Advancing High-Temperature Electrochemistry: New Insights into Chlorine Evolution in Molten Salts

ECS Advances is pleased to highlight a recent article that makes an important contribution to the understanding of high-temperature electrochemical processes: “Evaluating Platinum, Gold, Glassy Carbon, and Graphite Anodes for Chlorine Evolution in Molten Calcium Chloride Salt.” Authored by Cameron Vann, Shelssie Klvacek, Carlos Mejia,  and Devin Rappleye, this work provides timely and practical insights into materials selection for chlorine evolution under extreme conditions.

The chlorine evolution reaction (CER) in molten calcium chloride (CaCl₂) carries several critical technologies, including chlorination, metal refining, rare earth processing, and the treatment and purification of used nuclear fuel. Despite its importance, long-term anode stability and performance in molten salt environments remain persistent challenges. This study directly addresses those challenges through a systematic comparison of four commonly considered anode materials: platinum, gold, glassy carbon, and graphite.

Using consistent electrochemical conditions, the authors evaluated each material based on chlorine gas evolution, kinetic behavior, and structural robustness. Chlorine generation was directly confirmed for platinum, glassy carbon, and graphite using quadrupole mass spectrometry, while inductively coupled plasma mass spectrometry revealed a critical drawback for noble metals. Both platinum and gold exhibited significant mass loss and contributed to contamination of the molten salt bath—an important finding for researchers and engineers designing durable high-temperature electrochemical systems.

In contrast, glassy carbon and graphite demonstrated stable, sustained CER activity, positioning them as especially promising anode materials for molten CaCl₂ applications. The study further strengthens this conclusion by extracting kinetic parameters for the CER on glassy carbon through Tafel analysis, offering valuable mechanistic insight alongside practical performance data.

Taken together, these results support the use of glassy carbon and graphite anodes in chloride-based electrochemical processes, particularly those aimed at chloride volatility separation and purification of used nuclear fuel and rare earth elements. The work exemplifies the kind of rigorous, application-relevant research that ECS Advances seeks to amplify—research that bridges fundamental electrochemistry and real-world technological impact.

We congratulate Cameron Vann, Shelssie Klvacek, Carlos Mejia, and Devin Rappleye on this excellent contribution and invite readers to explore this article in full.

Read the article, share it with colleagues, and join the growing community advancing electrochemical science through ECS.

To discover more innovative and interdisciplinary research across electrochemistry and solid-state science, we also encourage you to browse other recent publications in ECS Advances.

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