700600]
- Beijing Municipal Science and Technology Commission [D181100004518003]
- National Natural Science Foundation of China [51822211, U1964205, Y5JC011E21]
- U.S. DOE, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering [DE-AC02-76SF00515]
By evaluating the Mn and O states in Li2MnO3, it is found that Mn(III/IV) redox dominates the reversible bulk redox, while surface reactions contribute to the initial charge plateau with oxygen release and carbonate decomposition. The absence of lattice oxygen redox in Li2MnO3 questions the origin of oxygen redox in Li-rich compounds, suggesting opportunities for using alkali-rich materials for catalytic reactions.
A SUMMARY Li2MnO3 has been considered to be a representative Li-rich compound with active debates on oxygen activities. Here, by evaluating the Mn and O states in the bulk and on the surface of Li2MnO3, we clarify that Mn( III/IV) redox dominates the reversible bulk redox in Li2MnO3, while the initial charge plateau is from surface reactions with oxygen release and carbonate decomposition. No lattice oxygen redox is involved at any electrochemical stage. The carbonate formation and decomposition indicate the catalytic property of the Li2MnO3 surface, which inspires Li-CO2/air batteries with Li2MnO3 acting as a superior electrocatalyst. The absence of lattice oxygen redox in Li2MnO3 questions the origin of the oxygen redox in Li-rich compounds, which is found to be of the same nature as that in conventional materials based on spectroscopic comparisons. These findings provide guidelines on understanding and controlling oxygen activities toward high-energy cathodes and suggest opportunities on using alkali-rich materials for catalytic reactions.
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