Additive Manufacturing as a Design Enabler for Air-Breathing Electrochemical Devices: A PEM Fuel Cell Case Study.

Portable air-breathing electrochemical devices, particularly polymer electrolyte membrane fuel cells (PEMFCs), offer simple, lightweight, and compact power generation by using atmospheric oxygen as the oxidant. Their performance, however, depends strongly on cathode plate geometry that governs reactant transport, thermal and water management, and mechanical integrity. Conventional manufacturing has historically restricted this architectural design space. This perspective examines how additive manufacturing (AM) enables three-dimensional geometries that can overcome these constraints. An open columnar cathode plate for air-breathing PEMFCs is used as a case study to show how manufacturing-enabled design can improve passive transport, increase the hydrogen conversion efficiency, and integrate multiple functions within a compact component. The same design philosophy can then be extended to metal-air batteries, microbial fuel cells, direct methanol fuel cells, electrolyzers, CO2 electrochemical reactors, and electrochemical sensors. Finally, the remaining barriers and future opportunities associated with advanced materials, computational design, topology optimization, artificial intelligence, and digital manufacturing are discussed. Overall, AM is presented as a design-enabling platform for next-generation portable electrochemical devices.