Capacitance of Basal Plane and Edge-Oriented Highly Ordered Pyrolytic Graphite: Specific Ion Effects

Research output: Contribution to journalArticle

  • External authors:
  • Pawin Iamprasertkun
  • Wisit Hirunpinyopas
  • Bin Wang

Abstract

Carbon materials are ubiquitous in energy storage; however, many of the fundamental electrochemical properties of carbons are still not fully understood. In this work, we studied the capacitance of highly ordered pyrolytic graphite (HOPG), with the aim of investigating specific ion effects seen in the capacitance of the basal plane and edge-oriented planes of the material. A series of alkali metal cations, from Li+, Na+, K+, Rb+, and Cs+ with chloride as the counterion, were used at a fixed electrolyte concentration. The basal plane capacitance at a fixed potential relative to the potential of zero charge was found to increase from 4.72 to 9.39 μF cm–2 proceeding down Group 1. In contrast, the edge-orientated samples display capacitance ca. 100 times higher than those of the basal plane, attributed to pseudocapacitance processes associated with the presence of oxygen groups and largely independent of cation identity. This work improves understanding of capacitive properties of carbonaceous materials, leading to their continued development for use in energy storage.

Bibliographical metadata

Original languageEnglish
Pages (from-to)617-623
JournalJournal of Physical Chemistry Letters
Volume2019
Issue number10
Early online date23 Jan 2019
DOIs
Publication statusPublished - 2019