Raman Spectroscopy of Electrochemically Exfoliated Graphene: Defect Evolution, Doping Effects, and Interpretive Frameworks

Abstract

Electrochemical exfoliation offers a scalable method for graphene production, but it introduces a complex interplay of structural defects, chemical functionalization, and electronic doping. These factors result in Raman signatures that differ significantly from those observed in mechanically exfoliated graphene and high-quality chemical vapor deposition (CVD) graphene. Consequently, conventional Raman metrics require careful and context-specific reinterpretation. Raman spectroscopy remains essential for graphene characterization due to its high sensitivity to disorder and charge-transfer effects. This review provides a critical assessment of the Raman characteristics of electrochemically exfoliated graphene (EEG), integrating established defect models with a systematic analysis of Raman datasets from the literature. Detailed examination of key spectral parameters, including the I(D)/I(G) and I(D′)/I(G) intensity ratios, G-band position and full width at half maximum, and 2D-band position, reveals the coexistence of basal-plane defects, edge-related contributions, and dopant-induced effects in EEG. These findings indicate that Raman responses in EEG deviate from pristine graphene benchmarks and challenge the direct application of standard interpretative frameworks. The influence of electrolyte chemistry and applied potential on defect landscapes and doping levels is further evaluated through direct comparison with mechanically exfoliated and CVD graphene. Finally, emerging approaches such as in situ Raman spectroscopy, multivariate analysis, and machine-learning-assisted interpretation are identified as promising strategies for achieving more reliable structure-property correlations in EEG.