Tuning Local Structural Configurations to Improve Oxygen-Redox Reversibility of Li-Rich Layered Oxides

Yan Gong; Xiao Li; Lingcai Zeng; Yuanfei Huang; Bao Qiu; Zhaoping Liu

doi:10.1021/acs.jpclett.3c00616

Tuning Local Structural Configurations to Improve Oxygen-Redox Reversibility of Li-Rich Layered Oxides

J Phys Chem Lett. 2023 May 18;14(19):4575-4582. doi: 10.1021/acs.jpclett.3c00616. Epub 2023 May 10.

Authors

Yan Gong^{1

2}, Xiao Li^{1

2}, Lingcai Zeng^{1

3}, Yuanfei Huang^{1

2}, Bao Qiu^{1

2}, Zhaoping Liu^{1

2}

Affiliations

¹ Ningbo Institute of Materials Technology & Engineering (NIMTE), Chinese Academy of Sciences, Ningbo 315201, P. R. China.
² College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences (UCAS), Beijing 100049, P. R. China.
³ School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P. R. China.

PMID: 37162124
DOI: 10.1021/acs.jpclett.3c00616

Abstract

Li-rich layered oxides (LLOs) are regarded as one of the most desirable cathode materials due to their high specific capacity. Nevertheless, the irreversible oxygen release associated with low oxygen stability prevents their widespread application. Herein, an improved oxygen redox reversibility was achieved by constructing Ni²⁺-O^2--Ni²⁺ configurations. Superconducting Quantum Interference Device (SQUID) magnetometry measurements are used to track the evolution of the Ni²⁺-O^2--Ni²⁺ configuration during the electrochemical process. The strongest 180° superexchange interaction in the Ni²⁺-O^2--Ni²⁺ configuration, derived from the inevitable Li/Ni mixing in LLOs, regulates the local structure to form the ferrimagnetic (FiM) structural units. Consequently, the FiM structural units prevent the irreversible oxygen release and endow LLOs with high initial Coulombic efficiency (ICE). This work emphasizes the importance of the Ni²⁺-O^2--Ni²⁺ configuration for LLOs with high reversible capacity and proposes a synthesis approach to modulate the amount of FiM structural units.