Metal-Ligand Spin-Lock Strategy for Inhibiting Anion Dimerization in Li-Rich Cathode Materials

Zewen Jiang; Kun Zhang; Qihang Ding; Chuan Gao; Yuxuan Zuo; Hangchao Wang; Junfei Cai; Biao Li; Xinping Ai; Dingguo Xia

doi:10.1021/jacs.4c10815

Metal-Ligand Spin-Lock Strategy for Inhibiting Anion Dimerization in Li-Rich Cathode Materials

J Am Chem Soc. 2025 Jan 1. doi: 10.1021/jacs.4c10815. Online ahead of print.

Authors

Zewen Jiang^{1

2}, Kun Zhang², Qihang Ding¹, Chuan Gao², Yuxuan Zuo², Hangchao Wang², Junfei Cai², Biao Li², Xinping Ai¹, Dingguo Xia²

Affiliations

¹ Hubei Key Laboratory of Electrochemical Power Sources, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China.
² Beijing Key Laboratory of Theory and Technology for Advanced Batteries Materials, School of Materials Science and Engineering, Peking University, Beijing 100871, P. R. China.

PMID: 39743315
DOI: 10.1021/jacs.4c10815

Abstract

Anion dimerization poses a significant challenge for the application of Li-rich cathode materials (LCMs) in high-energy-density Li-ion batteries because of its deleterious effects, including rapid capacity and voltage decay, sluggish reaction kinetics, and large voltage hysteresis. Herein, we propose a metal-ligand spin-lock strategy to inhibit anion dimerization, which involves introducing an Fe-Ni couple having antiferromagnetic superexchange interaction into the LCM to lock the spin orientations of the unpaired electrons in the anions in the same direction. As proof of concept, we applied this strategy to intralayer disordered Li₂TiS₃ (ID-LTS) to inhibit S-S dimerization. Electrochemical characterization using the galvanostatic charge/discharge and intermittent titration technique demonstrated the considerably enhanced anionic redox activity, reduced voltage hysteresis, and improved kinetics of the Fe-Ni-couple-incorporated ID-LTS. Fe L_2,3-edge X-ray absorption spectroscopy and magnetic susceptibility measurements revealed that the metal-ligand spin-lock effect and consequent suppression of anion dimerization involve ligand-to-metal charge transfer between S and Fe. Further electrochemical tests on a Fe-Ni-couple-incorporated Li-rich layered oxide (Li_0.7Li_0.1Fe_0.2Ni_0.1Mn_0.6O₂) indicated the importance of the π backbond in enhancing ligand-to-metal charge transfer from S to Fe. These findings demonstrate the potential application of our metal-ligand spin-lock strategy in the development of high-performance LCMs.