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Concept

Capacité thermique volumique

La capacité thermique volumique d'un matériau, anciennement appelée chaleur volumique, est sa capacité à emmagasiner la chaleur rapportée à son volume. Elle est définie par la chaleur nécessaire pour élever de la température d'un mètre cube de matériau. C'est une grandeur intensive égale à la capacité thermique rapportée au volume du corps étudié. C'est donc le produit de la masse volumique (ρ) d'un matériau et de sa capacité thermique massique (c_p). Elle s'exprime en joules par mètre cube-kelvin (soit ou parfois ). Pratique Capacité thermique volumique de quelques matériaux :

air :
laine de verre :
polystyrène :
laine de coton :
ouate de cellulose :
laine de bois :
paille :
liège :
fibre de bois dense :
terre sèche :
béton ordinaire :
fonte :
fer :
eau :

Voir aussi Bibliographie

Jean-Pier

À propos de ce résultat

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Résumé

air :
laine de verre :
polystyrène :
laine de coton :
ouate de cellulose :
laine de bois :
paille :
liège :
fibre de bois dense :
terre sèche :
béton ordinaire :
fonte :
fer :
eau :

Voir aussi Bibliographie

Jean-Pier

Source officielle

À propos de ce résultat

Publications associées (17)

Publications associées

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Personnes associées (1)

Personnes associées

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Unités associées (1)

Unités associées

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Concepts associés (13)

Concepts associés

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Cours associés (13)

Cours associés

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Séances de cours associées (23)

Séances de cours associées

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An integrated flexible film as cathode for High-Performance Lithium-Sulfur battery

Rui Guo, Yong Li, Wen Liu, Yuhang Wang, Kangning Zhao

Poor cycling stability and low volumetric capacity of sulfur cathode prevents practical application of Lithium-sulfur (Li-S) batteries. Herein, we demonstrate a strategy to address the two drawbacks of sulfur cathode by synthesizing a compact and flexible film cathode with bilayer structure using a two-step vacuum filtration method. Two layers make up the sulfur cathode, active layer (sulfur-acethlene black (S-C) spheres) and barrier layer (three dimensional MnO2-graphene oxide-multi-walled carbon nanotubes (MnO2-GO-CNTs) composites), which are integrated together by reduced graphene oxide (rGO) through self-binding. The rGO sheets provide an electrical conductive framework and a stable architecture to accommodate volume changes of sulfur. S-C spheres stacked orderly between the rGO layers facilitate fast Li+ storage and energy release. Polar MnO2-GO-CNTs composites with large specific surface area have not only afforded efficient sites for chemically binding polysulfides, but also provided fast electron trans-fer for accelerating polysulfides redox reaction. Consequently, the integrated film cathode exhibits an unprecedented cycling stability of similar to 0.0279% capacity decay per cycle over more than 600 cycles at 1C and high volumetric capacity of 1021.9 Ah L-1 at 2C. Meanwhile, a foldable Li-S battery based on this flexible cathode is fabricated and shows excellent mechanical and electrochemical properties. The integrated flexible sulfur cathode of this study sheds light on the design strategies for application in flexible high volumetric capacity system. (C) 2021 Elsevier Inc. All rights reserved.

ACADEMIC PRESS INC ELSEVIER SCIENCE2022

Chargement

Solid electrochemical energy storage for aqueous redox flow batteries: The case of copper hexacyanoferrate

Christopher Raymond Dennison, Solène Cindy Gentil, Hubert Girault, Grégoire Clément Gschwend, Pekka Eero Peljo, Danick Reynard, Evgeny Smirnov, Elena Zanzola

All redox flow batteries suffer from low energy storage density in comparison with conventional Li-ion batteries. However, this issue can be mitigated by utilization of solid energy storage materials to enhance the energy storage capacity. In this paper we demonstrate the utilization of copper hexacyanoferrate (CuHCF) Prussian blue analogue for this purpose, coupled with N,N,N-2,2,6,6-heptamethylpiperidinyl oxy-4-ammonium chloride (TEMPTMA) as a soluble redox mediator to target the redox transitions of the solid material. In this case, indirect charging and discharging of CuHCF suspended in the electrolyte by electrochemically oxidized/reduced TEMPTMA was observed by chronoamperometry. Secondly, electrochemistry of different CuHCF composites with carbon black and multi-walled carbon nanotubes were investigated, highlighting that the high conductivity of the solid energy storage materials is crucial to access the maximal charge storage capacity. Finally, a CuHCF-TEMPTMA/Zn aqueous redox flow battery achieved stable cycling performances with high coulombic efficiency of 95% and volumetric capacity of 350 C mL−1.

2019

Chargement

Redox Solid Energy Boosters for Flow Batteries: Polyaniline as a Case Study

Véronique Amstutz, Alberto Battistel, Christopher Raymond Dennison, Hubert Girault, Pekka Eero Peljo, Heron Vrubel, Elena Zanzola

In this work, the viability of polyaniline as a solid charge storage material in an aqueous redox-mediated flow battery is investigated. Fe(III/II) and V(IV/III) were identified as potential redox mediators to target the emeraldine-pernigraniline and leucoemeraldine-emeraldine redox transitions of the polymer. An indirect chemical cycling method was developed and used to investigate the charging/discharging of the polymer by the selected redox mediators. With Fe(III/II) as a redox mediator, respectable specific capacity and cycling stability were demonstrated over 25 cycles. V(IV/III) was deemed unsuitable as a redox mediator, due to rather poor kinetics. When added to the electrolyte tanks of a complete flow battery, a conductive composite of polyaniline and carbon black provided a significant improvement in capacity, exhibiting a specific capacity of 64.8 mA h g−1 at a current density of 38.5 mA cm−2. This represents a three-fold improvement in volumetric capacity, compared with the electrolyte alone. Moreover, the addition of the polyaniline composite was observed to lower the average potential at the positive electrode, providing a considerable improvement in voltage efficiency. This work demonstrates the potential of utilizing redox mediators to enable bulk solid-phase charge storage in the tanks of aqueous redox flow batteries

Elsevier2017

Chargement

Capacité thermique

La capacité thermique (anciennement capacité calorifique) d'un corps est une grandeur qui mesure la chaleur qu'il faut lui transférer pour augmenter sa température d'un kelvin. Inversement, elle per

Capacité thermique massique

La capacité thermique massique (symbole usuel c), anciennement appelée chaleur massique ou chaleur spécifique, est la capacité thermique d'un matériau rapportée à sa masse. C'est une grandeur qui ref

Conductivité thermique

La conductivité thermique (ou conductibilité thermique) d'un matériau est une grandeur physique qui caractérise sa capacité à diffuser la chaleur dans les milieux sans déplacement macroscopique de ma

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