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1.
Electrolytes having 3.5 M hydroxide-ion concentration were tested in 1.35 Ah Zn/NiOOH cells to evaluate their ability to reduce the extent of zinc species migration and slow the rate of cell capacity decline. Alkaline-fluoride and alkaline-borate electrolytes, in which ZnO solubility is approximately 25% of that in standard 7.4 M KOH electrolyte, exhibited 0.09-0.14%/cycle zinc-electrode area loss, which may be compared to a value of 0.46%/cycle observed in standard electrolyte. In addition, no zinc penetration of the separator occurred in cells that employed alkaline-fluoride and alkaline-borate electrolytes, even when zinc-electrode overpotentials reached 290 mV at the end of charge. Less than 2% of the zinc remaining after cycling was electrochemically inactive.  相似文献   

2.
Electrolytes having 3.5 M hydroxide-ion concentration were tested in 1.35 Ah Zn/NiOOH cells to evaluate their ability to reduce the extent of zinc species migration and slow the rate of cell capacity decline. Alkaline-fluoride and alkaline-borate electrolytes, in which ZnO solubility is approximately 25% of that in standard 7.4 M KOH electrolyte, exhibited 0.09-0.14%/cycle zinc-electrode area loss, which may be compared to a value of 0.46%/cycle observed in standard electrolyte. In addition, no zinc penetration of the separator occurred in cells that employed alkaline-fluoride and alkaline-borate electrolytes, even when zinc-electrode overpotentials reached 290 mV at the end of charge. Less than 2% of the zinc remaining after cycling was electrochemically inactive.  相似文献   

3.
Methyl butyrate (MB) has been investigated as a co-solvent for lithium-ion battery electrolytes to improve the performance at low temperature (?10 to ?30 °C). The cycling performance of graphite/LiNi1/3Co1/3Mn1/3O2 cells with 1.2 M lithium tetrafluorooxalatophosphate (LiFOP) in 2:2:6 EC/EMC/MB was compared to 1.2 M LiPF6 in both 3:7 EC/EMC and 2:2:6 EC/EMC/MB. The LiFOP/MB electrolyte has a good operational temperature window and comparable cycling performance to the LiPF6 electrolyte at both room temperature and low temperature (?10 °C). However, after accelerated aging the LiFOP/MB electrolyte has worse performance at very low temperature (?30 °C) compared to LiPF6 electrolytes. Ex-situ surface analysis was conducted by scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier transfer infrared spectroscopy to provide insight into the performance differences.  相似文献   

4.
Rechargeable lithium/sulfur battery with suitable mixed liquid electrolytes   总被引:1,自引:0,他引:1  
The suitability of some single/binary liquid electrolytes and polymer electrolytes with a 1 M solution of LiCF3SO3 was evaluated for discharge capacity and cycle performance of Li/S cells at room temperature. The liquid electrolyte content in the cell was found to have a profound influence on the first discharge capacity and cycle property. The optimum, stable cycle performance at about 450 mAh g−1 was obtained with a medium content (12 μl) of electrolyte. Comparison of cycle performance of cells with tetra(ethylene glycol)dimethyl ether (TEGDME), TEGDME/1,3-dioxolane (DIOX) (1:1, v/v) and 1,2-dimethoxyethane (DME)/di(ethylene glycol)dimethyl ether (DEGDME) (1:1, v/v) showed better results with the mixed electrolytes based on TEGDME. The addition of 5 vol.% of toluene in TEGDME had a remarkable effect of increasing the initial discharge capacity from 386 to 736 mAh g−1 (by >90%) and stabilizing the cycle properties, attributed to the reduced lithium metal interfacial resistance obtained for the system. Polymer electrolyte based on microporous poly(vinylidene fluoride) (PVdF) membrane and TEGDME/DIOX was evaluated for ionic conductivity at room temperature, lithium metal interfacial resistance and cycle performance in room-temperature Li/S cells. A comparison of the liquid electrolyte and polymer electrolyte showed a better performance of the former.  相似文献   

5.
The polymer electrolytes based on a polymerized ionic liquid (PIL) as polymer host and containing 1,2‐dimethyl‐3‐butylimidazolium bis(trifluoromethanesulfonyl)imide (BMMIM‐TFSI) ionic liquid, lithium TFSI salt, and nanosilica are prepared. The PIL electrolyte presents a high ionic conductivity, and it is 1.07 × 10?3 S cm?1 at 60°C, when the BMMIM‐TFSI content reaches 60% (the weight ratio of BMMIM‐TFSI/PIL). Furthermore, the electrolyte exhibits wide electrochemical stability window and good lithium stripping/plating performance. Preliminary battery tests show that Li/LiFePO4 cells with the PIL electrolytes are capable to deliver above 146 mAh g?1 at 60°C with very good capacity retention. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40928.  相似文献   

6.
A hydrogel composite that has been prepared by using waste linear low‐density polyethylene, acrylic acid, and organo‐montmorillonite (LLDPE‐g‐PAA/OMMT) is used as a hydrogel electrolyte. An absorbency test was used to determine the percentage of ZnCl2 solution absorbed by the hydrogel composite. The swelling behavior of the hydrogel composite in the ZnCl2 solution was then studied. The highest absorbency was recorded when the concentration of ZnCl2 solution was 3 M. The conductivity of ZnCl2‐hydrogel composite electrolytes is dependent on the solution's concentration. A mixture of ZnCl2 solution with hydrogel composite yields a good hydrogel composite electrolyte with a conductivity of 0.039 S cm?1 at 3 M ZnCl2. The hydrogel composite electrolyte was used to produce zinc‐carbon cells. The fabricated cell gives capacity of 7.8 mAh, has an internal resistance of 9.9 Ω, a maximum power density of 15.78 mWcm?2, and a short‐circuit current density of 43.75 mAcm?2 for ZnCl2‐hydrogel composite electrolytes. J. VINYL ADDIT. TECHNOL., 22:279–284, 2016. © 2014 Society of Plastics Engineers  相似文献   

7.
Solid-state polymer electrolytes (SPEs) have attracted significant attention owing to their improvement in high energy density and high safety performance. However, the low lithium-ion conductivity of SPEs at room temperature restricts their further application in lithium-ion batteries (LIBs). Herein, we propose a novel poly (ethylene oxide) (PEO)-based nanocomposite polymer electrolytes by blending boron-containing nanoparticles (BNs) in the PEO matrix (abbreviated as: PEO/BNs NPEs). The boron atom of BNs is sp2-hybridized and contains an empty p-orbital that can interact with the anion of lithium salt, promoting the dissociation of the lithium salts. In addition, the introduction of the BNs could reduce the crystallinity of PEO. And thus, the ionic conductivity of PEO/BNs NPEs could reach as high as 1.19 × 10−3 S cm−1 at 60°C. Compared to the pure PEO solid polymer electrolyte (PEO SPEs), the PEO/BNs NPEs showed a wider electrochemical window (5.5 V) and larger lithium-ion migration number (0.43). In addition, the cells assembled with PEO/BNs NPEs exhibited good cycle performance with an initial discharge capacity of 142.5 mA h g−1 and capacity retention of 87.7% after 200 cycles at 2 C (60°C).  相似文献   

8.
The recently developed technique of cold sintering process (CSP) enables densification of ceramics at low temperatures, i.e., <300°C. CSP employs a transient aqueous solvent to enable liquid phase‐assisted densification through mediating the dissolution‐precipitation process under a uniaxial applied pressure. Using CSP in this study, 80% dense Li1.5Al0.5Ge1.5(PO4)3 (LAGP) electrolytes were obtained at 120°C in 20 minutes. After a 5 minute belt furnace treatment at 650°C, 50°C above the crystallization onset, Li‐ion conductivity was 5.4 × 10?5 S/cm at 25°C. Another route to high ionic conductivities ~10?4 S/cm at 25°C is through a composite LAGP ‐ (PVDF‐HFP) co‐sintered system that was soaked in a liquid electrolyte. After soaking 95, 90, 80, 70, and 60 vol% LAGP in 1 M LiPF6 EC‐DMC (50:50 vol%) at 25°C, Li‐ion conductivities were 1.0 × 10?4 S/cm at 25°C with 5 to 10 wt% liquid electrolyte. This paper focuses on the microstructural development and impedance contributions within solid electrolytes processed by (i) Crystallization of bulk glasses, (ii) CSP of ceramics, and (iii) CSP of ceramic‐polymer composites. CSP may offer a new route to enable multilayer battery technology by avoiding the detrimental effects of high temperature heat treatments.  相似文献   

9.
Flexible, transparent, and crosslinked polymer films were synthesized by polymerization of PEG‐modified urethane acrylate using a simple method. A series of novel solid polymer electrolytes and gel electrolytes were prepared based on this type of polymer film. To understand the interactions among salt, solvent, and polymer, the swelling behaviors of the crosslinked polymer in pure propylene carbonate (PC) and liquid electrolyte solutions (LiClO4/PC) were investigated. The results showed that the swelling rate in the electrolyte solution containing moderate LiClO4 was greater than that in pure PC. Thermogravimetric analysis (TGA) also supported the interaction between the solvent and polymer. The morphology and crystallinity of the crosslinked polymer and polymer electrolytes were studied using atomic force microscopy (AFM) and wide‐angle X‐ray diffraction (WAXD) spectroscopy. The effects of the content of the electrolyte solution on the ionic conductivity of gel electrolytes were explored. The dependence of the conductivity on the amount of the electrolyte solution was nonlinear. With a different content of the plasticizer, the ionic conduction pathway of the polymer electrolytes would be changed. The best ionic conductivity of the gel electrolytes, which should have good mechanical properties, was 4 × 10r?3 S cm?1 at 25°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 340–348, 2003  相似文献   

10.
《Ceramics International》2023,49(5):7935-7945
Solid polymer electrolytes (SPEs) have attracted much attention because of their potential in improving energy density and safety. Vanadium doped ceramic matrix Li6.7La3Zr1.7V0.3O12 (LLZVO) was synthesized by high-temperature annealing, and formed a composite electrolyte with polyethylene oxide (PEO). Compared with pure PEO electrolyte membrane, the composite electrolyte membrane exhibited better ionic conductivity (30 °C: 3.2 × 10?5 S cm?1; 80 °C: 3.6 × 10?3 S cm?1). The combination of LLZVO was beneficial to improve the lithium ion transference number (tLi+) of SPE, which was as high as 0.81. The Li/SPE/LiFePO4 battery shows good cycling ability, with a specific capacity of 142 mAh g?1 after a stable cycle of 150 cycles. Meanwhile, the symmetrical lithium battery with composite electrolyte can work continuously for 1200 h without short circuit at the current density of 0.1 mA cm?2 at 50 °C, and the capacity is 0.176 mAh. Vanadium doped ceramic matrix LLZVO as an active ionic conductor, improved the overall performance of solid electrolyte.  相似文献   

11.
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   

12.
The rate of the extraction of zinc by trilaurylammonium chloride (TLAHC1) dissolved in toluene was investigated at different aqueous chloride concentrations, using lithium chloride as bulk electrolyte, ranging from 0.5 mol.dm -3 to 2.0 mol dm -3. The experiments were performed using a modified Lewis cell at 25?°C. The rate of metal extraction was found to increase by increasing the aqueous chloride concentration. The data treatment indicated that ZnCl2 and ZnCl4 2- are both kinetically active species. The addition reaction with ZnCl2 is favoured at low chloride concentration while the anion exchange of ZnCl4 2- prevails at high chloride concentration. The addition reaction was explained in terms or interfacial reaction steps. The anion exchange reaction, due to its fast nature, seems to be controlled by diffusion.  相似文献   

13.
A new hybrid polymer electrolyte system based on chemical‐covalent polyether and siloxane phases is designed and prepared via the sol–gel approach and epoxide crosslinking. FT‐IR, 13C solid‐state NMR, and thermal analysis (differential scanning calorimetry (DSC) and TGA) are used to characterize the structure of these hybrids. These hybrid films are immersed into the liquid electrolyte (1M LiClO4/propylene carbonate) to form plasticized polymer electrolytes. The effects of hybrid composition, liquid electrolyte content, and temperature on the ionic conductivity of hybrid electrolytes are investigated and discussed. DSC traces demonstrate the presence of two second‐order transitions for all the samples and show a significant change in the thermal events with the amount of absorbed LiClO4/PC content. TGA results indicate these hybrid networks with excellent thermal stability. The EDS‐0.5 sample with a 75 wt % liquid electrolyte exhibits the ionic conductivity of 5.3 × 10?3 S cm?1 at 95°C and 1.4 × 10?3 S cm?1 at 15°C, in which the film shows homogenous and good mechanical strength as well as good chemical stability. In the plot of ionic conductivity and composition for these hybrids containing 45 wt % liquid electrolyte, the conductivity shows a maximum value corresponding to the sample with the weight ratio of GPTMS/PEGDE of 0.1. These obtained results are correlated and used to interpret the ion conduction behavior within the hybrid networks. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1000–1007, 2006  相似文献   

14.
Crosslinked polymer electrolyte networks were prepared from poly(ethylene glycol) diglycidyl ether blended with an epoxy resin (diglycidyl ether of bisphenol A) in different ratios and then cured with α,ω‐diamino poly(propylene oxide) in the presence of lithium perchlorate (LiClO4) as a lithium salt. The ionic conductivities of these polymer electrolytes were determined by alternating current (AC) impedance spectroscopy. Propylene carbonate (PC) was used as a plasticizer to form gelled polymer electrolyte networks. The conductivities of the polymer electrolytes containing 46 wt % PC plasticizer were approximately 5 × 10?4 S cm?1 at 25°C and approximately 10?3 S cm?1 at 85°C. These polymer electrolytes were homogeneous and exhibited good mechanical properties. The effects of the polymer composition, plasticizer content, salt concentration, and temperature on the ionic conductivities of the polymer electrolytes were examined. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1264–1270, 2004  相似文献   

15.
By changing from the usual solvent-fixed frame of reference for flows to one based upon a fixed anion, electro-osmotic transference numbers are defined for any electrolyte, for which transport numbers are known. For sulphonate membranes, chloride electrolyte analogues were chosen. Agreement between observed transference numbers and those of the model electrolytes are shown to be excellent for both polystyrene based and perfluoro-sulphonic acid membranes.From irreversible thermodynamics it is shown that the transference number for any membrane will have a maximum value equal to the molar ratio of water to fixed charge in the membrane and independent of ionic form. The observed value is in addition, proportional to the fraction of the total water friction, which is due to water interaction with counterion. It is the latter which is estimated successfully from model electrolytes. The ionic forms used were Li+, Na+, K+, Rb+, Cs+ and H+ at 25°C in membranes in which electrolyte exclusion was almost complete.  相似文献   

16.
Conductivity measurements were made for the solid electrolyte systems N,N,N,N′,N′,N′-hexamethylethylenediamine diiodidesilver iodide (HMED-AgI) and N,N,N,N′,N′,N′-hexamethyl-1,2-propanediamine diiodidesilver iodide (HPMD-AgI). The conductivity of the two systems reached maximum values which correspond to AgI concentrations of 97 and 92 mole % in the HMED and HMPD electrolytes, respectively. The HMED-AgI double salt showed a conductivity of 0·11 (Ω cm)?1 at 22°C compared to the value of 0·03 (Ω cm)?1 obtained for the HMPD-AgI species. The Arrhenius activation energy in the temperature range 22–90°C was 9·0 and 11·8 kJ/mole of the ethylenediamine and propylenediamine electrolytes, respectively.  相似文献   

17.
Poly(vinylidene fluoride-co-hexafluoropropene) (PVDF–HFP)-based polymer electrolytes embedded with 1-ethyl-3-methylimidazolium tetrafluoroborate ioniliquid have been synthesized to improve the ionic conductivity. Electric double-layer capacitors (EDLC) have been prepared using the synthesized polymer electrolytes. Inorganic oxide fillers (5 wt %) such as titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles have been added to polymer electrolytes to compare the electrochemical behavior of the fabricated EDLC. The intrinsic dielectric constant of nanoparticles contributes in ionic dissociation which enhances ionic conductivity of electrolytes and also controls the specific capacitance of the EDLC fabricated with these electrolytes. Physicochemical properties of polymer nanocomposites have been investigated using X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared analysis, which confirms decrease of crystalline phase in host polymer PVDF–HFP. The maximum voltage stability is obtained for TiO2-based polymer electrolyte. The high specific capacitance as well as high energy density is obtained for the EDLC cell with TiO2-based polymer electrolyte compared to EDLC with ZnO nanoparticles-based electrolyte. EDLC cells show specific capacitance of 76.4 and 44.51% of initial specific capacitance value at 2000th cycle for ZnO and TiO2-based polymer electrolytes, respectively. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48757.  相似文献   

18.
The most efficient DSSCs reported till date contains liquid electrolytes with I?/I3? redox couple. However, the disadvantages of liquid electrolytes lead to reduce the impact of DSSCs. In the present work, the I?/I3? liquid electrolyte was replaced by quasi-solid gel polymer electrolytes (GPEs) using polyethylene glycol (Mwt = 20,000), which are incorporated in small fractions (0, 1, 5, 10, 15 and 20 % w/v) into the liquid iodine/iodide electrolyte matrix. The roughness and homogeneity of the GPEs on the surface of the TiO2 electrodes was monitored by atomic force microscope which indicates the physical cross linking of polymer chains in a gel network. The conductivity (σ) and the thermal stability (TGA) of the GPEs compared with the liquid electrolyte were studied in details. The photovoltaic characteristics [Voc, Isc, fill factor and efficiency (η)] of the DSSCs based GPEs were recorded, The results revealed the DSSCs assembled with the gel polymer electrolyte reports a higher short circuit density (JSC) and lower or similar open circuit voltage (VOC) than the cells with liquid electrolyte. The overall light-to-electrical-energy conversion efficiencies (η) of the cells based GPEs showed a relatively higher stability over a period of time compared with those based liquid electrolyte, indicating that the quasi-solid nature of the GPEs may impart flexibility to DSSCs so that some large-scale productions such as roll-to-roll process can be realized.  相似文献   

19.
ABSTRACT

This study investigated the ability of the electrocoagulation process to remove urea from synthetic and real wastewater using zinc electrodes. The electrocoagulation cell was operated under various conditions of current density, initial pH, electrode spacing, and electrolytes. The results indicated that the maximum urea removal reached was 66%, which occurred at a current density of 21 mA/cm2, initial pH = 7.0, 4 cm electrode spacing, and using magnesium chloride as the electrolyte. By-products were analyzed using FTIR. The anode’s morphology was examined using a scanning electron microscope. Results were compared with chemical coagulation using zinc sulfate as the coagulant.  相似文献   

20.
A series of new gel polymer electrolytes (GPEs) based on different concentrations of a hydrophobic ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide (EMIMTFSI) entrapped in an optimized typical composition of polymer blend-salt matrix [poly(vinyl chloride) (PVC) (30 wt%) / poly(ethyl methacrylate) (PEMA) (70 wt%) : 30 wt% zinc triflate Zn(CF3SO3)2] has been prepared using facile solution casting technique. The AC impedance analysis has revealed the occurrence of the maximum ionic conductivity of 1.10 × 10?4 Scm?1 at room temperature (301 K) exhibited by the PVC/PEMA- Zn(OTf)2 system containing 80 wt% ionic liquid. The addition of EMIMTFSI into the optimized PVC/PEMA- Zn(OTf)2 system in different weight percentages enhances the number of free zinc ions thereby leading to enrichment of ionic conductivity. The structural and complexation behaviour of the as prepared polymer gel electrolytes was substantiated by subjecting these electrolyte films to X-ray diffraction (XRD) and Attenuated total reflectance - Fourier transformed infrared (ATR-FTIR) investigations. The wider electrochemical stability window ~ 3.23 V and a reasonable cationic transference number (tZn 2+) of 0.63 have been attained for the polymer gel electrolyte film containing higher loading of (80 wt%) ionic liquid. The development of the amorphous phase of these gel polymer electrolyte membranes with increasing ionic liquid content was observed from scanning electron microscopic (SEM) analysis. The results of the current work divulge the assurance of developing GPEs based on ionic liquids for prospective application in zinc battery systems.  相似文献   

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