In-Depth Analysis of PEM Electrolyzer Structure and Working Principle

1. Overview of PEM Electrolysis Technology

Proton Exchange Membrane (PEM) water electrolysis technology is one of the most promising green hydrogen production technologies today. Compared to traditional alkaline electrolysis, the PEM electrolytic system uses a solid polymer electrolyte membrane instead of liquid electrolyte, fundamentally solving the problem of gas crossover permeation. This technology originated in the 1960s from fuel cell technology developed by General Electric for aerospace projects in the United States and has gradually achieved commercial application after more than half a century of development.

The core advantages of the PEM electrolytic system are mainly reflected in three aspects: first, its proton exchange membrane has an extremely low gas permeability rate, ensuring that hydrogen purity can reach over 99.99%, requiring only simple dehydration treatment to meet industrial hydrogen standards; second, the electrolyzer adopts a zero-gap compact structure design that significantly reduces ohmic resistance, allowing system efficiency to exceed 75%; third, it features rapid response characteristics capable of power adjustment within seconds, making it particularly suitable for use with fluctuating renewable energy sources. Currently, high equipment costs remain a major bottleneck limiting large-scale applications of PEM electrolysis technology, with precious metal catalysts and special materials accounting for over 60%.

2. Detailed Explanation of Core Components in PEM Electrolyzers

2.1 Membrane Electrode Assembly The Membrane Electrode Assembly (MEA) is the heart component of a PEM electrolyzer composed as an integrated structure consisting of proton exchange membrane, catalyst layer, and gas diffusion layer. Currently commercialized PEM membranes primarily utilize perfluorosulfonic acid polymer materials; representative products include DuPont's Nafion series and Dow Chemical's Dow membranes. These materials maintain stable proton conduction performance under harsh conditions such as strong acidity (pH ≈ 2) and high potential (1.8-2.0V).

Research on catalyst layers is key to reducing costs associated with PEM electrolysis systems. The anode side typically employs precious metals like Iridium (Ir), Ruthenium (Ru), or their oxides as oxygen evolution reaction (OER) catalysts; among them IrO2 stands out due to its excellent electrochemical stability becoming mainstream choice recently . Latest studies indicate that constructing Ir-Ru binary alloys or introducing Sn as a third component can significantly enhance catalytic activity and durability . For instance ,the Ir0 .6Sn0 .4catalyst developed by Dalian Institute Of Chemical Physics at Chinese Academy Of Sciences requires only 1 .82 V operating voltage at current density up To two A/cm² while extending lifespan by more than thirty percent.

2 .2 Bipolar Plates And Flow Field Design Bipolar plates serve multiple functions including current conduction ,gas management,and heat dissipation within an electrolyzer ;their cost accounts for approximately forty-eight percent total cost.The most commonly used bipolar plate material consists titanium alloy which usually needs gold plating or carbon coating applied reduce contact resistance.Advanced flow field designs such as interdigitated channels,snake-like pathways optimize two-phase flow ensuring uniform distribution reactants effectively removing generated bubbles. nIt’s worth noting when operating under high-pressure conditions,bipolar plates face severe challenges regarding mechanical strength airtightness.Some manufacturers adopt thin designs combined reinforced polymer frames maintaining structural integrity while controlling thickness below two millimeters enabling single-cell working pressure exceeding six MPa. n###3.Technical Challenges Development Trends n **3 .1 Precious Metal Reduction Technologies **Reducing usage precious metals represents core pathway lowering overall costs associated PEMelectrolyte systems.Current research focuses three main directions:first developing highly dispersed catalysts,such NSTF( Nano Structured Thin Film )technology from company drops iridium loading down point twenty-five mg/cm² ;second exploring non-precious metal alternatives like Co-MOF catalyst developed NREL lab costing merely one-twentieth traditional options;third optimizing carrier materials where porous titanium-based carriers outperform conventional carbon counterparts better corrosion resistance conductivity, n **3 .2 System Integration Optimization **A complete PEMelectrolyzing setup includes not just stacks but also auxiliary components like power conversion units ,water treatment facilities,gaseous separation processes(BOP).Modern devices generally feature modular architectures capable generating individual stack powers exceeding MW levels.For example,a ninety-five kW module mentioned utilizes IGBT switching tech achieving conversion efficiencies surpassing ninety-eight percent paired PLC control systems facilitating millisecond-level responses.System-wide thermal management equally crucial employing deionized water cooling loops simultaneously replenishing electrolyte recovering waste heat functionalities., n ###4.Commercialization Status According International Energy Agency(IEA)data indicates global installed capacity surpassed GW threshold during year twenty-two.Leading firms Siemens Energy ITM Power have launched commercial offerings boasting five MW output efficiencies beyond seventy-four percentage lifespans exceeding eighty thousand hours.Cost-wise present level stands around three dollars/kg projected drop below two dollars/kg mark by year thirty.Furthermore noteworthy domestic breakthroughs occurred China concerning critical material localization Shandong Dongyue Group’s Proton Exchange Membranes nearing international advanced standards thus providing vital support reducing equipment expenses.Future trends suggest continued focus enhancing efficiency scaling operations minimizing expenditures EU Hydrogen Strategy aims establish forty GW capacity by year thirty alongside China's fourteen five-year plan prioritizing this sector amid declining renewable electricity prices improving carbon pricing mechanisms suggesting broader adoption heavy industries steel chemical sectors.