Recent advances and applications of electrochemical mass spectrometry for real-time monitoring of electrochemical reactions

Real-time monitoring of electrochemical reaction is crucial for advancing energy conversion and storage, electrocatalysis, organic electrosynthesis, and electroanalysis. Despite progress in in-situ spectroscopic and electrochemical techniques, these methods fail to directly resolve and track multiple electrogenerated species simultaneously during electrochemical processes. Electrochemical mass spectrometry (EC-MS) bridges this gap by providing direct molecular-level compositional and structural information while simultaneously monitoring the evolution of newborn species at the electrode-electrolyte interfaces (EEIs). Propelled by the ongoing improvements in ionization sources and electrochemical cells, EC-MS methods have broadened the functions scope from online detection of reaction products to rapid capture of fleeting intermediates, and most recently, to simultaneous real-time tracking of multiple intermediates dynamics. This progressive advancement establishes EC-MS as a robust methodology for mechanistic investigation of electrochemical reactions. This review focuses on the recent advances in the EC-MS methods and the applications in exploring organic electrosynthesis, electrocatalysis, lithium-ion batteries (LIBs) and electrochemiluminescence (ECL). Finally, we outline the current limitations and future directions for EC-MS technology, forecasting its expanding utility in electrochemical reaction monitoring.