Solid Electrolyte Membrane Research Articles

High-performance free-standing hybrid solid electrolyte membrane combined with Li6.28Al0.24La3Zr2O12 and hexagonal-BN for all-solid-state lithium-based batteries

Hybrid solid electrolytes (HSEs) have received intensive attentions for all-solid-state lithium-based batteries (ASSBs) because of their high ionic conductivity, high mechanical strength, improved electrochemical stability, and effective lithium dendrite suppression capability. In this study, free-standing HSE membranes were fabricated using a poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) matrix and Li6.28Al0.24La3Zr2O12 (LALZO)/hexagonal-BN (h-BN) composite ceramic fillers with different amounts of h-BN. The optimal proportion of h-BN (10 wt%) in the HSE membrane reduces the crystallinity of PVDF-HFP matrix, increases the proportion of the electroactive β phase, and enhances the mechanical strength of the HSE membrane. Furthermore, the PVDF-HFP/LALZO/h-BN 10% HSE membrane exhibited improved electrochemical properties, for example, a lithium-ion transference number of 0.63 at 55 °C, ionic conductivity of 1.1 × 10-4 S cm−1 at 25 °C, electrochemical stability window of ~5.0 V vs. Li/Li+, and effective lithium dendrite suppression capability. The ASSB consisting of a LiFePO4 cathode, PVDF-HFP/LALZO/h-BN 10% HSE, and Li metal anode delivered improved battery performance with an average capacity of 131 mAh g−1 at 0.2C, > 99% coulombic efficiency, and a capacity retention of 92% after 100 cycles.

Interfacial optimization between cathode and 20 μm-thickness solid electrolyte membrane via in-situ polymerization for lithium metal batteries

Solid electrolyte membranes face a huge challenge in achieving satisfactory interfacial contact with electrodes, which severely impairs the rate performance and cycle life of solid-state lithium batteries. In this work, we fabricated an ultrathin solid polymer electrolyte (SPE) membrane, and based on it we demonstrated the interfacial contact optimization strategy by in-situ polymerization. The free-stranding PVDF-HFP-LiTFSI membrane with a thickness of 20 μm shows an ionic conductivity of 1.2 × 10−4 S cm−1 at room temperature. The poly(ethylene glycol) diacrylate-based in-situ polymerized electrolyte tightly connects the cathode and the SPE membrane, decreasing the interfacial resistance from 9380 Ω cm2 to 1100 Ω cm2. Compared with the traditional method employing liquid electrolyte for interfacial wetting, extended electrochemical window (4.6 V) and much improved thermal stability are obtained. Full cell employing LiFePO4 cathode and lithium metal anode shows an initial capacity of 138.9 mAh g−1 under a charge/discharge rate of 0.5C (85 mA g−1) at 60 °C, with a capacity retention ratio of 84.9% and a high average Coulombic efficiency (98.7%) after 300 cycles, remarkably better than those of its liquid electrolyte-used counterpart. Our work demonstrates that the application of in-situ polymerization into interfacial contact improvement between SPE and cathode possesses wide application prospects.

Super Long‐Cycling All‐Solid‐State Battery with Thin Li6PS5Cl‐Based Electrolyte

AbstractAll‐solid‐state batteries (ASSBs) using sulfide electrolytes have attracted ever‐increasing interest due to high ionic conductivity of the sulfides. Nevertheless, a thin, strong solid‐state sulfide electrolyte membrane maintaining high ionic conductivity is highly desired for ASSBs. Here, a thin, flexible composite solid electrolyte membrane composed of argyrodite sulfide Li6PS5Cl and a polar poly(vinylidene fluoride‐co‐trifluoroethylene) (P(VDF‐TrFE)) framework is prepared via an electrospinning‐infiltration‐hot‐pressing method. The interaction between Li6PS5Cl and polar P(VDF‐TrFE) ensures a high lithium‐ion conductivity (≈1.2 mS cm–1) at room temperature and good mechanical ductility of the composite electrolyte membrane. The coin‐type ASSB cells with the thin composite electrolyte membrane, a composite cathode of LiNbO3‐coated LiNi0.8Co0.1Mn0.1O2 and Li6PS5Cl, and a lithium‐indium anode, show super cycling performance, and the capacity retention is 92% after 1000 cycles and 71% even after 20 000 cycles at 1.0 mA cm–2 (i.e., 1.61 C) at room temperature. Moreover, pouch‐type ASSB cells with a high mass loading of active materials are made to demonstrate the potential and feasibility in future commercial applications.

Acid-in-Clay Electrolyte for Wide-Temperature-Range and Long-Cycle Proton Batteries.

Proton conduction underlies many important electrochemical technologies. A family of new proton electrolytes is reported: acid-in-clay electrolyte (AiCE) prepared by integrating fast proton carriers in a natural phyllosilicate clay network, which can be made into thin-film (tens of micrometers) fluid-impervious membranes. The chosen example systems (sepiolite-phosphoric acid) rank top among the solid proton conductors in terms of proton conductivities (15 mS cm-1 at 25°C, 0.023 mS cm-1 at -82°C), electrochemical stability window (3.35V), and reduced chemical reactivity. A proton battery is assembled using AiCE as the solid electrolyte membrane. Benefitting from the wider electrochemical stability window, reduced corrosivity, and excellent ionic selectivity of AiCE, the two main problems (gassing and cyclability) of proton batteries are successfully solved. This work draws attention to the element cross-over problem in proton batteries and the generic "acid-in-clay" solid electrolyte approach with superfast proton transport, outstanding selectivity, and improved stability for room- to cryogenic-temperature protonic applications.

A High-Performance Self-Reinforced PEO-Based Blend Solid Electrolyte Membrane for Solid-State Lithium Ion Batteries

A High-Performance Self-Reinforced PEO-Based Blend Solid Electrolyte Membrane for Solid-State Lithium Ion Batteries

Facile Li-ion conduction and synergistic electrochemical performance via dual functionalization of flexible solid electrolyte for Li metal batteries

Herein, a novel polymer electrolyte membrane based on poly(arylene ether sulfone)-g- poly(vinylethylene carbonate)/poly(ethylene glycol) (PAES-g-PVEC/PEG) combined with 1-butyl-1-methylpyrrolidinium bis(trifluoromethyl sulfonyl)imide was prepared to achieve the superior electrochemical performance with good thermal and mechanical stability. The synergistic effect was provided for the lithium ion transport and electrochemical performance by the dual functional groups of polyether and polycarbonate grafted on the rigid PAES backbones. The membrane containing 30 mol% PVEC and 70 mol% PEG exhibited the ionic conductivity of 0.81 × 10 − 3 S cm −1 and Li + transference number of 0.65 at room temperature, maintaining the thermal and mechanical stability in the flexible solid state. As this membrane illustrated a good interfacial compatibility with Li metal electrode, the LiFePO 4 ||Li cell demonstrated an outstanding cycling discharge capacity of ∼151 mA h g −1 and the coulomb efficiency 99% after 100 cycles under 0.1C. Based on this excellency, the PAES-g-PVEC/PEG electrolyte herein synthesized is considered to be a promising candidate for the application of all-solid-state lithium metal batteries with high power and energy density. • PAES-g-PVEC/PEG was synthesized to prepare flexible solid electrolyte membranes. • Enhanced single Li + conduction was realized by dual functional grafts. • It exhibited Li + conductivity of 0.81 × 10 −3 S cm −1 and transference number of 0.65. • It showed quite low interfacial resistance with Li metal anode.

Copper-iron ternary metal fluorides from multi-metallic template fluorination and their first use as cathode in solid state Li-batteries

Conversion cathodes such as metal fluorides are particularly interesting for their theoretical capacities up to 711 mAh/g when used in Li-ion batteries. However, they generally suffer from high hysteresis and/or poor cyclability. To overcome these problems, ternary metal fluorides are being explored to improve electrochemical properties compared to the usual binary fluorides: a polymer electrolyte membrane is also used to avoid undesirable cathode-electrolyte reactions and to assess the compatibility of such cathode materials with All Solid State Batteries (ASSB). Among the multi-metallic models, copper hexacyanoferrate Cu3[Fe(CN)6]2.nH2O from the Prussian blue analogue family (PBA), is fluorinated under pure fluorine gas at selected temperatures according to preliminary thermogravimetric mass spectrometry analyses. Using X-ray absorption spectroscopy and diffraction, an inverse perovskite structure [Cu(H2O)4]3·(FeF6)2 is identified at a fluorination temperature of 140 ​°C and an intimate mixture of CuF2 and FeF3 is formed at 350 ​°C. The cyclic voltammogram of the latter compared to that of a ball-milled sample of similar composition CuF2/FeF3 highlights the advantages of MMTF multi-metallic template fluorination for electrochemical properties, interpreted by the high level of homogeneous dispersion of the redox centers obtained with this method compared to the mechanical milling reference evaluated by SEM. The fluorides are also found to be compatible with the commercial solid polymer electrolyte membrane PEO-LiTFSI (Poly Ethylene Oxide impregnated with Lithium bis(trifluoromethanesulfonyl)imide), underlining the suitability of the MMTF-prepared cathodes for use in the ASSB.

Accelerated ion conduction by co-grafting of poly(ethylene glycol) and nitrile-terminated ionic liquid on poly(arylene ether sulfone) for solid electrolyte membranes for lithium ion battery

Solid polymeric electrolytes (SPE) are fabricated from poly(arylene ether sulfone)-co-poly(ethylene glycol)/nitrile terminated ionic liquid (PAES-co-PEG/ILCN) for lithium ion battery. Ionic liquid (IL) based on 1-butyl-1-methylpyrrollidum bis(fluoromethanesulfonyl) imide (Pyr-TFSI) is prepared and blended with 0.5 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) for promotion of the lithium (Li) ion transport in the membrane. Because of the compatibility difference, the synthesized membranes show the phase separation between PAES and PEG/IL components where PAES plays a role as mechanically robust matrix and PEG/IL acts as ion transport pathways. The PAES-co-(PEG70/ILCN30) membrane containing 70 wt% of 0.5 M LiTFSI/Pyr-TFSI illustrates high Li ion conductivity (0.72 × 10−3 S cm−1) with the Li transport number value of 0.38 at room temperature. No thermal de-composition is observed up to 200 °C, maintaining the mechanical flexibility and rigidity with 1.25 MPa of tensile strength and 108% of elongation at fracture. The lithium ion phosphate (LiFePO4/SPE/Li) cell test exhibits the discharge capacity value of 139.7 mAh g−1 and high stable cyclic performance up to 100th cycle at 0.1 C-rate.

Fluoride-Rich Solid Electrolyte Membrane in Solid-State Li–S Batteries: Improvement of Lithium Cycle Stability and Shuttle Effects

Although employing solid polymer electrolytes (SPEs) in solid-state Li–S batteries (SSLSBs) is a promising approach to obtain both high energy density and safety, the actual cycle property is still rather unsatisfactory. In this work, by combining experiments and calculations, we revealed that a coupling effect between lithium polysulfides (LiPSs) and polyethylene oxide (PEO)-based SPEs was the cause of interfacial instability of the poor cyclelife of lithium anode in SSLSBs. In light of this, a fluorine-rich polymer perfluoropolyether alcohol (PFA) was introduced as an interfacial layer between the SPE and lithium anode. PFA decouples from LiPSs because of the shielding effect of F in PFA on the electron cloud of O and the spatial effect. As a result, the PFA interlayer plays a role in preventing corrosion of the lithium metal from LiPSs and the electrochemical decomposition of PEO-based SPEs. The PEO-based SSLSBs with PFA showed a discharge capacity of 627.4 mA h gS–1 after 100 cycles at 0.05 mA cm–2 and 60 °C. This work emphasized the significance of SPE decoupling from LiPSs in SSLSBs and provided a feasible guidance for the design of high-performance SSLSBs.

Hierarchical Interconnected Hybrid Solid Electrolyte Membrane for All-Solid-State Lithium-Metal Batteries Based on High-Voltage NCM811 Cathodes

Hierarchical Interconnected Hybrid Solid Electrolyte Membrane for All-Solid-State Lithium-Metal Batteries Based on High-Voltage NCM811 Cathodes

All-solid-state electric double layer supercapacitors using Li1.3Al0.3Ti1.7(PO4)3 reinforced solid polymer electrolyte

In this work, we report the fabrication and characterization of all-solid-state supercapacitors based on a conductive filler dispersed solid polymer electrolyte. Fast ionic Li1.3Al0.3Ti1.7(PO4)3 (LATP) reinforced PEO-PEG-LITFSI composite solid polymer electrolyte (CSPE) membranes are prepared by milling assisted route. The electric double-layer capacitor (EDLC) cells, using a hot-roll lamination technique, are fabricated using a CSPE membrane as electrolyte and activated charcoal (surface area ∼ 817m2g−1) on graphite sheet as electrode. The EDLCs display appreciable areal capacitance of ∼ 12 Fcm−2 and ∼40 Fcm−2 at 40 °C and 80 °C, respectively at ∼0.65 mAcm2 and 2 V. These solid-state EDLCs at 40 °C exhibit stability up to ∼16,000 cycles. Further, the electrode-electrolyte (solid-solid) interface remains quite stable after the charge-discharge cycling. The electrical conductivity of the CSPE membranes correlates well with the EDLC performance. The LATP content in the CSPE membranes play important role in enhancing the capacitance. The present investigation suggests that CSPE membranes with conductivity between ∼10−4–10−5 Scm−1 are useful for low-power EDLC applications. The EDLCs cells with LATP dispersed CSPE exhibit better stability during thermal cycling between 40 °C-80 °C.

Effects of 1-hexyl-1-methylimidazolium iodide ionic liquid to poly(vinyl alcohol)–based solid polymer electrolyte

A solid polymer electrolyte (SPE) membrane has been fabricated using poly (vinyl alcohol) (PVA) as polymer host dissolved in deionized (DI) water. Lithium bis(oxalato) borate (LiBOB) electrolyte salt and 1-hexyl 1-methylimidazolium iodide (HMII) are incorporated into the membrane to contribute free ions, enhancing ionic conductivity. SPE was produced using the solution cast technique on Petri dishes. Then these slurries were dried at room temperature. The final product is a self-standing opaque membrane with visually homogenous surfaces. Further observation using FE-SEM revealed magnified images of membrane surfaces and cross-sections. Molecule interaction and crystallinity were observed using FT-IR and XRD. Impedance measured using EIS was used to calculate ionic conductivity. It was found that ionic conductivity of pure PVA film was 3.9×10-7 S/cm while ionic conductivity of SPE before and after ionic liquid addition was 4.77×10-7 S/cm and 2.66×10-6 S/cm.

Engineering Catalyst-Electrolyte Microenvironments to Optimize the Activity and Selectivity for the Electrochemical Reduction of CO2 on Cu and Ag.

The electrochemical reduction of carbon dioxide (CO2R) driven by renewably generated electricity (e.g., solar and wind) offers a promising means for reusing the CO2 released during the production of cement, steel, and aluminum as well as the production of ammonia and methanol. If CO2 could be removed from the atmosphere at acceptable costs (i.e., <$100/t of CO2), then CO2R could be used to produce carbon-containing chemicals and fuels in a fully sustainable manner. Economic considerations dictate that CO2R current densities must be in the range of 0.1 to 1 A/cm2 and selectivity toward the targeted product must be high in order to minimize separation costs. Industrially relevant operating conditions can be achieved by using gas diffusion electrodes (GDEs) to maximize the transport of species to and from the cathode and combining such electrodes with a solid-electrolyte membrane by eliminating the ohmic losses associated with liquid electrolytes. Additionally, high product selectivity can be attained by careful tuning of the microenvironment near the catalyst surface (e.g., the pH, the concentrations of CO2 and H2O, and the identities of the cations in the double layer adjacent to the catalyst surface).We begin this Account with a discussion of our experimental and theoretical work aimed at optimizing catalyst microenvironments for CO2R. We first examine the effects of catalyst morphology on the production of multicarbon (C2+) products over Cu-based catalysts and then explore the role of mass transfer combined with the kinetics of buffer reactions in the local concentration of CO2 and pH at the catalyst surface. This is followed by a discussion of the dependence of the local CO2 concentration and pH on the dynamics of CO2R and the formation of specific products over both Cu and Ag catalysts. Next, we explore the impact of electrolyte cation identity on the rate of CO2R and the distribution of products. Subsequently, we look at utilizing pulsed electrolysis to tune the local pH and CO2 concentration at the catalyst surface. The last part of the discussion demonstrates that ionomer-coated catalysts in combination with pulsed electrolysis can enable the attainment of very high (>90%) selectivity to C2+ products over Cu in an aqueous electrolyte. This part of the Account is then extended to consider the difference in the catalyst-nanoparticle microenvironment, present in the catalyst layer of a membrane electrode assembly (MEA), with respect to that of a planar electrode immersed in an aqueous electrolyte.

Polymer blend based solid electrolyte membranes for fully solid state sodium ion cell applications

Research work carried out to develop solid electrolyte (SE) membranes with advantageous characteristics of enhanced ionic conductivity and geometric flexibility for the generation of sodium ion cells with fully solid state architecture, constitutes the prime focus of the present paper. Blend solutions of poly ethylene oxide (PEO) with polyvinylidene fluoride (PVdF) which are complexed with various concentrations of sodium nitrate solution are made use of to grow freestanding, transparent and flexible SE membranes using the technique of casting from solution. Structural, morphological and electrochemical characterizations of these SE membranes are conducted, utilizing XRD, FE-SEM, electrochemical impedance spectroscopy and cyclic voltammetry techniques. For the membrane with 15 weight % of NaNO3 used for reacting with the polymer blend of PEO with PVdF, ionic conductivity calculated using electrochemical impedance spectroscopy is around 2.34 × 10−6 S cm−1. From cyclic voltammetry experiment, remarkably wide electrochemical steadiness window up to 5 V has been detected, giving additional emphasis for the impressive electrochemical behaviour of these SE membranes. Polymer based, solid electrolyte membranes of the present studies offer application prospects in developing fully solid state sodium ion cells.

Enhancing Puncture Voltage of La0.8sr0.2ga0.8mg0.2o3-Δ Solid Electrolyte Membrane by Improving Co2 Reduction Kinetics

Enhancing Puncture Voltage of La0.8sr0.2ga0.8mg0.2o3-Δ Solid Electrolyte Membrane by Improving Co2 Reduction Kinetics

PREPARATION AND CHARACTERIZATION OF SOLID POLYMER ELECTROLYTE MEMBRANES BASED on PVDFco-HFP POLYMER AND MgTf3 AS A DOPANT

In this particular study, porous structured solid PVDF-co-HFP: MgTf3 polymer electrolytic membranes are made by using the solution cast method. PVDF-co-HFP is a material that has outstanding performance and has been extensively used in the preparation of solid polymer electrolyte membranes (SPEM). The use of SPEM with high porosity structure has the potential to increase the conductivity, which may result in enormous applications in the development of future batteries. The addition of the inorganic salt particles (Magnesium trifluoromethanesulfonate (MgTf3)) and coating of the SPEM with a variety of polymer media for the manufacture of storage devices are just two of the many methods that have been tried in an effort to decrease the pore size and the number of pores in the SPEM. The current research was successful in decreasing pores’ size and increasing the amorphous nature of the solid polymer membrane with the addition of the metal salt particles as an inorganic filler. The chemical structure of the prepared SPEM was investigated using Fourier transform infrared spectroscopy (FTIR), and a scanning electron microscope (SEM) was utilized to explore the surface morphology and to find pores in the SPEM. X-ray diffraction (XRD) analysis was used to confirm the surface morphology of the PVDF-co-HFP membrane and the PVDF-co-HFP-MgTf3. A differential scanning calorimetry (DSC) investigation was carried out the determining the electrochemical consistency of the PVDF-coHFP and PVDF-co-HFP: MgTf3 membranes. According to the research, inorganic salt particles can make PVDF-coHFP: MgTf3 membranes less porous, increase the conductivity of ions and make the membrane more stable when it is filled with electrolytes and electrodes.

The effect of [EMIm]BF4/Li+ Ionic liquid on PEO-based solid polymer electrolyte membranes characteristics as lithium-ion batteries separator

Lithium-ion batteries have liquid electrolytes, which are corrosive and volatile, that would cause leakage and explosion during the rechargeable process at high temperatures. To overcome these problems, it is necessary to change the liquid electrolyte into a solid one, namely a solid polymer electrolyte. This work has prepared the solidpolymer electrolyte membranes by casting various 1-ethyl-3-tetrafluoroborate, [EMIm]BF4/Li+ ionic liquid, and PEO. In this study, [EMIm]BF4/Li+ , a Li+ ion-attached ionic liquid, has been synthesized using a simple metathesis reaction between 1-ethyl-3- methylimidazolium-bromide, [EMIm]Br, and lithium tetrafluoroborate, LiBF4 salt. [EMIm]Br has been synthesized from 1- methylimidazole and bromoethane precursors using Microwave Assisted Organic Synthesis (MAOS) method. The functional groups and structures of [EMIm]Br and [EMIm]BF4/Li+ have been confirmed by Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectra analysis. The analysis of ionic conductivities, crystallinities, mechanical properties, surface morphologies, and thermal stabilities have been confirmed by using Electrochemical Impedance Spectroscopy (EIS), X-ray Diffraction (XRD), and tensile tester, Scanning Electron Microscopy (SEM), and Thermogravimetry Analysis (TGA), respectively. The highest ionic conductivity is 1.83 x 10-3 S.cm-1 at room temperature for polymer electrolyte membrane with 16% weight of the [EMIm]BF4/Li+ ionic liquid and also exhibits good mechanical flexibility and thermal stability

Ion dynamics in PEO/PVP blend added with sodium triflouromethane sulphonate

The solid polymer electrolyte membranes are required to fabricate safe and low-cost sodium batteries. This paper reports ion-dynamics studies on solid polymer electrolyte consisting of polyethylene oxide (PEO) and polyvinylpyrrolidone (PVP) as polymer blend and sodium triflate (NaCF3SO3) as sodium ion conducting salt. The solid polymer electrolytes PEO/PVP/NaCF3SO3 have been prepared using solution cast techniques. The electrochemical impedance spectroscopy has been utilized to study the role of incorporating NaCF3SO3 in varying amounts within PEO/PVP polymer blend. The optimized solid polymer electrolyte with 10 wt% NaCF3SO3 salt reports an ionic conductivity of 2.2 × 10-9 Scm−1 at room temperature. The ionic conductivity versus frequency plots indicates an increase in ionic conductivity values as the frequency increases. In order to explore the ion-dynamics the dielectric and modulus formulation has been adopted. The dielectric constant plots indicate polarizing effects at low frequencies and tangent loss curves shows presence of a relaxation peak. The frequency and relaxation time corresponding to the relaxation peak for optimized solid polymer electrolyte gives relaxation time of 2.69 × 10-3 s, charge carrier density of 1.18 × 1012 cm−3 and mobility of 0.01169 cm2 V−1 s−1. The safe potential window range of the optimized solid polymer electrolyte is determined to be 4.2 V which is good enough for usage in sodium batteries.

A Self-Supporting Solid Electrolyte Membrane with Fibrous Network Structure for Solid State Lithium Metal Batteries

A Self-Supporting Solid Electrolyte Membrane with Fibrous Network Structure for Solid State Lithium Metal Batteries

Enhanced mixed proton and electron conductor at room temperature from chemically modified single-wall carbon nanotubes.

Remarkably high mixed proton and electron conduction arising from oxidized single-wall carbon nanotubes at room temperature is demonstrated. The respective proton and electronic conductivities are 1.40 and 8.0 × 10−2 S cm−1 in the in-plane direction, and 3.1 × 10−2 and 1.1 × 10−3 S cm−1 in the out-of-plane direction, indicating their potential in a wide range of solid electrolyte membranes.