Polymer Gel Research Articles

Solvation Structure Engineering via Inorganic–Organic Composite Layer for Corrosion‐Resistant Lithium Metal Anodes in High‐Concentration Electrolyte

AbstractHigh‐concentration electrolytes have been reported to form an anion‐derived, inorganic‐rich solid electrolyte interphase on lithium metal electrodes; however, these electrodes suffer from high Li corrosion by the coordinated anions and consequent anion depletion. Herein, the study reports a composite layer comprising single‐ion conducting ceramic (SICC) nanoparticles and a gel polymer electrolyte (GPE), which can suppress the Li corrosion in a high‐concentration electrolyte based on lithium bis(fluorosulfonyl)imide (LiFSI) and a weakly solvating solvent (N,N‐dimethylsulfamoyl fluoride, FSA). The lithium‐ion space charges formed at the SICC/GPE interface reduce the coordination of anions in the composite layer, suppressing their decomposition. A Li | LiNi0.8Co0.1Mn0.1O2 (NCM811) pouch bi‐cell with a composite layer‐coated thin lithium metal anode (N/P = 1, thickness: 20 µm) delivers projected gravimetric (316 Wh kg−1) and projected volumetric (1433 Wh L−1) energy densities and exhibits stable operation for 350 cycles, with 70% capacity retention at 1/3 C charge–discharge rate. The engineering of the solvation structure through the inorganic–organic composite layer represents a practical strategy for developing corrosion‐resistant lithium metal anodes in high‐concentration electrolytes.

Effect of Fluorine Segments in Fluoropolymer Matrix on the Properties of Gel Polymer Electrolytes

AbstractPolymer quasi‐solid electrolytes have been paid widely attention in account of their outstanding advantages in safety, flexibility, viscoelasticity and film formation. Fluoropolymer is used as matrix of gel electrolytes not only has high electrochemical stability, but also facilitates the dissociation of lithium salts owning to the strong electron‐absorbing C−F groups, which makes it a very promising choice for the further development of gel electrolytes. Due to the different sites of C−F bonds, their activity is also diverse, which results in the difference of the mobility of lithium ions and the LiF composition of SEI film on the surface of lithium metal anode. As a result, distinct fluorine‐containing gel polymer electrolytes are prepared by in‐situ polymerization of two different monomers, HFMA and TFMA. Compared with −CF3 on terminal group in TFMA, the gel electrolyte polymerized with HFMA whose C−F group with stronger electronegativity is at the intermediate carbon site, as polymer matrix has better performance. The ionic conductivity achieves 7.02×10−3 S cm−1 at room temperature, and the assembled batteries have a capacity retention rate of 91 % after 200 cycles of 1 C. Our research has laid a solid theoretical foundation for the further development of quasi‐solid electrolyte.

Synergistic Advancements of Acrylate-Grafted Poly(vinylidene Fluoride-co-hexafluoropropylene) Gel Polymer Electrolytes for Lithium-ion Batteries

Synergistic Advancements of Acrylate-Grafted Poly(vinylidene Fluoride-co-hexafluoropropylene) Gel Polymer Electrolytes for Lithium-ion Batteries

A Comparison of the Electrical Properties of Gel Polymer Electrolyte-Based Supercapacitors: A Review of Advances in Electrolyte Materials

Flexible solid-state-based supercapacitors are in demand for the soft components used in electronics. The increased attention paid toward solid-state electrolytes could be due to their advantages, including no leakage, special separators, and improved safety. Gel polymer electrolytes (GPEs) are preferred in the energy storage field, likely owing to their safety, lack of leakage, and compatibility with various separators as well as their higher ionic conductivity (IC) than traditional solid electrolytes. This review covers the classification, properties, and configurations of different GPE-based supercapacitors and recent advancements that have occurred in this area of energy storage. Ionic liquid (IL)-based materials are popular GPEs for electrochemical energy storage and can be used to prepare unprecedented flexible supercapacitors due to their great IC and wide potential range. A comparative assessment of the GPEs-based supercapacitors reveals that in a majority of them, the value of specific capacitance is generally under 1000 F g−1, energy density reaches around 125 Wh kg−1, and the power density is seen to be less than 1500 W kg−1. The results of this research serve as an essential reference for upcoming scholars, and could significantly improve our comprehension of the efficacy of GPE-containing supercapacitors.

Cellulose Derivative and Polyionic Liquid Crosslinked Network Gel Electrolytes for Sodium Metal Quasi‐Solid‐State Batteries

AbstractSodium metal batteries have gained attention as a potential solution to the low energy densities presented by current sodium‐ion batteries. However, the commonly available electrolyte systems usually fall short in safety performance. Gel polymer electrolytes, closely resembling liquid electrolytes, offer a promising balance of performance and developmental potential. A proposed polymer plastic‐crystal ionic gel composite electrolyte, featuring a polycation auxiliary chain, innovatively copolymerizes ionic liquid cations with electrolyte additives. These auxiliary chains crosslink with the main chain, attracting anions from the ionic liquid and sodium salts. Both experimental evidence and theoretical calculations affirm that this electrolyte exhibits high cation transference numbers and significant mean square displacement radii. By facilitating uniform sodium ion migration, the electrolyte has powered sodium symmetrical cells for over 550 h and has supported stable cycling of Na3V2(PO4)3 (NVP)‐sodium metal batteries at a 1 C rate for more than 800 cycles. These achievements underscore its potential in advancing the development of condensed‐state sodium metal batteries.

Polymerizable Ionic Liquid-Based Gel Polymer Electrolytes Enabled by High-Energy Electron Beam for High-Performance Lithium-Ion Batteries

Polymerizable ionic liquid-based gel polymer electrolytes (PIL-GPEs) were developed for the first time using high-energy electron beam irradiation for high-performance lithium-ion batteries (LIBs). By incorporating an imidazolium-based ionic liquid (PIL) into the polymer network, PIL-GPEs achieved high ionic conductivity (1.90 mS cm−1 at 25 °C), a lithium transference number of 0.62, and an electrochemical stability exceeding 5 V. E-beam irradiation enabled rapid polymer network formation within a metal-cased battery structure, eliminating the need for initiators and improving the process efficiency. In the NCM811/PIL-GPE/Li cells, PIL-GPE (8:2) delivered an initial discharge capacity of 198.8 mAh g−1 with 82% retention at 100 cycles, demonstrating enhanced thermal stability and cycling performance compared to traditional GPEs. The demonstrated PIL-GPEs demonstrate strong potential for high-stability, high-performance LIB applications.

A Molecular Catalyst-Driven Sustainable Zinc-Air Battery Assembly.

Bidirectional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts are key for molecular oxygen-centric renewable energy transduction via metal-air batteries. Here, a molecular cobalt complex is covalently tethered on a strategically functionalized silica surface that displayed both ORR and OER in alkaline media. The detailed X-ray absorbance spectroscopy (XAS) studies indicate that this catalyst retains its intrinsic molecular features while playing a central role during bidirectional electrocatalysis and demonstrating a relatively lower energy gap between O2/H2O interconversions. This robust molecular catalyst-silica composite (deposited on a porous carbon paper) is assembled along with a zinc foil and polymeric gel membrane to devise an active single-stack quasi-solid zinc-air battery (ZAB) setup. This quasi-solid ZAB assembly displayed impressive power density (60 mWcm-2@100 mAcm-2), specific capacity (818 mAh g-1@ 5mAcm-2), energy density (757 Whkg-1 @5mAcm-2), and elongated charging/discharging life (28 h). An appropriate assembly of these ZAB units is able to power practical electronic appliances, requiring ≈1.6-6.0V potential requirements.

Flexible and Compact PVDF/PMMA-Based Gel Polymer Electrolytes for High-Performance Sodium Metal Batteries.

Sodium is gaining recognition as a promising alternative to lithium for battery applications, particularly in sodium metal batteries (SMBs), where the performance is critically influenced by the choice of electrolyte. Although conventional organic liquid electrolytes are widely used, they pose significant issues. Gel membrane (GM)-based electrolytes have demonstrated enhanced reliability and stability. Nevertheless, there remains a pressing need to improve their electrochemical and mechanical properties to fulfill the demands of next-generation batteries, which require extended lifespan, rapid charging capabilities, and excellent flexibility. To address these challenges, a compact and flexible GM is developed by gelating a cast Polyvinylidene fluoride (PVDF)/Polymethyl methacrylate (PMMA) blend film. The resulting GM possesses a suitable sodium ionic conductivity of 0.507 mS cm-1 and an impressive ion transference number of 0.47, enabling dendrite-free reversible sodium plating and stripping for up to 300 h at a current density of 0.8 mA cm-2. Furthermore, the effectiveness of sodium dendrite suppression is demonstrated in Na/GM/Na3V2(PO4)3 cells, which exhibit a high discharge capacity and excellent cycling stability. The flexible SMB retains stable voltage output and continues to function even when bent or twisted. This study introduces a novel strategy for creating gel electrolytes for high-performance flexible SMBs.

Timed-Release Silica Microcapsules for Consistent Fragrance Release in Topical Formulations

Microcapsules are widely utilized in various applications to preserve active ingredients for prolonged durations while enabling controlled release. However, limited release of active ingredients often hampers their effectiveness in daily-use products. In this study, we demonstrated the synthesis of silica core–shell microcapsules designed for controlled fragrance release in topical formulations. The microcapsules were synthesized via the sol–gel polymerization of tetraethyl orthosilicate (TEOS) on the surface of an oil/water emulsion, leveraging the shrinkage and deformation characteristics of sol–gel-derived silica during drying. The concentrations of dipalmitoylethyl dimethylammonium chloride, a cationic emulsifier used in cosmetics, and TEOS were optimized to sustain fragrance release for up to 24 h after topical application. An additional silica coating on the microcapsules reduced the Brunauer–Emmett–Teller surface area by 76.54%, enhancing fragrance stability for long-term storage. The timed-release behavior was assessed using fragrance evaluation tests and gas chromatography–mass spectrometry. The fragrance intensity and release profiles confirmed the potential of these microcapsules in daily-use cosmetics. These findings suggest that silica microcapsules with extended-release properties have application potential in both cosmetic and pharmaceutical products.

Ionic Conductivity and Viscosity Behavior of PMMA-based Nano-dispersed Polymer Gel Electrolytes Containing Lithium Perchlorate

Abstract: In this study, nano-dispersed polymer gel electrolytes containing polymethylmethacrylate (PMMA), lithium perchlorate (LiClO4), diethyl carbonate (DEC), dimethylacetamide (DMA), and nano-sized fumed silica (SiO2) have been synthesized and characterized. The electrolytes showed high ionic conductivity for electrolytes with higher dielectric constant solvents. The polymer enhanced the ionic conductivity of liquid electrolytes having a lower dielectric constant solvent (DEC) at all PMMA concentrations than the electrolytes containing a high dielectric constant solvent (DMA). Further, with the addition of nano-sized fumed silica, the ionic conductivity showed a small increase along with an increase in the mechanical stability of the electrolytes. The viscosity behavior of the electrolytes was also discussed, and it was correlated with the results of the ionic conductivity test. Nano-dispersed polymer gel electrolytes exhibited high ionic conductivity (10-2 S/cm). Further, the conductivity showed only a small change (by a factor, not by an order) over the 25-100°C temperature range and did not vary with time, which is desirable for their use in practical applications.

Damage mechanism analysis of polymer gel to petroleum reservoirs and development of new protective methods based on NMR technique

Polymer gels are widely used in water control and enhanced oil recovery in oil fields. However, the damage mechanism of polymer gels to layers with remaining oil and not requiring plugging and corresponding protective measures are unclear. In this paper, we investigated polymer gels' damage and protection performance through static gel-breaking experiments and dynamic plugging and oil recovery evaluations on rock cores. Moreover, nuclear magnetic resonance (NMR) technology was combined to analyze the damage performance of polymer gels on cores from the pore scale. In addition, a protective technique based on gel breakers for layers with remaining oil and not requiring plugging was proposed. Results showed that when polymer gels were injected into heterogeneous cores, they plugged high-permeability layers while also penetrating low-permeability layers. When the damage to the low-permeability layers was not alleviated, the conformance and oil displacement efficiency were significantly reduced. When the concentration of ammonium persulfate was 2%–5%, the gel-breaking time was shortest and the residue was very minimal. Ammonium persulfate could be used as a gel breaker and reservoir protective material. Furthermore, after injecting ammonium persulfate into heterogeneous reservoir cores, the gel damage on the face of low-permeability layers was relieved. Consequently, the improvement in sweep efficiency was achieved, showing the re-activation of the remaining oil in medium-low permeability layers. Therefore, the low-permeability layer protection process and core experiment study based on gel-breaking agents proposed in this study were suggested to provide a new technique for the field application of conformance modification agents, aiming to achieve higher recovery degrees.

Enhanced ionic conductivity and electrochemical performance of environmental friendly guar gum-based bio polymer gel electrolytes doped with Al2O3 nanofibers for Li-ion batteries.

Recently, biopolymers made from natural resources are gaining popularity as polymer electrolytes (PEs) in electrochemical devices. In the present work, a series of guar gum (GG)-based biopolymer gel electrolytes (BGEs) filled with different amounts of Al2O3 nanofibers are synthesized and tested. The BGEs containing 7.5 wt% Al2O3 nanofibers show the maximum room temperature ionic conductivity of 2.37 × 10-3 S/cm at an uptake ratio of 120 %. Given the high conductivity, this uptake ratio is low, demonstrating that Al2O3 nanofibers affect GG's ion transport characteristics. XRD reveals that the Al2O3 in GG can create conducive environment for ion conduction. FTIR and XPS analyses demonstrate that nanofibers have the ability to generate supplementary routes for ion conduction in GG. Electrochemical investigations show that BGEs with 7.5 wt% nanofibers have a broad electrochemical potential range of 4.6 V. BGEs are stable at metallic electrodes and have a cationic transference number of 0.59. The initial discharge capacity at 0.5C has been measured to be 127 mAh g-1 for Li|BGE|LiFePO4 cell in the first cycle and 116 mAh g-1 with coulombic efficiency of over 94 % after 100 cycles. Nanofiber-dispersed BGEs have high thermal and mechanical stabilities, according to TGA, DSC, and UTM tests.

Semi-interpenetrating polymer network-based gel polymer electrolytes for Li-ion batteries applications

Semi-interpenetrating polymer network-based gel polymer electrolytes for Li-ion batteries applications

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.

Li-ion batteries with poly[poly(ethylene glycol) methyl ether methacrylate]-grafted oxidized starch solid and gel polymer electrolytes

Polymer electrolytes are considered in lithium-ion batteries because of their high safety and properties such as flexibility, easy moldability, etc. Starch is one of these polymers from renewable resources. Considering the semi-crystal structure of starch and ion conduction in amorphous phase, herein starch is oxidized and then modified with poly[poly(ethylene glycol) methyl ether methacrylate]. Solid polymer electrolytes (SPEs) are prepared by dissolution of lithium salt within polymer while gel polymer electrolytes (GPEs) as crosslinked structures are swollen in lithium salt solution. After validation of successful syntheses, all SPEs and GPEs with different oxidation state and various PEGMA/oxidized starch are evaluated in Li-ion battery performance. The synthesized GPEs and SPEs show the highest ionic conductivity of 5.5 × 10−3 and 2.19 × 10⁻⁴ S cm⁻1, respectively at room temperature. Lithium ion transfer number (t+) of 0.6–0.9 and electrochemical stability window of 4.4–4.9 V are obtained for SPEs and GPEs. The discharge capacity is ∼180 mAh g−1 at 0.2 C with capacity retention of 75 % after 100 cycles.

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.

Development, characterization and radiation dosimetry evaluation of Bovine gelatin crosslinked with Gum Arabic Aldehyde as brain phantom gel material in radiation therapy

Brain phantom gel materials are of critical importance for accuracy of dosimetry, treatment planning and quality assurance in radiotherapy. Development of reliable and realistic phantoms enhances improved radiotherapy practices. Gel dosimeters have unique property to record radiation dose distribution in three dimensions. Polymer gels also have added advantages for brachytherapy dosimetry. Objective of the study was to develop an alternative polymeric gel material equivalent to human brain for conducting radiation dosimetry studies in radiotherapy. Hydrogel prepared from gelatin and gum arabic aldehyde was used to develop a brain phantom gel material for radiation dosimetry in radiotherapy. The results of comparative studies with G-GAAB gel strongly suggest, the gel can successfully be utilized as a brain equivalent material for radiation dosimetry in place of standard water phantom by measuring (a) CT number values (b) mass attenuation coefficient values at two X-ray energies used in radiation treatment (c) absorbed dose values at different depths for various setup conditions. The midrange CT number values inside gel material and that of human brain measured from CT images were 25.5HU and 25HU respectively with a variation of 2%. The mass attenuation coefficients for brain, water and gel material at 6MV photons were 0.0275cm2/g, 0.0280cm2/g,0.0270cm2/g and for 15MV photons, the attenuation coefficients were 0.0192cm2/g, 0.0190cm2/g and 0.0180cm2/g respectively. The percentage deviation of all measurements of absorbed dose values in gel phantom material, compared with the values of standard water phantom at various radiation dosimetry setup parameters, is less than 2%.

Poly(Ionic) Liquid-Enhanced Ion Dynamics in Cellulose-Derived Gel Polymer Electrolytes.

Gel polymer electrolytes (GPEs) are regarded as a promising alternative to conventional electrolytes, combining the advantages of solid and liquid electrolytes. Leveraging the abundance and eco-friendliness of cellulose-based materials, GPEs were produced using methyl cellulose and incorporating various doping agents, either an ionic liquid (1-Butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [Pyr14][TFSI]), its polymeric ionic liquid analogue (Poly(diallyldimethylammonium bis(trifluoromethylsulfonyl)imide) [PDADMA][TFSI]), or an anionically charged backbone polymeric ionic liquid (lithium poly[(4-styrenesulfonyl)(trifluoromethyl(S-trifluoromethylsulfonylimino) sulfonyl) imide] LiP[STFSI]). The ion dynamics and molecular interactions within the GPEs were thoroughly analyzed using Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR), Heteronuclear Overhauser Enhancement Spectroscopy (HOESY), and Pulsed-Field Gradient Nuclear Magnetic Resonance Diffusion (PFG-NMR). Li+ transference numbers (tLi+) were successfully calculated. Our study found that by combining slow-diffusing polymeric ionic liquids (PILs) with fast-diffusing lithium salt, we were able to achieve transference numbers comparable to those of liquid electrolytes, especially with the anionic PIL, LiP[STFSI]. This research highlights the influence of the polymer's nature on lithium-ion transport within GPEs. Additionally, micro supercapacitor (MSC) devices assembled with these GPEs exhibited capacitive behavior. These findings suggest that further optimization of GPE composition could significantly improve their performance, thereby positioning them for application in sustainable and efficient energy storage systems.

Fabrication of Ionic Supramolecular Oleogel Lubricants Enhanced with Liquid Metal Nanodroplets for Superior Tribological Performance.

Supramolecular Oleogel lubricants provide a versatile and reliable strategy for optimizing the long-term dispersion stability of nanoadditives in the base oils. In this work, GLM-based ionic gelators constructing supramolecular oleogels were prepared by adding ultrasonically treated gallium-based liquid metal (GLM) nanodroplets carrying free radicals and vinyl-containing ionic liquids (ILs) directly to a free radical polymerization system of polymer gelators. The electrostatic interactions between the ionic liquids and GLM nanodroplets enhanced the cross-linking degree of supramolecular gels and formed denser self-assembled structures. The as-prepared GLM-based ionic oleogels as thermoreversible gels exhibit exceptional thixotropic properties. Compared to the base oil PAO10, the coefficient of friction (COF) for both GLM@IGel-1 and GLM@IGel-2 decreased significantly from 0.192 to 0.097, while the wear volume dropped from 100.10 × 104 μm3 to 13.28 × 104 μm3 for GLM@IGel-1, and to 9.69 × 104 μm3 for GLM@IGel-2. In addition, GLM@IGel-2 demonstrates a higher load-bearing capacity of 550 N due to further chemical cross-linking by ionic liquids. The outstanding lubrication performance of GLM-based ionic oleogels is achieved by the synergy of GLM nanodroplets and gel lubricants, promoting the formation of a stable tribo-chemical reaction film.

A PVDF-HFP-Based Gel Polymer Electrolyte onto Air Cathode by UV-Curing for Lithium–Oxygen Batteries

A PVDF-HFP-Based Gel Polymer Electrolyte onto Air Cathode by UV-Curing for Lithium–Oxygen Batteries