Polymer Gel Research Articles

A polysaccharide extracted from guar beans-based gel polymer electrolytes for efficient dye-sensitized solar cells

Liquid electrolytes in dye-sensitized solar cells (DSSCs), while effective in minimizing recombination of TiO2 conduction band with redox couple (I−/I3−), suffer from leakage and evaporation issues, hindering commercialization. Although solid-state electrolytes were introduced as an alternative, their performance is constrained by poor electrode contact. To solve these issues, gel polymer electrolytes (GPE) have been formulated based on guar gum (GG) crosslinked with poly (ethylene glycol) (PEG 200) incorporating potassium iodide (KI) as the doping salt. The incorporation of PEG 200 into the GPE allows a stable gel polymer electrolyte to form by using dimethyl sulfoxide (DMSO) as the organic solvent. The GPE boasts a structure free from leakage, showcases captivating ionic conductivity and thermal stability. Comprehensive structural and thermal analyses, including Fourier Transform Infrared spectroscopy (FTIR), Differential Scanning Calorimeter (DSC), and Thermogravimetric Analysis (TGA) have been carried out. The electrochemical properties of the GPE were also studied via Electrical Impedance Spectroscopy (EIS) and are significantly enhanced with higher concentration of KI introduced into the GPE. The highest ionic conductivity (σ) value of 9.76 × 10−3 S cm−1 is obtained in the GPE contained 40 wt% KI, with an efficiency of 5.65 %. Importantly, this study introduces a better and effective approach for designing electrolyte materials with high ionic conductivity, efficiency, and stability in DSSC.

Comparative Study of Quasi-Solid-State Dye-Sensitized Solar Cells Using Z907, N719, Photoactive Phenothiazine Dyes and PVDF-HFP Gel Polymer Electrolytes with Different Molecular Weights

The present study investigates the influence of photosensitizer selection and the polymer electrolyte composition on the performance of quasi-solid-state dye-sensitized solar cells (QsDSSCs). Two benchmark ruthenium dyes, N719 and Z907, alongside a novel photoactive phenothiazine dye were used. Each dye was incorporated into a QsDSSC architecture employing poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) as the gel electrolyte matrix, with varying molecular weights, to investigate their impacts on the overall device performance and long-term stability. Our results demonstrated that the N719 dye exhibited the highest power conversion efficiency (PCE), attributed to its strong absorption in the visible spectrum and efficient electron injection into the TiO2 photoanode. Z907, on the other hand, showed moderate PCE due to its broader absorption profile but slower electron injection kinetics. The phenothiazine dye revealed promising PCE, with tunable absorption properties and efficient charge transfer. Furthermore, the impact of PVDF-HFP polymer gel electrolytes with varying molecular weights on cell stability was explored. The QsDSSC incorporating the PVH80 polymer with the phenothiazine dye exhibited reduced dye desorption, due to the effective dye molecules’ immobilization by the gel matrix, and consequently enhanced long-term stability over 600 h. This comparative study sheds light on the interplay between dye selection, the polymer gel’s properties, and QsDSSCs’ performance. These insights are crucial in designing robust and efficient QsDSSCs for practical applications.

Enhancing temperature resistance of polymer gel fracturing fluids: The role of alcohol

The temperature resistance of polymer gel fracturing fluids is the key to ensure its application in deep oil and gas reservoirs. Currently, the methods to improve the temperature resistance of polymer gel fracturing fluids are mainly based on the additives commonly used in fracturing fluids, but rarely studied on improving the strength of crosslinked systems by strengthening its non-covalent interactions. Herein, we separately introduce ethanol and glycol into the partially hydrolyzed polyacrylamide (HPAM) crosslinked zirconium polymer gels to form the fracturing fluid system with higher temperature-resistant ability. The concentrations of the HPAM and crosslinking agent are all 0.6 wt%. After shearing at 120 °C and 170 s−1 for 1 h, the addition of ethanol and glycol can increase the retention viscosity of the polymer gels from 43 mPa s to 148 mPa s and 204 mPa s, respectively. Microscopic characterization demonstrates that the addition of ethanol and glycol makes the polymer gels more dense “honeycomb” and “dendritic” structures, which may be the main reasons for the temperature resistance enhancement of the system. Additionally, the molecular dynamics simulations show that the supramolecular interaction in the polymer gel system is greatly enhanced by the formation of hydrogen bonds when the alcohol is added at low concentrations. Meanwhile, the zirconium ions play a bridging role in connecting oxygen atoms in the carboxyl group in HPAM and oxygen in the alcohol hydroxyl group. The hydrogen bonds and O-Zr-O bridges can strengthen the non-covalent interactions of the system, inhibiting the destruction of polymer gel structure at high temperatures and enhancing its temperature resistance. However, when the alcohol concentration of the system is too high, the crosslinking strength of the polymer gels is weakened to different degrees due to the competitive effect of the alcohol on the crosslinking agent. Both experimental results and theoretical simulation further deepen the understanding of alcohol to improve the temperature resistance of polymer gels, and can promote the subsequent application of alcohol to polymer gel fracturing fluids for property enhancement.

Fast-dissolving electroactive drug delivery systems: Gelatin/Poly(sulphonic acid diphenyl aniline) electrospun nanofibers

In this study, bovine gelatin (Gel)/poly(sulfonic acid diphenyl aniline) (PSDA) electrospun nanofibers were produced with PSDA, a water-soluble polyzwitterion ion thanks to sulfonyl groups, and Gel, a biocompatible and biodegradable natural polymer. These electrospun nanofibers are both electroactive and water-soluble. Cyclic voltammetry technique was used to examine the electroactivity of these nanofibers, which were used as unsupported direct working electrodes. According to the cyclic voltammograms, when the PSDA ratio in Gel/PSDA nanofibers was increased from 5% to 20%, the highest oxidation current value increased from 3.29 nA to 14.33 nA. These water-soluble electroactive nanofibers were loaded with methimazole as a model drug, and their cumulative release occurred within a few seconds. FTIR, UV–Vis spectroscopy, TG/DTA, XRD, DMA, SEM and EDS were used for characterizations.These water-based fast-dissolving electroactive Gel/PSDA electrospun nanofibers, presented for the first time in this study, were produced safely, quickly and at relatively low cost. In addition to being used as a new water-soluble drug delivery system, these nanofibers can also be used in other bioapplications such as biosensors and tissue engineering because they are electroactive.

Materials Design and Mechanistic Understanding of Tellurium and Tellurium-Sulfur Cathodes for Rechargeable Batteries.

ConspectusThe market demand for lithium-ion batteries (LIBs) has been proliferating in wide applications, from portable electronics and electric vehicles to renewable energy storage, due to their advantages of high energy density and reliable life cycles. Currently, further development of LIBs is hindered by the limited specific/volumetric capacity and high cost of conventional intercalation-type cathode materials. In this context, sulfur (S) has gained intensive attention as a conversion-type cathode because of its abundance, low cost, and high theoretical capacity (1675 mAh g-1). However, the insulating nature of S causes severe issues of sluggish redox kinetics, low S utilization, and unsatisfactory practical capacity. So far, extensive efforts have been devoted to boosting Li-S redox kinetics and enhancing cycling stability by inhibiting the shuttle effect, including developing functional electrolyte additives, introducing redox catalysts, and tailoring the S cathode structure. Partially substituting S atoms in S8 rings with high-electrical-conductivity elements (e.g., selenium, 1 × 10-3 S m-1) at the molecular level proves to be an effective strategy for tackling the above-mentioned challenges in Li-S batteries. It is noteworthy that tellurium (Te), with remarkable electrical conductivity (2 × 102 S m-1) and high density (6.24 g cm-3), is a promising battery electrode material that can realize fast electron transport and deliver volumetric capacity comparable to that of S or Se. Additionally, Te-S molecular regulation is one facile strategy to reshape Li-S chemistry, accelerate redox kinetics, and manipulate the lithiation/delithiation behaviors. Te is an effective eutectic accelerator that prevents polysulfide dissolution in Li-S batteries under the dissolution-deposition mechanism. Meanwhile, the Li-Te electrochemistry can contribute to reversible capacity in Li-TexSy batteries through Te-Li2Te conversion and enhance the materials utilization of TexSy.This Account highlights state-of-the-art advancements in applying Te or TexSy as high-capacity cathodes for rechargeable batteries. First, battery configuration and reaction pathways in Li-Te batteries are discussed, followed by the introduction of cathode design strategies to improve cathode structure stability. The limitations of this Te-only cathode are outlined in terms of the abundance, cost, and energy density. Second, the role of Te in Li-S chemistry is clarified by the analysis of the crystal structure, electrochemical behaviors, solid electrolyte interphase composition, and energy profiles. Third, recent progresses on quasi-solid-state Li-Te batteries have been introduced, focusing on flexible gel polymer electrolytes with adjustable ionic conductivity. Afterward, advancements in interface engineering by the atomic layer deposition technique in metal-Te batteries are highlighted. Additionally, mechanistic analysis in emerging zinc-TexSy batteries with outstanding areal capacity is demonstrated. Finally, we provide insightful perspectives on the future directions of material design in Te-based energy storage technologies. This Account is expected to deepen the fundamental understanding of metal-Te/TexSy chemistry and offer inspiration for the further development of Te-based high-energy-density rechargeable batteries.

In Situ Formed Gel Polymer Electrolytes Enable Stable Solid Electrolyte Interface for High-Performance Lithium Metal Batteries.

Carbonate-based electrolytes show distinct advantages in high-voltage cathodes but generate nonuniform and mechanically fragile solid-electrolyte interphase (SEI) in lithium (Li) metal batteries. Herein, we propose a LiF-rich SEI incorporating an in situ polymerized poly(hexamethylene diisocyanate)-based gel polymer electrolyte (GPE) to improve the homogeneity and mechanical stability of SEI. Fluoroethylene carbonate (FEC) as a fluorine-based additive for building LiF-rich SEI on Li metal electrodes. With this strategy, the assembled Li symmetric batteries cycled stably for 700 h, and the formation of byproducts on the Li electrode surface was significantly inhibited. The Li/LiFePO4 battery delivered significant capacity retention (91% retention after 800 cycles) at 1 C. With high-voltage LiNi0.8Co0.1Mn0.1O2 (NCM811) as cathode, the Li/GPE-FEC/NCM811 cell delivered a discharge capacity of 168.9 mAh g-1 with a capacity retention of 82% after 300 cycles at 0.5 C. From the above, the work could assist the rapid development of high-energy-density rechargeable Li metal batteries toward remarkable performance.

In situ construction of 3D crossing-linked gel polymer electrolyte toward high performance and safety lithium metal batteries

Our study focuses on developing high-performance gel polymer electrolytes (GPEs) tailored for lithium metal batteries (LMBs), harnessing the combined benefits of high conductivity of liquid electrolytes and the enhanced safety of solid electrolytes. To this end, we engineered an in situ polymerized GPE (PMIA- TP) that integrates trifluoroethyl methacrylate (TFMA) and pentaerythritol triacrylate (PETA) monomers within an electrospun poly (m-phthaloyl-m-phenylenediamine) (PMIA) supporting membrane. In addition to high ionic conductivity, high lithium ion transference number, enhanced tensile strength and good thermal stability, the resulting PMIA-TP GPE exhibits satisfactory electrochemical stability against lithium electrodes, enabling long-term and stable lithium plating/stripping in symmetric Li//Li cells, and good rate capability and prolonged cycle life for LiFePO4//Li cells. Further X-ray photoelectron spectroscopy analysis and density functional theory calculations revealed that the electrochemical stability of the PMIA-TP GPE towards lithium metal electrode is due to the formation of a fluorine-rich solid electrolyte interphase (SEI) layer facilitated by reactions involving the –CF3 groups in TFMA, which is beneficial for the effective Li+ transport and lithium dendrite suppression. In summary, our study offers a promising approach to fabricating GPEs that offer high safety and high performance for LMBs.

Operando Raman and in-Situ UV-Vis Spectroscopy Unveil the Impact of Solvent Donor and Acceptor Numbers on Gel Polymer Electrolytes in Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries boast a specific capacity five times greater than current Li-intercalation systems. Still, practical implementation faces challenges tied to liquid electrolytes, i.e., lithium metal dendrites formation, polysulfide redox-shuttle, and flammability [1]. Thus, we focus on developing biodegradable gel polymer electrolytes to overcome these issues, fostering eco-friendly, safer, and more effective energy storage solutions. Polycaprolactone (PCL) emerges as a promising GPE candidate due to its biodegradable nature and broad stability range (~5V vs Li0/Li+). Our current study investigates the influence of solvent selection, explicitly focusing on donor and acceptor numbers, in formulating gel polymer electrolytes for Lithium-Sulfur batteries. Leveraging operando Raman and in-situ UV-Vis spectroscopy, our research provides real-time insights into the dynamic interactions within the gel during battery operation, shedding light on the evolving electrochemical processes. Moreover, by systematically analyzing the impact of solvent properties on gel characteristics, we reveal a nuanced relationship, emphasizing the importance of tailored solvent selection for optimizing gel performance. Operando Raman spectroscopy enables the observation of bond formations and structural changes in the gel, while in-situ UV-Vis spectroscopy tracks the behavior of polysulfides, facilitating the identification of specific interactions and offering a comprehensive understanding of the gel's role in mitigating polysulfide shuttling. This work aims to advance our fundamental knowledge of gel polymer electrolytes and provide a pathway for optimizing battery performance and mitigating degradation mechanisms. Notably, our study introduces a novel dimension by employing a custom-built UV-Vis setup, enhancing the versatility and applicability of these spectroscopic techniques in probing the intricate interactions within gel polymer electrolytes.Reference1-Pervez, S. A.; Vinayan, B. P.; Cambaz, M. A.; Melinte, G.; Diemant, T.; Braun, T.; Karkera, G.; Behm, R. J.; Fichtner, M., Electrochemical and compositional characterization of solid interphase layers in an interface-modified solid-state Li–sulfur battery. Journal of Materials Chemistry A2020, 8 (32), 16451-16462.

Tetra-Peg Gels with Highly Concentrated Sulfolane-Based Electrolytes Exhibiting High Li-Ion Transference Numbers

To achieve high safety of lithium-ion batteries (LIBs), non-flammable electrolytes and prevention of liquid electrolytes are desirable. Sulfolane (SL) is a thermally stable and non-flammable solvent, and can dissolve high concentration Li salts. Recently, highly concentrated electrolytes (HCEs) containing Li salts over 3 mol dm−3 have attracted much attention for their attractive properties such as high thermal stability and wide electrochemical windows. We previously reported that SL-based HCEs exhibit Liion hopping conduction mechanism.1,2 In SL-based HCEs, a unique solvation structure is formed in which different Li+ ions are cross-linked by the SL and anions. In the cross-linked structure, Li+ ions dynamically exchange the ligands (SL and anion) and diffuse/migrate faster than SL solvent and anion, leading to high transference numbers of Li+ ion (>0.5). The high transference number of Li+ is effective in suppressing the concentration polarization during high-rate charging and discharging of a LIB.Gelation of the HCEs can prevent the leakage of liquids and further improve the safety of LIBs. In the case of polymer gel electrolytes, liquid electrolytes are incorporated in the polymer network. Ionic conductivity of a gel electrolyte is generally lower than that of its parent liquid electrolyte. However, to prepare self-standing and mechanically robust gel electrolytes high polymer concentrations (typically over 20 wt%) are required. To achieve both high ionic conductivity and mechanical toughness of a gel electrolyte, the use of tetra-arm poly(ethylene glycol) (TPEG) has been proposed.3 TPEG gels obtained by the end-coupling reaction of two symmetrical TPEGs with different terminals exhibit excellent mechanical properties.4 TPEG forms a homogeneous polymer network, allowing the resulting gels to uniformly disperse external stresses. Consequently, TPEG gels possess excellent mechanical toughness even at low polymer concentrations (<10 wt%). In this work, we prepared self-standing TPEG gel membranes containing a high concentration LiN(SO2CF3)2/SL electrolyte.5 The mechanical, ion transport, and electrochemical properties of the gels were characterized. TPEG gels exhibited high transference numbers of Li+. The low polymer concentration and homogeneous polymer network in the gel electrolyte were useful in achieving both mechanical reliability and high Li+ transport ability. Li/LiCoO2 cell with a TPEG gel electrolyte membrane could discharge at a current density of 2.9 mA cm−2 despite the low ionic conductivity (0.26 mS cm−1) of the gel electrolyte. Acknowledgements : This study was partially supported by the JSPS KAKENHI (Grant No. JP19H05813, JP22H00340, and JP23K17370). References K. Dokko, et al, J. Phys. Chem. B, 2018, 122, 10736–10745.A. Nakanishi, et al., J. Phys. Chem. C, 2019, 123, 14229–14238.K. Fujii, et al., Soft Matter, 2012, 8, 1756–1759T. Sakai, et al., Macromolecules, 2008, 41, 5379–5384.N. Tasaki, et al., Phys. Chem. Chem. Phys., 2023, 25, 17793–17797

(Invited) From Solid-State Li-S to Polysulfide Flow Batteries: Challenges and Opportunities

Despite several decades of research and development work on Li-S batteries, there are still several fundamental issues that limits their performance and life. Controlling the polysulfide dissolution remains the major bottle neck in liquid electrolyte-based system. To alleviate this issue, there has been a steady progress in transitioning to quasi solid-state gel electrolytes and solid-state sulfur. The talk will cover some recent results on soft-chemistry approach by using a polymer gel electrolyte that has high ionic conductivity at RT and buffers volume changes during electrochemical activity. One example relates to fabrication a gel S-cathode on a carbon nanotube (CNT) matrix coated with a crosslinked network of polyethyleneimine -poly (ethylene oxide) (PEI-PEO), and solvated Li salt (LiTFSI). By optimizing the salt and polymer composition the conductivity of gel electrolyte exceeded 1x10-4 S/cm at RT. Design of high-performance solid-state sulfur cathode relies on effective ionic and electronic wiring with optimal composition of solid- electrolyte and electronic diluent such as carbon nanotube of highly graphitic carbon. Achieving high loading solid-state sulfur cathode is challenging due to limited ion-transport. The talk will cover recent work on catholyte design for sulfur cathodes using sulfide based solid electrolytes. In contrast, RT Li/Na polysulfide flow batteries provide a completely different geometry and architecture where the energy and power density is dictated by the solubility of the polysulfide species in the desired solvent and membrane design and stability. Acknowledgment This research is supported by Asst. Secretary, Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (VTO) through the Advanced Battery Materials Research (BMR) Program and Energy Storage Program, Office of Electricity, Department of Energy, USA.

(Invited) Towards Rechargeable Zn/CuO Batteries for Grid-Scale Storage

Alkaline Zn batteries are a strong candidate for electrical grid storage applications due to Zn’s high capacity (820 mAh/g), established materials supply chain and low cost. To realize the highest energy dense batteries, Zn needs to be coupled with a similarly low cost, abundant and high-capacity cathode. CuO (674 mAh/g) is an intriguing high-capacity cathode when paired with a Zn anode in alkaline electrolyte, a battery that until recently has been relegated to the history books as a primary system. In 2021 Schorr et al. reported a rechargeable Zn/CuO battery that utilized 10% of a Bi additive to help facilitate the electrochemical reversibility of the Cu conversion electrode. Bi2O3, a species with comparable redox potentials to Cu2O, promoted reversibility and minimized passivation in the historically non-reversible system. The battery cycled without any observable Cu and Bi mixed oxide phases, cycling between metallic Cu and Bi and Cu2O/Cu(OH)2 and Bi2O3, respectively. Although the Bi additive did not eliminate capacity fade completely, limiting the cells to a 30% depth of discharge (relative to CuO) enabled 250 cycles at > 124 Wh/L. Optimization studies performed for Bismuth content indicate that changes in Bi2O3 concentration can impact the charge-discharge behavior of the CuO cathodes resulting in the suppression of metal hydroxide-related redox peaks on charge. The absence of these peaks correlates with improved cyclability, suggesting that methods and materials approaches to further suppress these recharge pathways may lead to CuO high-capacity cathodes with improved cycle-life in the future.Seeking to improve performance and minimize the spatial segregation of Cu- and Bi-phases observed upon cycling in the prior system, D. Arnot et al. prepared nanoscale carbon coated (Cu/Bi) particles, where the coating partially minimized dissolution and diffusion of soluble cuprate and bismuthate complexes, where 200 cycles at 300 mAh/g was demonstrated (@ ~ 100 Wh/L). CuBi2O4 and CuO phases were formed upon oxidation, indicating carbon coatings can also affect the battery cycling mechanism and may have future roles of increasing performance.Data collected from a variety of experimental techniques, including cyclic voltammetry, rotating ring-disk electrode voltammetry, electrochemical impedance spectroscopy, electron microscopy, transmission electron microscopy, Raman spectroscopy, operando energy-dispersive X-ray diffraction measurements, battery cycling along with recent DFT modeling will be presented to help elucidate the role of additives, carbon coatings, polymer gel electrolytes and ion selective polymers in enabling reversible Cu-based cathodes. The general challenges of achieving a highly reversible energy dense battery based on two conversion electrodes operating in highly alkaline environment will be covered as will development towards a > 200 Wh/L industrially relevant Zn/CuO battery.This work was supported by the U.S. Department of Energy Office of Electricity. This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. The views expressed in this article do not necessarily represent the views of the U.S. Department of Energy or the United States Government. This article has been co-authored by an employee of National Technology & Engineering Solutions of Sandia, LLC under Contract No. DE-NA0003525 with the U.S. Department of Energy (DOE). The employee owns all right, title and interest in their contribution to the article and is solely responsible for its contents. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this article or allow others to do so, for United States Government purposes. The DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan.

Electrochemical Characterization of Non-Aqueous and Aqueous Gel Polymer Electrolytes for Zinc-Ion Fiber Batteries

The increasing miniaturization of integrated circuits has enabled a wide variety of new applications for embedded sensors and smart devices. Miniaturization of their power sources, however, has lagged in comparison. There are many challenges to devising a space-conscious battery, including the power density, mechanical stability, and chemical safety. Batteries made in fiber formats are of interest for use in wearable electronics. Recent studies have shown the feasibility of Li-ion battery chemistries in drawn polymer fibers via thermally induced phase separation (TIPS)1,2 but key performance gaps in safety and reliability of these fiber batteries remain.In addition to Li-ion, zinc-manganese dioxide (Zn-MnO2) chemistries are particularly good candidates for fiber format batteries due to their relatively low raw material cost, low reactivity, and tolerance of environmental contaminants such as water. Our work has focused on two Zn-MnO2 gel polymer electrolyte (GPE) cell formats: one non-aqueous polyvinylidene fluoride (PVDF) based gel polymer electrolyte, the other an aqueous polyvinyl alcohol (PVA) based GPE. In this work, we synthesize, characterize, and compare these two electrolyte formats head-to-head in both Zn-Zn symmetric cells and Zn-MnO2 full cells.After the GPEs were synthesized, thermo-gravimetric analysis was used to characterize the gels and evaluate the feasibility of drawing the GPE of interest into fibers. We synthesized zinc salt containing PVDF-based GPEs and characterized them in ionic blocking cells via electrochemical impedance spectroscopy (EIS), achieving conductivities of 1.8 mS/cm2. We also assembled Zn-Zn symmetric cells, investigated key performance characteristics such as the transport number and the electrochemical stability window, and stably cycled them for over 500 hours at 0.5 mA/cm2. Lastly, we assembled Zn-MnO2 full cells to confirm the battery performance.

Shedding Light on Lithium-Sulfur Battery Dynamics: Real-Time Insights through in-Situ UV-Vis Spectroscopy on Modified Lab Equipment

In current post-lithium-ion research, the focus is directed toward Lithium-Sulfur (Li-S) batteries, motivated by their outstandingly high energy density (2640 Wh/kg) and the widespread availability of sulfur in the Earth's crust. Moreover, in-situ UV-Vis spectroscopy has proven to be instrumental, allowing for the real-time observation of alterations in the chemical composition of various battery components during operational cycles [1,2].Our current study delves into the influence of solvent selection, particularly donor and acceptor numbers, in formulating gel polymer electrolytes for Lithium-Sulfur batteries. Leveraging in-situ UV-Vis spectroscopy, our research provides real-time insights into dynamic interactions within the gel during battery operation, shedding light on evolving electrochemical processes. Systematically analyzing the impact of solvent properties on gel characteristics reveals a meaningful relationship, underscoring the importance of tailored solvent selection for optimizing gel performance. Moreover, this technique tracks polysulfide behavior, offering a comprehensive understanding of the gel's role in mitigating polysulfide shuttling. Notably, our study introduces a novel dimension by employing a custom-built in-situ UV-Vis cell featuring 3D-printed components, enhancing the versatility and applicability of these spectroscopic techniques in probing intricate interactions within gel polymer electrolytes. Moreover, by combining the UV-Vis results with Nuclear Magnetic Resonance and FTIR, we aim to advance fundamental knowledge and provide a pathway for optimizing battery performance and mitigating degradation mechanisms.References1- Patel, Manu UM, Rezan Demir‐Cakan, Mathieu Morcrette, Jean‐Marie Tarascon, Miran Gaberscek, and Robert Dominko. "Li‐S Battery Analyzed by UV/Vis in Operando Mode." ChemSusChem 6, no. 7 (2013): 1177-1181.2- He, Qi, Anna TS Freiberg, Manu UM Patel, Simon Qian, and Hubert A. Gasteiger. "Operando identification of liquid intermediates in lithium–sulfur batteries via transmission UV–vis spectroscopy." Journal of The Electrochemical Society 167, no. 8 (2020): 080508.

Understanding Electrode-Electrolyte Interfaces in Gel Polymer Electrolytes Using in-Operando Raman Spectroscopy

Gel polymer electrolytes hold enormous potential for advancing battery performance and technology, promising high energy densities and safe, rechargeable quasi solid-state batteries. GPEs offer higher ionic conductivities than solid electrolytes and enhanced safety in comparison to liquid electrolytes. A particular advantage of these electrolytes has been their ability to create robust electrode electrolyte interfaces that guide uniform deposition and stripping of lithium via their mechanical strength from the polymer and interface species that form during initial cycling.Herein we report that 1:1 dimethoxyethane (DME) and dioxolane (DOL) with lithium bistrifluoromethanosulfonyl imide (LiTFSI) and lithium nitrate entrapped in Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) gel polymer electrolytes have shown stability for up to 500 hours in lithium metal symmetric cells at 1 mAh/cm2 and performs at 5mAh/cm2 in dynamic symmetric cell cycling. To understand the fundamental interfacial phenomenon governing lithium deposition and growth in this system in-operando Raman was conducted on an anodeless Cu|PVDF-HFP|Li cell. Copper was sputtered onto the polymer electrolyte before assembly with a thickness of 20nm, providing an optically transparent electrode through which the Raman laser could pass through to detect interfacial species. We observe that PVDF-HFP acted as a chemically stable polymer electrolyte while Raman shifts associated with TFSI anions disappear near the electrode surface. The spectral and electrochemical data allow us to build a model for the growth and evolution of interfaces in an anodeless lithium metal battery cell with a GPE.Acknowledgement: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists, Office of Science Graduate Student Research (SCGSR) program. The SCGSR program is administered by the Oak Ridge Institute for Science and Education for the DOE under contract number DE‐SC0014664. Figure 1

Association of Opioid Disposal Practices with Parental Education and a Home Opioid Disposal Kit Following Pediatric Ambulatory Surgery.

The majority of opioid analgesics prescribed for pain after ambulatory pediatric surgery remain unused. Most parents do not dispose of these leftover opioids or dispose of them in an unsafe manner. We aimed to evaluate the association of optimal opioid disposal with a multidisciplinary quality improvement (QI) initiative that proactively educated parents about the importance of optimal opioid disposal practices and provided a home opioid disposal kit before discharge after pediatric ambulatory surgery. Opioid disposal behaviors were assessed during a brief telephone interview pre- (Phase I) and post-implementation (Phase II) after surgery. For each phase, we aimed to contact the parents of 300 pediatric patients ages 0 to 17 years who were prescribed an opioid after an ambulatory surgery. The QI initiative included enhanced education and a home opioid disposal kit including DisposeRX®, a medication disposal packet that renders medications inert within a polymeric gel when mixed with water. Weighted segmented regression models evaluated the association between the QI initiative and outcomes. We considered the association between the QI initiative and outcome significant if the beta coefficient for the change in intercept between the end of Phase I and the beginning of Phase II was significant. Safe opioid disposal and any opioid disposal were evaluated as secondary outcomes. The analyzed sample contained 161 pediatric patients in Phase I and 190 pediatric patients in Phase II. Phase II (post-QI initiative) cohort compared to Phase I cohort reported higher rates of optimal (58%, n = 111/190 vs 11%, n = 18/161) and safe (66%, n = 125/190 vs 34%, n = 55/161) opioid disposal. Weighted segmented regression analyses demonstrated significant increases in the odds of optimal (odds ratio [OR], 26.5, 95% confidence interval [CI], 4.0-177.0) and safe (OR, 4.4, 95% CI, 1.1-18.4) opioid disposal at the beginning of Phase II compared to the end of Phase I. The trends over time (slopes) within phases were nonsignificant and close to 0. The numbers needed to be exposed to achieve one new disposal event were 2.2 (95% CI, 1.4-3.7]), 3.1 (95% CI, 1.6-7.4), and 4.3 (95% CI, 1.7-13.6) for optimal, safe, and any disposal, respectively. A multidisciplinary approach to educating parents on the importance of safe disposal of leftover opioids paired with dispensing a convenient opioid disposal kit was associated with increased odds of optimal opioid disposal.

Sequence and gelation in supramolecular polymers.

Supramolecular polymer networks exhibit unique and tunable thermodynamic and dynamic properties that are attractive for a wide array of applications, such as adhesives, rheology modifiers, and compatibilizers. Coherent states (CS) field theories have emerged as a powerful approach for describing the possibly infinite reaction products that result from associating polymers. Up to this point, CS theories have focused on relatively simple polymer architectures. In this work, we develop an extension of the CS framework to study polymers with reversible bonds distributed along the polymer backbone, opening a broad array of new materials that can be studied with theoretical methods. We use this framework to discern the role of reactive site placement on sol-gel phase behavior, including the prediction of a microstructured gel phase that has not been reported for neutral polymer gels. Our results highlight the subtleties of thermodynamics in supramolecular polymers and the necessity for theories that capture them.

Methacrylated Wood Flour-Reinforced Gelatin-Based Gel Polymer as Green Electrolytes for Li-O2 Batteries.

With its very high theoretical energy density, the Li-O2 battery could be considered a valid candidate for future advanced energy storage solutions. However, the challenges hindering the practical application of this technology are many, as for example electrolyte degradation under the action of superoxide radicals produced upon cycling. In that frame, a gel polymer electrolyte was developed starting from waste-derived components: gelatin from cold water fish skin, waste from the fishing industry, and wood flour waste from the wood industry. Both were methacrylated and then easily cross-linked through a one-pot ultraviolet (UV)-initiated free radical polymerization, directly in the presence of the liquid electrolyte (0.5 M LiTFSI in DMSO). The wood flour works as cross-linking points, reinforcing the mechanical properties of the obtained gel polymer electrolyte, but it also increases Li-ion transport properties with an ionic conductivity of 3.3 mS cm-1 and a transference number of 0.65 at room temperature. The Li-O2 cells assembled with this green gel polymer electrolyte were able to perform 180 cycles at 0.1 mA cm-2, at a fixed capacity of 0.2 mAh cm-2, under a constant O2 flow. Cathodes post-mortem analysis confirmed that this electrolyte was able to slow down solvent degradation, but it also revealed that the higher reversibility of the cells could be explained by the formation of Li2O2 in the amorphous phase for a higher number of cycles compared to a purely gelatin-based electrolyte.

Gel Polymer Electrolyte Enables Low-Temperature and High-Rate Lithium-Ion Batteries via Bionic Interface Design.

Traditional ethylene carbonate (EC)-based electrolytes constrain the applications of silicon carbon (Si-C) anodes under fast-charging and low-temperature conditions due to sluggish Li+ migration kinetics and unstable solid electrolyte interphase (SEI). Herein, inspired by the efficient water purification and soil stabilization of aquatic plants, a stable SEI with a 3D desolvation interface is designed with gel polymer electrolyte (GPE), accelerating Li+ desolvation and migration at the interface and within stable SEI. As demonstrated by theoretical simulations and experiment results, the resulting poly(1,3-dioxolane) (PDOL), prepared by in situ ring-opening polymerization of 1,3-dioxolane (DOL), creates a 3D desolvation area, improving the Li+ desolvation at the interface and yielding an amorphous GPE with a high Li+ ionic conductivity (5.73 mS cm-1). Furthermore, more anions participate in the solvated structure, forming an anion-derived stable SEI and improving Li+ transport through SEI. Consequently, the Si-C anode achieves excellent rate performance with GPE at room temperature (RT) and low temperature (-40°C). The pouch full cell coupled with LiFePO4 cathode obtains 97.42 mAh g-1 after 500 cycles at 5 C/5 C. This innovatively designed 3D desolvation interface and SEI represent significant breakthroughs for developing fast-charging and low-temperature batteries.

Shallow penetration conformance sealants (SPCS) based on organically cross-linked polymer and particle gels—An overview

Shallow penetration conformance sealants (SPCS) based on organically cross-linked polymer and particle gels—An overview

Interplay of chromatin organization and mechanics of the cell nucleus

The nucleus of eukaryotic cells is constantly subjected to different kinds of mechanical stimuli, which can impact the organization of chromatin and, subsequently, the expression of genetic information. Experiments from different groups showed that nuclear deformation can lead to transient or permanent condensation or decondensation of chromatin and the mechanical activation of genes, thus altering the transcription of proteins. Changes in chromatin organization, in turn, change the mechanical properties of the nucleus, possibly leading to an auxetic behavior. Here, we model the mechanics of the nucleus as a chemically active polymer gel in which the chromatin can exist in two states: a self-attractive state representing the heterochromatin and a repulsive state representing euchromatin. The model predicts reversible or irreversible changes in chromatin condensation levels upon external deformations of the nucleus. We find an auxetic response for a broad range of parameters under small and large deformations. These results agree with experimental observations and highlight the key role of chromatin organization in the mechanical response of the nucleus.