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Start Over Descriptor "Cell potential" Journal journal of power sources
4 results on '"Cell potential"'

1. On the possible influence of the Fermi–Dirac statistics on the potential and entropy of galvanic cells.

Author

Mertin, Gerrit Karl, Richter, Ernst, Oldenburger, Marc, Hofmann, Markus Hans, Wycisk, Dominik, Wieck, Andreas Dirk, and Birke, Kai Peter

Subjects
*ELECTRIC batteries, *OPEN-circuit voltage, *LITHIUM-ion batteries, *ENTROPY, *LITHIUM cells, *TEMPERATURE effect
Abstract

The open circuit voltage of galvanic cells is temperature dependent and the effect responsible for this dependency is its entropy. While it is well known that the Nernst equation plays an important role in describing this temperature dependency of the open-circuit voltage, this paper displays another effect. Measurements of the entropy for lithium-ion batteries show a significant temperature dependency, which cannot be explained by the linear Nernst equation. But this temperature dependency can be described by the free electron potential adapting via Fermi–Dirac statistics. This approach results in a quadratic temperature dependence of the measured potentials, which in the here shown cases for commercial lithium ion cells, could explain the measured effect. • Precise measurements of the voltage and entropy coefficient temperature dependency. • Extraction of a parabolic voltage and linear entropy regarding the temperature. • This effect has not been described in the literature yet. • Entropy was described by thermal distribution functions. • Application of Fermi–Dirac statistics could explain the measured effects. [ABSTRACT FROM AUTHOR]

Published
2021
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2. Intermediate temperature SOFC – a promise for the 21st century

Author

G.M. Christie, J.P.P. Huijsmans, and F.P.F. van Berkel

Subjects
Materials science, Renewable Energy, Sustainability and the Environment, Cell potential, Energy Engineering and Power Technology, Electrolyte, Microstructure, Chemical engineering, Operating temperature, Electrode, Intermediate temperature, Cubic zirconia, Solid oxide fuel cell, Electrical and Electronic Engineering, Physical and Theoretical Chemistry
Abstract

World-wide a number of activities are concerned with the optimisation and development of cell materials and microstructures with the aim of reducing the solid oxide fuel cell (SOFC) operating temperature. Advantages for reduced operating temperatures are considered to be longer life time and reduced costs of the total system. Conventional zirconia based electrolyte cells with highly optimised electrodes have produced 500 mA/cm2 at 700 mV and 800°C. At a similar temperature and cell potential, small scale, co-fired, electrode supported thin-electrolyte cells have produced 700 mA/cm2. For SOFC operation at temperatures below 750°C the conventional 8 mol% Y2O3–ZrO2 electrolyte is replaced with either Ce0.9Gd0.1O1.95 (10GCO) or La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) electrolytes. Up-scaled 10×10 cm2 or 12 cm circular 10GCO and LSGM cells have been manufactured and the initial results of cell tests are very promising.

Published
1998

3. Modeling the performance of rechargeable lithium-based cells: design correlations for limiting cases

Author

Marc Doyle and John Newman

Subjects
Renewable Energy, Sustainability and the Environment, Cell potential, Energy Engineering and Power Technology, chemistry.chemical_element, Mineralogy, Limiting, Power (physics), Distribution (mathematics), Porous electrode, chemistry, Specific energy, Lithium, Electrical and Electronic Engineering, Physical and Theoretical Chemistry, Concentration gradient, Biological system
Abstract

We use simplified models based on porous-electrode theory to describe the discharge of rechargeable lithium batteries and derive analytic expressions for the cell potential, specific energy, and average power in terms of the relevant system parameters. The resulting theoretical expressions are useful for design and optimization purposes and also can be used as a tool for the identification of system limitations from experimental data. The system treated is an ohmically-limited cell with no concentration gradients having an insertion reaction whose open-circuit potential depends linearly on state-of-charge. Although the slope of the open-circuit potential controls the reaction distribution in the porous electrode, we find that the cell potential is independent of this slope. The results are applied to a cell of the form Li|polymer|LiyMn2O4 in order to illustrate their utility.

Published
1995

4. Crystal chemistry of electrochemically inserted LixV2O5

Author

Michel Broussely, J. Labat, Jean-Pierre Doumerc, J.M. Cocciantelli, and Michel Pouchard

Subjects
Renewable Energy, Sustainability and the Environment, Crystal chemistry, Chemistry, Cell potential, Intercalation (chemistry), Inorganic chemistry, Energy Engineering and Power Technology, chemistry.chemical_element, Crystal structure, Electrochemistry, Reversible reaction, Crystallography, Lamellar structure, Lithium, Electrical and Electronic Engineering, Physical and Theoretical Chemistry
Abstract

The capacity of Li/V2O5 batteries is improved by the extension of the usual cycling domain from 0 ⩽ x ⩽ 1 to 0 ⩽ x ⩽ 1.8. Such behavior is attributed to the formation of a γ-LiV2O5 bronze for x ⩾ 1. Reversible deintercalation of lithium from the γ-phase leads to a new form of V2O5 that explains the enhancement of cell potential.

Published
1991

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