Recent progress on insights into surface and interface modification of carbon electrodes and their enhancing mechanism of flow battery performance

As the core functional unit of the flow battery system, the surface and interface microenvironment of carbon electrode materials determine the electrochemical polarization behavior and energy storage performance. From the perspectives of microstructural regulation and electronic structure modulation, this review systematically examines carbon electrode surface/interface modification strategies and their mechanisms for enhancing flow battery performance. It systematically discusses how microstructural regulation and electronic structure modulation can effectively optimize mass transport kinetics, charge transfer efficiency, and electrocatalytic activity, consequently mitigating electrode polarization. Particular emphasis is placed on unveiling the underlying structure-performance relationships and the structure-function interplay between the electrode microenvironments and their resultant electrochemical properties. Furthermore, advanced characterization techniques, including synchrotron radiation, X-ray absorption spectroscopy, in situ Raman spectroscopy, and first-principles calculations, are summarized to elucidate the dynamic evolution of carbon electrodes. These methods provide crucial insights into how surface chemical modifications reconstruct electronic structures and active sites, leading to suppressed concentration and electrochemical polarization. Building on recent progress in atomically dispersed metal electrocatalysts, we also propose the rational design of single-atom catalyst modified carbon electrodes. Moreover, synergistic strategies integrating high-throughput computation with machine learning are envisioned to establish multidimensional predictive models based on band structure, adsorption energy, and reaction pathways, thereby addressing the bottlenecks of metal utilization efficiency and structure-performance correlation. Overall, this review delivers a multidimensional theoretical framework and technological roadmap for the rational design and practical deployment of high-performance carbon electrodes in next-generation flow batteries.