2024 journal article
(Invited) Probing Local Ion Insertion through Operando AFM
ECS Meeting Abstracts.
UN Sustainable Development Goal Categories
7. Affordable and Clean Energy
(OpenAlex)
Source: ORCID
Added: August 22, 2024
Electrode volume change during ion insertion or intercalation has been one of the main failure mechanisms for several energy storage devices, especially Li-based batteries. Fundamental understanding of the relationship between the amount of the ions/charge stored and the induced volume changes of the hosting electrodes, and how this relationship impact the materials’ performance are necessary to develop the next generation batteries. However, most of the studies on the volume change were based on bulk techniques, which study the entire electrode including binders and additives. Here, we use operando atomic force microscopy (AFM), which allows tracking local volume changes and other mechanical responses with sub-nanometer spatial resolution under the conditions close to the device operation. In this work, we monitored electrode volume change via operando AFM and demonstrated the electro-chemo-mechanical coupling behaviors during proton insertion into WO 3 materials. The concept of mechanical cyclic voltammetry (mCV) curves was developed, and the relationship between electrochemical current and strain was investigated with simplified models. The results revealed multiple ion-intercalation processes with different mechanical responses are involved during electrode cycling. Local heterogeneity was investigated via mCV mapping, confirming that the charging mechanisms varied across the electrode. These local variations could be further correlated to local morphology, crystal orientations, or chemical compositions. We further demonstrate that the mCV approach is applicable to a variety of energy storage materials (e.g., birnessite, MXene and metal nitrides) with the increasing complexity of current-deformation relationships.