期刊
ACS APPLIED MATERIALS & INTERFACES
卷 12, 期 6, 页码 7277-7284出版社
AMER CHEMICAL SOC
DOI: 10.1021/acsami.9b21738
关键词
high capacity battery; oxygen redox reaction; proton insertion; Li-rich oxides cathode; resonant inelastic X-ray scattering (RIXS)
资金
- National Natural Science Foundation of China (NNSFC) [21233004, 21473148, 21621091, 21761132030]
- National Key R&D Program of China [2018YFB0905400, 2016YFB0901500]
- office of Basic Energy Sciences (BES)
- Office of Science of the DOE
- National High Magnetic Field Lab (NHMFL) - NSF [DMR-1644779]
- State of Florida
- DOE Office of Science User Facility [DE-AC02-05CH11231]
- Energy Biosciences Institute through the EBI-Shell program
- graduate exchange program of Xiamen University
- double first-rate program in College of Chemistry and Chemical Engineering of Xiamen University
As a parent compound of Li-rich electrodes, Li2MnO3 exhibits high capacity during the initial charge; however, it suffers notoriously low Coulombic efficiency due to oxygen and surface activities. Here, we successfully optimize the oxygen activities toward reversible oxygen redox reactions by intentionally introducing protons into lithium octahedral vacancies in the Li2MnO3 system with its original structural integrity maintained. Combining structural probes, theoretical calculations, and resonant inelastic X-ray scattering results, a moderate coupling between the introduced protons and lattice oxygen at the oxidized state is revealed, which stabilizes the oxygen activities during charging. Such a coupling leads to an unprecedented initial Coulombic efficiency (99.2%) with a greatly improved discharge capacity of 302 mAh g(-1) in the protonated Li2MnO3 electrodes. These findings directly demonstrate an effective concept for controlling oxygen activities in Li-rich systems, which is critical for developing high-energy cathodes in batteries.
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