Ionic Conductivity Properties Research Articles

Regulation of Lithium‐Ion Flux by Nanotopology Lithiophilic Boron‐Oxygen Dipole in Solid Polymer Electrolytes for Lithium‐Metal Batteries

Inhomogeneous lithium‐ion (Li+) deposition is one of the most crucial problems, which severely deteriorates the performance of solid‐state lithium metal batteries (LMBs). Herein, we discovered that covalent organic framework (COF‐1) with periodically arranged boron‐oxygen dipole lithiophilic sites could directionally guide Li+ even deposition in asymmetric solid polymer electrolytes. This in situ prepared 3D cross‐linked network Poly(ACMO‐MBA) hybrid electrolyte simultaneously delivers outstanding ionic conductivity (1.02 × 10−3 S cm−1 at 30 °C) and excellent mechanical property (3.5 MPa). The defined nanosized channel in COF‐1 selectively conducts Li+ increasing Li+ transference number to 0.67. Besides, The COF‐1 layer and Poly(ACMO‐MBA) also participate in forming a boron‐rich and nitrogen‐rich solid electrolyte interface to further improve the interfacial stability. The Li‖Li symmetric cell exhibits remarkable cyclic stability over 1000 h. The Li‖NCM523 full cell also delivers an outstanding lifespan over 400 cycles. Moreover, the Li‖LiFePO4 full cell stably cycles with a capacity retention of 85% after 500 cycles. the Li‖LiFePO4 pouch full exhibits excellent safety performance under pierced and cut conditions. This work thereby further broadens and complements the application of COF materials in polymer electrolyte for dendrite‐free and high‐energy‐density solid‐state LMBs.

Matching silicon-based anodes with sulfide-based solid-state electrolytes for Li-ion batteries

Thanks to their high ionic conductivity and appropriate mechanical properties, sulfide-based solid electrolytes (SSE) are increasingly studied for a use in all-solid-state batteries (ASSBs). Silicon is abundant, non toxic and has a high theoretical capacity, and therefore is a promising active material in ASSBs. We first study the compatibility between two different solid electrolytes with similar ionic conductivity, Li10SnP2S12 (LSnPS) and Li6PS5Cl (LPSCl), and micron-sized silicon based anode. LPSCl appears to be less reactive than LSnPS and it is then used to determine the most appropriate silicon size and shape for efficient cycling. Two silicon materials are compared, micron-sized silicon particles (μSi) and silicon nanowires (SiNWs). Energy Dispersive X-ray spectroscopy (EDX) mapping of the composite powders shows a better dispersion of the SiNWs in the LPSCl matrix. Galvanostatic cycling and Electrochemical Impedance Spectroscopy (EIS) measurements highlight the greater compatibility of SiNWs compared to μSi in ASSBs with a high specific delithiation capacity of 2600 mAh/gSi at the first cycle, while limiting the polarization and maintaining a relatively stable lithiation mechanism during cycling.

Dendritic Solid Polymer Electrolytes: A New Paradigm for High-Performance Lithium-Based Batteries.

Li-ions battery is widely used and recognized, but its energy density based on organic electrolytes has approached the theoretical upper limit, while the use of organic electrolytes also brings some safety hazards (leakage and flammability). Polymer electrolytes (PEs) are expected to fundamentally solve the safety problem and improve energy density. Therefore, Li-ions battery based on solid PE has become a research hotspot in recent years. However, low ionic conductivity and poor mechanical properties, as well as a narrow electrochemical window limit its further development. Dendritic PEs with unique topology structure has low crystallinity, high segmental mobility, and reduced chain entanglement, providing a new avenue for designing high-performance PEs. In this review, the basic concept and synthetic chemistry of dendritic polymers are first introduced. Then, this story will turn to how to balance the mechanical properties, ionic conductivity, and electrochemical stability of dendritic PEs from synthetic chemistry. In addition, accomplishments on dendritic PEs based on different synthesis strategies and recent advances in battery applications are summarized and discussed. Subsequently, the ionic transport mechanism and interfacial interaction are deeply analyzed. In the end, the challenges and prospects are outlined to promote further development in this booming field.

Magnesium Anode Protection by an Organic Artificial Solid Electrolyte Interphase for Magnesium-Sulfur Batteries.

In the search for post-lithium battery systems, magnesium-sulfur batteries have attracted research attention in recent years due to their high potential energy density, raw material abundance, and low cost. Despite significant progress, the system still lacks cycling stability mainly associated with the ongoing parasitic reduction of sulfur at the anode surface, resulting in the loss of active materials and passivating surface layer formation on the anode. In addition to sulfur retention approaches on the cathode side, the protection of the reductive anode surface by an artificial solid electrolyte interphase (SEI) represents a promising approach, which contrarily does not impede the sulfur cathode kinetics. In this study, an organic coating approach based on ionomers and polymers is pursued to combine the desired properties of mechanical flexibility and high ionic conductivity while enabling a facile and energy-efficient preparation. Despite exhibiting higher polarization overpotentials in Mg-Mg cells, the charge overpotential in Mg-S cells was decreased by the coated anodes with the initial Coulombic efficiency being significantly increased. Consequently, the discharge capacity after 300 cycles applying an Aquivion/PVDF-coated Mg anode was twice that of a pristine Mg anode, indicating effective polysulfide repulsion from the Mg surface by the artificial SEI. This was backed by operando imaging during long-term OCV revealing a non-colored separator, i.e. mitigated self-discharge. While SEM, AFM, IR and XPS were applied to gain further insights into the surface morphology and composition, scalable coating techniques were investigated in addition to ensure practical relevance. Remarkably therein, the Mg anode preparation and all surface coatings were prepared under ambient conditions, which facilitates future electrode and cell assembly. Overall, this study highlights the important role of Mg anode coatings to improve the electrochemical performance of magnesium-sulfur batteries.

Structural investigation of lithium borate glasses by Raman spectroscopy: Quantitative evaluation of structural units and its correlation with density

Lithium borate glass is a widely studied system, mainly due to its good ionic conductivity, thermal conductivity and thermoluminescence properties. The properties of lithium borate glass are determined by its structure, and the change of microstructure unit has great influence on its properties. In this work, the xLi2O⋅(1-x) B2O3 (0.1 ≤ x ≤ 0.48) glass was studied by Raman spectroscopy combined with peaks fitting and density analysis. Through quantitative analysis of Raman spectrum, the change in trend of each structural unit as well as the change of the tetracoordinated boron content (N4) were obtained with the increase of Li2O content. Especially, a more detailed assignment and general transformation mechanism of structural units were presented, and the common inflection points of properties (mass density, molar volume, etc.) and structural units content changes were found. The correlation between the properties (mass density, atomic density and molar volume) and the basic structural units (BØ3, BØ2O− and BØ4−) of the lithium borate glass was established by the genetic function approximation algorithm (GFA). The study on the structural units in xLi2O⋅(1-x) B2O3 (0 ≤ x ≤ 0.48) glass network and the mutual transformation mechanism between each structural unit is helpful to explore the effects on macroscopic properties as the structural units change.

Design of biodegradable polymer blend electrolytes with decoupled ion motion for EDLC device Application: Electrical and electrochemical properties

In this work, plasticized polymer blend electrolytes (PBEs) that are flexible and have quasi-solid-state properties have been prepared using the casting technique. Herein, we present the manufacture and characterization of biopolymer blend electrolytes based on chitosan (CS) and polyvinyl alcohol (PVA) with decoupled ion motion for EDLC device applications. Electrochemical impedance spectroscopy (EIS) was utilized to analyze the dielectric and ion conduction properties of the produced PBEs. Lithium nitrate (LiNO3) salt was used as an ion provider for the host polymers. With an increase in glycerol plasticizer concentration, both ion conduction and dielectric properties were significantly enhanced. The Argand diagram established that conductivity relaxation dynamics (pure ionic relaxation) is dominant at higher plasticizer concentrations. The highest ionic conductivity of 1.707×10-4 S/cm was recorded for the host medium plasticized with 40 wt% of glycerol, and it has been used as a mediator in the EDLC fabrication. Linear sweep voltammetry (LSV) was used to validate the eligibility of the PBE in terms of stability, and it was shown that the film was stable up to 2.93 V. The dominancy of ions as the main carrier in the prepared electrolyte was confirmed using transference number measurement (TNM) analysis, with tion = 0.922. The CR2032 coin cell type EDLC with activated carbon electrodes and the most conductive PBE film had a significantly high specific capacitance of ∼ 33F/g through the cyclic voltammetry (CV) technique. The efficiency of the fabricated EDLC was remarkable, with an average of about 85% over 1000 cycles. Due to its high energy and power densities (4.5 Wh/kg and 1100 W/kg, respectively), this PBE system is well-suited for EDLC.

Conductive polymers for cardiac tissue engineering and regeneration.

Cardiovascular diseases, such as myocardial infarction, are considered a significant global burden and the leading cause of death. Given the inability of damaged cardiac tissue to self-repair, cell-based tissue engineering and regeneration may be the only viable option for restoring normal heart function. To maintain the normal excitation-contraction coupling function of cardiac tissue, uniform electronic and ionic conductance properties are required. To transport cells to damaged cardiac tissues, several techniques, including the incorporation of cells into conductive polymers (CPs) and biomaterials, have been utilized. Due to the complexity of cardiac tissues, the success of tissue engineering for the damaged heart is highly dependent on several variables, such as the cell source, growth factors, and scaffolds. In this review, we sought to provide a comprehensive overview of the electro CPs and biomaterials used in the engineering and regeneration of heart tissue.

An improved PEG-based molecular crowding electrolyte using Zn(TFSI)2 vs. Zn(OTf)2 for aqueous Zn//V2O5 battery

Aqueous zinc batteries (AZBs) are promising candidates for scalable and sustainable energy storage applications because of their cost and safety advantages. However, the inevitable parasitic reactions on the Zn anode, mainly attributed to water-induced side reactions, should be solved. Recently, a molecular crowding electrolyte (MCE) strategy has been proposed to mitigate these parasitic reactions, but at the cost of kinetics and thus rate. In this article, we report an improved Zn//V2O5 battery using a newly developed MCE with a crowding agent and 1 m Zn(TFSI)2 as an advanced salt (MCE–1m Zn(TFSI)2). Our MCE–1m Zn(TFSI)2 shows enhanced ionic conductivity and ion-transport properties, conferring superior rate capability to Zn//V2O5 – releasing 57 vs 0 mAh/g at 10C compared to MCE–1m Zn(OTf)2, state-of-the-art MCE. Furthermore, due to the decrease in the fraction of ‘free water’ molecules, both MCEs produce an enhanced stability window and improved reversibility of Zn plating/stripping with superior Coulombic efficiencies compared to the conventional electrolyte (1 m Zn(TFSI)2). Consequently, Zn//V2O5 in MCE–1m Zn(TFSI)2 simultaneously delivers superior cycle stability (260 (78%) vs. 0 (0%) mAh/g (capacity retention)) after 1000 and 350 cycles, respectively, and low self-discharge vs. 1 m Zn(TFSI)2. These combined results show that this advanced MCE strategy can be used to design safe, high-reversible, fast, and long-cycled AZBs for practical applications.

Boosting fast electrode reaction kinetics of silicon suboxide anodes by fluoroethylene carbonate-based electrolyte

The growing demand for electric vehicles has led to an urgent need for higher-energy-density batteries. Silicon (Si) has been regarded as an alternative to graphite as an anode material owing to its high theoretical capacity. Nevertheless, the large volume change in Si during repeated charge/discharge causes serious particle fracture, leading to rapid capacity degradation. Silicon suboxide (SiOx) anodes show better cycling performance than Si because of their alleviated volume variation, yet still have unsatisfactory electrode reaction kinetics. Herein, fluoroethylene carbonate (FEC)-based electrolyte is proposed to enhance the electrochemical properties of SiOx anodes. A higher specific capacity of ∼1500 mAh g−1 at 0.5 A g−1 and an excellent rate capability of ∼1050 mAh g−1 at 4 A g−1 are obtained for the SiOx anode, which ensures an 83.5% capacity retention of SiOx||LiFePO4 cells after 300 cycles. The theoretical calculations and experimental studies reveal that FEC forms a weakly solvating electrolyte, enabling easier Li-ion desolvation and fast electrode reaction kinetics. Moreover, FEC reinforces the Li+-anion coordination owing to its weak solvating capability, thus a LiF-rich electrode/electrolyte interphase is formed through the co-decomposition of FEC and PF6− anions, leading to a tough SEI film formation with rapid ionic conductivity and good mechanical property.

A gradient “Ceramic-in-Ionogel” electrolyte with tidal ion flow for ultra-stable lithium metal batteries

Composite solid-state electrolytes are considered as key components for safe and high-energy-density lithium metal batteries, given their superior mechanical properties and ion conductive kinetics. However, it still remains a challenge to simultaneously guarantee high ionic conductivity and excellent interfacial compatibility. Herein, a gradient “Ceramic-in-Ionogel” electrolyte with tidal ion flow is proposed for decoupling ionic conductivity and interfacial property. It is composed of poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP))/EMIMTFSI/Al2O3 (30 wt. %) layer (Ionogel-dual30) toward cathode and P(VDF-HFP)/EMIMTFSI/Al2O3 (50 wt. %) layer (Ionogel-dual50) to Li-metal anode. Ionogel-dual50 can provide a relatively large number of Al2O3 particles for the formation of AlF3 and Li3AlF6 after being offered electrons at lithium-metal anode and carbon-fluorine bond cleavage in TFSI-, resulting in rapid Li+ transfer and insulated electron transport at interface. Both simulation and experimental characterization suggest that the tidal-flow-like ion transport pathway can offer [Li+-NMP]-P(VDF-HFP) dominant pathway in Ionogel-dual30 and [Li(TFSI)x]+-Al2O3 interface dominant pathway in Ionogel-dual50, achieving a high ionic conductivity of 0.25 mS cm−1. Benefiting from these unique merits, the cycling performance of symmetric Li batteries was greatly improved with a lifetime of over 1000 h at 0.1 mA h cm−2. The effect of this gradient ionogel electrolyte could be well demonstrated in various full cells, evidenced by substantially enhanced cyclability under large current density (2 C), wide voltage range (3–4.5 V) and extreme conditions. This novel “Ceramic-in-Ionogel” electrolyte with tidal ion flow will accelerate the commercialization of high-energy-density lithium metal batteries.

Environmentally stable, highly stretchable strain sensor based on a conductive single-network hydrogel with non-drying and adhesive properties

Conductive hydrogels inevitably face dehydration, which deteriorates the conductive and tensile properties. Herein, a single-network hydrogel was constructed via the free-radical polymerization of 3-acrylamidopropyl trimethylammonium chloride (ATAC) and 2-hydroxyethyl methacrylate (HEMA) to enhance stretchability and adaptability to the environment. The single-network hydrogel exhibited excellent mechanical properties (fracture strain of 1812.96 %, fracture stress of 124.80 kPa, Young’ s modulus of 73.29 kPa, and toughness of 1426.01 KJ m−3) due to the existence of abundant hydrogen bonds. ATAC can suppress the vaporization of water by breaking the hydrogen bonds between water molecules, endowing the hydrogel with anti-drying performance and greatly broadening its application fields. This work provides a facile strategy for the construction of a single-network hydrogel with high stretchability, ion conductivity, adhesive and non-drying properties and offers new insights into the design of wearable sensors applicable in open environments.

Compatible composite electrolyte membrane Li7La3Zr2O12/SB-PVDF for solid-state lithium ion battery

Organic/inorganic composite solid electrolyte has been a hot topic due to combining the merits of both components. Herein, a series of organic/inorganic composite solid electrolytes were prepared by casting method, in which polyvinylidene fluoride (PVDF) was modified with amphoteric sulfonate betaine (SB) and combined with the different contents (0 %, 10 %, 20 % and 30 %) of Li7La3Zr2O12 (LLZO) and 20 % bis(trifluoromethane) sulphonyl (LiTFSI). The resultant samples were marked as 0%LLZO/SB-PVDF/LiTFSI, 10%LLZO/SB-PVDF/LiTFSI, 20%LLZO/SB-PVDF/LiTFSI and 30%LLZO/SB-PVDF/LiTFSI, respectively. As expected, composite solid electrolyte exhibited the desirable overall performances. Especially, 20%LLZO/SB-PVDF/LiTFSI membrane exhibited high ionic conductivity (1.73 × 10−4 S/cm), wide electrochemical window (5.22 V), high Li+ transference number (tLi+ = 0.67) and high mechanical property, probably due to the synergistic effect of LLZO and amphoteric SB modification. Specifically, the amphoteric SB promoted the dissociation of LiTFSI and endowed PVDF matrix with the ionic conductivity, while LLZO facilitated high ionic conductivity, tLi+ and mechanical property. Resultantly, Li//LiFePO4 cell with 20%LLZO/SB-PVDF/LiTFSI membrane delivered 129.5 mAh/g at 1.0C for 200 cycles and 94.0 % capacity retention, demonstrating high application feasibility in the solid-state lithium ion battery. Furthermore, density functional theory (DFT) calculations showed that the binding energy of the amphoteric SB-Li+ (C11H21NO5S-Li+) system was 80.93 kcal/mol, higher than 75.55 kcal/mol of the LiTFSI system, indicating that the amphoteric SB could indeed promote the dissociation of LiTFSI.

I-Rich Thioantimonate Argyrodite Glass-Ceramic Electrolyte with High Air Stability and Compatibility with Lithium

The argyrodite solid electrolyte has been actively studied due to its high ionic conductivity and good physical properties. However, it has various problems due to low air stability characteristics and low critical current density. In this study, the air stability and electrochemical performance of the solid electrolyte were improved by introducing a method to improve the performance of the solid electrolyte by adding excess iodine based on a thioantimonate-based argyrodite solid electrolyte with excellent air stability. I-rich glass-ceramic argyrodite Li6–xSbS5–xIx was prepared through high-energy ball milling. The structural properties were confirmed using powder X-ray diffraction (XRD). The synthesized Li5.6SbS4.6I1.4 electrolyte showed a higher ionic conductivity of 0.66 mS/cm and a lower activation energy of 0.32 eV compared to pristine Li6SbS5I (0.17 mS/cm, 0.33 eV) at 25 °C. In addition, the high lithium compatibility of the Li5.6SbS4.6I1.4 solid electrolyte was confirmed through DC cycling and cyclic voltammetry, and it showed a high ion conductivity retention rate of 61% after exposure to the atmosphere for 30 min. Finally, the optimized cell with Li6PS5Cl–Li5.6SbS4.6I1.4 solid electrolyte showed a higher initial discharge capacity of 154 mAh/g and Coulombic efficiency of 70%. In particular, it was confirmed that the performance at a high C rate was greatly improved compared to the cell made with Li6PS5Cl.

High Proton Conductivity of a Bismuth Phosphonate Metal–Organic Framework with Unusual Topology

Despite the interest in proton exchange membrane (PEM) technologies (fuel cells and electrolyzers) for energy applications, the low stability of the electrolyte materials under working conditions (i.e., humidity and temperature) is one of their major limitations. Metal–organic frameworks (MOFs) have recently emerged as promising electrolytes due to their higher stability compared with the currently applied organic polymers, proton conductivity, and outstanding porosity. Here, a novel robust Bi phosphonate MOF (branded as IEF-7) was successfully synthesized and fully characterized, exhibiting an unusual topology due to the irregular coordination geometry of the bismuth cations. Furthermore, IEF-7 exhibited potential porosity, very high chemical and thermal stability, and free −PO3H groups involved in its ultrahigh proton conductivity, reaching 1.39 × 10–2 S cm–1 at 90 °C and 90% relative humidity for, at least, 3 cycles. In order to improve the consolidation and shaping of the powder for testing its ion conductivity properties, a highly MOF-loaded composite (90 wt %) was prepared by adding a proton conductive sulfonated polysulfone binder. The proton conductivity of the resulting composite was in the same order of magnitude as the compacted MOF powder, making this polymeric composite electrolyte very promising for PEM technologies.

Oxygen Ion Conduction Property of Solid Oxide Membrane Based on Multi-scale Analysis

There have been reports of decreased ion transport properties at the grain boundaries (GB). Multiscale analysis is necessary to analyze the relationship between small-scale phenomena near the GB and large-scale ion transport properties across the membrane. We perform bottom-up analysis from Density Functional Theory (DFT) to kinetic Monte Carlo methods. In this study, we analyzed the effect of GB on ion transport properties using DFT-based molecular dynamics (MD) simulation. The following results were obtained by changing the number of SrSc0.1Co0.9O3-δ (SSC) and Sm0.2Ce0.8O2-δ (SDC) unit cells in the dual-phase solid oxide electrolyte membrane (SOEM). As the crystal size of SSC increased, both the diffusion coefficient and activation energy increased. As the crystal size of SDC increased, the diffusion coefficient decreased, and the activation energy increased. Furthermore, the calculated diffusivity of the x, y, and z directions show that the diffusivity was decreasing in the direction of the GB exist.

Columnar Liquid Crystals of Copper(I) Complexes with Ionic Conductivity and Solid State Emission.

Two neutral copper(I) halide complexes ([Cu(BTU)2X], X = Cl, Br) were prepared by the reduction of the corresponding copper(II) halides (chloride or bromide) with a benzoylthiourea (BTU, N-(3,4-diheptyloxybenzoyl)-N'-(4-heptadecafluorooctylphenyl)thiourea) ligand in ethanol. The two copper(I) complexes show a very interesting combination of 2D supramolecular structures, liquid crystalline, emission, and 1D ionic conduction properties. Their chemical structure was ascribed based on ESI-MS, elemental analysis, IR, and NMR spectroscopies (1H and 13C), while the mesomorphic behavior was analyzed through a combination of differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and powder X-ray diffraction (XRD). These new copper(I) complexes have mesomorphic properties and exhibit a hexagonal columnar mesophase over a large temperature range, more than 100 K, as evidenced by DSC studies and POM observations. The thermogravimetric analysis (TG) indicated a very good thermal stability of these samples up to the isotropization temperatures and over the whole temperature range of the liquid crystalline phase existence. Both complexes displayed a solid-state emission with quantum yields up to 8% at ambient temperature. The electrical properties of the new metallomesogens were investigated by variable temperature dielectric spectroscopy over the entire temperature range of the liquid crystalline phase. It was found that the liquid crystal phases favoured anhydrous proton conduction provided by the hydrogen-bonding networks formed by the NH…X moieties (X = halide or oxygen) of the benzoylthiourea ligand in the copper(I) complexes. A proton conductivity of 2.97 × 10-7 S·cm-1 was achieved at 430 K for the chloro-complex and 1.37 × 10-6 S·cm-1 at 440K for the related bromo-complex.

Unveiling the Growth Mechanism of the Interphase between Lithium Metal and Li2S‐P2S5‐B2S3 Solid‐State Electrolytes

AbstractChalcogenides with high ionic conductivity and appropriate mechanical properties are promising solid‐state electrolytes (SSEs) to substitute current liquid electrolytes in lithium‐ion batteries. Yet, their practical applications in all‐solid‐state batteries are still retarded by both the low critical current density and the inferior interfacial stability toward electrodes. In this work, a series of superior SSEs, that is, Li2S‐P2S5‐B2S3 electrolytes, are developed via a ball‐milling and then melt‐quenching strategy. These SSEs exhibit a high critical current density of 1.65 mA cm−2 and a long cycling life of over 300 h. In addition, the evolution mechanism of the interphase between SSEs and metallic lithium is revealed via operando electrochemical impedance spectroscopy, depth‐profiling XPS, and in situ Raman spectroscopy. The structural and chemical heterogeneities are found to be the main origins of the continual interphase evolution. The resulting “multi‐layer mosaic like” interphase facilitates the suppression of Li dendrite growth, and hence, prolongs the lifetime of lithium‐ion all‐solid‐state batteries. In addition, the preparation technique of SSEs developed in the present work is feasible for scale‐up production.

Properties of Bacterial Cellulose/Polyvinyl Composite Membrane for Polymer Electrolyte Li ion Battery

High ionic conductivity and porous properties of material play important role as a solid polymer electrolyte in Li ion battery application. In this study, a bacterial cellulose (BC)- based polymer was modified with polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA). Blending the polymer host is one more approach to work on the morphology pore and electrochemical properties of polymer electrolytes. The slurry of BC is rich of fibers that contribute to forming of the pore template for solid electrolyte membrane. Polyvinyl act as material to creating pore and increases the polymer segmental ion lithium mobility. Pore morphology of BC-PVA and -PVP composite membrane homogeneously distributed by SEM observations. The presence of many pores makes the tensile strength of the BC PVA membrane lower. For solid electrolytes purposes, it does not affect battery performance but has a greater possibility for battery lifetime. The presence of pores contributes to the absorption of electrolytes membranes. In addition, enhancement of the conductivity upon addition of salt is correlated to the enhancement of pores from solid polymer electrolyte. The conductivity of BC-PVA composite is reported 8.7 x 10-5 Scm-1 , and this ion conductivity is slightly higher than conductivity in BC-PVP 8.4 x 10-7 Scm-1 at room temperature. In the future, BC-PVA can be applied for solid electrolyte membranes material based on cellulose.

Initiator-free in-situ synthesized polymer electrolytes with high ionic conductivity for dendrite-free lithium metal batteries

In-situ preparation of polymer electrolytes (PEs) can enhance electrolyte/electrode interface contact and accommodate the current large-scale production line of lithium-ion batteries (LIBs). However, reactive initiators of in-situ PEs may lead to low capacity, increased impedance and poor cycling performance. Flammable and volatile monomers and plasticizers of in-situ PEs are potential safety risks for the batteries. Herein, we adopt lithium difluoro(oxalate)borate (LiDFOB)-initiated in-situ polymerization of solid-state non-volatile monomer 1,3,5-trioxane (TXE) to fabricate PEs (In-situ PTXE). Fluoroethylene carbonate (FEC) and methyl 2,2,2-trifluoroethyl carbonate (FEMC) with good fire retardance, high flash point, wide electrochemical window and high dielectric constant were introduced as plasticizers to improve ionic conductivity and flame retardant property of In-situ PTXE. Compared with previously reported in-situ PEs, In-situ PTXE exhibits distinct merits, including free of initiators, non-volatile precursors, high ionic conductivity of 3.76 × 10−3 S cm−1, high lithium-ion transference number of 0.76, wide electrochemical stability window (ESW) of 6.06 V, excellent electrolyte/electrode interface stability and effectively inhibition of Li dendrite growth on the lithium metal anode. The fabricated LiFePO4 (LFP)/Li batteries with In-situ PTXE achieve significantly boosted cycle stability (capacity retention rate of 90.4% after 560 cycles) and outstanding rate capability (discharge capacity of 111.7 mAh g−1 at 3C rate).

Ionic conducting characteristics of the solid electrolyte LiMgPO4

Li+ ion-conducting properties in Lithium magnesium orthophosphate compound were investigated in the present study. Our compound was prepared with the standard ceramic method.Vibrational study and impedance spectroscopy were explored to understand the ion dynamics and dielectric properties. The surface morphology of the sample was examined by SEM analysis. Rietveld's refinement of the X-ray diagram shows that the synthesized material was well crystallized in the orthorhombic olivine structure with the Pnma space group.The complex impedance spectra analysis reveals that the electrical properties of the material are heavily dependent on frequency and temperature, indicating a relaxation phenomenon and semiconductor-type behavior.A typical universal dielectric response in the frequency-dependent conductivity at different temperatures was found. The alternative current conductivity is discussed in the framework of Jonscher's model. The Correlated Barrier Hopping "CBH" conduction process is proposed to investigate the transport properties in the dynamic region of the studied compound.Cationic disorder plays a major role in the charge carriers transport. Fitting parameters obtained from the theoretical aspect have been discussed.