Superexchange interaction regulates Ni/Mn spin states triggering Ni-t<sub>2g</sub>/O-2p reductive coupling enabling stable lithium-rich cathode.
basic_science · Level V
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- Record sourced from PubMed, PMID 40274819.
- Also identified by DOI 10.1038/s41467-025-59159-6 and PMC identifier 12022161.
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Abstract
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<sub>1.2</sub>Mn<sub>0.6</sub>Ni<sub>0.2</sub>O<sub>2</sub> by Be doping, which generates the superexchange interaction and activates Ni-t<sub>2g</sub> orbitals. The activation of Ni-t<sub>2g</sub> orbitals triggers the reductive coupling mechanism between Ni/O, which improves the reversibility and kinetics of anionic redox. The strong π-type Ni-t<sub>2g</sub>/O-2p 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<sup>-1</sup>), with a rate performance of 187 mAh/g at 10 C (6 min, 2500 mA g<sup>-1</sup>), providing a strategy for stabilising oxygen redox chemistry and designing high performance lithium-rich cathodes.