TiO2 structural support effects on the durability and recovery characteristics of proton exchange membrane fuel cell electrodes

Proton-exchange membrane fuel cells (PEMFCs) have been deployed commercially in transportation applications; however, further enhancement of their durability remains essential for competitiveness with internal combustion engines. Among the various degradation pathways, cathode deterioration is particularly critical, with carbon support corrosion causing irreversible structural collapse within the electrode. Although structural additives have been proposed to mitigate such degradation, their inherent electronic or ionic conductivity has obscured the exclusive role of structural reinforcement. In this study, a star-shaped TiO₂ (ST) structure—characterized by low electronic and ionic conductivity as well as high corrosion resistance—is employed to isolate and evaluate the structural stabilization effect on electrode durability. Gas chromatography confirmed that ST addition did not alter the extent of carbon corrosion. Nevertheless, ST-containing electrodes exhibited superior preservation of electrode thickness, pore morphology, and double-layer capacitance compared with reference electrodes. Consequently, the optimized ST electrode demonstrated more than twice the durability of the baseline while maintaining comparable or superior initial performance. These findings confirm that mechanical and structural degradation, rather than conductivity loss, primarily limits PEMFC durability under carbon corrosion. This work provides the first experimental quantification of a pure structural stabilization effect, offering a new design paradigm for next-generation durable PEMFC electrodes.