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1.
Lithium-ion batteries are currently the alternative of choice to overcome the increasing demand of energy. However, besides the scarcity of lithium and limited geolocation, it is believed that such batteries have already reached their maximum maturity. Sodium batteries emerge as an alternative to produce the new, so called, post-lithium batteries. In this study, we explore (i) the effect of sodium content and sintering temperature in solid electrolytes based in NASICON-type compounds and (ii) the use of two methodologies to obtain porous NASICON samples: application of natural substances and organic materials as pore-formers and freeze casting. The main purpose is the attainment of hybrid quasi-solid state electrolytes, with enhanced room temperature conductivity, based on porous ceramic electrolyte layers infiltrated with ionic liquids. Using this approach, porous samples with different microstructure and porous morphology and distribution were achieved, providing an enhancement in conductivity (ranging from 0.45 to 0.96 mS cm−1 at 30 °C) of one order of magnitude for infiltrated samples respect to pore-free samples. According to these results the porous NASICON might be considered as a functional macroporous inorganic separator that can act as a Na+ reservoir.  相似文献   
2.
《Ceramics International》2021,47(22):31920-31926
The Sr and Ba bearing Tl-1212 phase, Tl(Ba,Sr)CaCu2O7 is an interesting superconductor. The Sr only bearing TlSr2CaCu2O7 is not easily prepared in the superconducting form. The Ba only bearing TlBa2CaCu2O7 on the other hand does not show improvement in the transition temperature with elemental substitution. In this work the influence of multivalent Se (non-metal) and Te (metalloid) substitutions at the Tl-site of Tl1-xMx(Ba,Sr)CaCu2O7 (M = Se or Te) superconductors for x = 0–0.6 was studied. The samples were prepared via the conventional solid-state reaction method. XRD patterns showed a single Tl-1212 phase for x = 0 and 0.1 Se substituted samples. The critical current density at the peak temperature, Tp of the imaginary (χ”) part of the AC susceptibility (χ = χ’ +χ”), Jc-inter(Tp) for all samples was between 15 and 21 A cm−2. The highest superconducting transition temperature was shown by the x = 0.3 Se-substituted sample (Tc-onset = 104 K, Tc-zero = 89 K, Tcχ’ = 104 K and Tp = 80 K). Te suppressed the superconductivity of Tl-1212 phase. The order of highest transition temperatures are as follows: Tl1-xTex(Ba,Sr)CaCu2O7<Tl(Ba,Sr)CaCu2O7<Tl1-xSex(Ba,Sr)CaCu2O7. This work showed that Se was better than Te in improving the transition temperature and flux pinning of the Tl-1212 phase. The roles of ionic radius of Se and Te on the superconductivity of Tl(Ba,Sr)CaCu2O7 are discussed in this paper.  相似文献   
3.
《Ceramics International》2022,48(8):10733-10740
Multivalent ion-conducting ceramics are required for the manufacture of high-safety, high-capacity rechargeable batteries. However, the low ionic conductivity of solid electrolytes and discrepancies in the thermal expansion between the battery components limit their widespread application. Furthermore, anisotropic thermal expansion in crystals during battery manufacturing and the charge-discharge cycles causes the formation of microcracks, which degrade the battery performance. The physical properties of ceramic materials with anisotropic crystal structures can be modified by varying the crystallographic orientation of their grains. In this study, a co-precipitation approach was used to synthesize an Mg2+-conducting (Mg0.1Hf0.9)4/3.8Nb(PO4)3 solid electrolyte, and the grain orientation in the bulk sample was controlled using strong magnetic fields during the slip casting process. The results showed that inducing an orientation along the c-axis enhanced the apparent ionic conductivity of the bulk sample. It was also observed that (Mg0.1Hf0.9)4/3.8Nb(PO4)3 crystal has a negative volumetric thermal expansion despite a positive linear thermal expansion along its c-axis. By adjusting the c-axis orientation of the grains, (Mg0.1Hf0.9)4/3.8Nb(PO4)3 electrolytes with negative or positive linear thermal expansion coefficient have been produced. The findings of this study suggest that solid-electrolytes with negative, positive, or zero linear thermal expansion can be produced to create more compatible and higher-performance solid-state devices.  相似文献   
4.
Structure design is the primary strategy to acquire suitable ionomers for preparing proton exchange membranes (PEMs) with excellent performance. A series of comb-shaped sulfonated fluorinated poly(aryl ether sulfone) (SPFAES) membranes are prepared from sulfonated fluorinated poly(aryl ether sulfone) polymer (SPFAE) and sulfonated poly(aryl ether sulfone) oligomer (SPAES-Oligomer). Chemical structures of the comb-shaped membranes are verified by 1H nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectra. The comb-shaped SPFAES membranes display more continuous hydrophilic domains for ion transfer, because the abundant cations and flexible side-chains structure possess higher mobility and hydrophilicity, which show significantly improved proton conductivity, physicochemical stability, mechanical property compared to the linear SPFAE membranes. In a H2/O2 single-cell test, the SPFAES-1.77 membrane achieves a higher power density of 699.3 mW/cm2 in comparison with Nafion® 112 (618.0 mW/cm2) at 80 °C and 100% relative humidity. This work offers a promising example for the synthesis of highly branched polymers with flexible comb-shaped side chains for high-performance PEMs.  相似文献   
5.
Gel polymer electrolytes (GPEs) can avoid the electrolyte leakage risk of electrochemical double layer capacitors (EDLCs). But aqueous GPEs often suffer from narrow electrochemical windows. Herein, a series of deep eutectic solvent (DES)-based supramolecular GPEs are firstly developed for carbon-based EDLCs with wide voltage windows. The as-fabricated DES-based GPE shows an ionic conductivity of ~58 mS cm?1, which makes the stable voltage window of a carbon-based EDLC reach 2.4 V. The carbon-based EDLC exhibits a specific capacitance of 32.1 F g?1, an energy density of 24.6 Wh kg?1 and a capacitance retention of ~90% after 15,000 charge-discharge cycles. Moreover, when quinhydrone is added into the DES-based GPE, the specific capacitance and energy density of the corresponding EDLC can be further expanded to 60 F g?1 and 43.6 Wh kg?1, respectively. Therefore, our work may present a universal strategy to prepare novel supramolecular GPEs for high-performance EDLCs with wide voltage windows.  相似文献   
6.
Electrochemical reduction of CO2 is a novel research field towards a CO2-neutral global economy and combating fast accelerating and disastrous climate changes while finding new solutions to store renewable energy in value-added chemicals and fuels. Ionic liquids (ILs), as medium and catalysts (or supporting part of catalysts) have been given wide attention in the electrochemical CO2 reduction reaction (CO2RR) due to their unique advantages in lowering overpotential and improving the product selectivity, as well as their designable and tunable properties. In this review, we have summarized the recent progress of CO2 electro-reduction in IL-based electrolytes to produce higher-value chemicals. We then have highlighted the unique enhancing effect of ILs on CO2RR as templates, precursors, and surface functional moieties of electrocatalytic materials. Finally, computational chemistry tools utilized to understand how the ILs facilitate the CO2RR or to propose the reaction mechanisms, generated intermediates and products have been discussed.  相似文献   
7.
Three Brønsted acidic imidazole dicationic ionic liquids (ILs) with different length of alkyl chains, [Cn(Mim)2][HSO4]2 (n = 3, 6, 12), were prepared and used as catalyst for the esterification reaction of free fatty acids and methanol. Taking oleic acid as model acid, the catalytic performances of the synthesized ILs for the esterification were evaluated. The main physicochemical properties of the ILs, thermal stability, acidity, solubility in common solvents, and causticity on Austenitic stainless steel 316, were examined. [C3(Mim)2][HSO4]2 demonstrated the highest catalytic activity and enabled to assess the preliminary optimum esterification condition of oleic acid and methanol. Under optimized reaction conditions, the yield of oleic acid methyl ester was up to 95 %. The ILs have great potential as catalysts for producing fatty acid methyl esters from long‐chain free fatty acids.  相似文献   
8.
Ionic liquids (ILs) have gained wide‐spread focus owing to its negligible vapor pressure, low heat capacity, high thermal stability, and structural diversity. The solubility and selectivity toward carbon dioxide has made ILs a unique platform that possess the potential in gas separations. In particularly, combining functional ILs with membranes and porous supports is an efficient way to design task‐specific materials for CO2 separations. This minireview summarizes the developments and advances of ionic liquids‐based membranes for CO2 separations in recent three years, with an emphasis on the strategy of incorporating ionic liquids and CO2 separation performance.  相似文献   
9.
The performance of low-to-intermediate temperature (400–800?°C) solid oxide fuel cells (SOFCs) depends on the properties of electrolyte used. SOFC performance can be enhanced by replacing electrolyte materials from conventional oxide ion (O2-) conductors with proton (H+) conductors because H+ conductors have higher ionic conductivity and theoretical electrical efficiency than O2- conductors within the target temperature range. Electrolytes based on cerate and/or zirconate have been proposed as potential H+ conductors. Cerate-based electrolytes have the highest H+ conductivity, but they are chemically and thermally unstable during redox cycles, whereas zirconate-based electrolytes exhibit the opposite properties. Thus, tailoring the properties of cerate and/or zirconate electrolytes by doping with rare-earth metals has become a main concern for many researchers to further improve the ionic conductivity and stability of electrolytes. This article provides an overview on the properties of four types of cerate and/or zirconate electrolytes including cerate-based, zirconate-based, single-doped ceratezirconate and hybrid-doped ceratezirconate. The properties of the proton electrolytes such as ionic conductivity, chemical stability and sinterability are also systematically discussed. This review further provides a summary of the performance of SOFCs operated with cerate and/or zirconate proton conductors and the actual potential of these materials as alternative electrolytes for proton-conducting SOFC application.  相似文献   
10.
Low cost processing of lignocellulosic biomass is of great importance for sustainable chemistry and engineering. Herein, a low cost system composed of 1-butyl-3-methylimidazolium chloride ([C4C1im]Cl), HCl and formaldehyde (FA) was developed for the pretreatment of corn stalk at 80℃. The efficiency of this technology was compared with that in dioxane system or without FA addition. Due to FA stabilization, the extent of acid-hydrolysis of carbohydrate fraction can be significantly decreased while 70% above of lignin was removed with the pretreatment of[C4C1im]Cl/HCl/FA system at 80℃ for 2 h. A maximum reducing sugar yield of 93.7% and glucose concentration of 7.0 mg·ml-1 were subsequently obtained from enzymatic hydrolysis of the slurry. There were great differences in compositions of small molecule degraded products obtained with FA addition or not. The present[C4C1im]Cl based system exhibits great potential of substituting volatile organic solvents (i.e. dioxane) in developing low cost lignocellulosic biomass pretreatment at low temperature. Also, this work would gain insight into understanding on the roles of stabilization methods on the economic improvement of IL based biomass processing.  相似文献   
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