Electrochemical reactions at solid–liquid interfaces are inherently heterogeneous, with local reactivity influenced by surface structure, crystallographic orientation, defects, and chemical composition. Conventional electrochemical techniques provide spatially averaged responses, making it difficult to identify the specific structural features responsible for electrochemical activity. Scanning electrochemical cell microscopy (SECCM) addresses this limitation by confining electrochemical reactions within a nanoscale meniscus formed at the tip of an electrolyte-filled pipette, enabling spatially resolved electrochemical measurements at individual surface locations [1,2]. This capability provides a powerful approach to investigating electrochemical processes at the single-entity level.
In this talk, our recent advances in SECCM and its integration with complementary analytical techniques are presented, highlighting applications to electrocatalysis, photoelectrochemistry, and battery materials. First, SECCM-based electrochemical imaging has revealed significant variations in local reactivity associated with specific structural features of carbon-based and two-dimensional materials. In particular, studies of graphene, graphite, and transition metal dichalcogenides have demonstrated the influence of engineered edges, dopants, and defects on electrochemical activity, providing insights into structure–activity relationships at the nanoscale [3–7]. Furthermore, the extension of SECCM to photoelectrochemical measurements has enabled the investigation of localized photocurrent responses and crystallographic anisotropy in semiconductor electrodes, revealing spatially dependent reaction characteristics that are obscured in conventional measurements [8,9].
More recently, we have developed Raman-integrated SECCM, which enables simultaneous acquisition of localized electrochemical responses and Raman spectroscopic information under operating conditions. Using single-crystalline LiFePO₄ as a model battery electrode, this approach successfully tracked reversible lithium-ion extraction and insertion together with the associated structural transformations within a spatially confined electrochemical reaction region [10]. This integration represents an important step toward directly correlating local electrochemical activity with structural evolution during electrochemical processes.
These advances establish SECCM not merely as an electrochemical imaging technique, but as a versatile analytical platform for investigating the structural origins and dynamic behavior of electrochemical reactions at individual entities. By combining spatially resolved electrochemistry with optical and spectroscopic measurements, integrated SECCM approaches offer new opportunities for mechanistic understanding and rational design of functional electrochemical interfaces.
References:
[1] Y. Takahashi et al., Analytical Chemistry 89, 342 (2017).
[2] A. Kumatani and T. Matsue, Current Opinion in Electrochemistry 22, 228 (2020).
[3] A. Kumatani et al., Electrochimica Acta 499, 144688 (2024).
[4] A. Kumatani et al., Advanced Science 6, 1900119 (2019).
[5] A. Kumatani et al., Journal of Vacuum Science and Technology B 41, 052401 (2023).
[6] A. Kumatani et al., APL Energy 2, 016107 (2024).
[7] C. H. Chiang et al., Nano Letters 24 (35), 11012 (2024).
[8] E. Tachizaki et al., Journal of Vacuum Science and Technology B 43, 052402 (2025).
[9] H.-Y. Du et al., ChemRxiv, doi.org/10.26434/chemrxiv.15005115/v1
[10] A. Kumatani et al., Applied Physics Letters 128, 163905 (2026).