Double cross-linked polyetheretherketone proton exchange membrane for fuel cell

► The proton exchange membrane was prepared via two steps of crosslink. ► The membrane exhibited relatively high proton conductivity compared to Nafion. ► The second crosslink reduced the water uptake and methanol cross-over. ► The preparation of the membrane did not involve the use of expensive materials. ► Good performance of direct methanol fuel cell was carried out in this work.