Gradient membrane electrode assembly based on non-precious metal cathode for anion exchange membrane fuel cells

The cathode catalyst layer (CCL) in anion exchange membrane fuel cells (AEMFC) requires a highly stable structure for electrochemical reactions while maintaining high porosity for mass transfer. However, current non-precious metal-based membrane electrode assembly (MEA) often exhibit low catalyst mass activity, leading to high CCL loading and resulting challenges such as CCL delamination, low porosity, poor ion transport performance, and reduced durability. In this study, a gradient distribution strategy for anion exchange ionomer (AEI) and catalyst is implemented in the CCL based on the controllably synthesized Co@CNTs-900 catalyst, effectively optimizing the structure of CCL. Results demonstrate that compared to conventional MEA, the gradient-distributed MEA exhibits higher porosity, effectively reducing gas transport resistance, enhancing ion transport rates, and establishing a more efficient three-phase reaction interface. Notably, the MEA with AEI gradient distribution in CCL achieve a power density of 0.82 W cm −2 , with outstanding durability reaching 270 h at 0.2 A cm −2 and a voltage decay rate as low as 971.1 μV h −1 . This strategy significantly advance the optimization of existing CCL structures and provide important insights for future diversified MEA design research. • Preparation of cathode catalyst layers via gradient strategy. • Gradient-based AEI significantly increase the pore volume and conductivity of CCL. • Gradient strategies can effectively address the issue of CCL detachment. • An improved peak power density of 0.82 W cm −2 is obtained. • Durability over 270 h for continuous discharge operation at 0.2 A cm −2 .