Diethylzinc-Assisted Atomic Surface Reduction to Stabilize Li and Mn-Rich NCM

Rosy, Sarah Taragin, Eliran Evenstein, Sebastian Maletti, Daria Mikhailova, Malachi Noked

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Li and Mn-rich nickel cobalt manganese oxide (LMR-NCM) is one of the most promising cathode materials for realizing next-generation Li-ion batteries due to its high specific capacity of >250 mA h g-1and operating potential > 4.5 V. Nevertheless, being plagued by severe capacity fading and voltage decay, the commercialization of LMR-NCM appears to be a distant goal. The anionic activity of oxygen and associated phase transformations are the reasons behind the unstable electrochemical performance. The tendency of LMR-NCM to react with CO2and moisture further makes it prone to interfacial instability and degradation. Here, we report a neoteric method to mitigate the stability issues and improve the electrochemical performance of LMR-NCM by changing the electronic configuration of constituting O and transition metals via diethylzinc-assisted atomic surface reduction (Zn-ASR) using an extremely facile protocol. With the proposed Zn-ASR, a 2-3 nm thin layer of a reduced surface enriched with complex ZnOxor ZnOxRy was obtained on the LMR-NCM particles. X-ray photoelectron spectroscopy suggested the transfer of ethyl groups of diethylzinc to O atoms on the LMR-NCM surface, which ultimately led to the reduction of near-surface Mn and Ni atoms and impeded irreversible anionic activity. The presence of ZnOx/ZnOxRy also resulted in superior charge transfer and resistance against HF. As a result, in contrast to LMR-NCM, the Zn-ASR-treated sample exhibited substantially improved rate capabilities, facilitated charge transfer, enhanced capacity retention, reduced parasitic reactions, and long-term stability as reflected from in-depth electrochemical analysis, in operando gaseous evolution studies, and post-mortem microscopic analysis.

Original languageEnglish
Pages (from-to)44470-44478
Number of pages9
JournalACS Applied Materials and Interfaces
Volume13
Issue number37
DOIs
StatePublished - 22 Sep 2021

Bibliographical note

Publisher Copyright:
© 2021 American Chemical Society

Funding

R.| is thankful to the Planning and Budgeting Committee of the Council of High Education for awarding post-doctoral research fellowship. M.N. is thankful to Israel National Center for Electrochemical Propulsion (INREP). The authors thank the ISF for equipment support (grant nos. 2028/17 and 2209/17).

FundersFunder number
Council of High Education

    Keywords

    • Li-ion battery
    • Li-rich NCM
    • atomic layer deposition
    • cathode electrolyte interface
    • interfacial engineering
    • zinc oxide

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