New hybrid inorganic-organic proton conducting membranes containing a ZrTa nanofiller dispersed in a Nafion 1 matrix are described. The ZrTa nanofiller exhibits a ''core-shell'' morphology, where the harder ZrO 2 forms the ''core'', which is covered by a ''shell'' of the softer Ta electrode assembly (MEA) containing the hybrid membrane is better than that of the MEA containing Nafion, particularly at low values of relative humidity. The hybrid membranes require much less water to conduct protons effectively and are more efficient at retaining water than Nafion at low water activities.