13C-Labeled Mesoporous N-Doped Carbon Nanospheres and N-Doped Hydrothermal Carbon Aerogels as Model Materials for Carbon Corrosion Determination in Electrode Structures

Abstract

Carbon nanostructures are widely used in electrodes for energy storage and conversion applications due to their unique properties. Unfortunately, carbon materials can degrade under harsh oxidative electrochemical conditions, leading to carbon corrosion to CO and CO₂. Therefore, it is necessary to develop methods for in situ monitoring of carbon corrosion during system operation. In this work, ¹³C labeling is introduced into mesoporous N-doped carbon nanospheres and N-doped hydrothermal carbon aerogels, allowing the selective detection of ¹³CO₂ via electrochemically coupled mass spectrometry during carbon corrosion. Different labeling degrees (unlabeled, partially and fully labeled) are achieved while maintaining the carbon material's morphology and physicochemical properties. These materials and mixtures of unlabeled and fully labeled materials are subjected to accelerated stress tests to evaluate their carbon corrosion behaviour. The results demonstrated that ¹³CO₂ can only be found in labeled samples, regardless of whether they are partially labeled or a mixture of unlabeled and fully labeled materials. This technique facilitates in situ detection of carbon corrosion, even in the presence of a CO₂ background in air. More importantly, it allows us to distinguish between corrosion originating from the carbon material itself and other carbon-containing components within electrochemical systems, thereby advancing the understanding of carbon materials in such systems.