氟离子电极全固态结构的研究

STUDIES ON STRUCTURE OF ALL-SOLID STATE FLUORIDE ELECTRODES

本文对不同内部接触体系的全固态氟电极进行了实验比较,通过在氟化镧晶体表面电解形成氟化铋及氟化铅的实验,直接观察到氟离子在氟化镧单晶膜中的迁移现象。认为BiF_(3)-Bi-Ag体系较适宜用作全固态氟电极的内部接触。并测试了制得的全固态氟离子电极的电位响应特性。

For the construction of an all-solid state fluoride electrode it is necessaryi to find a suitable inner solid state junction between the ion-conducting LaF_(3)membrane and the electron-conducting metalic lead.In order to achleve a good electrode quality,it is essential to get a non-blocking,ohmic contact.Various fluorides and/or metals have been deposited on the LaF_(3) crystal membrane using’vacuum evaporation method:Bi(A);Bl(B);BiF_(3)-Bi-Ag(B1);Pb(C);PbF_(2)-Pb(D);Ag(E);AgF-Ag(F);Au(G);Al(H).The electrochemical properties of the inner junctions have been tested by mea-suring current-voltage characteristics.That the contact obtained is an ohmic one is indicated by linear current-voltage relationship which is independent of the polarity.It has been shown that in systems of direct junction between a metal and LaF_(3) crystalmembrane the contact resistance shows nonohmic behavior(Fig.2,A,C,E,G,H).These blocking contacts also possess rectiflying properties.The contact can be made ohmic when a layer of ion-conducting fluoride(BiF_(3),F_(2) or AgF)is sandwiched in between the LaF_(3) crystal membrane and the corresponding metal deposit layer(Bi,Pb or Ag;Fig.2,B,D,F).The migration of fluoride ions in the LaF_(3) membrane has been experimentally observed by electrolytic formation of fluorides of bismuth and lead on the LaF_(3);crystal,membrape surface.The system B1(BiF_(3)-Bi-Ag)is recommended as especially suitable for the construction of all-solid state fluoride electrodes.The potential resiponse characteristics of the constructed electrodes have been evaluated.