Composite cathodes

The general configuration of one system that has reached an advanced stage of development (22) is shown in Figure 1. The negative electrode consists of thin lithium foil. The composite cathode is composed of vanadium oxide [12037-42-2] 6 13 with polymer electrolyte. Demonstration... 

Being isomorphous, PbSe and PbTe form solid solutions in the whole range of compositions. Cathodic electrodeposition of the PbSe Tei-x ternary (0 < x < 1)... 

Wang et al. [96] constructed a Na/S battery with a sodium metal anode, liquid electrolyte, and a sulfur (dispersed in polyacrylonitrile) composite cathode and tested its electrochemical characteristics at room temperature. The charge/discharge curves indicated that sodium could reversibly react with the composite cathode at room temperature. Average charge and discharge voltage was 1.8 and 1.4 V, respectively. Similar to lithium batteries, dendrite formation was noted as a critical problem for these cells. 

Wang J, Yang J, Nuh Y, Holze R (2007) Room temperature Na/S batteries with sulfur composite cathode materials. Electrochem Common 9 31-34... 

FIGURE 3.12 Impedance curves of LSCF ad LSCF/GDC composite cathodes in air measured at different temperatures. (From Hwang, H.J. et al., J. Power Sources, 145 243-248, 2005. With permission.)... 

MIEC with an additional ionically conductive phase, such as GDC or SDC, typically extends the electrochemically active region still further due to the higher ionic conductivity of GDC and SDC compared to that of the perovskites. The optimal composition of a two-phase composite depends in part on the operation temperature, due to the larger dependence of ionic conductivity on temperature compared to electronic conductivity. A two-phase composite of LSCF-GDC therefore has an increasingly large optimal GDC content as the operating temperature is reduced [14], A minimum cathode Rp for temperatures above approximately 650°C has been found for 70-30 wt% LSCF-GDC composite cathodes, while at lower temperatures, a 50-50 wt% LSCF-SDC composite cathode was found to have a lower Rp [15]. 

A similar trend was found for LSC-SSC composite cathodes, with a sintering temperature of 1000°C recommended by the authors, and a temperature of 1200°C observed to cause excessive sintering and lower cathode performance [81]. 

White BD, Kesler O, and Rose L. Air plasma spray processing and electrochemical characterization of SOFC composite cathodes. J. Power Sources 2008 178 334—343. 

Song HS, Kim WH, Hyun SH, and Moon J. Influences of starting particulate materials on micro structural evolution and electrochemical activity of LSM-YSZ composite cathode for SOFC. J. Electroceram. 2006 17 759-764. 

Song HS, Hyun SH, Moon J, and Song RH. Electrochemical and microstructural characterization of polymeric resin-derived multilayered composite cathode for SOFC. J. Power Sources 2005 145 272-277. 

Barthel K and Rambert S. Thermal spraying and performance of graded composite cathodes as S( )F( -component. Mat. Sci. Forum. 1999 308-311 800-805. 

Fu C, Sun K, Zhang N, Chen X, and Zhou D. Electrochemical characteristics of LSCF-SDC composite cathode for intermediate temperature SOFC. Electrochim. Acta 2007 52 4589-4594. 

Zhou W, Shao Z, Ran R, Zeng P, Gu H, Jin W et al. Ba05Sr0 5Co0 8Fe02O3 5 + LaCo03 composite cathode for Sm0 2Ce0 80,9-electrolyte based intermediate-temperature solid-oxide fuel cells. J. Power Sources 2007 168 330-337. 

Xia C, Zhang Y, and Liu M. LSM-GDC composite cathodes derived from a sol-gel process. Electrochem. Solid State Lett. 2003 6 A290-A292. 

G.E. Jabbour, S.E. Shaheen, M.M. Morrell, B. Kippelen, N.R. Armstrong, andN. Peyghambarian, Aluminum composite cathodes a new method for the fabrication of efficient and bright organic light-emitting devices, Opt. Photon. News, 10 (4), 24, 1999. 

Figure 21. FTIR spectra (diffuse reflectance mode) measured from a pristine LiNi02 composite cathode and with a cathode after galvanostatic cycling in Li salt/EC/DMC solutions. (Reproduced with permission from ref 292 (Figure 1). Copyright 2000 The Electrochemical Society.)...

A more conspicuous example is the anodic stability of linear carbonate (Figure 23). While the anodic limits for both DMC and EMC are above 5.0 V on GC, as observed by similar measurements, the major decomposition current starts before 4.5 V for both solvents when a composite cathode based on spinel LiMn204 is used as working electrode.Apparently, the enormous difference between GC and a composite cathode could not be explained solely by the larger surface area of the latter. It seems more likely that the irreversible oxidative processes were catalyzed by the active mass of the spinel surface, possibly involving spinel lattice disproportionation. Therefore, the stability limits as measured on all of these nonactive and nonporous electrodes can be... 

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