title: Suppressing the P2-O2 Phase Transition of Na0.67 Mn0.67 Ni0.33 O2 by Magnesium Substitution for Improved Sodium-Ion Batteries.
abstract: Room-temperature sodium-ion batteries (SIBs) have shown great promise in grid-scale energy storage, portable electronics, and electric vehicles because of the abundance of low-cost sodium. Sodium-based layered oxides with a P2-type layered framework have been considered as one of the most promising cathode materials for SIBs. However, they suffer from the undesired P2-O2 phase transition, which leads to rapid capacity decay and limited reversible capacities. Herein, we show that this problem can be significantly mitigated by substituting some of the nickel ions with magnesium to obtain Na0.67 Mn0.67 Ni0.33-x Mgx O2 (0≤x≤0.33). Both the reversible capacity and the capacity retention of the P2-type cathode material were remarkably improved as the P2-O2 phase transition was thus suppressed during cycling. This strategy might also be applicable to the modulation of the physical and chemical properties of layered oxides and provides new insight into the rational design of high-capacity and highly stable cathode materials for SIBs.
authors.affiliation: CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing, 100190, P.R. China.|University of Chinese Academy of Sciences, Beijing, 100049, P.R. China.
authors.forename: Peng-Fei
authors.initials: PF
authors.lastname: Wang
authors.affiliation: CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing, 100190, P.R. China.
authors.forename: Ya
authors.initials: Y
authors.lastname: You
authors.affiliation: CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing, 100190, P.R. China.
authors.forename: Ya-Xia
authors.initials: YX
authors.lastname: Yin
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences (CAS), Beijing, 100190, P.R. China.
authors.forename: Yue-Sheng
authors.initials: YS
authors.lastname: Wang
authors.affiliation: CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing, 100190, P.R. China.
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Wan
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences (CAS), Beijing, 100190, P.R. China. l.gu@iphy.ac.cn.
authors.forename: Lin
authors.initials: L
authors.lastname: Gu
authors.affiliation: CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing, 100190, P.R. China. ygguo@iccas.ac.cn.|University of Chinese Academy of Sciences, Beijing, 100049, P.R. China. ygguo@iccas.ac.cn.
authors.forename: Yu-Guo
authors.initials: YG
authors.lastname: Guo
keywords: cyclability; electrochemistry; magnesium; phase transitions; sodium-ion batteries