Tuning Oxygen Redox Reaction through the Inductive Effect with Proton Insertion in Li-Rich Oxides

Jue Wu; Xiaofeng Zhang; Shiyao Zheng; Haodong Liu; Jinpeng Wu; Riqiang Fu; Yixiao Li; Yuxuan Xiang; Rui Liu; Wenhua Zuo; Zehao Cui; Qihui Wu; Shunqing Wu; Zonghai Chen; Ping Liu; Wanli Yang; Yong Yang

doi:10.1021/acsami.9b21738

Tuning Oxygen Redox Reaction through the Inductive Effect with Proton Insertion in Li-Rich Oxides

ACS Appl Mater Interfaces. 2020 Feb 12;12(6):7277-7284. doi: 10.1021/acsami.9b21738. Epub 2020 Jan 29.

Authors

Jue Wu^{1

2}, Xiaofeng Zhang³, Shiyao Zheng¹, Haodong Liu⁴, Jinpeng Wu², Riqiang Fu⁵, Yixiao Li¹, Yuxuan Xiang¹, Rui Liu¹, Wenhua Zuo¹, Zehao Cui¹, Qihui Wu⁶, Shunqing Wu³, Zonghai Chen⁷, Ping Liu⁴, Wanli Yang², Yong Yang¹

Affiliations

¹ State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, College of Chemistry and Chemical Engineering, and College of Energy , Xiamen University , Xiamen 361005 , China.
² Advanced Light Source , Lawrence Berkeley National Laboratory , One Cyclotron Road , Berkeley , California 94720 , United States.
³ Department of Physics, Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices, Key Laboratory of Low Dimensional Condensed Matter Physics (Department of Education of Fujian Province), and Jiujiang Research Institute , Xiamen University , Xiamen 361005 , China.
⁴ Department of NanoEngineering , University of California, San Diego , La Jolla , California 92093 , United States.
⁵ National High Magnetic Field Laboratory , Florida State University , 1800 E. Paul Dirac Drive , Tallahassee , Florida 32310 , United States.
⁶ Department of Materials Chemistry, School of Chemical Engineering of Materials Science , Quanzhou Normal University , Quanzhou 362000 , China.
⁷ Chemical Sciences and Engineering Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States.

PMID: 31961644
DOI: 10.1021/acsami.9b21738

Abstract

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.

Keywords: Li-rich oxides cathode; high capacity battery; oxygen redox reaction; proton insertion; resonant inelastic X-ray scattering (RIXS).