Proton exchange membrane for fuel cell (FC) is a promising environmentally friendly and oil-free technology. One of its key components is the polymer electrolyte membrane acting as separator and proton conductor. Improving both the performances and durability of the membrane is a crucial issue. Different strategies have been explored to improve the mechanical properties of the membrane and to reduce the ageing impact. Despite a lot of progress, their functional properties (conductivity, water sorption, thermomechanical properties, chemical stability…) stay below expectation when operated above 100°C whereas higher operating temperature (150°C). Therefore, there is currently an increasing interest in using reliable alternative membranes that are capable of operating at higher temperatures, low relative humidity to ensure long term performances. Popular candidates are polyaromatic polymers like sPEEK which present good mechanical properties at high temperatures but poor functional properties (proton conductivity and durability in FC). We will demonstrate that the sPEEK performances can be significantly improved using a suitable hydrothermal treatment up to becoming equivalent to that of Nafion the benchmark material. SAXS analyses performed on hydrothermally treated sPEEK show that the increase in molecular mobility induced by the pretreatment (water, temperature) allows a gradual nano-structuration of the membrane and a sharp increase of its proton conductivity. To improve the membrane durability, we have developed an original strategy based on the insertion of a chemical stabilizing network by a sol-gel process. These hybrid membranes will combine excellent proton conductivity at high temperature and low relative humidity and will be stable under hard operating conditions. The process involved should be universal allowing to improve the membrane properties of common ionomer membrane