Blue energy case study and analysis: Attack of chloride ions on chromia passive film on metallic electrode of nanogenerator

The corrosion issue has been considered as the greatest challenge in metallic devices, which will not only degrade the performance but also cause safety concerns. Within the Blue Energy framework, the metallic electrode in nanogenerators will always face the risk of chloride attack through different approaches in the long-term applications within the extreme oceanic conditions. Here in this work, the chloride ion accumulation in the passive film that initiates from the surface adsorption via the surface defects towards the internal migration has been unravelled in our case study and analysis. The underlying chloride ion migration mechanism will be ascribed to the anion Frenkel pair-like mechanism as a defect induced energy transfer process. The molecule dynamic simulations under 300 K also support the evident damage of the passive film induced by the subtle chloride attack. The in-depth understanding of the corrosion process from a microscopic perspective can further assist for diagnosing and remediation of corrosion of the future nanogenerator electrode and other metallic devices.