High Safety Fuel Cells Based on Gas Diffusion Layer Suppressed Uneven Current and Thermal Runaway

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AbstractThermal runaway poses a critical safety concern for fuel cells, significantly impairing their performance and durability. Uneven current often leads to uneven temperature, exacerbating the risk of thermal runaway. The inadequate electrical and thermal conductivity of the gas diffusion layer (GDL) is identified as the primary cause of the safety issues. To address this, a multilayer composite gas diffusion layer (MC‐GDL) is proposed and designed to enhance both electrical and thermal conductivity. The in‐plane electrical conductivity of the MC‐GDL reaches an impressive 9.1 × 104 S m−1. Under extreme uneven current, the fuel cell's performance with MC‐GDL only declines by 3.7%, compared to a substantial 58.1% decline observed with commercial GDL. Additionally, the in‐plane thermal conductivity of the MC‐GDL is notably high at 337.0 W m−1 K−1. Under extreme uneven temperature, the maximum temperature of Nafion membrane in fuel cell equipped with MC‐GDL is only 84.2 °C significantly lower than the 180.7 °C observed with commercial GDL. Consequently, the MC‐GDL effectively prevents the melting, thinning, and perforation of the Nafion membrane, thereby mitigating thermal runaway. Furthermore, the superior electrical and thermal conductivity of MC‐GDL can enhance the safety of other electrochemical devices by minimizing uneven current and thermal runaway.