Operational strategies to improve the performance and long-term cyclability of intermediate temperature sodium-sulfur (IT-NaS) battery

Based on the preliminary investigation of the intermediate temperature sodium-sulfur (IT-NaS) battery (150 °C), herein we advance this energy storage system, by re-tuning the catholyte formulation; namely i) concentration, ii) layer thickness and iii) cut-off limits during galvanostatic charge-discharge cycling, lowering the operating temperature and improving cell design. The systematic implementation of these strategies boosted the cell performance markedly, delivering 112 mAh/g-sulfur, 90% of its theoretical specific capacity (125 mAh/g-sulfur), and 50 deep reversible charge-discharge cycles with coulombic and round-trip energy efficiencies of 97 ± 3% and 73 ± 4%, respectively. Along with the stability and improvement of cycle life, this study demonstrates, for the first time, the practicality of the tubular IT-NaS technology at a temperature as low as 125 °C

Operational strategies to improve the performance and long-term cyclability of intermediate temperature sodium-sulfur (IT-NaS) battery

Based on the preliminary investigation of the intermediate temperature sodium-sulfur (IT-NaS) battery (150 °C), herein we advance this energy storage system, by re-tuning the catholyte formulation; namely i) concentration, ii) layer thickness and iii) cut-off limits during galvanostatic charge-discharge cycling, lowering the operating temperature and improving cell design. The systematic implementation of these strategies boosted the cell performance markedly, delivering 112 mAh/g-sulfur, 90% of its theoretical specific capacity (125 mAh/g-sulfur), and 50 deep reversible charge-discharge cycles with coulombic and round-trip energy efficiencies of 97 ± 3% and 73 ± 4%, respectively. Along with the stability and improvement of cycle life, this study demonstrates, for the first time, the practicality of the tubular IT-NaS technology at a temperature as low as 125 °C.</p

INTERSUBLATTICE RELAXATION OF HIGH-FREQUENCY MAGNONS

Intersublattice relaxation of optically generated high-frequency magnons is measured at 1.5 K in MnF2. The spectral width of these magnons is determined from the magnetic-field dependence of the magnon relaxation time

OPTICAL GENERATION OF MAGNONS BY DIRECT SPIN-MAGNON RELAXATION IN MnF2 : Er3+

La génération et la détection optiques des magnons monochromatiques sont démontrées en MnF2 : Er3+ à 1.5 K en utilisant la transition directe des niveaux Zeeman les plus bas de la multiplette 4F9/2. Une calculation perturbationelle est en bon rapport avec les expérimentations. Des indications pour la réabsorption des magnons sont obtenues.The optical generation and detection of monochromatic magnons is demonstrated in MnF2 : Er3+ at 1.5 K employing the direct transition between the lowest Zeeman levels of the 4F9/2 multiplet. A perturbation calculation yields good agreement with the experimental results. Indications of magnon reabsorption are obtained

EXCITATION TRANSFER WITHIN THE OPTICALLY EXCITED DOUBLET Ē(2E) IN RUBY

Transport spectral assisté par processes Orbach via 2Ā(2E) est demontré en dedans la transition élargie inhomogènement entre les composantes Zeeman de l'état Ē(2E) en 130 ppm rubis à 1.5 K. La méthode experimentale est brûler un trou avec d'excitation de microsecondes sur bande variable. La largeur homgène du transition est trouvée d'être 6.0 ± 0.5 MHz.Phonon-assisted spectral transport mediated by Orbach processes via 2Ā(2E) is demonstrated to occur within the inhomogeneously broadened transition between the Zeeman components of the Ē(2E) state in 130 at.ppm ruby at 1.5 K. The experimental method is hole burning with microwave excitation over a variable band-width. The homgeneous width of the transition was found to be 6.0 ± 0.5 MHz

Thin film silicon modules on plastic superstrates

The aim of this research is to fabricate high efficiency a-Si/μc-Si tandem solar cell modules on flexible (polymer) superstrates using the Helianthos concept. As a first step we began by depositing the top cell which contains an amorphous silicon (a-Si:H) i-layer of 350 nm made by VHF PECVD at 50 MHz in a high vacuum multichamber system called ASTER, with hydrogen to silane gas flow ratio of 1:1. Such amorphous cells on-foil showed an initial active area (0.912 cm2) efficiency of 7.69% (Voc = 0.834 V, FF = 0.71). These cells were light soaked with white light at a controlled temperature of 50 °C. The efficiency degradation was predominantly due to degradation of FF that amounted to only 11% after 1000 h of light soaking. The cell-on-foil data prove that thin film silicon modules of high stability on cheap plastics can be made at a reasonable efficiency within 30 min of deposition time. A minimodule of 8 × 7.5 cm2 area (consisting of 8 cells interconnected in series) with the same single junction a-Si:H p–i–n structure had an initial efficiency of 6.7% (Voc = 6.32 V, FF = 0.65)

Flexible amorphous and microcrystalline silicon tandem solar modules in the temporary superstrate concept

van den Donker MN, Gordijn A, Stiebig H, et al. Flexible amorphous and microcrystalline silicon tandem solar modules in the temporary superstrate concept. Solar Energy Materials and Solar Cells. 2007;91(7):572-580