Surface modification strategies for direct methane and direct ammonia solid oxide fuel cell anodes: current approaches and future directions

Abstract

Solid oxide fuel cells (SOFCs) offer high efficiency and fuel flexibility for next-generation energy conversion, yet direct utilization of methane and ammonia remains hindered by anode degradation from carbon coking, nitridation, and sluggish reaction kinetics in conventional Ni-based cermets. This review systematically examines surface modification strategies, specifically infiltration, exsolution, and atomic layer deposition (ALD), to enhance anode stability and performance. Emphasis is placed on ALD as an emerging, transformative technique, prized for its atomic-level precision, superior conformality over complex porous architectures, and ability to achieve low catalyst loading with controllable uniformity—challenges that conventional methods often struggle to address. Comparative literature analysis confirms that ALD surface modifications enhance anode performance and stability more effectively than infiltration (nonuniform) or exsolution (limited tunability) by enabling precise engineering of triple-phase boundaries and protective interfaces. Looking forward, scalable ALD processes, multifunctional multilayers, and hybrid integrations are identified as key avenues for enabling the commercialization of durable, direct-fueled SOFCs.