Solid State Ionics 

About: Solid State Ionics is an academic journal published by Elsevier BV. The journal publishes majorly in the area(s): Conductivity & Ionic conductivity. It has an ISSN identifier of 0167-2738. Over the lifetime, 14922 publications have been published receiving 515562 citations.

Appraisal of Ce1−yGdyO2−y/2 electrolytes for IT-SOFC operation at 500°C

Abstract: Recent thermodynamic and electrical conductivity data are evaluated to select the most appropriate electrolyte composition for IT-SOFC operation at 500°C. Ce 0.9 Gd 0.1 O 1.95 has an ionic lattice conductivity of 10 −2 S cm −1 at 500°C, and the Gd 3+ ion is the preferred dopant, compared to Sm 3+ and Y 3+ , at this temperature. Thermodynamic investigations indicate that for CeO 2 –Re 2 O 3 solid solutions at intermediate temperatures it becomes easier to reduce Ce 4+ as the concentration of Re 2 O 3 is increased. As the associated electron mobilities do not appear to be a strong function of composition it follows that Ce 0.9 Gd 0.1 O 1.95 has a wider ionic domain than Ce 0.8 Gd 0.2 O 1.9 at intermediate temperatures. Particular attention is drawn to the deleterious effects of impurities (principally SiO 2 ) which are responsible for large dopant concentration dependent grain boundary resistivities. These grain boundary resistivities can obscure the intrinsic lattice ionic conductivities and cause investigators to select non-optimal dopant compositions. It follows that the use of clean (SiO 2 6 O 11 . Finally the I – V characteristics of single cells incorporating 25-μm thick Ce 0.9 Gd 0.1 O 1.95 electrolytes are modelled, and the requirements for composite electrodes briefly discussed so that power densities of 0.4 W cm −2 at 500°C can be attained.

Physical, chemical and electrochemical properties of pure and doped ceria

Abstract: This paper gives an extract of available data on the physical, chemical, electrochemical and mechanical properties of pure and doped ceria, predominantly in the temperature range from 200 to 1000°C. Several areas are pointed out where further research is needed in order to make a better basis for the evaluation of the real potential and limits for the practical application of ceria in solid oxide fuel cells and other solid state electrochemical devices.

A Nonlinear Least Squares Fit procedure for analysis of immittance data of electrochemical systems

Abstract: A Nonlinear Least Squares Fit (NLLSF) program is described, with which frequency dispersion data of electrochemical systems can be analyzed in terms of an equivalent circuit. The NLLSF procedure uses a combination of an analytical and gradient search according to the Marquardt algorithm. Through the use of an unique Circuit Description Code (CDC) different equivalent circuits may be used with the program. The use of an analytical derivatives routine enhances the execution speed. The power of such a fit procedure is demonstrated in multi parameter fits, on synthetic and real data, performed by the program “EQIVCT”.

A short review of failure mechanisms of lithium metal and lithiated graphite anodes in liquid electrolyte solutions

Abstract: Li electrodes in any relevant electrolyte solution (i.e., polar aprotic) are covered by surface films of a very complicated structure. It was found that even in cases where the surface films formed on lithium contain elastomers, or where the lithium metal reactivity is reduced by doping with elements such as N, As, Al, Mg, Ca, etc., it is impossible to achieve sufficient passivation with lithium electrodes and liquid solutions. Passivation is considerably worsened when Li electrodes are operated at high rates (especially at high charging, Li deposition rates). Thus, there is no way that rechargeable Li batteries can compete with Li-ion batteries in any application that requires high charging rates (e.g., in powering portable electronic devices). The electrochemical behavior of lithiated graphite electrodes also depends on passivation phenomena. The surface films formed on lithiated graphite are similar to those formed on Li metal in the same solutions. The volume changes of graphite electrodes during Li insertion–deinsertion are small enough to enable their reasonable passivation in a variety of electrolyte solutions. A critical factor that determines the stability of graphite electrodes is their morphology. It was found that the shape of graphite particles plays a key role in their application as active mass in anodes for Li-ion batteries.

Ceria-based solid electrolytes

Abstract: Ceria-based solid electrolytes are reviewed in terms of electrical conductivity, diffusivity and transference number. The electrical conductivity and diffusion constants of various fluorite compounds are compared and those of ceria-based oxides are almost the highest among these fluorite oxides. The electrical conductivity of doped ceria is much dependent on the kind and the concentration of dopants. The reason for this behavior and a guideline to obtain more electrically conductive materials are discussed. The effect of sample preparation on the electrical conductivity is described in terms of the character of raw materials, impurities and the sintering condition. The factors to determine the transference number and the methods to increase the transference number at low oxygen pressures are also discussed.