Utility on PEM-based Fuel Cells conversion into Energy

Green hydrogen produced via electrochemical splitting of water, powered by variable renewable energy, is gaining recognition as a key component of society's transition to low-carbon energy, particularly for the decarbonization of hard-to-abate industrial sectors such as steel, refining, and chemicals. As an energy carrier, green hydrogen can be flexibly converted and stored, enabling the long-term storage of large amounts of renewable energy, which is crucial for facilitating rapid, large-scale renewable energy development. The global total hydrogen indicates a need for 140-170 MtH₂eq by 2030 and 430-600 MtH₂eq by 2050 (Wang et al., 2025).  Proton exchange membranes (PEMs) are essential components of both proton exchange membrane fuel cells and proton exchange membrane water electrolysers, two key technologies critical to the sustainable energy infrastructure of the future. It converts the chemical energy of hydrogen and oxygen into electrical energy, providing a zero-emission alternative to conventional combustion engines. Meanwhile, PEMWEs enable the storage of renewable electricity in the form of hydrogen fuel through the electrolysis of water. In both applications, the PEM functions as a selective ion-conducting electrolyte, allowing proton transport while preventing reactant mixing, which is crucial for efficiency and safety.

To prepare, membrane thickness directly affects proton conductivity, gas cross-over and mechanical stability, making it one of the most important design parameters for PEM fuel cells. In the figure, experiments demonstrate that thinner membranes enhance the structure design and improve their properties during the conversion of energy cells. A molecular level of understanding of PEM functionality further underscores the importance of membrane thickness. It consists of hydrophobic domains that absorb water, creating pathways for efficient proton conduction. Hydrogen energy is widely utilised in this application, ranging from hydrogen cars and drones to naval submarines and marine unmanned systems, showcasing its versatility and emphasising the importance of optimising PEMs to meet diverse application needs. If a thicker membrane structure is good in the diffusion layer and enhances mechanical robustness, it incurs higher voltage losses and reduced efficiency. In this study, fabricated Simple PEM-based fuel cells for hydrogen to electricity with varying thickness, compared their performance, and analysed their electrochemical behaviour using EIS (Electrochemical impedance spectroscopy) to evaluate the effect of membrane thickness on device performance. Our results reveal that performance was the primary focus of our analysis. Durability testing results were not included, as it is widely recognised that thicker membranes generally provide better durability.

 

Figure: Preparation of PEM (Photon Exchange Membrane)-Based Fuel Cell for Energy Conversion

Material	Function
PEEK powder	Base polymer for the membrane
DMF (Dimethylformamide)	Solvent for dissolving PEEK
Sulfuric acid (H₂SO₄) or Chlorosulfonic acid (ClSO₃H)	Sulfonating agents
Deionized water	Washing and protonation
Glass plate	Casting surface for the membrane
Vacuum oven	For drying membranes

Procedure for the preparation of PEM for fuel cells

Prepare a solution for the dissolution of PEEK in DMF. Dissolve PEEK in DMF at a ratio of about 10–20 wt%. Stir the mixture at 80–120°C for several hours (typically 6–12 hours) under reflux until a homogeneous solution is obtained. Pour the viscous PEEK/DMF solution onto a clean glass plate or Petri dish to cast the membrane. Use a doctor blade or film applicator to ensure even thickness (100–200 µm typical). Dry at room temperature overnight, then in a vacuum oven at 80°C to remove residual DMF. Sulfonation of PEEK (to make it proton-conductive). Immerse the dried PEEK film in chlorosulfonic acid (ClSO₃H) or concentrated sulfuric acid at room temperature or 50–60°C for 12–24 hours. This introduces –SO₃H groups, making it a SPEEK (sulfonated PEEK) membrane.

PEEK+SO₃→SPEEK

Washing and Protonation Wash the sulfonated membrane thoroughly with deionised water to remove acid. Optionally, treat with 0.5 M H₂SO₄ and then wash again with DI water. Store in DI water to keep hydrated. 

Design of the fuel cells