Thin-Film Silver Halide Electrolyte Cells

Abstract

Thin-film solid-state batteries ranging in thickness from 5 to 12~ were prepared on quartz substrates by vacuum-deposition techniques. Silver films ~1000A thick were used in all cases as the reversible electrode, while platinum and in some cases gold films of a similar thickness were used as the counterelectrode. Electrolyte films consisted of evaporated AgI, evaporated AgBr, and a double electrolyte of AgI evaporated onto a film of AgC1 or AgBr. Cells consisting of the above types of electrolytes were rechargeable, and the ones containing pure AgI or AgI -t-AgBr or AgC1 electrolyte exhibited long shelf life. Preliminary conductivity measurements using an a-c bridge method indicate, as expected, that the electrode-electrolyte interfaces rather than the electrolyte films are the principal sources of the high internal resistance exhibited by these batteries.The use of solid-state electrolytes in electrochemical cells was first demonstrated by Reinhold (1) during his studies of chemical equilibria between solid salts. Ionic conductivity in the solid state has since been studied by a number of workers and an extensive review of the subject has been presented by Lidiard (2). A more recent review by Raleigh (3) deals with the general aspects of solid-state electrochemical techniques and the use of solid-state galvanic cells for various thermodynamic calculations.Silver iodide, when contained between two metallic electrodes of which one is a reversible silver anode, has long been known to act as a solid electrolyte in which the ionic current is carried almost in its entirety by Ag + ions (4). In recent years, several articles have appeared in the literature on the utilization of silver iodide as an electrolyte in solid-state battery applications. A bead cell developed by Weininger (5) consists of a silver anode and a platinum or tantalum cathode embedded into the solid AgI electrolyte. In the presence of iodine vapor, the cell acts as a primary battery, the iodine being reduced at the inert Pt (or Ta) electrode. Mrgudich (6, 7) has recently reported on the performance of AgI pellet batteries in which the AgI electrolyte is compressed between silver and platinum electrodes, and he also suggested that the possibility of making an all thin-film version of the system be explored. The Mrgudich batteries are rechargeable concentration cells in which the cell voltage is a function of the activity of Ag ~ on the inert platinum electrode and is given by the Nernst concentration-cell equation

Electrocatalysis of oxygen reduction and small alcohol oxidation in alkaline media

“…The oxygen reduction reaction (ORR) in alkaline media is of great industrial importance. The ORR serves as the cathode reaction in numerous electrochemical technologies, including alkaline fuel cells (AFCs), 16,17 chlor-alkali electrolysis with airdepolarized cathodes, 6,7 and metal-air batteries. 8,9 The ORR is also important for electrochemical sensors 18 and in corrosion.…”

Applications of solid-state ionic materials

“…First of all, Vouros and Masters have reported a thin film-silver battery [95). They have patented thin-film electrochemical cell of the type Agi AgIlPt which gives an OCV of 550 mY.…”

Materials for electrolyte: Thin-films

“…To overcome the problem of high internal resistance in silver solid-state batteries many workers have elaborated various silver-ion-conducting thin-films such as Ag3SI [53,103], RbA~I5 [9,13,29,53,104], AW4Cr04 [64], AgBr [10,50,105]. Ionic conductivities and activation energies of selected silver-ion-conducting thin-films are listed in Table 4.5.…”