Reactive Force Field-Based Atomistic Studies Exploring the Effects of h-BN Nanosheets and Water on the Tensile Strength of Sulfonated PEEK for Fuel-Cell Applications

A Mittal and A Parashar, ACS APPLIED NANO MATERIALS, 8, 13838-13850 (2025).

DOI: 10.1021/acsanm.5c02413

This study explores the effects of nanoparticles, degree of sulfonation (DS), and hydration on the structural properties of polyether-ether- ketone (PEEK) and sulfonated PEEK (S-PEEK) membranes using molecular dynamics (MD)-based simulations. The long-term structural durability of hydrocarbon-based proton exchange membranes is critical for their successful commercialization in fuel cell applications. The incorporation of nanoparticles significantly enhances the mechanical strength of polymer-based membranes. Compared to PEEK, S-PEEK exhibits superior electrochemical and thermomechanical properties, making it a promising membrane material. However, increasing DS improves proton conductivity at the cost of structural stability, which declines drastically due to swelling-induced degradation. S-PEEK shows reduced mechanical strength at lower DS levels (e.g., DS < 30%). During fuel cell operation, immersion in water and electrolytes further weakens the membrane. At the atomistic level, the mechanism was explored using the radial distribution function (RDF). This reveals that water clustering (RDF peak at 1.42 & Aring;) and reduced hydrogen bonding with the polymer's polar groups contribute to mechanical degradation. This effect is more pronounced in pristine S-PEEK than in hexagonal boron nitride (h-BN)-reinforced S-PEEK, highlighting the reinforcing role of nanoparticles in improving membrane durability. These findings provide valuable insights into the structural stability of polymer-based proton exchange membranes and the potential of nanoparticle reinforcement for enhancing long-term performance.

Return to Publications page