Mg Substitution Induced TM/Vacancy Disordering and Enhanced Structural Stability in Layered Oxide Cathode Materials

Luyao Wang; Chu Zhang; Lu Yang; Shuwei Li; Hang Chu; Xiangfei Li; Ying Meng; Haoyu Zhuang; Yurui Gao; Zhiwei Hu; Jin-Ming Chen; Shu-Chih Haw; Cheng-Wei Kao; Ting-Shan Chan; Xi Shen; Zhaoxiang Wang; Richeng Yu

doi:10.1021/acsami.2c21608

Mg Substitution Induced TM/Vacancy Disordering and Enhanced Structural Stability in Layered Oxide Cathode Materials

ACS Appl Mater Interfaces. 2023 Mar 8;15(9):11756-11764. doi: 10.1021/acsami.2c21608. Epub 2023 Feb 21.

Authors

Luyao Wang^{1

2}, Chu Zhang^{1

2}, Lu Yang^{1

2}, Shuwei Li^{1

3}, Hang Chu^{1

2}, Xiangfei Li^{1

2}, Ying Meng^{1

3}, Haoyu Zhuang^{1

3}, Yurui Gao⁴, Zhiwei Hu⁵, Jin-Ming Chen⁶, Shu-Chih Haw⁶, Cheng-Wei Kao⁶, Ting-Shan Chan⁶, Xi Shen¹, Zhaoxiang Wang^{1

2

3}, Richeng Yu^{1

2

3

7}

Affiliations

¹ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
² College of Material Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100190, China.
³ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
⁴ Laboratory of Theoretical and Computational Nanoscience, CAS Key Laboratory for Nanosystem and Hierarchy Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, China.
⁵ Max Planck Institute for Chemical Physics of Solids, Dresden 01187, Germany.
⁶ National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
⁷ Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China.

PMID: 36808940
DOI: 10.1021/acsami.2c21608

Abstract

Anionic redox is an effective way to increase the capacity of the cathode materials. Na₂Mn₃O₇ [Na_4/7[Mn_6/7□_1/7]O₂, □ for the transition metal (TM) vacancies] with native and ordered TM vacancies can conduct a reversible oxygen redox and be a promising high-energy cathode material for sodium-ion batteries (SIBs). However, its phase transition at low potentials (∼1.5 V vs Na⁺/Na) induces potential decays. Herein, magnesium (Mg) is doped on the TM vacancies to form a disordered Mn/Mg/□ arrangement in the TM layer. The Mg substitution suppresses the oxygen oxidation at ∼4.2 V by reducing the number of the Na-O-□ configurations. Meanwhile, this flexible disordering structure inhibits the generation of the dissolvable Mn²⁺ ions and mitigates the phase transition at ∼1.6 V. Therefore, the Mg doping improves the structural stability and its cycling performance in 1.5-4.5 V. The disordering arrangement endows Na_0.49Mn_0.86Mg_0.06□_0.08O₂ with a higher Na⁺ diffusivity and improved rate performance. Our study reveals that oxygen oxidation is highly dependent on the ordering/disordering arrangements in the cathode materials. This work provides insights into the balance of anionic and cationic redox for enhancing the structural stability and electrochemical performance in the SIBs.

Keywords: anionic redox; disordering structure; electrochemical performance; sodium-ion batteries; structural stability.