Search results for "Roche"
showing 10 items of 2666 documents
<title>Functional models of electrochromic devices: cycling capacity and degradation</title>
1997
Electrical transfer and diffusion of ions and the irreversibility of ion and electron processes in heterojunctions are responsible for degradation of ionic devices. These processes for electrochromic devices (ECD) determine the cycling capacity and lifetime. The basic problem here is how to match the electrochemical parameters (including chemical potential) of heterojunction. The experiments had been carried out on ECD based on system: (phi) - -(phi) , where AAH is solid electrolyte based on antimony acid hydrates. The cycling capacity and degradation processes of ECD are investigated by electro-optical and electro-chemical spectroscopy. The analysis of experimental data are based on assump…
Heat-to-current conversion of low-grade heat from a thermocapacitive cycle by supercapacitors
2015
Thermal energy is abundantly available, and especially low-grade heat is often wasted in industrial processes as a by-product. Tapping into this vast energy reservoir with cost-attractive technologies may become a key element for the transition to an energy-sustainable economy and society. We propose a novel heat-to-current converter which is based on the temperature dependence of the cell voltage of charged supercapacitors. Using a commercially available supercapacitor, we observed a thermal cell-voltage rise of around 0.6 mV K-1 over a temperature window of 0 degrees C to 65 degrees C. Within our theoretical model, this can be used to operate a Stirling-like charge-voltage cycle whose eff…
Electrical power production from low-grade waste heat using a thermally regenerative ethylenediamine battery
2017
Abstract Thermally regenerative ammonia-based batteries (TRABs) have been developed to harvest low-grade waste heat as electricity. To improve the power production and anodic coulombic efficiency, the use of ethylenediamine as an alternative ligand to ammonia was explored here. The power density of the ethylenediamine-based battery (TRENB) was 85 ± 3 W m−2-electrode area with 2 M ethylenediamine, and 119 ± 4 W m−2 with 3 M ethylenediamine. This power density was 68% higher than that of TRAB. The energy density was 478 Wh m−3-anolyte, which was ∼50% higher than that produced by TRAB. The anodic coulombic efficiency of the TRENB was 77 ± 2%, which was more than twice that obtained using ammon…
Copolymerization of Polythiophene and Sulfur To Improve the Electrochemical Performance in Lithium–Sulfur Batteries
2015
We first report on the copolymerization of sulfur and allyl-terminated poly(3-hexylthiophene-2,5-diyl) (P3HT) derived by Grignard metathesis polymerization. This copolymerization is enabled by the conversion of sulfur radicals formed by thermolytic cleavage of S8 rings with allyl end-group. The formation of a C–S bond in the copolymer is characterized by a variety of methods, including NMR spectroscopy, size exclusion chromatography, and near-edge X-ray absorption fine spectroscopy. The S-P3HT copolymer is applied as an additive to sulfur as cathode material in lithium–sulfur batteries and compared to the use of a simple mixture of sulfur and P3HT, in which sulfur and P3HT were not covalent…
Improved composite materials for rechargeable lithium metal polymer batteries
1999
Abstract The performance of several polymer electrolytes for lithium metal batteries for electric vehicle applications are reported. The best performing electrolyte is the composite PEO 20 LiCF 3 SO 3 –γLiAlO 2 , which was prepared by a solvent-free procedure. It showed coulombic efficiency values of the lithium deposition–stripping process of 94%–96%. Electrochemical tests of lithium polymer battery (LPB) prototypes based on a 3 V LiMn 2 O 4 composite cathode material laminated together with the PEO 20 LiCF 3 SO 3 –γLiAlO 2 electrolyte gave promising results for electric vehicle applications. Even under non-optimized battery design, the prototypes delivered, at the C/3 rate and at 94°C, 40…
Metal Oxides for Rechargeable Batteries Energy Applications
2020
Nearly three decades of significant academic and commercialization progress, appreciations have to be credited for Li+ ion-based rechargeable secondary batteries, which conquered the entire world. The Li+ ion batteries dictate the consumer battery market and are considered crucial for the practical realization of plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs), and electric vehicles (EVs). Recently, post-lithium–ion batteries, particularly Na, K, Mg, and Zn, and Al–ion batteries have also been intensively explored for various energy storage tenders due to their natural abundance, low cost, and environmental safety of these materials. The utilization of metal oxides…
Composite polymer electrolytes with improved lithium metal electrode interfacial properties: II. Application in rechargeable batteries
1998
The application of a liquid-free, ceramic-added composite polymer electrolyte in a Li/LiMn{sub 2}O{sub 4} rechargeable battery is presented and discussed. As expected by the high stability of the electrolyte toward the lithium metal anode, the battery has promising characteristics in terms of reliability and cyclability.
Electrodes with Immobilized Particles and Droplets: Three-Phase Electrodes
2014
It is a common feature of electrodes with immobilized particles and droplets that three phases are in close contact with each other, i.e., each phase having an interface with the two other phases. This situation exists also in most of the so-called surface-modified or film electrodes, many battery and fuel cell electrodes, electrodes of the second kind, etc. In fact, the majority of surface-modified electrodes consist of arrays of particles that partially cover the electrode surface. It would be far beyond the scope of this book to include all chemical and electrochemical techniques to deposit films on electrodes. Here we shall deal only with electrodes where the particles or droplets have …
Atomic Layer Deposition of Spinel Lithium Manganese Oxide by Film-Body-Controlled Lithium Incorporation for Thin-Film Lithium-Ion Batteries
2013
Lithium manganese oxide spinels are promising candidate materials for thin-film lithium-ion batteries owing to their high voltage, high specific capacity for storage of electrochemical energy, and minimal structural changes during battery operation. Atomic layer deposition (ALD) offers many benefits for preparing all-solid-state thin-film batteries, including excellent conformity and thickness control of the films. Yet, the number of available lithium-containing electrode materials obtained by ALD is limited. In this article, we demonstrate the ALD of lithium manganese oxide, LixMn2O4, from Mn(thd)3, Li(thd), and ozone. Films were polycrystalline in their as-deposited state and contained le…
Naphthyridine Derivatives as a Model System for Potential Lithium-Sulfur Energy-Storage Applications
2015
Naphthyridines have been identified as structural elements in sulfurized polyacrylonitrile, which is a common electrode material in lithium–sulfur batteries. Some dibenzonaphthyridine derivatives with a fused dithiolo moiety were prepared as model compounds for battery studies. These heterocyclic systems were prepared via the corresponding diphenyldicarbamide intermediate. Followed by naphthyridione formation, stepwise installation of the dithiolane subunit occurred in a straightforward manner. In the solid state, the heteroaromatic system is completely planar and was thoroughly characterized. Initial battery cycling tests indicated a potential use of such structural motifs in sulfur–lithiu…