scholarly journals Identification of Restricting Parameters on Steps toward the Intermediate-Temperature Planar Solid Oxide Fuel Cell

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6404
Author(s):  
Yongqing Wang ◽  
Bo An ◽  
Ke Wang ◽  
Yan Cao ◽  
Fan Gao

To identify critical parameters upon variable operational temperatures in a planar SOFC, an experimentally agreeable model was established. The significance of temperature effect on the performance of SOFC components was investigated, and the effect of activation energy during the development of intermediate electrode materials was evaluated. It is found the ionic conductivity of electrolytes is identified to be unavoidably concerned in the development of the intermediate-temperature SOFC. The drop of the ionic conductivity of the electrolyte decreases the overall current density 63% and 80% at temperatures reducing to 700 °C and 650 °C from 800 °C. However, there exists a critical value on the defined ratio between the electric resistance of the electrolyte in the overall internal resistance of SOFC, above which the further increase in the ionic conductivity would not significantly improve the performance. The lower the operational temperature, the higher critical ratio of the electrical resistance in the overall internal resistance of the cell. The minimal decrease in the activation energy during the development of intermediate electrode materials can significantly enhance the overall performance. Considering the development trend toward the intermediate temperature SOFC, advanced electrode material with the decreased activation energy should be primarily focused. The result provides a guidance reference for developing SOFC with the operational temperature toward the intermediate temperature.

2021 ◽  
Author(s):  
Mohsen Sotoudeh ◽  
Manuel Dillenz ◽  
Axel Groß

Abstract In the area of sustainable energy storage, batteries based on multivalent ions such as magnesium have been attracting considerable attention due to their potential for high energy densities. Furthermore, they are typically also more abundant than, e.g., lithium. However, as a challenge their low ion mobility in electrode materials remains. This study addresses the ionic conductivity of magnesium in spinel host materials based on periodic density functional theory calculations in order to identify the critical parameters which determine the mobility and insertion of ions. We will in particular highlight the critical role that trigonal distortions of the spinel structure play for the ion mobility. In detail, we will show that it is the competition between coordination and bond length that governs the Mg site preference in ternary spinel compounds upon trigonal distortions which can only be understood by also taking covalent interactions into account. Based on our theoretical study, we rationalize the impact of the metal distribution in the host material and the ion concentration on the diffusion process. Furthermore, cathode-related challenges for practical devices will be addressed. Our findings shed light on the fundamentional mechanisms underlying ionic conductivity in solid hosts and thus may contribute to improve ion transport in battery electrodes.


2021 ◽  
Author(s):  
Mohsen Sotoudeh ◽  
Manuel Dillenz ◽  
Axel Groß

Abstract In the area of sustainable energy storage, batteries based on multivalent ions such as magnesium have been attracting considerable attention due to their potential for high energy densities. Furthermore, they are typically also more abundant than, e.g., lithium. However, as a challenge their low ion mobility in electrode materials remains. This study addresses the ionic conductivity in spinel host materials which represent a promising class of cathode and solid-electrolyte materials in Mg-ion batteries. Based on periodic density functional theory calculations, we identify the critical parameters which determine the mobility and insertion of ions. We will in particular highlight the critical role that trigonal distortions of the spinel structure play for the ion mobility. In detail, we will show that it is the competition between coordination and bond length that governs the Mg site preference in ternary spinel compounds upon trigonal distortions. This can only be understood by also taking covalent interactions into account. Furthermore, our calculations suggest that anionic redox plays a much more important role in sulfide and selenide spinels than in oxide spinels. Based on our theoretical study, we rationalize the impact of the metal distribution in the host material and the ion concentration on the diffusion process. Furthermore, cathode-related challenges for practical devices will be addressed. Our findings shed light on the fundamentional mechanisms underlying ionic conductivity in solid hosts and thus may contribute to improve ion transport in battery electrodes.


Cerâmica ◽  
2006 ◽  
Vol 52 (321) ◽  
pp. 22-30 ◽  
Author(s):  
M. L. F. Nascimento ◽  
E. Nascimento ◽  
W. M. Pontuschka ◽  
M. Matsuoka ◽  
S. Watanabe

We collected and analyzed literature data on ionic conductivity sigma and activation energy E A in the binary sodium silicate system in a wide composition range. The Anderson and Stuart model has been considered to describe the decreasing tendency of activation energy E A with alkali concentration in this system. In this analysis were considered experimental parameters, such as shear modulus G and relative dielectric permittivity epsilon. A general conductivity rule is found in 194 of 205 glasses, when one plots log sigma vs. E A/kB T, where kB is the Boltzmann constant and T is the absolute temperature. This fact means that the arrhenian relation has universal uniqueness of form sigma = sigma (E A,T) in wide Na2O composition range. The results also show that there is strong correlation by more than 19 orders of magnitude on conductivity with E A/kBT. An explanation for this behavior links ionic conductivity and microscopic structure. The problem of phase separation in this system is also considered.


2018 ◽  
Vol 790 ◽  
pp. 3-8 ◽  
Author(s):  
Shin Ichi Furusawa ◽  
Tomosato Ida

Tensile stress was applied to β-AgI thin film prepared on a polyethylene terephthalate film, and the ion conduction response in the direction of the tensile extension was investigated. The ionic conductivity of the β-AgI thin film decreases and the activation energy for ionic conduction increases with increasing extension ratio. This behaviour is attributed to the modulation of the crystal framework by the extension of the AgI thin film.


2018 ◽  
Vol 790 ◽  
pp. 9-14
Author(s):  
Shin Ichi Furusawa ◽  
Yohei Minami

MAlSi3O8 (M = Li, Na, K) was synthesized by solid-phase reaction at 1000 °C using M2CO3 (M = Li, Na, K), Al2O3, and SiO2 as the starting materials, and its ionic conduction was studied in the temperature range 475–800 K. It was confirmed from powder X-ray diffraction profiles that the crystalline phases of the prepared MAlSi3O8 were the same as those of orthoclase. Moreover, the ionic conductivity of NaAlSi3O8 was about 10 times higher than that of LiAlSi3O8 and KAlSi3O8. The activation energies for ionic conduction were estimated to be in the range of 0.70–0.77 eV, with NaAlSi3O8 exhibiting the lowest activation energy. The result suggests that the magnitude of the activation energy cannot be determined only from the ionic radius.


Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1648 ◽  
Author(s):  
Paweł Jeżowski ◽  
Przemysław Łukasz Kowalczewski

This work describes the use of commercially available starch as a binder for the preparation of conductive glue and electrode materials. It is demonstrated that starch can be successfully implemented as a binder in energy storage systems with non-aqueous electrolytes. These devices are characterized by a stable cycle life (for 50,000 cycles) at a nominal voltage of 2.5 V. Moreover, the use of starch-based conductive glue improves the electrochemical performance, especially reducing the internal resistance of the device. Starch-bound electrodes display lower equivalent distributed resistance (EDR) values than electrodes using carboxymethylcellulose (CMC) as the binder. This is due to the noticeably lower pore clogging by starch. An electric double-layer capacitor (EDLC) in organic electrolyte (1 mol L−1 TEABF4 in ACN) at a nominal voltage of 2.5 V can reach a specific power and energy of 100 kW kg−1 and 12 Wh kg −1, respectively. This study shows that starch-based conductive glues and electrode materials can be incorporated in EDLC systems.


2020 ◽  
Vol 22 (30) ◽  
pp. 17221-17228
Author(s):  
Abdulkadir Kızılaslan ◽  
Mine Kırkbınar ◽  
Tugrul Cetinkaya ◽  
Hatem Akbulut

The mechanism of the ionic conductivity enhancement in sulfur-doped Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolytes.


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