Self-assembly of porous curly graphene film as an efficient gas diffusion layer for high-performance Zn-air batteries

To enhance the performance of Zn -air batteries (ZABs), it is essential to improve the performance of all components at the cathode, rather than solely focusing on the activity of the electrocatalyst. For example, the intrinsic ORR activity of the widely used Pt/C electrocatalyst remains the best in a comprehensive evaluation, but its performance in ZAB is limited. In this study, we proposed that the discrepancies between electrocatalysts and ZAB cathodes were attributed to the deficiency of the gas diffusion layer (GDL). Subsequently, we developed a facile, energy-saving, and eco-friendly method to fabricate a porous curly graphene film (PCGF) GDL. In comparison with traditional GDL, the PCGF GDL exhibits curly aggregation, excellent conductivity, and porous microstructure. These features enhance electrocatalyst dispersion, charge collection, and gas transport, leading to high ZAB performance. Specifically, Pt/C@PCGF ZAB shows outstanding performance with a peak power density of 329 mW cm -2 , high round -trip efficiency of 72% and 62% at 2 and 10 mA cm -2 , and the round -trip efficiency can maintain 60% after 250 cycles at 10 mA cm -2 . These results significantly outperform those achieved with traditional GDL. Furthermore, the PCGF GDL can be universally used for various electrocatalysts, including precious metals, metal compounds, and carbon materials.