NOVELTY - Solid polymer electrolyte composite membrane (11) comprises: ceramic support (13) having opposing top surfaces (17) and bottom surfaces (19) and many pores extending from the top to bottom surface, where at least some of the pores are positioned in a peripheral portion of the ceramic support and at least some of pores are positioned in a non-peripheral portion of the ceramic support, and the pores are positioned in a greater concentration in the non-peripheral portion than in the peripheral portion; and a first solid polymer electrolyte (15) at least partially filling some of the pores.    USE - The solid polymer electrolyte composite membrane is useful in electrochemical devices including fuel cells, electrolyzers, sensors, gas concentrators, gas compressors, supercapacitors, ultracapacitors and industrial electrochemical process units.    ADVANTAGE - The solid polymer electrolyte composite membrane exhibits excellent dimensional stability when contacted with swelling agents, including water or alcohols, the catalyst ink can be directly applied to the membrane.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) preparing a solid polymer electrolyte composite membrane, comprising providing a ceramic support having the top surface and the bottom surface, lasing at least one pore in the ceramic support, where the pore extends transversely from the top surface to the bottom surface and filling at least one of the pore with a first solid polymer electrolyte; and    (2) preparing a perfluorosulfonic acid polymer, comprising providing a sulfonyl fluoride precursor of the perfluorosulfonic acid polymer and adding a weak base to the sulfonyl fluoride precursor to convert the sulfonyl fluoride precursor to the perfluorosulfonic acid polymer.    DESCRIPTION OF DRAWING(S) - The figure shows a sectional view of the solid polymer electrolyte composite membrane.    Solid polymer electrolyte composite membrane (11)    Support (13)    Solid polymer electrolyte (15)    Top surface (17)    Bottom surface (19)