First principles study of electrocatalytic behavior of olivine phosphates with mixed alkali and mixed transition metal atoms

Arup Chakraborty, Sooraj Kunnikuruvan, David Zitoun, Dan T. Major

Research output: Contribution to journalArticlepeer-review

Abstract

Lithium transition metal olivine phosphates are well known Li-ion battery cathode materials, but these materials can also be used as electrocatalyst. Recent experimental studies showed that olivine phosphates with mixed alkali metals (Li and Na) and mixed transition metals (Ni and Fe) provide better electrocatalytic activity compared to single alkali and transition metal alternatives. In the current work, we analyzed the role of alkali metals, transition metals and vacancies on the reactivity of a series of olivine phosphates with different stoichiometries using first principles calculations. To this end, we investigated the adsorption of water at the surface of these materials. We found that water binds preferably at Ni surface sites for materials devoid of alkali ion vacancies. We further found correlation between the calculated adsorption energy with experimentally measured overpotentials for a series of olivine phosphates. Additionally, we found correlation between the adsorption energy of the systems with the total charge polarization of surface and adsorbate. To explain the computed trends, we analyzed the occupancies of the partial density of states of the Ni and Fe 3d states and Bader atomic charges.

Original languageEnglish
Pages (from-to)29175-29180
Number of pages6
JournalRSC Advances
Volume10
Issue number49
DOIs
StatePublished - 5 Aug 2020

Bibliographical note

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© The Royal Society of Chemistry.

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