Mae Hwa Tai0000-0002-8952-4630Hui San ThiamTee Shiau Foon0000-0002-4082-3322Yun Seng Lim0000-0001-6467-0239Bernard Saw L H0000-0001-5867-9843Soon Onn Lai2025-10-162025-10-162025-02-2410.1002/app.56931https://dspace-cris.utar.edu.my/handle/123456789/11514Proton exchange membranes (PEMs) in direct methanol fuel cells (DMFCs) transport protons while minimizing fuel crossover. However, commercial Nafion membranes face durability and methanol permeability issues. This study introduces a novel self-healable mesoporous silica (MSN) modified sulfonated poly(ether ketone) (SPEEK)/polyvinyl alcohol (PVA) membrane to improve DMFC efficiency and longevity. The composite membrane comprising 3 wt% MSN (S/PVA/MSN3) shows proton conductivity comparable to the pristine SPEEK, despite the inclusion of non-conductive PVA. MSN's large specific surface area and high porosity enhance water retention and facilitate proton transport. The methanol permeability of S/PVA/MSN3 is reduced by 29% compared to the pristine SPEEK, attributed to the combined effect of PVA's superior selectivity for water over methanol and the tortuous pathways created by MSN. Thanks to its improved selectivity, a DMFC with S/PVA/MSN3 achieves a remarkable open-circuit voltage (OCV) of 0.63 V, even with a high methanol concentration of 8 M, and a peak power density of 8.79 mW cm(-2), which is 2.13 times greater than the commercial Nafion 117. Moreover, S/PVA/MSN3 demonstrates significant recoveries of 91% in OCV and 87% in maximum power output following damage and self-healing. These findings suggest that the self-healable S/PVA/MSN has the potential for future use in DMFCs.enPROTON-EXCHANGE MEMBRANEPOLYMER ELECTROLYTE MEMBRANESCOMPOSITE MEMBRANESPERFORMANCE EVALUATIONPOLY(VINYL ALCOHOL)SPEEKOXIDEACIDjournal-article