A novel nanocomposite proton-exchange membrane (PEM) was obtained by combined electrospinning and solution casting of a composite solution of sulfophenylated poly(ether ether ketone ketone) (SP-PEEKK) and maleic anhydride modified nanocellulose (MN). SP-PEEKK was prepared by polymerization between phenyl hydroquinone and 1,4-bis(4-fluorobenzoyl)benzene followed by post-sulfonation. Nanocellulose (NCC) was prepared by the acid treatment of MCC with sulfuric acid, and MN with carboxyl group was obtained by modifying NCC with maleic anhydride. PEMs with 2% MN (MN2)...