High-entropy Li-rich layered oxide cathode for Li-ion batteries

Kim, Jaemin; Yang, Songge; Zhong, Yu; Tompsett, Geoffrey; Jeong, Seonghun; Mun, Junyoung; Sunariwal, Neelam; Cabana, Jordi; Yang, Zhenzhen; Wang, Yan

doi:10.1016/j.jpowsour.2024.235915

DOE OSTI · 2575008

High-entropy Li-rich layered oxide cathode for Li-ion batteries

Kim, Jaemin·Yang, Songge·Zhong, Yu·Tompsett, Geoffrey·Jeong, Seonghun·Mun, Junyoung·Sunariwal, Neelam·Cabana, Jordi·Yang, Zhenzhen·Wang, Yan

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Abstract

High-entropy oxides (HEOs) are emerging as promising cathode materials for Li-ion batteries (LIBs) due to their stable solid-state phase and compositional flexibility. Herein, we investigate the structural and electrochemical properties of a novel non-equimolar high-entropy cathode material, termed high-entropy Li-rich layered oxide (HE-LLO, Li 1.15 Na 0.05 Ni 0.19 Mn 0.56 Fe 0.02 Mg 0.02 Al 0.02 O 1.97 F 0.03 ), in comparison to a pristine Li-rich layered oxide (PR-LLO, Li1.2Ni0.2Mn0.6O2). The incorporation of multiple cations (Na + , Al 3+ , Mg 2+ , Fe 3+ ) and anion (F - ) into HE-LLO introduces compositional diversity, enhancing structural stability through the entropy stabilization effect. Theoretical calculations confirm a significantly higher configurational entropy in HE-LLO compared to PRLLO, supporting its high-entropy nature. Electrochemical evaluations demonstrate that HE-LLO exhibits considerable capacity retention, preserving 76.8 % of its discharge capacity at 0.5C after 200 cycles, compared to only 36.2 % for PR-LLO. Even under high-temperature conditions, HE-LLO outperformed PR-LLO, maintaining 76.1 % of its discharge capacity after 100 cycles at 5C, while PR-LLO retained only 12.4 %. These enhancements are attributed to the improved phase reversibility and higher Li + ion diffusion coefficients of HE-LLO, validated by ex-situ characterizations using a synchrotron X-ray technique, along with density functional theory (DFT) calculations. In conclusion, these findings highlight the promise of non-equimolar HEOs as a novel design strategy for highperformance cathode materials.

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25 ENERGY STORAGE Cathode materials Li-ion batteries Li-rich layered oxides Non-equimolar high-entropy oxides

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Kim, Jaemin, Yang, Songge, Zhong, Yu, Tompsett, Geoffrey, Jeong, Seonghun, Mun, Junyoung, Sunariwal, Neelam, Cabana, Jordi, Yang, Zhenzhen, Wang, Yan. 2024-11-25. High-entropy Li-rich layered oxide cathode for Li-ion batteries. https://doi.org/10.1016/j.jpowsour.2024.235915

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