Microwaves reveal the nanoscale ion intercalation and edge activity of 2D catalyst

TL;DR

This paper introduces electrochemical scanning microwave microscopy (EC-SMM), a technique that enables nanoscale insight into ion intercalation and edge activity in 2D catalysts, revealing atomic-level details of electrochemical processes.

Contribution

The study demonstrates the application of EC-SMM at radio frequencies to detect and analyze electrochemical activity of 2D catalyst flakes with nanometer resolution, providing new insights into catalytic mechanisms.

Findings

Detected electrochemical activity in NiCo(OH)2 flakes at 16 nm resolution

Identified active sites and atomic-scale catalytic processes

Provided insights to optimize ion intercalation and surface adsorption

Abstract

The accelerated demand for electrochemical energy storage urges the need for new, sustainable, stable and lightweight materials able to store high energy densities rapidly and efficiently. Development of these functional materials requires specialized techniques that can provide a close insight into the electrochemical properties at the nanoscale. For this reason, we have introduced the electrochemical scanning microwave microscopy (EC-SMM) enabling local measurement of electrochemical properties with nanometer spatial resolution and sensitivity down to atto-Ampere electrochemical currents. The exceptional power of EC-SMM operated at radio frequency is exemplified here by the successful detection of the electrochemical activity and dynamics of molecularly thin NiCo(OH)2 flakes with a spatial resolution of 16 +/- 1 nm, uncovering the location of the active sites and providing atomistic details on the catalytic process that controls the electrocatalytic performance. Our results pinpoint the factors required to tune the thermodynamics of ion intercalation and to optimize the surface adsorption.