Thin-film electrolytes

Fabrication techniques, especially the preparation of thin films of functional materials, have made major progress in recent years. Thin-film solid electrolytes in the range of several nanometers up to several micrometers have been prepared successfully. The most important reason for the development of thin-film electrolytes is the reduction in the ionic resistance, but there is also the advantage of the formation of amorphous materials with stoichiometries which cannot be achieved by conventional techniques of forming crystalline compounds. It has often been observed that thin-film electrolytes produced by vacuum evaporation or sputtering provide a struc-... 

As noted in section 3.1. the fabrication of cells in which the cathode and anode are separated by a conformal thin-film electrolyte, perhaps a few tens of nanometers in thickness, is on the near horizon. Thus, it is interesting to consider potential phenomena. not normally considered in battery design, that... 

Figure 46. Performance characteristics of a cathode-supported thin film Ni—YSZ/YSZ/LSM fuel cell at 600 °C in humidified H2 and air with and without a dense protective yttria-doped ceria (YDC) protection layer introduced between the porous LSM cathode and the thin-film electrolyte. (Reprinted with permission from ref 296. Copyright 1997 Elsevier.)...

To measure the impedance of the thin-film electrolyte we used a current and voltage sampling (i-v sampling) method as shown in Figure 1. Because the impedance across the electrolyte slide (about 200 Kft d.c.) is much higher than the current sampling... 

Figure 6.5. Cross-sectional view of an electrochemical sensor.Key 1. Membrane 2. Thin-film electrolyte 3. Working electrode 4. Counter electrode 5. Electrolyte. (Courtesy of Enmet Corporation, Ann Arbor, Ml.)...

Batawi E etal., 1999, High Temperature Euel Cell with a Thin Film Electrolyte. US Patent 5,923,368. 

FIGURE 11.12 CVs of 100- and 350-nm-thick TiOj thin films. Electrolyte, 1 M L1CIO4 in propylene carbonate. (From Lin et al., 2008. J. Solid State Electrochem. 12, 1481-1486, with permission from Springer.)... 

Figure 16.5 shows the model proposed by Justi and Winsel [4] where the base of the pore faces the gas phase and the closest zone near the top of the cone on the electrolyte side. The meniscus is flat and with a finite contact angle forms a thin-film electrolyte layer on the catalyst. 

Strontium zirconate proton conducting thin film electrolytes have been successfully s mthesized and characterized. 

EXPLORATION OF COMBUSTION CVD METHOD FOR YSZ THIN FILM ELECTROLYTE OF SOLID OXIDE FUEL CELLS... 

For the practical application of the oxide ion conducting solid electrolytes for the SOFCs, there is another problem that they usually need high operation temperature over 800°C. In fact, the SOFCs based on the YSZ thin film electrolyte cannot provide acceptable power output due to the fundamental limit of YSZ that it is difficult to obtain enough conductivity below 650°C. The ceria-based oxides are. 

To reduce the resistance of the YSZ electrolyte, electrode-supported in particular anode-supported planar cells with thin film electrolyte of 5-20 pm are often adopted. To operate a SOFC at lower temperatures with high power output, an alternative electrolyte material with high ionic conductivity at low temperatures (500-650°C) should be used. Rare earth oxide-doped ceria (RDC, R is usually Y2O3, Gd203, and Sm203) is a material of choice due to its superior ionic conductivity, especially in low temperature range of 500-650°C [47]. 

Noh W.S., Satyanarayana L. and Park J.S. (2005), Potentiometric CO2 sensor using LP ion conducting Li3P04 thin film electrolyte . Sensors 5 (11), 465-472. 

The major contribution to ohmic overpotential is the ionic resistance of the electrolyte material. In the state of the art anode supported cell the ohmic losses are minimized by the use of thin film electrolytes which are usually 5-10 pm thick and high temperature operation. However, the high temperature operation is not preferred because of the detrimental effects on the cell life time and the cost of ceramic materials required for high temperature operation [80]. 

In the following, a physicochemical ECM for anode-supported single cells (ASCs) with thin-film electrolyte, developed at Forschungszentrum Jiihch (FZJ), is presented. 

Peters, C., A. Weber, B. Buts, D. Gerthsen, E. I. Tiffee (2009) Grain-Size Effects in YSZ Thin-Film Electrolytes, Journal of American Ceramics of Society, 92,2017-2024. 

Rupp JLM Infortuna A, Gauckler LJ. Thermodynamic stability of gadolinia-doped ceria thin film electrolytes for micro-solid oxide fuel cells. Journal of the American Ceramic Society 90(6) 1792—1797... 

Raman spectroscopy has also been used to study the structural properties of YSZ thin film electrolytes designed to operate at lower temperatures. Bernay et al. used Raman spectroscopy to characterise the structural... 

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