# Proton-exchange membrane fuel cell A proton-exchange membrane fuel cell runs the reaction canon quietly. [[Hydrogen]] is oxidised at the anode, its protons cross a polymer membrane while its electrons take the external circuit, and at the cathode they rejoin with [[Oxygen]] to make [[Water]]. Same [[Combustion|combination]], no flame, and a [[Voltage]] instead of heat. ## Water management is the whole engineering problem The membrane conducts protons only while it is hydrated, so it must stay wet — but the cathode is making [[Water]] continuously and flooding it starves the electrode of [[Oxygen]]. The cell therefore lives inside a narrow window, and running it is a [[Two-phase_flow]] control problem more than a chemical one, with [[Surface_tension]] deciding whether liquid clears the channels. Low operating temperature makes it start fast, which suits vehicles on the [[WT!Transportation_Center_of_Excellence|transportation]] bridge, at the price of needing very pure [[Hydrogen_production|hydrogen]] and a platinum catalyst. **Reads with:** *Electrolysers, Fuel Cells and Batteries: Analytical Modelling (2024)* — [OTL record](https://open.umn.edu/opentextbooks/textbooks/electrolysers-fuel-cells-and-batteries-analytical-modelling) · [download](https://books.open.tudelft.nl/home/catalog/book/176). Seeded from the Thury Hydrodynamics Apex Spine book shelf. **On the spine:** [[Fuel_cell]] · [[Electrochemistry]] · [[Oxyhydrogen]] · [[Two-phase_flow]] · [[WT!Thury_Hydrodynamics_Compendium]]. ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Proton-exchange_membrane_fuel_cell) : [Wikitube](https://en.wikitube.io/wiki/Proton-exchange_membrane_fuel_cell) ## Previous hub tags Hubs: `Life_Physics`, `Systems`. Portals: [[PORTAL_Thury_Hydrodynamics_Apex_Spine]], [[PORTAL_Hydrogen]], [[PORTAL_Energy]]. --- *Apex Spine wave · 2026-09-10 · stub · microsim layer deferred.*