A review of understanding electrocatalytic reactions in energy conversion and energy storage systems via scanning electrochemical microscopy

To address climate change and promote environmental sustainability, electrochemical energy conversion and storage systems emerge as promising alternative to fossil fuels, catering to the escalating demand for energy. Achieving optimal energy efficiency and cost competitiveness in these systems requires the strategic design of electrocatalysts, coupled with a thorough comprehension of the underlying mechanisms and degradation behavior occurring during the electrocatalysis processes. Scanning electrochemical microscopy (SECM), an analytical technique for studying surface electrochemically, stands out as a powerful tool offering electrochemical insights. It possesses remarkable spatiotemporal resolution, enabling the visualization of the localized electrochemical activity and surface topography. This review compiles crucial research findings and recent breakthroughs in electrocatalytic processes utilizing the SECM methodology, specifically focusing on applications in electrolysis, fuel cells, and metal-oxygen batteries within the realm of energy conversion and storage systems. Commencing with an overview of each energy system, the review introduces the fundamental principles of SECM, and aiming to provide new perspectives and broadening the scope of applied research by describing the major research categories within SECM.