Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE A SPEEK/CNCs composite membrane with 3 wt% cellulose nanocrystals achieves a tensile strength of 26 MPa and proton conductivity of 0.209 S cm−1 at 90°C. When evaluated in an electrochemical hydrogen compressor up to 5 MPa, the membrane substantially reduces compression time, energy consumption, and hydrogen back-diffusion compared with pristine SPEEK and Nafion 117, demonstrating its potential for high-pressure hydrogen compression applications.


ABSTRACT
Developing durable and high-performance proton exchange membranes with low hydrogen crossover is critical for advancing electrochemical hydrogen compressors (EHCs) technology. Here we report the properties of SPEEK/CNCs composite membranes reinforced with cellulose nanocrystals (CNCs) for the electrochemical compression systems. The physicochemical properties, including the morphology of composite membranes, water uptake (W
up), mechanical strength, ion exchange capacity (IEC), and proton conductivity (σ
H+), were evaluated. The composite membrane with 3 wt% CNCs exhibited a tensile strength of 26 MPa, which is approximately 1.9 times that of pristine SPEEK (13.7 MPa) and 1.5 times higher than that of Nafion 117 (17.6 MPa). The proton conductivity of this membrane reached 0.209 S cm−1 at 90°C, the highest among all evaluated membranes. The performance of EHCs was tested for voltage, compression time, and energy efficiency at pressures up to 5 MPa. Incorporation of nanocellulose crystals (CNCs) into SPEEK membrane resulted in better performance in energy consumption and energy efficiency with shorter compression time in EHC system. In addition, the composite membranes showed low hydrogen back-diffusion loss.