Spindle-like MOFs-derived porous carbon filled sulfonated poly (ether ether ketone): A high performance proton exchange membrane for direct methanol fuel cells

Abstract

The sulfonated spindle-like carbon derived from metal-organic framework, MOF-C-SO3H, has been employed as a filler for the SPEEK membrane. The obtained MOF-C-SO3H@SPEEK membrane shows improved properties as a PEM for DMFCs. In particular, with the presence of 3.0 wt% of MOF-C-SO3H, the MOF-C-SO3H@SPEEK membrane can exhibit higher proton conductivity and much lower methanol permeability than Nafion 115. The specific porous and sulfonated carbon structure is believed to play an important role in the high performance of the MOF-C-SO3H@SPEEK membrane. It helps the good dispersion of MOF-C-SO3H in the SPEEK matrix, decreasing the swelling ratio and methanol permeability of the membrane, and promotes the transport of protons through the membrane, improving the proton conductivity of the membrane. More interestingly, when used in the DMFCs, it can give maximum power density of 83.91 mW cm−2, which is ~50% higher than that of Nafion 115. This, together with its higher stability of the DMFC with the MOF-C-SO3H@SPEEK membrane than that with Nafion 115, suggests that the MOF-C-SO3H@SPEEK membrane is a promising proton exchange membrane for fuel cells.