Real-Space Charge Density Profiling of Electrode-Electrolyte Interfaces with Angstrom Depth Resolution

Lalith Krishna Samanth Bonagiri, Kaustubh S. Panse, Shan Zhou, Haiyi Wu, Narayana R. Aluru, Yingjie Zhang

Research output: Contribution to journalArticlepeer-review

Abstract

The accumulation and depletion of charges at electrode-electrolyte interfaces is crucial for all types of electrochemical processes. However, the spatial profile of such interfacial charges remains largely elusive. Here we develop charge profiling three-dimensional (3D) atomic force microscopy (CP-3D-AFM) to experimentally quantify the real-space charge distribution of the electrode surface and electric double layers (EDLs) with angstrom depth resolution. We first measure the 3D force maps at different electrode potentials using our recently developed electrochemical 3D-AFM. Through statistical analysis, peak deconvolution, and electrostatic calculations, we derive the depth profile of the local charge density. We perform such charge profiling for two types of emergent electrolytes, ionic liquids, and highly concentrated aqueous solutions, observe pronounced sub-nanometer charge variations, and find the integrated charge densities to agree with those derived from macroscopic electrochemical measurements.

Original languageEnglish (US)
Pages (from-to)19594-19604
Number of pages11
JournalACS Nano
Volume16
Issue number11
DOIs
StatePublished - Nov 22 2022
Externally publishedYes

Keywords

  • 3D atomic force microscopy
  • Electrode-electrolyte interface
  • atomic resolution imaging
  • charging profiling
  • double layer charging
  • electric double layer
  • electrochemical atomic force microscopy

ASJC Scopus subject areas

  • General Engineering
  • General Materials Science
  • General Physics and Astronomy

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