Anhydrous electrolytes with high proton conductivity and adequate chemical stability :in, the temperature range of 120-180 degrees C can be very useful in electrochemical devices, such as fuel cells, sensors, and electrolyzers. Developing, such proton-conducting materials has been challenging. We have fabricated and characterized the performance of such membranes, based on poly-2-vinylpyridinium dihydrogenphosphate (P2VP-DHP), that can operate in the range of 105-180 degrees C under anhydrous, conditions. The ionic conductivity of the membrane was 0.01 S, cm(-1) at 140 degrees C. Proton conduction occurs by ionization of the quaternary ammonium group and by Grotthus-type transport that involves the rapid rotation of the dihydrogenphosphate anion. The activation energy for proton transport was SO kJ/rnol. The transport number of the proton was measured by impedance spectroscopy and potential-step techniques. The measured value was in the range of 0.17-0.20. A membrane-and-electrode assembly using the P2VP-DHP was tested as an electrochemical hydrogen pump. This demonstration shows the advantage of membranes based on a polymer amine salt in electrochemical applications that require operating under water free conditions. Weight loss measurements at 120 degrees C in air confirmed the thermal and oxidative stability of the membrane. The properties of the P2VP-DHP membrane reported here provide the basis for further development of proton-conducting polymer electrolyte, membranes for operating temperatures above 100 degrees C in anhydrous environments.