In situ resistivity measurements and optical transmission and reflection spectroscopy of electrochemically loaded switchable YHx films

We describe an experimental method for in situ resistivity measurements dur ing the electrochemical hydrogen loading of thin, switchable metal hydride films. Using an oxygen-free electrolyte we are able to measure the hydrogen concentration in the films quantitatively and to determine the pressure-co mposition isotherms and the hydrogen concentration dependence of the resist ivity. Furthermore, the optical properties can be investigated by simultane ous transmission and reflection spectroscopy. The power of these in situ me asurements is discussed on the basis of results obtained on YHx films; poss ibilities for additional experiments are briefly described. (C) 1999 The El ectrochemical Society. S0013-4651(98)11-111-4. All rights reserved.