Poly Ethylene Oxide Research Articles

Electrochemically Stable and Ultrathin Polymer-Based Solid Electrolytes for Dendrite-Free All-Solid-State Lithium-Metal Batteries

Abstract Polymer-based composite solid electrolytes (PCSEs) are increasingly studied in all-solid-state lithium-metal batteries (ASSLMBs) due to the combined advantages of better flexibility of polymer and higher ion conductivity of ceramic electrolytes. However, most reported PCSEs are overly thick, increasing internal resistances. Besides, the poor stability at the Li metal-electrolyte interfaces often leads to severe lithium dendrite formation and reduced cycling stability. Here, we fabricate an ultrathin PCSE with a thickness of 12.4 μm, incorporating polyacrylonitrile (PAN) nanofibers as the structural matrix, and a filler with polyethylene oxide and Li6.5La3Zr1.5Ta0.5O12 (LLZTO). Due to the formation of the LiCN layer on the surface of the lithium metal and the Li-ion transport pathways induced by the dehydrocyanation reaction at the LLZTO/PAN interfaces, the PCSE exhibits a high critical current density of 1.8 mA cm-2 and a low energy barrier of 0.278 eV for Li-ion transfer, accommodating the fast Li-ion migration to avoid Li-dendrite growth. In addition, the stable nitrile groups and the dehydrocyanation reaction ensure the electrochemical stability of the PCSE with a high oxidation voltage of 5.5 V and an exceptional cycling stability (2100 h) in Li||PCSE||Li symmetric cells. Additionally, the Li||PCSE||LiFePO4 full cells demonstrate a high volumetric energy density of 338.3 Wh L-1 at 0.1 C and a robust stability over 100 cycles at 0.5 C. The study offers a new approach for fabricating ultrathin PCSEs and provides insights into the mechanisms of dendrite-free formation, guiding the development of high-performance PCSEs for ASSLMBs.

Cyanogroup-Modified PEO-Based Electrolytes Achieve High Free Al3+ Concentration and Improve the Transport Dynamics in Solid-State Aluminum-Ion Batteries.

Polymer-based solid electrolyte boasting ultra-high safety, energy density, mechanical strength and flexibility, attracting much attention in the field of battery applications. However, its widespread application is hindered by the low conductivity, insufficient aluminium salt dissociation, high crystallization degree, short service life, etc. To solve the above problems, a composite solid polymer electrolyte (SPE) design based on polyethylene oxide (PEO, Mw = 6 000 000) with AlCl3·6H2O as aluminum salt and butanedinitrile (SN) as plasticizer is proposed in this paper. The disorder and mobility of the PEO chains, conductivity, degree of aluminum salt dissociation, and service life are enhanced by the addition of plasticizer SN. Theoretical calculation demonstrates the formation of solvated sheath-like structure [SN…Al3+] has strong interactions with the polymer PEO, allowing rapid transport of Al3+ through the polymer segments. These results are also further verified by subsequent tests, which can reveal the Al3+ transport mechanism of room-temperature SPEs in a more reasonable way. Meanwhile, the relatively strong binding energy between PEO and SN can help to avoid the parasitic reaction between SN and Al, increase the service life of solid-state aluminium-ion batteries. Providing a promising solution for the design of solid-state battery electrolytes that can be applied at room temperature.

Starfish-Inspired Solid-State Li-ion Conductive Membrane with Balanced Rigidity and Flexibility for Ultrastable Lithium Metal Batteries.

The performance of solid-state lithium-metal batteries (SSLMB) is often constrained by the low ionic conductivity, narrow electrochemical window, and insufficient mechanical strength of polyethylene oxide (PEO)-based electrolytes. Inspired by the soft-outside, rigid-inside structure of starfish, we designed multifunctional "starfish-type" composite polymer electrolytes (CPEs) using electrospinning technology. These CPEs feature a three-dimensional rigid skeleton network composed of polyacrylonitrile/metal-organic frameworks/ionic liquids (PAN/MOFs/ILs), creating continuous and efficient Li+ transport channels: MOFs impart rigidity, PEO acts as a cushioning outer layer to enhance interfacial compatibility, and ILs reduce interfacial resistance. The resulting CPEs exhibited excellent ionic conductivity (4.37×10-4 S cm-1), a wide electrochemical window (5.34 V), uniform lithium-ion flux, and a high transference number (0.69). Leveraging these synergistic advantages, the Li/CPEs/Li symmetric cell demonstrated outstanding dendrite suppression for over 1300 hours, and the LiFePO4/CPEs/Li cell retained 90.1 % capacity after 2100 cycles at 1.0 C, which is the best performance reported for SSLMB with MOF/PEO. The formation of multi-component solid-electrolyte interphase and its role in stabilizing lithium metal cycling were systematically elucidated through theoretical simulations and spectroscopic analysis. This nature-inspired design provides a promising strategy for the development of stable solid-state electrolytes with extended lifespans.

Starfish‐Inspired Solid‐State Li‐ion Conductive Membrane with Balanced Rigidity and Flexibility for Ultrastable Lithium Metal Batteries

The performance of solid‐state lithium‐metal batteries (SSLMB) is often constrained by the low ionic conductivity, narrow electrochemical window, and insufficient mechanical strength of polyethylene oxide (PEO)‐based electrolytes. Inspired by the soft‐outside, rigid‐inside structure of starfish, we designed multifunctional "starfish‐type" composite polymer electrolytes (CPEs) using electrospinning technology. These CPEs feature a three‐dimensional rigid skeleton network composed of polyacrylonitrile/metal‐organic frameworks/ionic liquids (PAN/MOFs/ILs), creating continuous and efficient Li+ transport channels: MOFs impart rigidity, PEO acts as a cushioning outer layer to enhance interfacial compatibility, and ILs reduce interfacial resistance. The resulting CPEs exhibited excellent ionic conductivity (4.37×10‐4 S cm‐1), a wide electrochemical window (5.34 V), uniform lithium‐ion flux, and a high transference number (0.69). Leveraging these synergistic advantages, the Li/CPEs/Li symmetric cell demonstrated outstanding dendrite suppression for over 1300 hours, and the LiFePO4/CPEs/Li cell retained 90.1% capacity after 2100 cycles at 1.0 C, which is the best performance reported for SSLMB with MOF/PEO. The formation of multi‐component solid‐electrolyte interphase and its role in stabilizing lithium metal cycling were systematically elucidated through theoretical simulations and spectroscopic analysis. This nature‐inspired design provides a promising strategy for the development of stable solid‐state electrolytes with extended lifespans.

Utilisation of nanocellulose from cassava peels in polymer electrolyte membrane fabrication

AbstractIn recent decades, lithium‐ion batteries have become the leading energy storage solution due to their rechargeability, long lifespan, high energy density and lightweight design, although the conventional liquid electrolytes used raise performance and safety concerns, particularly regarding volatility and flammability at high temperatures. This study explores the incorporation of nanocellulose (NC) derived from cassava peels into polymer electrolyte membranes based on poly(ethylene oxide) (PEO). NC serves as a reinforcing agent, enhancing the mechanical properties of the membranes, such as tensile strength, while its natural abundance and biocompatibility offer a sustainable alternative for electrolyte materials. The membranes were prepared via the solution casting method utilising water as the solvent and subsequently characterised using Fourier transform infrared spectroscopy, XRD, a tensile tester, SEM and TGA/differential thermal analysis/DSC. Incorporating NC into the PEO matrix resulted in enhanced tensile strength and reduced strain at break, while negligibly impacting the ionic conductivity of the membrane. The most effective membrane composition was achieved at a PEO to NC ratio of 80:20, with the optimum ionic conductivity of the polymer electrolyte being 1.54 × 10−4 S cm−1, a tensile strength of 34.87 MPa and an elongation at break of 65.6%. This research sheds light on the potential of utilising NC from cassava peels to improve the performance and safety of polymer electrolyte membranes for lithium‐ion batteries. © 2024 Society of Chemical Industry.

Computationally aided design of single‐ion‐conducting block copolymer electrolytes to boost lithium‐ion conductivity

AbstractIn this work, we implement a combinatory approach that integrates molecular dynamics (MD) simulation and a Gaussian process regression (GPR) algorithm to explore optimal design strategies for a generic single‐ion‐conducting block copolymer electrolyte (SIC‐BCPE) model system that covers a rich design parameter space inspired by recently established poly(ethylene oxide)‐based block copolymer electrolytes. The GPR algorithm is employed to efficiently reveal the relationships between the desired lithium‐ion conductivity and four design parameters reflecting both chain architectural control and specific tuning of molecular chemistry. Guided by the GPR results, an optimal combination of four parameter values is inferred, and MD simulation confirms that the corresponding SIC‐BCPE system produces relatively higher lithium‐ion conductivity. To further understand the influence of each molecular parameter on the trends of lithium‐ion conductivity, we analyse the proportion variation of different types of lithium‐ion coordination and identify a strong correlation between the ion coordination pattern and ionic conductivity. Due to its generality, we expect that the MD‐GPR combinatory approach reported in this work is applicable to a broad range of other polymer‐based ion transport systems. © 2024 Society of Chemical Industry.

Effect of End-Tethered Methoxy-PEO Chain Density on Uremic Toxin Adsorption.

In 2023, around 850 million people globally were affected by chronic kidney disease, which leads to the retention of uremic toxins and excess fluid in the blood. This study examines the adsorption of these toxins to poly(ethylene oxide) (PEO) films, known for their low-fouling properties. The gold surfaces were treated with 5 mM end-thiolated methoxy-terminated PEO (m-PEO) and analyzed using dynamic contact angle measurements, X-ray photoelectron spectroscopy, and spectroscopic ellipsometry to confirm the PEO film's presence and determine chain density. The adsorption of 25 different uremic toxins to m-PEO films was evaluated by using liquid chromatography-mass spectrometry (LC/MS), focusing on their binding affinity and adsorption dynamics. Results showed the effective modification of surfaces with m-PEO, with a notable change in contact angles and chain density (∼0.5 and 0.8 chains/nm2). Interestingly, pyruvic acid showed significant adsorption, whereas other toxins, such as hippuric acid, creatinine, and xanthosine had minimal interactions with the film. This indicates that the adsorption of these toxins is not primarily concentration driven and is rather dependent on the chemical structure of each toxin. These findings provide important insights for designing low-fouling coatings for biomedical devices.

Design, Fabrication, and Wearable Medical Application of a High‐Resolution Flexible Capacitive Temperature Sensor Based on the Thermotropic Phase Transition Composites of PEO/PVDF‐HFP/H3PO4

AbstractPhase transition materials have the potential to be utilized as high‐resolution temperature‐sensitive materials. However, it is a challenge to develop them into temperature sensors with good stability and repeatability. In this work, inspired by phase transition theory and the electrical double‐layer capacitance principle, a novel high‐resolution flexible capacitive temperature sensor based on Polyethylene oxide(PEO)/Poly(vinylidene fluoride‐co‐hexafluoropropylene)/H3PO4 is proposed for the first time. By blending high and low molecular weight PEO and adding ionic solution, the proposed sensor exhibits high resolution (0.05 °C) and response speed (<12 s) within 35–43 °C. The novel introduction of a mesh structure aids the material in achieving microdomain control of PEO crystallization and improves the repeatability (Ex < 2.2%) of the sensor. The sensor is used for monitoring human body temperature and diabetic foot ulcers, and the results show that the sensor can achieve continuous and comfortable body temperature monitoring and early‐stage diabetic foot ulcer diagnosis, offering broad applications in health monitoring and rehabilitation medicine.

Bonding Optimization Strategies for Flexibly Preparing Multi-Component Piezoelectric Crystals.

Flexible films with optimal piezoelectric performance and water-triggered dissolution behavior are fabricated using the co-dissolution-evaporation method by mixing trimethylchloromethyl ammonium chloride (TMCM-Cl), CdCl2, and polyethylene oxide (PEO, a water-soluble polymer). The resultant TMCM trichlorocadmium (TMCM-CdCl3) crystal/PEO film exhibited the highest piezoelectric coefficient (d33) compared to the films employing other polymers because PEO lacks electrophilic or nucleophilic side-chain groups and therefore exhibits relatively weaker and fewer bonding interactions with the crystal components. Furthermore, upon slightly increasing the amount of one precursor of TMCM-CdCl3 during co-dissolution, this component gained an advantage in the competition against PEO for bonding with the other precursor. This in turn improved the co-crystallization yield of TMCM-CdCl3 and further enhanced d33 to ≈71 pC/N, exceeding that of polyvinylidene fluoride (a commercial flexible piezoelectric) and most other molecular ferroelectric crystal-based flexible films. This study presents an important innovation and progress in the methodology and theory for maintaining a high piezoelectric performance during the preparation of flexible multi-component piezoelectric crystal films.

Interfacial Ion Transport in Porous Polydimethylsiloxane–Polydopamine Composites for Solar Thermoelectric Conversion

AbstractRecent developments in iontronic materials and devices highlight the importance of efficient ion conduction in optimizing their performance. In particular, improving ion transport in polymer electrolytes is key to the progress of advanced energy conversion systems. This study presents a novel approach to enhance the ion conductivity of poly(ethylene oxide) (PEO)–NaOH electrolytes within porous polydimethylsiloxane (PDMS) composites. By coating PDMS with a thin layer of polydopamine (PDA) and filling it with PEO–NaOH, numerous hopping sites are generated at the PEO‐PDA interface for efficient Na+ transport, thereby improving ion conductivity. Additionally, by combining the broadband absorption of PDA with the scattering properties of porous PDMS, the ability of the PDA–PDMS composite to efficiently absorb and convert solar radiation into heat is demonstrated. The generated heat is confined to the light‐exposed region due to the thermal insulation provided by the porous PDMS. This confinement creates a temperature gradient across the composite, preferentially enhancing the thermal diffusion of Na+ cations over OH− anions to generate thermoelectric voltage. This unique property allows for the direct conversion of solar energy into electrical energy, offering new possibilities for sustainable and efficient energy technologies.

Effect of Uremic Toxins and Methoxy-PEO Chain Density on Plasma Protein Adsorption.

Protein adsorption can direct the host response to blood-contacting biomaterials. Poly(ethylene oxide) (PEO) is commonly employed to minimize nonspecific protein adsorption. Although chain density has been observed to play a role in the inherent resistance of protein adsorption by end-tethered films of PEO, only a few papers correlate the change in PEO chain densities with the adsorbed plasma protein composition. Almost all studies rely upon blood from healthy patients for these studies even though they are applied to the unhealthy. In the case of patients with kidney failure, there is a remarkable change in the blood composition due to retained metabolites. In the pursuit of personalized dialysis, we must address this dearth in the literature regarding the effect of metabolite accumulation in the blood compartment on the adsorption of protein to blood-contacting biomaterials. To this end, surface films of different methoxy-PEO (mPEO) chain densities were used to evaluate the changes in adsorbed proteins in the presence of uremic metabolites (i.e., uremic toxins). End-tethered mPEO films were characterized using contact angles, ellipsometry, and X-ray photoelectron spectroscopy. Plasma protein adsorption was conducted with and without uremic toxins commonly found in patients with end stage kidney disease, and the adsorbed protein profile was identified using immunoblots. It was found that the presence of uremic toxins led to a notable increase in the adsorption of almost all of the proteins. It was evident that while chain density plays a role in overall protein resistance, the effect of uremic toxins led to substantial increases in adsorbed proteins and needs to be considered when designing next-generation blood-contacting materials.

Research on the preparation of antimicrobial material based on thermoplastic polyurethane and drug release control.

It's crucial of antimicrobial properties in materials is growing as people desire to live healthier. The purpose of this work was to use thermoplastic polyurethane (TPU) as a matrix to produce an antimicrobial material with a tunable drug release rate. Filaments with a diameter of 1.75 ± 0.08mm were prepared by hot-melt processing technology utilizing TPU, the modifier polyethylene oxide (PEO) and ciprofloxacin hydrochloride monohydrate (CPFX) as raw materials. The corresponding models were then printed using fused deposition type (FDM) 3D printing for performance testing. Results demonstrate the uniform fiber morphology and strong mechanical properties of the four samples, each of which was composed of a different ratio of components. The addition of PEO caused a change to the drug release mechanism, increased the material hydrophilicity, and generated extra pores during the dissolution process. This composite exhibited sustained antimicrobial activity even after 21days of rotary immersion, as shown by in vitro dissolution and zone inhibition tests.

Synergistic Combination of Cross-Linked Polymer and Concentrated Ionic Liquid for Electrolytes with High Stability in Solid-State Lithium Metal Batteries.

Poly(ethylene oxide)-(PEO-based solid polymer electrolytes (SPEs) are regarded as excellent candidates for solid-state lithium metal batteries (SSLMBs) due to their inherent safety advantages, processability, low cost, and excellent Li+ ion solvation. However, they suffer from limited oxidation stability (up to 4 V vs Li+/Li). In this study, a crosslinked polymer-in-concentrated ionic liquid (PCIL) SPE consisting of PEO, N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (C3mpyrFSI) ionic liquid (IL), and lithium bis(fluorosulfonyl)imide (LiFSI) salt is developed. The adopted UV-crosslinking strategy synergistically reduces PEO crystallinity while increasing the amount of encompassed lithium salt and IL and improves PEO oxidative stability, therefore leading to enhanced electrochemical performance. The physical and electrochemical properties of both linear and crosslinked SPEs are explored and compared. The designed cross-linked SPEs exhibited a promisingly high oxidative stability of 4.9 V vs Li+/Li and high ambient temperature ionic conductivity of 4 × 10-4 S cm-1. Stable and reversible lithium plating/stripping is demonstrated in symmetrical Li||Li cells over hundreds of hours. High-loading solid-state lithium iron phosphate (LFP)||Li cells show favorable cycling with over 90% capacity retention at 0.1C over 100 cycles at 50 °C. High voltage solid-state lithium manganese oxide (LMO)||Li cells exhibit promising cycling with a 93% capacity retention at a 0.2 C rate over 50 cycles at 50 °C. Thus, the combination of concentrated ionic liquid electrolytes in a crosslinked PEO-based matrix enables a pathway for designing high-performing SPEs for high energy density solid-state LMBs.

Single ion conducting gel polymer electrolytes containing polybenzimidazole-based ionomers with abundant Li+ transport channels for dendrite-free lithium metal batteries

Single ion conducting polymer electrolytes (SIPEs) have attracted much attention due to their ability to effectively inhibit the growth of lithium dendrites, but still confront the problems of low ionic conductivity and poor mechanical properties. In this study, a new polybenzimidazole-based ionomer (M-OPBI) is synthesized by chemically modifying aromatic poly(2,2′-(p-oxydiphenylene)-5,5′-bibenzimidazole) (OPBI), and two series of novel SIPEs (i.e. M-OPBI/PEO and M-OPBI/PVDF) are achieved after blending with different polymer matrices (i.e. poly(ethylene oxide) (PEO) and poly(vinylidene fluoride) (PVDF)). Afterwards, some single ion conducting gel polymer electrolytes (SIGPEs) with abundant Li+ transport channels are fabricated by absorbing appropriate amount of plasticizers. The imidazole anions and sulfonylimide anions in the ionomer present low binding energies with Li+, which is beneficial for the dissociation and transport of Li+. Moreover, in view of the presence of rigid aromatic structure in the main chain of the ionomer and the interactions between the polymers, polybenzimidazole-based SIPEs all exhibit excellent thermal and mechanical properties. Most importantly, in comparison with PVDF matrix, PEO is approved to be more compatible with the ionomer and provide additional Li+ conduction sites, and this will enhance the interfacial compatibility and facilitate the construction of abundant Li+ transport channels in M-OPBI/PEO membranes. As a result, M-OPBI/PEO-0.4 membrane shows the lowest activation energy of 0.098 eV, the highest room-temperature ionic conductivity of 9.9 × 10-5 S cM-1, and a satisfactory lithium ion transference number of 0.88. Thanks to these merits, the symmetric Li||Li cell assembled with M-OPBI/PEO-0.4 membrane exhibits an excellent reversible lithium plating/stripping performance without short circuit over 2160 h. This study provides a new design strategy for the development of SIGPEs for application in dendrite-free lithium metal batteries.

Blood vessel wall shear stress determines regions of liposome accumulation in angiogenic vasculature.

Nanoparticles used for drug delivery often require intravenous administration exposing them to fluid forces within the vasculature, yet the impact of blood flow on nanoparticle delivery remains incompletely understood. Here, we utilized transgenic zebrafish embryos to investigate the relationship between the accumulation of fluorescently labeled PEGylated liposomes and various hemodynamic factors (such as flow velocity, wall shear stress (WSS), and flow pattern) across a wide range of angiogenic blood vessels. We reconstructed 3D models of vascular structures from confocal images and used computational fluid dynamics to calculate local WSS, velocities, and define flow patterns. The spatial distribution of fluorescently labeled liposomes was subsequently mapped within the same 3D space and correlated with local hemodynamic parameters. Through the integration of computational fluid dynamics and in vivo experimentation, we show that liposomes accumulated in vessel regions with WSS between 0.1-0.8 Pa, displaying an inverse linear correlation (R2 > 0.85) between time-averaged wall shear stress and liposome localization in vivo. Interestingly, flow pattern did not appear to impact liposome accumulation. Collectively, our findings suggest the potential of stealth liposomes for passive targeting of low-flow vasculature, including capillaries and intricate angiogenic vasculature resembling that of tumor vessel networks.

Electrospun PAN membrane encapsulated in PEO as a polymer electrolyte for lithium metal batteries

The novel two-step fabrication method of polymer electrolyte membrane was proposed. In the first step, the polyacrylonitrile nano fibrous membrane was prepared with the help of electrospinning. In the second step, the polyethylene oxide solution was prepared along with lithium salt and plasticizers. The solution was poured on the electrospun polyacrylonitrile to get polymer electrolyte membrane in the form of PAN membrane encapsulated in PEO. The polymer electrolyte membrane was boosted by the liquid LiPF6 before assembled in the lithium metal batteries. The polymer electrolyte membrane was compared with the commercial Celgard separator when assembled in coin cell for the application of lithium metal batteries. The polymer electrolyte membrane outperformed and exhibited a good ultimate tensile strength of 20 MPa and the better thermal stability of 97 % at 305 °C. Moreover, the polymer electrolyte membrane also exhibited excellent ionic conductivity of 1.2 mS cm−1, good lithium-ion transference number of 0.57 and uniform lithium plating/stripping cycles for up to 500 cycles without internal short circuiting. The polymer electrolyte membrane represented outstanding rate capability and exhibited the good discharge capacity of 141 mA h g−1 after 100 cycles at 0.5 C rate.

Quasi-solid-state monolithic DSSCs with optimized spacer layers and composite electrolytes for better efficiency and stability

In this study, high-performance quasi-solid-state monolithic dye-sensitized solar cells (QS-M-DSSCs) were designed using an optimized spacer layer architecture to enhance electrolyte transport and improve cell performance. Spacer layers, made from a combination of zirconium oxide (ZrO2) and titanium dioxide (TiO2), were precisely tuned to reduce mass-transport limitations. A 5.2 μm thick ZrO2/TiO2 layer provided good light reflectance and incident photon-to-current conversion efficiency compared to double layers of either material alone. Electrochemical impedance spectroscopy analysis of the m-DSSCs revealed that this architecture (photoelectrode TiO2 layer/ZrO2/TiO2 spacer layer/counter electrode catalyst layer) significantly increased recombination resistance, leading to an improvement in open-circuit voltage. As a result, acetonitrile iodide liquid-DSSCs using N719 dye achieved a high power conversion efficiency (PCE) of 8.45 %, surpassing cells with alternative spacer designs. For fully printable QS-M-DSSCs, printable gel electrolytes (PGEs) composed of polyethylene oxide and polymethyl methacrylate in 3-methoxypropionitrile (MPN) were employed. A 5 wt% PEO/PMMA composition demonstrated fast and efficient penetration of the PGEs through spacer layers. Moreover, incorporation of 4 wt% TiO2 nanoparticles into PGEs further enhanced their electrochemical properties, achieving a PCE (7.31 %) higher than cells with liquid electrolytes (6.72 %). QS-M-DSSCs demonstrated greater stability than liquid-state DSSCs.

FORMULATION AND EVALUATION OF FLOATING BIOADHESIVE TABLET OF GLYBURIDE FOR DIABETES

The Floating tablets of Glyburide were prepared by granulation technique based on effervescent approach. HPMC and polyethylene oxide were used as polymer, for gas generation sodium bicarbonate was used. Talc, avicel, and magnesium stearate were used. In the present study, on the basis of results it was concluded that with increase in the concentration of polymers decrease the drug release profile. On the other hand there was no effect on release of drug by changing the HPMC viscosity grades. Increased sodium bicarbonate concentration can decrease the floating lag time and there is no significant change on drug release profile. So by using appropriate concentration of polymer and sodium bicarbonate can develop sustained release floating tablet.

A PET-enhanced PEO-ionic liquid-based gel polymer electrolyte for solid state lithium metal batteries

Gel polymer electrolytes (GPEs) are attractive for their promising prospect in lithium metal batteries (LMBs) owing to their outstanding thermal stability and remarkable electrochemical performance. Nevertheless, the practical application of traditional GPEs is significantly impeded by their limited mechanical strength. In order to address this issue, this study introduces an ultrathin and mechanically-strong poly(ethylene terephthalate) (PET) nonwoven fabric (PET-NW) as a rigid support layer for the GPEs composed of poly (ethylene oxide) (PEO) and ionic liquid (IL) EMIM-TFSI. The resulting PEO-IL/PET-NW-based GPE (NW GPE) demonstrates an excellent lithium ionic conductivity of 4.21 × 10−4 S cm−1, a lithium ion transference number of 0.20, and an ultrahigh mechanical strength of 53.2 MPa. These characteristics collectively contribute to the suppression of lithium dendrites growth and improved electrochemical performance of Li|NW GPE|LiFePO4 full cells which exhibit enhanced rate capability and cycling stability in comparison with Li|GPE-I30|LiFePO4 full cells. The employment of PET-NW in the fabrication of GPEs can pave a viable way for significant advancements in high-performance solid state LMBs for various practical applications.

In Situ Welding Ionic Conductive Breakpoints for Highly Reversible All-Solid-State Lithium-Sulfur Batteries.

Poly(ethylene oxide) (PEO)-based solid-state lithium-sulfur batteries (SSLSBs) have garnered considerable interest owing to their impressive energy density and high safety. However, the dissolved lithium polysulfide (LiPS) together with sluggish reaction kinetics disrupts the electrolyte network, bringing about ionic conductive breakpoints and severely limiting battery performance. To cure this, we propose an in situ welding strategy by introducing phosphorus pentasulfide (P2S5) as the welding filler into PEO-based solid cathodes. P2S5 can react with LiPS to form ion-conducting lithium polysulfidophosphate (LSPS), which suppresses the interaction with PEO and in situ weld breakpoints within the ionic conductive network. Of interest, LSPS also shows another function, that is, to catalyze sulfur redox reactions by decreasing the activation energy of sulfur reduction reaction from 0.87 to 0.75 eV, mitigating the shuttle effect. The in situ welding strategy helps the assembled SSLSB to feature exceptional cycling stability and a high energy density of up to 358 Wh·kg-1 due to the high sulfur utilization. Our findings pave an avenue for practical high-performance SSLSBs with a novel welding filler for in situ welding of ionic conductive network.