Incorporation of ultralow manganese dioxide for improving the durability of sulfonated poly (ether ether ketone) membranes in passive direct methanol fuel cell

In this study, a novel composite membrane is prepared by incorporating the manganese dioxide (MnO₂) nanorod into sulfonated poly (ether ether ketone) (SPEEK) matrix to wrestle with the limitation of poor durability on the development of SPEEK membranes. In Fenton's solution, the start broken-up time of the composite membrane with only 2.5% MnO₂ loading, prepared by the solution-casting method, is about 4 times that of pure SPEEK membrane. This suggests that the MnO₂ addition effectively improves the durability of SPEEK membranes. In the passive direct methanol fuel cell (DMFC) test, SPEEK-2.5% MnO₂ membrane exhibits the max power density of 24 mW cm⁻² (at 8 M methanol and 25 °C) and better durability than pure SPEEK membrane, as well as the possibility of SPEEK-MnO₂ composite membrane for the fuel cell application. The addition of low-cost MnO₂ improved the stability of the SPEEK membrane, contributing to the promotion of its commercialization process.