NOVELTY - A fuel cell membrane comprises at least one sulfonated aromatic polyether copolymer containing a poly-arylen-ether-ketone (PEK) moiety or its sulfonated derivative.    USE - For production membrane useful in assembling of fuel cell (claimed).    ADVANTAGE - The spiro-bis-indanol lacks acidic receptor sites and is therefore not affected by an acid environment. Sulfonated derivatives of spiro-bis-indanol have satisfactory mechanical and oxidative stability and are thus suitable as starting materials for the synthesis of the membranes (particularly proton exchange). Derivatives of 4,4'-(hexafluoroisopropylidene) diphenol (BPAF) have a better chemical stability. The membranes exhibit good mechanical properties, stability in oxidative and acid conditions, no cross-over of fuel and reaction gases across the membrane, easy processability (as they are soluble in most organic solvents), easy functionalization, innovation and improvement of the membrane, and low production costs.    DETAILED DESCRIPTION - A fuel cell membrane comprises at least one sulfonated aromatic polyether copolymer containing a poly-arylen-ether-ketone (PEK) moiety or its sulfonated derivative. The copolymer is of formula H-(-O-Ar1-O-Ar2-)n-Z (I).    Ar1=group of formula (Ia);    X=spiro-bis-indanyl (SBI) of formula (Ib) or 4,4'-(hexafluoroisopropylidene) diphenol (BPAF) of formula (Ic);    Y'=H or SO3H;and    Ar2=group of formula (II);    W'=CO or SO2;    Z=OH or Cl;and    n=2-50.    At least one of Ar1 or Ar2 comprises at least one sulfonic group. An INDEPENDENT CLAIM is included for production of a fuel cell membrane having sulfonated aromatic polyether copolymer (I) involving    (A) synthesizing a protected diphenylketone (DPK) selected from the group comprising 4-chloro-4'-hydroxybenzophenone (CHDPK) and 4-fluoro-4'-hydroxybenzophenone (FHDPK) (preferably FHDPK);    (B) condensing a HO-X-OH compound selected from spiro-bis-indanol, 4,4'-(hexafluoroisopropylidene) diphenol (BPAF), or their sulfonated derivatives and the protected diphenylketone to form at least one HO-Ar1-OH compound protected on the hydroxyl groups;    (C) hydrolyzing the protected HO-Ar1-OH compound to form at least one HO-Ar1-OH compound; and    (D) polycondensing the HO-Ar1-OH with a J-Ar2-J compound.    J=leaving group.