N-doped Carbon Additives in the Anode Catalyst Layer for Improved Pore Structure and Water Management of Anion Exchange Membrane Fuel Cells.

Abstract

Membrane electrode assembly (MEA), as the core component of anion exchange membrane fuel cells (AEMFCs), directly determines their performance. However, the peak power density (PPD) and durability are often limited by the flooding issues at the anode catalyst layer (ACL), especially for those without enough pores, resulting from water generated by the hydrogen oxidation reaction. In this study, N-doped carbon (NC) with large pore size, excellent dispersion, and rich defects are synthesized by the functional group self-assembly technique and is applied as an additive for ACL, which not only increases the pore volume and improves water management to avoid the flooding issues, but also enhances the conductivity of ACL. As a result, the MEA containing NC additive with optimized physicochemical properties and content show much improved PPD and durability. The PPD of the optimized MEA increased by 25.7%, from 1.36 to 1.71 W cm-2, and the durability under 0.2 A cm-2 is extended from 280 to 1000 h, with a voltage decay rate of only 186.6 µV h-1. This study provides empirical guidance for other AEM-based energy conversion devices (e.g., water electrolyzers, flow redox cell).