Direct Chemical Synthesis of Lithium Sub-Stochiometric Olivine Li0.7Co0.75Fe0.25PO4 Coated with Reduced Graphene Oxide as Oxygen Evolution Reaction Electrocatalyst

Yelena Gershinsky, David Zitoun

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

The oxygen evolution reaction (OER) is of fundamental importance for the development of renewable energies. Research on earth-abundant, efficient, and stable OER electrocatalysts is a key factor for the technological improvement of water-splitting systems. In this article, we demonstrate OER performance of olivine-type lithium earth-abundant transition-metal phosphates coated with reduced graphene oxide (rGO). We report on LiCoPO4/rGO and the solid solutions Li1-xCoyFe1-yPO4/rGO synthesized by a nonaqueous sol-gel microwave reaction. Interestingly, such conditions allow for the direct synthesis of substochiometric Li0.7Co0.75Fe0.25PO4/rGO compound with improved OER activity. The materials crystallize in the olivine orthorhombic phase with nanoplatelet-like shape with nanometer-size thickness and micrometer-size width. The substochiometric phase Li0.7Co0.75Fe0.25PO4/rGO exhibits the best OER activity in alkaline medium, generating a current density of 5 mA cm-2 at an overpotential of 0.39 V and a Tafel slope of 44.5 mV dec-1 in 6 M KOH with a low 51 μg cm-2 loading, outperforming previously reported results in terms of mass effectivity and Tafel slope.

Original languageEnglish
Pages (from-to)8715-8725
Number of pages11
JournalACS Catalysis
Volume8
Issue number9
DOIs
StatePublished - 7 Sep 2018

Bibliographical note

Publisher Copyright:
© 2018 American Chemical Society.

Funding

The authors acknowledge Dr. Gregory Gershinsky for his kind assistance with HRSEM, Yulia Kostikov for the her kind assistance with English proofreading, Dr. Hagit Aviv for her kind assistance with Raman and David Keller for his kind assistance with optical measurements. This work is partially supported by the Planning & Budgeting Committee of the Council of High Education and the Prime Minister Office of Israel, in the framework of the INREP project.

FundersFunder number
Council of High Education
Prime Minister office of Israel

    Keywords

    • electrocatalysis
    • electrolysis
    • graphene
    • olivine
    • oxygen evolution reaction
    • water splitting

    Fingerprint

    Dive into the research topics of 'Direct Chemical Synthesis of Lithium Sub-Stochiometric Olivine Li0.7Co0.75Fe0.25PO4 Coated with Reduced Graphene Oxide as Oxygen Evolution Reaction Electrocatalyst'. Together they form a unique fingerprint.

    Cite this