Superexchange interaction regulates Ni/Mn spin states triggering Ni-t2g/O-2p reductive coupling enabling stable lithium-rich cathode

• Published in: Nature communications Vol. 16; no. 1; pp. 3900 - 13
• Main Authors: Zheng, Chaoliang, Wang, Yaqing, Mao, Huican, Zhang, Juan, Yang, Xiaoxu, Li, Jie, Zhang, Di, Wang, Xindong, Kang, Feiyu, Li, Jianling
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 25.04.2025; Nature Publishing Group; Nature Portfolio
• Subjects: 119/118; 140/131; 140/133; 140/146; 140/58; 147/135; 147/143; 639/4077/4079/891; 639/638/161/891; Cathodes; Coupling; Decay; Decay rate; Doping; Electric potential; Humanities and Social Sciences; Kinetics; Lithium; Lithium-ion batteries; Manganese; multidisciplinary; Nickel; Orbitals; Oxidation; Science; Science (multidisciplinary); Voltage
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-025-59159-6

Lithium-rich layer oxides are expected to be high-capacity cathodes for next-generation lithium-ion batteries, but their performance is hindered by irreversible anionic redox, leading to voltage decay, lag, and slow kinetics. In order to solve these problems, we regulate the Ni/Mn spin state in Li 1.2 Mn 0.6 Ni 0.2 O 2 by Be doping, which generates the superexchange interaction and activates Ni-t 2g orbitals. The activation of Ni-t 2g orbitals triggers the reductive coupling mechanism between Ni/O, which improves the reversibility and kinetics of anionic redox. The strong π-type Ni-t 2g /O-2 p interaction forms a stable Ni-(O–O) configuration, suppressing excessive anion oxidation. In this work, the Be modified cathodes have good cycle stability, 0.04 mAh/g and 0.5 mV decay per cycle over 400 cycles at 1 C (60 min, 250 mA g −1 ), with a rate performance of 187 mAh/g at 10 C (6 min, 2500 mA g −1 ), providing a strategy for stabilising oxygen redox chemistry and designing high performance lithium-rich cathodes. Li-rich oxides face challenges such as voltage decay and slow kinetics due to irreversible anionic reaction. Here, authors activated the Ni-t2g orbitals through generating superexchange interactions via Be doping. By triggering the reduction coupling mechanism, the reversibility and kinetics of the anionic reaction are effectively improved.