Quantitative Identification of Dopant Occupation in Li-Rich Cathodes

Tianhao Wu; Xu Zhang; Yuqiang Li; Haozhe Du; Tongchao Liu; Yubo Yang; Zihe Zhang; Xiaosong Liu; Qingzhen Huang; Yang Ren; Jiangtao Qu; Shu Zhao; Boya Wang; Rongkun Zheng; Khalil Amine; Haijun Yu

doi:10.1002/adma.202408543

Quantitative Identification of Dopant Occupation in Li-Rich Cathodes

Adv Mater. 2024 Nov 25:e2408543. doi: 10.1002/adma.202408543. Online ahead of print.

Authors

Tianhao Wu^{1

2}, Xu Zhang^{1

2}, Yuqiang Li^{1

2}, Haozhe Du^{1

2}, Tongchao Liu³, Yubo Yang^{1

2}, Zihe Zhang^{1

2}, Xiaosong Liu⁴, Qingzhen Huang⁵, Yang Ren^{6

7}, Jiangtao Qu⁸, Shu Zhao^{1

2}, Boya Wang^{1

2}, Rongkun Zheng⁹, Khalil Amine³, Haijun Yu^{1

2}

Affiliations

¹ Institute of Advanced Battery Materials and Devices, College of Materials Science and Engineering, Beijing University of Technology, Beijing, 100124, P. R. China.
² Key Laboratory of Advanced Functional Materials (Beijing University of Technology), Ministry of Education, Beijing, 100124, P. R. China.
³ Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL, 60439, USA.
⁴ Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China.
⁵ NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.
⁶ Department of Physics and Centre for Neutron Scattering, City University of Hong Kong, Hong Kong, 999077, P. R. China.
⁷ Shenzhen Research Institute, City University of Hong Kong, Shenzhen, 518057, P. R. China.
⁸ Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW, 2006, Australia.
⁹ School of Physics, The University of Sydney, Sydney, NSW, 2006, Australia.

PMID: 39584379
DOI: 10.1002/adma.202408543

Abstract

Elemental doping is widely used to improve the performance of cathode materials in lithium-ion batteries. However, macroscopic/statistical investigation on how doping sites are distributed in the material lattice, despite being a key prerequisite for understanding and manipulating the doping effect, has not been effectively established. Herein, to solve this predicament, a universal strategy is proposed to quantitatively identify the locations of Al and Mg dopants in lithium-rich layered oxides (LLOs). Solid evidence confirms that Al prefers to occupy the transition metal (TM) layer, while Mg evenly occupies both TM and Li layers. As a result, Mg significantly reduces the thickness of LiO₂ slabs at room temperature, which will increase the energy barrier of oxygen activation and enhance the structure stability of LLOs. The suppressed oxygen activity in Mg-doped LLO can be kinetically unlocked at 55 °C. The different characteristics of Al and Mg enlighten an Al/Mg co-doping strategy to optimize LLOs, which significantly improves the cycle performance while lifting the capacity. These insights from the quantitative identification of doping sites shed light on the manipulation of doping effects toward better cathodes.

Keywords: cycle performance; doping sites; lithium‐ion battery; lithium‐rich layered oxides; oxygen activity.

Abstract

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