Computational studies on structural and electronic properties of NiCo2S4 (001)/KOH electrolyte interface

Hui Hui Hu, Kun Peng Dou, Guang Yuan, Wen Lei

Research output: Contribution to journalArticle

Abstract

In this work, we present a study on the atomic details and the electronic structure of the NiCo2S4/KOH electrolyte interface via first-principles calculation. Both Ni-terminated and CoS2-terminated NiCo2S4 (001) surfaces are studied in order to understand the electronic structure of the interface and surface reactivity. The surface free energy indicates that the Ni-capped NiCo2S4 (001) surface is more stable than the CoS2-capped one. Upon adsorption, KOH received more electrons (0.1e) from the latter surface than from the former and the planar average differential charge density indicates that a larger electric dipole forms in CoS2-terminated NiCo2S4/KOH interface. These analyses prove that the CoS2-terminated NiCo2S4 (001) surface presents a stronger affinity for OH in the electrolyte, which leads to the enhanced electrochemical performance. These results will not only contribute to a better understanding of the fundamental knowledge of the NiCo2S4/KOH electrolyte interface, but also provide a guidance as to enhance the electrochemical activity of NiCo2S4 materials, which will benefit the ultimate application of NiCo2S4 (001) as electrode material for electrochemical energy storage.

Original languageEnglish
JournalJournal of Electronic Materials
DOIs
Publication statusE-pub ahead of print - 16 Jul 2019

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