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Superexchange interaction regulates Ni/Mn spin states triggering Ni-t2g/O-2p reductive coupling enabling stable
Chaoliang Zheng1, Yaqing Wang1, Huican Mao2
1State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, China.
Nature Communications
|April 24, 2025
Summary
Beryllium doping stabilizes high-capacity lithium-rich layered oxide cathodes by regulating nickel/manganese spin states. This enhances anionic redox reversibility and kinetics, improving battery performance and cycle life.
Area of Science:
- Materials Science
- Electrochemistry
- Battery Technology
Background:
- Lithium-rich layered oxides offer high capacity for next-generation lithium-ion batteries.
- Their practical application is limited by irreversible anionic redox, causing voltage decay and poor kinetics.
- Existing strategies struggle to stabilize oxygen redox chemistry in these materials.
Purpose of the Study:
- To improve the electrochemical performance of lithium-rich layered oxide cathodes.
- To address voltage decay and slow kinetics associated with anionic redox.
- To explore the effect of Beryllium (Be) doping on Ni/Mn spin states and oxygen redox activity.
Main Methods:
- Synthesis of Beryllium-doped Li1.2Mn0.6Ni0.2O2 cathode material.
- Investigation of Ni/Mn spin state modulation and Ni-t2g orbital activation via Be doping.
- Analysis of the Ni-t2g/O-2p interaction and its role in stabilizing anionic redox.
Main Results:
- Beryllium doping successfully regulates Ni/Mn spin states, activating Ni-t2g orbitals and promoting a reductive coupling mechanism between Ni and O.
- This activation enhances the reversibility and kinetics of anionic redox, forming a stable Ni-(O-O) configuration and suppressing excessive anion oxidation.
- Be-modified cathodes exhibit excellent cycle stability (0.04 mAh/g and 0.5 mV decay per cycle over 400 cycles at 1C) and rate capability (187 mAh/g at 10C).
Conclusions:
- Beryllium doping provides an effective strategy for stabilizing oxygen redox chemistry in lithium-rich layered oxides.
- The study demonstrates a pathway for designing high-performance lithium-rich cathodes by controlling spin states and electronic interactions.
- This approach offers significant potential for advancing next-generation lithium-ion battery technology.
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