Enhanced ionic transport and interfacial properties of Sr/Gd Co-doped CeO2 electrolytes for IT-SOFCs

In present research work, homogeneous anion exchange membranes based on polysulfone (QAPSFs) were prepared via chloromethylation, amination and alkalization. In amination step, trimethylamine and N,N,N',N'-tetramethyl-1,6-hexanediamine were used as amination and crosslinking agents, respectively. The chloromethylated polysulfone was characterized by 1HNMR spectroscopy and chloromethylation degree was calculated using peak area integration. Ion transport properties such as ionic conductivity, ion exchange capacity, activation energy for hydroxide ion transport were measured for the prepared anion exchange membranes. Furthermore, water content associated properties such water uptake and hydrated number were determined for these membranes. According to the obtained results, the membrane with crosslinking agent (QAPSF-2) shows ion transport properties nearly similar to the membrane without crosslinker (QAPSF-1). Although, QAPSF-2 has more improved water content associated properties and reasonable dimensional stability in contrast to QAPSF-1. Finally, According to the ionic transport measurements and water content characterizations, the prepared QAPSF membranes can be denoted as good candidates for solid alkaline fuel cell application.

High-affinity potassium transporters (HKTs) play an important role in plants responding to salt stress, but the transport properties of the soybean HKT transporters at the molecular level are still unclear. Here, using Xenopus oocyte as a heterologous expression system and two-electrode voltage-clamp technique, we identified four HKT transporters, GmHKT1;1, GmHKT1;2, GmHKT1;3 and GmHKT1;4, all of which belong to type I subfamily, but have distinct ion transport properties. While GmHKT1;1, GmHKT1;2 and GmHKT1;3 function as Na+ transporters, GmHKT1;1 is less selective against K+ than the two other transporters. Astonishingly, GmHKT1;4, which lacks transmembrane segments and has no ion permeability, is significantly expressed, and its gene expression pattern is different from the other three GmHKTs under salt stress. Interestingly, GmHKT1;4 reduced the Na+/K+ currents mediated by GmHKT1;1. Further study showed that the transport ability of GmHKT1;1 regulated by GmHKT1;4 was related to the structural differences in the first intracellular domain and the fourth repeat domain. Overall, we have identified one unique GmHKT member, GmHKT1;4, which modulates the Na+ and K+ transport ability of GmHKT1;1 via direct interaction. Thus, we have revealed a new type of HKT interaction model for altering their ion transport properties.

Ion conduction in nanoscale ion channels or ion pumps to produce electrical signals is the basis of many fundamental biological processes. Inspired by biological ion channels, artificial nanochannels have been extensively explored to mimic the regulation of ion transport in nanochannels and to be applied in salinity gradient power generation. In this study, sulfonated polyether sulfone (SPES) membranes with many nanochannels were constructed via a phase separation method and applied in the salinity gradient power generation field. The nanochannel structure (nanochannel size and length) in the membrane was adjusted by controlling the SPES content and the thickness of the casting solution. These SPES membranes exhibited typical surface charge governing ion transport and excellent cation selectivity. The numerical simulation of ion transport properties for nanochannels with a series of nanochannel sizes and lengths was performed to analyze the effect of the nanochannel structure on the ion transport and salinity gradient power generation properties. The calculated results show that the nanochannels with length and size satisfying a certain relation possess optimal salinity gradient power generation properties. These SPES membranes were also used to generate electricity by mixing artificial seawater (0.5 M NaCl) and river water (0.01 M NaCl). The output power densities of the SPES membranes (M30–10 and M30–50) with the optimized nanochannel structure reached up to 5.8 and 5.6 W m–2, respectively.

The ion transport properties of epithelial cells from the bovine trachea grown in culture were investigated. The cellular uptake of 22Na+, 36Cl- and 86Rb+ was measured and the sensitivity of ion uptake to amiloride and bumetanide revealed the presence of the transport pathways that exist in the native tissue. The action of corticosteroids, dexamethasone and aldosterone (0.1 or 1.0 microM), was studied by measuring the short-circuit current and the uptake of Na+ and Cl- following a treatment of 18 h, 2 or 8 days. The results showed that, in each situation, dexamethasone enhanced markedly the amiloride-sensitive current and Na+ uptake. In contrast, aldosterone exerted no detectable effect on the ion transport and electrical properties.

Fluorine‐free ionic liquids (ILs) and electrolytes based on ether‐functionalized pyrrolidinium or imidazolinium cations coupled with a “greener”, non‐basic, and hydrolytically stable saccharinate (Sac) anion, are herein presented with their thermal, transport and electrochemical properties. The thermal stability, glass transition temperature, and electrochemical stability of the imidazolinium based ILs surpasses the pyrrolidinium IL, while the latter offer better (ion) transport properties. Ether‐functionalization of the IL cation improves the transport properties with negligible effects on the thermal and electrochemical stabilities. The Li+ conducting electrolytes – created by adding 10 mol % of lithium saccharinate (LiSac) to the neat (BMMIm)(Sac) and (C201MMIm)(Sac) ILs show an as low initial overpotential as ±0.05 V and outstanding Li stripping/plating performance over 100 hours at 60 °C for the latter, but a very large polarization interfacial resistance, 4730 Ω cm2, impeding the kinetics of stripping/plating, even at these elevated temperatures for the former. Hence the rather modest modification has an enormous impact in practice.

Unraveling the effect of charge distribution in a polyelectrolyte multilayer nanofiltration membrane on its ion transport properties

Time-resolved electromechanical and conductive behavior of nanostructured bilayers tethered to the surface of the electrode with incorporated channel proteins and peptides

Cystic fibrosis (CF) airway epithelia exhibit altered Cl(-) and Na(+) transport properties and increased IL-8 secretion. In the present study, we examined whether a small proportion of cells with a normal phenotype could normalize the ion transport and IL-8 secretion properties of a CF airway epithelial cell layer. We obtained three types of primary cultures of human bronchial epithelial cells: one composed of 100% non-CF cells, one of 100% CF cells, and one of 10% non-CF and 90% CF cells ("cocultures"). Measurement of the bioelectric properties in Ussing chambers revealed that the cocultures displayed Cl(-) and Na(+) transports similar to those observed in the 100% non-CF cultures and significantly different from CF cultures. IL-8 concentration in the coculture supernatant was not different from non-CF cultures, but was significantly lower than in CF cultures. This study provides evidence that 10% bronchial epithelial cells expressing a normal phenotype are sufficient to functionally correct a primary culture of CF bronchial epithelial cells in vitro. We postulate that 10% cells with a non-CF phenotype can be used as a goal for the design of gene therapy and cell therapy trials for CF lung disease.

Highly concentrated electrolytes (HCEs) have a similarity to ionic liquids (ILs) in high ionic nature, and indeed some of HECs are found to behave like an IL. HCEs have attracted considerable attention as prospective candidates for electrolyte materials in future lithium secondary batteries owing to their favorable properties both in the bulk and at the electrochemical interface. In this study, we highlight the effects of the solvent, counter anion, and diluent of HCEs on the Li+ ion coordination structure and transport properties (e. g., ionic conductivity and apparent Li+ ion transference number measured under anion-blocking conditions, ). Our studies on dynamic ion correlations unveiled the difference in the ion conduction mechanisms in HCEs and their intimate relevance to values. Our systematic analysis of the transport properties of HCEs also suggests the need for a compromise to simultaneously achieve high ionic conductivity and high values.

Sintering behavior, ac conductivity and dielectric relaxation of Li1.3Ti1.7Al0.3(PO4)3 NASICON compound

There is an enormous drive for moving toward cathode material research in LIBs due to the proposal of zero-emission electric vehicles together with the restriction of cathode materials in design. LiNi0.5Mn1.5O4 (LNMO) attracts great research interests as high-voltage Co-free cathodes in LIBs. However, a more extensive study is required for LNMO due to its poor electrochemical performance, especially at high temperature, because of the instability of the LNMO interface. Herein, we design structural modifications using Mg and Zr to alleviate the above-mentioned drawbacks by limiting Mn dissolution and tailoring interstitial sites (which are shown by structural and electrochemical characterizations). This strategy enhances the cycle life up to 1000 cycles at both 25 and 50 °C. In addition, a thorough characterization by impedance spectroscopy is applied to give an insight into the electronic and ionic transport properties and the intricate phase transitions occurring upon oxidation and reduction.

Complex magnesium organohaloaluminate electrolytes were studied by electrochemical transport measurements and in-situ electrochemical/X-ray absorption spectroscopy. Cyclic voltammetry was employed to examine the reversibility of electrochemical magnesium deposition. To better understand the role of this electrolyte system, ionic transport properties such as transference number, ionic conductivity, and diffusion coefficient of Mg-ion species were measured at different concentrations. Transference number was determined by atomic absorption spectroscopy by quantifying the amount of potentiometric Mg deposition on Pt electrode. Despite exhibiting 100% Coulombic efficiency for Mg deposition and dissolution, the electrolyte showed low ionic conductivity and transference number at moderate and higher concentrations. To further investigate the observed transport properties, electrochemical deposition of magnesium from [Mg2(μ-Cl)3·6(OC4H8)]+ was monitored with in-situ/in-operando X-ray absorption spectroscopy of t...

Bipolar membranes (BPMs) are a unique construction of ion exchange membranes with anion exchange and cation exchange layers in series. Due to the unique transport processes in BPMs, they are becoming an increasingly attractive option for many electrochemical devices, especially in water electrolysis and carbon dioxide reduction. However, because a large number of anion and cation exchange membranes are available, it can be difficult to select the layers for BPM fabrication, particularly when targeting specific properties for use in a device. In this study, a survey of nine anion and nine cation exchange membranes was conducted to assess their steady-state ion transport properties. The primary application of this work is seawater electrolysis; therefore, measurements of salt flux and area resistance in 0.5 mol/L sodium chloride solutions were performed. These measurements displayed a trade-off behavior, with membranes displaying higher area resistance and having a lower salt flux. Conversely, membranes with lower area resistance had a higher salt flux. From these individual membrane results, a methodology was formulated to select component membranes for BPM fabrication, primarily considering their transport characteristics. Three BPMs were fabricated using this methodology. A model was developed to integrate the parameters and ion transport properties measured from individual membranes to predict salt flux and area resistance values for a BPM. Values produced from the model were then compared with experimental salt flux and area resistance BPM measurements. Both the model and experimental salt flux and area resistance BPMs exhibited an area resistance-flux trade-off, like that of the component membranes.

Phosphate-based cathode materials are considered safe, reliable and commercially viable for perfecting the next generation of metal-ion batteries for grid applications. Contrary to oxides, phosphates tend to form more sophisticated and diverse crystal structures thus expanding playground for designing and tuning electrochemical properties. Coupled with fluoride anions phosphates might offer not only even higher electrode potentials but also a richer crystal chemistry and then ampler opportunities in developing new cathode materials. Recently we proposed a novel series of vanadium-based AVPO4F (A = Li, Na, K, Rb) cathode materials crystallizing in a unique KTiOPO4 (KTP)-type structure. The target materials were synthesized via different soft-chemistry routes including hydrothermal method and freeze-drying. The KTP-type “VPO4F” framework featured outstanding rate capability and capacity retention especially in Li cells: the material maintained more than 75% of the initial specific capacity at the 40C rate with an average potential of 4.0 V vs. Li/Li+ [1]. The structural evolution during Li de/insertion was examined by operando X-ray diffraction and ex situ electron tomography. The material experienced a series of phase transitions characterized by a volume variation just within 2%. Another quality of this framework is supporting reversible Na+, K+ and even Rb+ ions de/insertion sustaining the host structure [2]. The experimental electrochemical performance and ion transport properties were different for various alkali ions. The ion diffusion coefficients obtained by PITT were the lowest for Li+ (10-12 – 10-14 cm2/s) and the highest for K+ (10-11 – 10-12 cm2/s), with the latter anticipating high-power applications of KVPO4F in K-ion batteries [3]. According to DFT calculations, the “VPO4F” framework manifested extremely low energy barriers for K+ and Rb+ migration of less than 0.2 eV in accordance with experimental transport properties. Furthermore, the full extraction of K+ in KVPO4F occurred at the highest potential of ~4.6 V vs. K/K+ compared to Li+, Na+ and Rb+. At the same time the average potential of the material (4.3 V vs. K/K+) lay within a stability window of commercial electrolytes that validates KVPO4F as the most prospective cathode material for high-voltage K-ion batteries [4]. Additionally, the “VPO4F” framework demonstrated reversible electrochemical activity in the low-voltage domain (below 1.8 V vs. A/A+) in Li, Na and K cells thus opening prospects for creating anode materials for metal-ion batteries. In this talk we will focus on our recent activities on the KTP-type fluoride-phosphates as promising electrode materials for metal-ion rechargeable batteries.

Ion transport properties and hydrogen solubility in brine play pivotal roles in various engineering and scientific scopes including chemical, physical, geochemical, and geothermal domains. Molecular dynamics simulations were performed to obtain transport properties of NaCl in the binary H2O + NaCl system using different force fields. Brine density, ion diffusivity, molar conductivity, conductivity, and hydrogen solubilities were obtained as functions of temperature and salt concentration. We compared the performance of different force fields against the experimental correlation model and developed three mathematical models. The first was the modified brine density model based on the simulated brine density over a wide range of salinity levels, and the second and third analytical mathematical models were derived for the ion diffusivity and molar conductivity as a function of salinity and temperature. The results of this study illustrated that the modified brine density model not only produced the same results of the previous model for lower salinity levels but also applied well to predict the brine density for a higher salinity level. The derived mathematical models indicated that the ion diffusivity and molar conductivity decreased linearly with salinity, and the slope and y-intercept of the lines of diffusivity and molar conductivity versus temperature were third-order polynomials of temperature. The developed models provided the mechanism for the behavior of decreasing molar conductivity with increasing salinity and increasing conductivity with increasing salinity. The directions of the effect of salinity on the molar conductivity and conductivity were opposite. The molar conductivity increased with a decreasing salinity level. However, the conductivity increased with increasing salinity, as the contribution of the ion concentration or salinity level to conductivity dominated over that of the ion movement.