Modification of the Ni-Rich Layered Cathode Material by Hf Addition: Synergistic Microstructural Engineering and Surface Stabilization

Bo Wang; Feipeng Cai; Chenxiao Chu; Boyang Fu; Konrad Świerczek; Linsen Li; Hailei Zhao

doi:10.1021/acsami.3c18865

Modification of the Ni-Rich Layered Cathode Material by Hf Addition: Synergistic Microstructural Engineering and Surface Stabilization

ACS Appl Mater Interfaces. 2024 Mar 13;16(10):12599-12611. doi: 10.1021/acsami.3c18865. Epub 2024 Mar 4.

Authors

Bo Wang^{1

2

3}, Feipeng Cai^{2

3}, Chenxiao Chu^{2

3}, Boyang Fu⁴, Konrad Świerczek⁴, Linsen Li⁵, Hailei Zhao^{1

6}

Affiliations

¹ School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
² Energy Research Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250014, China.
³ School of Energy and Power Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250014, China.
⁴ Faculty of Energy and Fuels, AGH University of Krakow, al. A. Mickiewicza 30, Krakow 30-059, Poland.
⁵ Department of Chemical Engineering, Shanghai Electrochemical Energy Device Research Center (SEED), School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai 200240, China.
⁶ Beijing Municipal Key Laboratory for Advanced Energy Materials and Technologies, Beijing 100083, China.

PMID: 38437708
DOI: 10.1021/acsami.3c18865

Abstract

The rapid decline of the reversible capacity originating from microcracks and surface structural degradation during cycling is still a serious obstacle to the practical utilization of Ni-rich LiNi_xCo_yAl_1-x-yO₂ (x ≥ 0.8) cathode materials. In this research, a feasible Hf-doping method is proposed to improve the electrochemical performance of LiNi_0.9Co_0.08Al_0.02O₂ (NCA90) through microstructural optimization and structural enhancement. The addition of Hf refines the primary particles of NCA90 and develops them into a short rod shape, making them densely arranged along the radial direction, which increases the secondary particle toughness and reduces their internal porosity. Moreover, Hf-doping stabilizes the layered structure and suppresses the side reactions through the introduction of robust Hf-O bonding. Multiple advantages of Hf-doping allowed significant improvement of the cycling stability of LiNi_0.895Co_0.08Al_0.02Hf_0.005O₂ (NCA90-Hf0.5), with a reversible capacity retention rate of 95.3% after 100 cycles at 1 C, as compared with only 82.0% for the pristine NCA90. The proposed synergetic strategy combining microstructural engineering and crystal structure enhancement can effectively resolve the inherent capacity fading of Ni-rich layered cathodes, promoting their practical application for next-generation lithium-ion batteries.

Keywords: Hf-doping; Ni-rich layered cathode; lattice oxygen stabilization; microcrack suppression; microstructure regulation.