Ionic conductivity is one of the most important properties for
electrolyte membrane. The hydroxyl conductivities of the OH form
membranes were measured by a two-electrode AC impedance
method in a homemade cell. The cell was connected to a Parstat
263 electrochemical equipment (Princeton Advanced Technology,
USA). The membrane sample was sandwiched between the two
stainless steel electrodes and the resistance through the plane was
measured, as described in our previous works [13,16,20,21]. The
impedance spectrum was recorded in the frequency range from
0.1 Hz to 100 KHz. All the membrane samples were soaked in
deionized water for at least 48 h before the test. The ionic conductivity
can be calculated as follow: