The performances of electrochemical systems are often limited by the charge and mass transfer along surfaces and across interfaces. Fundamental understanding of these electrochemical processes, especially the rate-limiting steps, is vital to achieving rational design of a new generation of intermediate-temperature fuel cells powered by a wide variety of readily available fuels. Also, surface modification has been successfully used to dramatically enhance electro-catalytic activity and durability of electrode materials. This presentation will highlight some recent advances in surface modifications and characterization of electrodes in energy storage and conversion systems. Surface enhanced Raman spectroscopy (SERS) has been used for probing and mapping new phases and reaction intermediates on electrode surfaces under or near operating conditions. It has also been demonstrated that SiO₂ shell isolated Ag nanoparticles have excellent chemical and thermal robustness and stability for in situ SERS study of electrode materials under in situ or operando conditions, providing valuable information on reaction intermediates or structural changes that critically influence the performance and stability of the electrodes. Further, synchrotron-based X-ray absorption spectroscopy (XAS) and XPS have been used to characterize the local atomistic structure and oxidation state of electrode surfaces and interfaces, which may critically affect the activation or degradation processes of electrodes. These experimental studies, together with modeling and simulation, have helped us to gain important insights into the mechanisms of chemical and energy transformation, electro-catalytic reactions, and degradation processes, providing valuable guidelines for rational design of new electrode materials, surfaces, and interfaces with desired functionalities.