Li4.3AlS3.3Cl0.7: A Sulfide-Chloride Lithium Ion Conductor with a Highly Disordered Structure

Mixed anion materials and anion doping are very promising strategies to improve solid-state electrolyte properties by enabling an optimized balance between good electrochemical stability and high ionic conductivity. In this work, we present the discovery of a novel lithium aluminum sulfide-chloride phase. The structure is strongly affected by the presence of chloride anions on the sulfur site, as this stabilizes a higher symmetry phase presenting a large degree of cationic site disorder, as well as disordered octahedral lithium vacancies, in comparison with Li-Al-S ternaries. The effect of disorder on the lithium conductivity properties was assessed by a combined experimental-theoretical approach. In particular, the conductivity is increased by a factor 10³ compared to the pure sulfide phases. Although it remains moderate (10⁻⁶ S·cm^-1), Ab Initio Molecular Dynamics and Maximum Entropy (applied to neutron diffraction data) methods show that disorder leads to a 3D diffusion pathway, where Li atoms move thanks to a concerted mechanism. An understanding of the structure-property relationships is developed to determine the limiting factor governing lithium ion conductivity. This analysis, added to the strong step forward obtained in the determination of the dimensionality of diffusion paves the way for accessing even higher conductivity in materials comprising an <i>hcp</i> anion arrangement.

Li4.3AlS3.3Cl0.7: A Sulfide-Chloride Lithium Ion Conductor with a Highly Disordered Structure

Mixed anion materials and anion doping are very promising strategies to improve solid-state electrolyte properties by enabling an optimized balance between good electrochemical stability and high ionic conductivity. In this work, we present the discovery of a novel lithium aluminum sulfide-chloride phase. The structure is strongly affected by the presence of chloride anions on the sulfur site, as this stabilizes a higher symmetry phase presenting a large degree of cationic site disorder, as well as disordered octahedral lithium vacancies, in comparison with Li-Al-S ternaries. The effect of disorder on the lithium conductivity properties was assessed by a combined experimental-theoretical approach. In particular, the conductivity is increased by a factor 10³ compared to the pure sulfide phases. Although it remains moderate (10⁻⁶ S·cm^-1), Ab Initio Molecular Dynamics and Maximum Entropy (applied to neutron diffraction data) methods show that disorder leads to a 3D diffusion pathway, where Li atoms move thanks to a concerted mechanism. An understanding of the structure-property relationships is developed to determine the limiting factor governing lithium ion conductivity. This analysis, added to the strong step forward obtained in the determination of the dimensionality of diffusion paves the way for accessing even higher conductivity in materials comprising an <i>hcp</i> anion arrangement.

Synthesis of Hydronium-Potassium Jarosites: The Effect of pH and Aging Time on Their Structural, Morphological, and Electrical Properties

Structural and morphological properties of hydronium-potassium jarosite microstructures were investigated in this work, and their electrical properties were evaluated. All the microstructures were synthesized at a very low temperature of 70 °C with a reduced reaction time of 3 h. An increase in the pH from 0.8 to 2.1 decreased the particle sizes from 3 µm to 200 nm and an increase in the aging time from zero, three, and seven days resulted in semispherical, spherical, and euhedral jarosite structures, respectively. The Rietveld analysis also confirmed that the amount of hydronium substitution by potassium in the cationic site increased with an increase in pH. The percentages of hydronium jarosite (JH)/potassium jarosite (JK) for pH values of 0.8, 1.1, and 2.1 were 77.72/22.29%, 82.44/17.56%, and 89.98/10.02%, respectively. Microstructures obtained in this work were tested as alternative anode materials and the voltage measured using these electrodes made with hydronium-potassium jarosite microstructures and graphite ranged from 0.89 to 1.36 V. The results obtained in this work show that with reduced particle size and euhedral morphology obtained, modified jarosite microstructures can be used as anode materials for improving the lifetime of lithium-ion batteries.

Early Stage of the Single-Crystal Growth and Tipping Point of the Cationic Site-Preference in the Gd-doped Zintl Phase Thermoelectric Materials

Three novel Zintl phase solid-solutions in the Ca11-xGdxSb10-y (0.36(2) ≤ x ≤ 0.58(4), 0.26(1) ≤ y ≤ 0.37(1)) system have been successfully synthesized by arc-melting, and their crystal structures were...

Synthesis of Hydronium-Potassium Jarosite; Effect of pH and Aging Time on their Structural, Morphological and Electrical Properties

Structural and morphological properties of the hydronium-potassium jarosite microstructures were investigated in this work, and their electrical properties were evaluated. All microstructures were synthesized at a reasonable temperature of 343 K with a reduced reaction time of 3 hours. Increase in the pH from 0.8 to 2.1 decreased the particle sized from 3 &micro;m to 200 nm and increasing the aging time from 0, 3 to 7 days resulted in semispherical, spherical and euhedreal jarosite structures, respectively. A Rietveld analysis also was done, finding that increasing pH, the amount of hydronium substitution by potassium in the cationic site also increases, having a 77.72 % of hydronium jarosite (JH) plus 22.29 % potassium jarosite (JK) at pH 0.8; 82.44 % (JH) and 17.56 % (JK) at pH 1.1, and 89.98 % (JH) plus 10.02 % (JK) at pH 2.1. The results obtained in this work show that the obtained hydronium potassium jarosite microstructures with reduced particle size and euhedreal morphology can be used as anode materials for improving the life time of lithium ion batteries, due that during the analysis of the voltage obtained using electrodes made with this particles and graphite, this ranged from 0.89 to 1.36 V.

BIOACCUMALATION AND BIOMEGNEFICATION STUDY OF THE PLANTS OF AL-CHIBAYISH MARSH, SOUTHERN IRAQ

An aggregate of 30 samples (water, sediments, and plants) was collected from Al-Chibayish Marsh, located in Dhi-Qar Governorate southern of Iraq to investigate the bioaccumulation and biomagnification in marsh plants (flora) and to assess the marsh plants pollution condition. The study was conducted by testing the macro elements, microelements, heavy metals, and organic compositions in water, sediments, and plants. Plant analyses revealed that the Salvinia natans plant species had the highest concentrations of macroelements Mg, Ca, Na, P, and N compared with other marsh plants and sediments. As a result, the cation binds itself to be more than one charged cationic site and this behaviour was observed in Salvinia natans sp. which has the highest organic composition (protein, fibre, oil, ash, carbohydrate) reaching 30% compared with marsh plants species. Due to the leaching effect it appeared to be more involved in the dissolution of the minerals and in the binding process, since the percentage of the heavy metals (Fe, Cu, Zn, Mn, and Mo) concentrations was reached to 51%. In our results, we found that the microelements tend to be the highest percentage (68%) in the Ceratophyllum sp. compared to other plants Sp. and sediments. Accumulation of heavy metals was highest in Vulgaris (10%), and there was 5%, 9%, 4%, 4%, 5%, and 8% in Salvinia natans, ceratophyllum, Schoenoplectus litoralis, Typha australis leaves, Typha australis roots and sediments, respectively. The study also shows that the mean concentrations of microelements and heavy metals were in the order of Fe> Mn> As> Se> Pb> Cu> Zn> Mo> Ni> Cr> Cd> Li> Co. The concentrations of microelements and heavy metals in plant samples were much greater than the concentrations in water samples of Al-Chibayish Marsh (these water samples were taken from the same locations of plant samples). This is a clear indication of bioaccumulation and biomagnifications of micro elements and heavy metals in plant tissues.

Isothermal Kinetic Investigation of the Water-Cations Interaction in Natural Clinoptilolite

The kinetics of water adsorption by a natural zeolite (clinoptilolite) sample has been investigated by high-frequency AC current intensity measurements. According to the achieved kinetic results, cations should play a relevant role in the clinoptilolite hydration, in fact most of adsorbed water stay in the cationic sites. The water molecules associate withcation one-by-one. In particular, the forced adsorption of water molecules in a wet atmosphere is a quite slow process, while water desorption in air or dry atmosphere is a spontaneous and fast process. The observed increase of cation mobility could be adequately explained by assuming an arrangement of water molecules between the cation and the negatively charged oxygens contained in the cationic site. Such molecular arrangement could increase the strength of both dipole-cation and hydrogen bond interactions.