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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Color as a tool for quantitative analysis of heterogeneous polymer degradation

Polymers are widely used industry, but degrade due to environmental conditions, such as elevated temperature or radiation. The degradation of polymers is dominated oxidation in oxygenated environments. Such oxidation is commonly referred to as thermal-oxidation or photo-oxidation and in many situations is heterogeneous through thickness of the polymer. While heterogeneous oxidation of polymers is a common phenomenon, the effect on the lifetime of polymers is not well understood as methods to evaluate such oxidation are time consuming and challenging to implement. Here we show a novel method for quantitative evaluation of heterogeneous oxidation in polymers using a fast and accurate color approach. The proposed color approach was observed to improve the efficiency of obtaining heterogenous oxidation profiles in half the time of common approaches, such as indention or Fourier transform infrared spectroscopy. Furthermore, the method was found to produce trends similar to that observed using common approaches and the applicability of the method was verified by mapping oxygen concentration through thickness using energy dispersive X-ray spectroscopy. Lastly, the utility of the proposed method was demonstrated through the generation of an oxidation design space, which is envisioned to assist with designing experiments towards estimation of polymer lifetime. Finally, we anticipate this work to be a starting point for further evaluation of heterogeneous oxidation in polymers using optical properties.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Developing A New NG Super-Absorbent Polymer (NG-SAP) for a Practical NG Storage System with Low Pressure, Ambient Temperature, and High Energy Density

This R&D project proposed a systematical study to develop a new class of NG super-absorbent polymer (NG-SAP) with the objective to achieve similar CNG volumetric storage level ~250 cm 3 -STP/cm 3 and fast sorption-desorption kinetics at ambient temperature but lower operational pressure (<100 bar). We suggested two consecutive research phases, including (i) a systematical investigation of various polymer systems to identify the suitable classes that can exhibit methane (C1) binding energy in the range of 20-25 kJ/mol and then (ii) focusing on the potential class polymers to identify the specific structure and morphology that can achieve the project objective.In first research phase (1st year), the major tasks included design and synthesis of several representative polymers with various structure attributes, examining their molecular structures, pore morphology, and BET surface area as the prepared samples, and then studying their C1 binding energy and sorption capacity.

03 NATURAL GAS↗
DOE OSTI2025

Nanofilm Composite Membranes of Bottlebrush Poly(1,3‐Dioxolane) Plasticized by Poly(Ethylene Glycol) for CO 2 /N 2 Separation

Abstract Poly(1,3‐dioxolane) has emerged as a leading membrane material for post‐combustion CO 2 capture due to its high ether oxygen content and strong affinity toward CO 2 . However, they are often cross‐linked to inhibit crystallization, which makes them impossible to fabricate into industrial thin‐film composite membranes. Herein, soluble and high molecular weight bottlebrush polymers ( b PDXLA) are synthesized using reversible addition‐fragmentation chain transfer polymerization and demonstrate the feasibility of fabricating nanofilm (≈100 nm) composite membranes (NCMs). Furthermore, b PDXLA can be plasticized using a miscible additive of poly(ethylene glycol) dimethyl ether (PEGDME) to improve CO 2 permeability while retaining good CO 2 /N 2 selectivity. For example, adding 20 mass% PEGDME improves CO 2 permeance from 930 to 1300 GPU and decreases CO 2 /N 2 selectivity from 74 to 53 at 25 °C; the membrane exhibits stable separation performance competitive with state‐of‐the‐art commercial membranes. This work unveils a practical approach to designing uncross‐linked, highly polar polymers for practical membrane gas separation and highlights a facile way to enhance performance by incorporating miscible plasticizers using industrial manufacturing processes.

Zhang, Gengyi [Department of Chemical and Biologic↗
DOE OSTI2024

Molecular structures of residual solvent in polyacrylonitrile based electrolytes: Implications for conductivity and stability

Lithium-ion batteries increasingly play significant roles in modern technologies; however, increased energy density also raises concerns about electrolyte safety. Traditional electrolytes that use volatile organic solvents face risks of thermal runaways and fires from electrode shorting. In response, polymer-based solid electrolytes have been developed for replacement. Polyacrylonitrile (PAN) is a promising fire-resistant component for electrolyte fabrication, but its limited solubility necessitates using low-volatility solvents, which are notoriously difficult to remove in subsequent drying processes. Here, we use femtosecond two-dimensional infrared spectroscopy to provide an in-depth understanding of how residual solvent from processing affects the molecular structures and dynamics within a polymer electrolyte. To this end, linear and nonlinear infrared spectroscopies are employed to interrogate the molecular interactions in PAN-based electrolytes containing various contents of N,N-dimethylformamide (DMF). We show that the amount of DMF within the PAN electrolyte affects the Li+ structure. Further, the coordination can proceed through the carbonyl group and/or the amide nitrogen to form antiparallel structures with the nitrile groups of PAN through dipole–dipole interactions. The free motion of DMF is drastically inhibited upon interaction with Li+ and PAN, which decreases the ionic conductivity and potentially affects the stability (resistance toward removal and chemical decomposition). These findings have implications for the design and processing of solid polymer electrolytes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Explicit solvent machine-learned coarse-grained model of sodium polystyrene sulfonate to capture polymer structure and dynamics

In this article, strongly charged polyelectrolytes (PEs) demonstrate complex solution behavior as a function of chain length, concentrations, and ionic strength. The viscosity behavior is important to understand and is a core quantity for many applications, but aspects remain a challenge. Molecular dynamics simulations using implicit solvent coarse-grained (CG) models successfully reproduce structure, but are often inappropriate for calculating viscosities. To address the need for CG models which reproduce viscoelastic properties of one of the most studied PEs, sodium polystyrene sulfonate (NaPSS), we report our recent efforts in using Bayesian optimization to develop CG models of NaPSS which capture both polymer structure and dynamics in aqueous solutions with explicit solvent. We demonstrate that our explicit solvent CG NaPSS model with the ML-BOP water model [Chan et al. Nat Commun 10, 379 (2019)] quantitatively reproduces NaPSS chain statistics and solution structure. The new explicit solvent CG model is benchmarked against diffusivities from atomistic simulations and experimental specific viscosities for short chains. We also show that our Bayesian-optimized CG model is transferable to larger chain lengths across a range of concentrations. Overall, this work provides a machine-learned model to probe the structural, dynamic, and rheological properties of polyelectrolytes such as NaPSS and aids in the design of novel, strongly charged polymers with tunable structural and viscoelastic properties

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2025

Understanding and tuning organocatalysts for versatile condensation polymer deconstruction

Plastics are widely used for their durability and versatility, but recycling remains a major challenge, especially for mixed or contaminated waste. Mechanical recycling works well for clean, single-polymer streams like PET but has limited efficiency for complex waste streams. Chemical recycling, particularly glycolysis, is often employed to selectively deconstruct condensation polymers under mild conditions. This study explores catalyst design for glycolysis using linear free energy (Hammett) analysis to evaluate how catalyst structure influences polymer deconstruction. Polycaprolactone (PCL) is used as a model polyester due to its solubility and low deconstruction temperature. Triazabicyclodecene (TBD) paired with benzoic acid derivatives depicts a clear linear trend in depolymerization rates with Hammett values. TBD with p-aminobenzoic acid (PABA) stands out for its catalytic efficiency, thermal stability, and scalability, along with PABA's commercial availability as vitamin B-10. The TBD : PABA catalyst not only effectively breaks down PCL but also enables sequential deconstruction of polycarbonate, PET, and Nylon in mixed waste streams. These results highlight the value of Hammett-guided catalyst design and establish TBD : PABA as a promising, scalable organocatalyst for mixed plastic recycling, enabling recovery of individual polymer building blocks from blended waste and offering a practical route toward circular plastics.

Zheng, Jackie [Univ. of Tennessee, Knoxville, TN (↗
DOE OSTI2026

A structural and electrochemical study of perfluoropolyether-poly(ethylene oxide) solid polymer electrolytes

Solid polymer electrolytes offer attractive safety, processability, and interfacial adhesion for enabling high–energy solid-state lithium batteries, but they are often limited by narrow oxidative stability windows and low lithium-ion transference numbers. In an attempt to broaden the electrochemical stability window and increase lithium-ion transference number of poly(ethylene oxide) (PEO)-based solid polymer electrolytes, we produce an optically clear, crosslinked membrane of PEO and perfluoropolyether (PFPE) using a mixed solvent method and subsequently infuse the membrane with a lithium salt. Structural and thermal analyses reveal nanoscale phase separation between fluorocarbon and hydrocarbon domains with characteristic spacings of 7–8 nm and an elevated glass transition for the hydrocarbon phase. Consistent with this, PFPE-containing membranes exhibit substantially lower ionic conductivity than PEO analogs (dry and plasticized). The transference number and electrochemical stability are similar to pure PEO. These results demonstrate that fluorination implemented as segregated nanoscale domains does not deliver the anticipated transport or stability benefits; instead, phase separation increases tortuosity and suppresses hydrocarbon-phase dynamics. The work underscores the importance of fluorine placement and morphology control, guiding the design of partially fluorinated solid polymer electrolytes toward architectures that avoid detrimental nanoscale phase separation.

Carden, Peyton [ORNL] (ORCID:0000000162296538)↗
DOE OSTI2021

Integrating Emerging Polymer Chemistries for the Advancement of Recyclable, Biodegradable, and Biocompatible Electronics

Abstract Through advances in molecular design, understanding of processing parameters, and development of non‐traditional device fabrication techniques, the field of wearable and implantable skin‐inspired devices is rapidly growing interest in the consumer market. Like previous technological advances, economic growth and efficiency is anticipated, as these devices will enable an augmented level of interaction between humans and the environment. However, the parallel growing electronic waste that is yet to be addressed has already left an adverse impact on the environment and human health. Looking forward, it is imperative to develop both human‐ and environmentally‐friendly electronics, which are contingent on emerging recyclable, biodegradable, and biocompatible polymer technologies. This review provides definitions for recyclable, biodegradable, and biocompatible polymers based on reported literature, an overview of the analytical techniques used to characterize mechanical and chemical property changes, and standard policies for real‐life applications. Then, various strategies in designing the next‐generation of polymers to be recyclable, biodegradable, or biocompatible with enhanced functionalities relative to traditional or commercial polymers are discussed. Finally, electronics that exhibit an element of recyclability, biodegradability, or biocompatibility with new molecular design are highlighted with the anticipation of integrating emerging polymer chemistries into future electronic devices.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Impact of Backbone Rigidity on the Thermomechanical Properties of Semiconducting Polymers with Conjugation Break Spacers

There remains a lack of fundamental understanding in theroleofbackbonerigidityonthe thermomechanical properties of conjugated polymers. Here, we provide the first holistic approach to understand the fundamental influence of backbone rigidity on an n-type naphthalene diimide-based conjugated polymer, denoted by PNDI-Cx, through insertion of a flexible conjugation break spacer (CBS). CBS lengths are varied from fully conjugated with zero alkyl spacer (PNDI-C0) to a seven- carbon alkyl spacer (PNDI-C 7 ), with the CBS engineered into each repeat unit for systematic evaluation. Solution small-angle neutron scattering and oscillatory shear rheometry were employed to provide the first quantitative evidence of CBS influence over conjugated polymer chain rigidity and entanglement molecular weight (M e ), demonstrating a reduction in the Kuhn length from 521 to 36 Å for fully conjugated PNDI-C0 and PNDI-C6, respectively, as well as a nearly consistent Me of ~15 kDa upon the addition of CBS. Thermomechanical properties, such as elastic modulus and glass-transition temperature, were shown to decrease with an increasing length of CBS. An extraordinary ductility, upwards of 400% tensile strain before fracture, was observed for high-molecular-weight PNDI-C4, which we attribute to a high number of entanglements and disruption of crystallization. Furthermore, the deformation mechanism for PNDI-Cx was studied under strain through X-ray diffraction, polarized UV-vis spectroscopy, and atomic force microscopy. Overall, this work sheds light on the important role of backbone rigidity in designing flexible and stretchable conjugated polymers.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Role of Molecular Architecture on Ion Transport in Ethylene oxide-Based Polymer Electrolytes

This work aims to develop a detailed mechanistic understanding of the role of a graft polymer architecture on lithium ion (Li + ) transport in poly(ethylene oxide)-based polymer electrolytes. Specifically, we compare Li + transport in poly-(ethylene oxide) (PEO) versus poly(oligo oxyethylene methacrylate) (POEM) polymers doped with lithium bis( trifluoromethanesulfonyl) (LiTFSI) salts, using both experimental electrochemical characterization and molecular dynamics (MD) simulations. Furthermore, our results indicate that POEM exhibits a range of relaxation processes that cannot be interpreted solely in terms of glass-transition temperature (T g ) effects. Due to its side-chain architecture, the segmental relaxation of POEM is nonuniform across ether oxygens (EOs) and shows a more pronounced sensitivity to temperature above T g compared to PEO. Moreover, POEM also exhibits a nonuniform Li + coordination behavior, in which Li + is primarily solvated by two different chains in POEM, compared to a single chain in PEO. Li + transport in POEM occurs via two events with distinct characteristic times: a fast intrachain hopping along side chains and a slow interchain hopping between side chains. Taken together, the relaxation processes and ion transport mechanisms identified in POEM provide useful insights into design of more effective solid polymer electrolytes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Enhancing cathode composites with conductive alignment synergy for solid-state batteries

Enhancing transport and chemomechanical properties in cathode composites is crucial for the performance of solid-state batteries. Our study introduces the filler-aligned structured thick (FAST) electrode, which notably improves mechanical strength and ionic/electronic conductivity in solid composite cathodes. The FAST electrode incorporates vertically aligned nanoconducting carbon nanotubes within an ion-conducting polymer electrolyte, creating a low-tortuosity electron/ion transport path while strengthening the electrode’s structure. This design not only mitigates recrystallization of the polymer electrolyte but also establishes a densified local electric field distribution and accelerates the migration of lithium ions. The FAST electrode showcases outstanding electrochemical performance with lithium iron phosphate as the active material, achieving a high capacity of 148.2 milliampere hours per gram at 0.2 C over 100 cycles with substantial material loading (49.3 milligrams per square centimeter). This innovative electrode design marks a remarkable stride in addressing the challenges of solid-state lithium metal batteries.

Science & Technology - Other Topics↗
DOE OSTI2025

Minimizing Energy Loss by Designing Multifunctional Solid Additives to Independent Regulation of Donor and Acceptor Layers for Efficient LBL Polymer Solar Cells

Solid additives are crucial in layer-by-layer (LBL) polymer solar cells (PSCs). Despite its importance, the simultaneous application of solid additives into both donor and acceptor layers has been largely overlooked. In this work, two multifunctional solid additives are actively designed, and investigated the synergistic effect on both donor and acceptor layers. Incorporating the multifunctional solid additives into the donor layer could effectively enhance the aggregation and molecular stacking of the donor polymer, leading to reduced energy disorder and minimizing ΔE 2 . When the multifunctional solid additives are introduced into the acceptor layer, they just play a role in optimizing the morphology, thereby reducing the ΔE 3 . Excitedly, the simultaneous addition of the multifunctional solid additives into both donor and acceptor layers produced a synergistic effect for decreasing ΔE 2 and ΔE 3 simultaneously, especially adding SA2, thus enabling an excellent power conversion efficiency (PCE) of 19.95% (certified as 19.68%) with an open-circuit voltage (V oc ) of 0.921 V, a short circuit current density (J sc ) of 27.08 mA cm -2 and a fill factor (FF) of 79.98%. The work highlights the potential of multifunctional solid additives in independently regulating the properties of donor and acceptor layers, which is expected as a promising approach for further developing higher performance PSCs.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Tuning Transport via Interaction Strength in Cationic Conjugated Polyelectrolytes

Tuning polymer-ion interaction strength is critical for balancing ion solvation and transport in solid polymer electrolytes for battery applications. In mixed Li + /electron conducting systems for improved battery binders, the design space is further complicated by seemingly opposing design rules for electron and ion conducting polymers. Conjugated polymers functionalized with cationic side chains have demonstrated high ionic conductivity, lithium transport, and electronic conductivity by combining long-range polymer ordering with diffuse ion interactions. Herein, we demonstrate a family of mixed conducting polythiophenes functionalized with a range of cationic side chains, namely imidazolium, trimethylammonium, and ammonium groups. The strength of ionic interactions and structure of the side chains govern lithium-selective transport, resulting in high Li + conductivity (~10 –4 S/cm at 80 °C) and electronic conductivity. The more diffuse imidazolium ion affords labile ionic interactions, resulting in higher lithium transference than the other cations studied. Electronic conductivity is also higher in the imidazolium system, stemming from the ability of the planar side chains to stack while also accommodating the bulky TFSI – counterions. Finally, these results demonstrate the importance of interaction strength in ion transport while also indicating that the physical structure of the side chain has an impact on electronic conduction. The imidazolium group strikes a balance, achieving superior properties across all metrics.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Multifunctional Tunable Polymethacrylates for Enhanced Shear Stability and Wear Prevention

This paper describes the design, synthesis, and characterization of linear, polar, and non-polar polymethacrylates designed for use as lubricant viscosity index improvers with enhanced shear and anti-wear resistance. The polymers were prepared via Reversible Addition-Fragmentation Chain Transfer (RAFT) to obtain relatively low, narrow, molecular weights, with random polar moieties. The resulting polymers were evaluated as oil solutions to determine their viscosity index, shear stability performance, and antiwear characteristics. The polymers had molecular weights (Mw) ranging from 120-170 kDa, and the resulting viscosity indexes (VIs) in general tracked the Mw. Although the VIs were modest (140-189), all polymers displayed higher values than a commercial product designed for similar applications, both at 2% (w/w) and when kinematic viscosities (KVs) were normalized to the lowest KV100 of ~5cSt. One of the imidazole-containing polymers displayed an anomalously high VI for a low apparent Mw. As hypothesized, many of the polar polymers demonstrated substantial wear reduction compared to the non-polar homopolymers or a commercial benchmark. The low-molecular-weight imidazole-containing polymer produced less than 4% of the wear displayed by the commercial standard. The higher molecular weight polymers containing imidazole, hydroxy group and amino group also produced as little as 10% of the wear shown by the benchmark. The strategy demonstrated the benefit of low, narrow, molecular weight polymers to achieve good shear stability in viscosity modifiers while minimizing wear, rendering them suitable for fluid-power applications.

friction modifiers↗
DOE OSTI2021

An unprecedented quinoid–donor–acceptor strategy to boost the carrier mobilities of semiconducting polymers for organic field-effect transistors

Quinoidal–aromatic conjugated polymers hold great application potential in organic field-effect transistors (OFETs). However, the development of high mobility quinoidal–aromatic conjugated polymers still lags behind the more popular donor–acceptor (D–A) conjugated polymers, mainly owing to the lack of a rational design strategy and efficient building block. Herein, a novel quinoid–donor–acceptor (Q–D–A) strategy is demonstrated to modulate the energy-level and boost the charge carrier transport mobility of conjugated polymers as opposed to the D–A system. On the basis of this strategy, a quinoidal–aromatic conjugated polymer, namely PAQM-BT, is designed and synthesized. With the combined use of quinoid, donor and acceptor units in the backbone, the resulting Q–D–A polymer PAQM-BT displays the narrowest bandgap with the deepest-lying lowest unoccupied molecular orbital (LUMO) energy level, highest backbone coplanarity, enhanced thin-film crystallinity and smallest effective hole mass ($m^*_h$) in comparison with the corresponding D–A polymer PT3B1 and quinoid–donor (Q–D) polymer PAQM-3T. Benefitting from the more effective intra- and inter-chain charge transport, as corroborated by experiment and theoretical calculations, OFET devices based on PAQM-BT exhibit a highly boosted hole mobility of up to 5.10 cm 2 V -1 s -1 , which is one and four orders of magnitude higher than that of PAQM-3T and PT3B1, respectively, and is among the highest for quinoidal–aromatic conjugated polymers. Finally, the potent Q–D–A strategy not only allows the energy level to be modulated but also leads to effective charge carrier transport, opening up possibilities to the development of high mobility quinoidal–aromatic conjugated polymers based on a variety of quinoids, donors, and acceptors.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Accessibility and Mechanical Stability of Nanoporous Zinc Oxide and Aluminum Oxide Coatings Synthesized via Infiltration of Polymer Templates

The conformal nanoporous inorganic coatings with accessible pores that are stable under applied thermal and mechanical stresses represent an important class of materials used in the design of sensors, optical coatings, and biomedical systems. Here, we synthesize porous AlO x and ZnO coatings by the sequential infiltration synthesis (SIS) of two types of polymers that enable the design of porous conformal coatings—polymers of intrinsic microporosity (PIM) and block co-polymer (BCP) templates. Using quartz crystal microbalance (QCM), we show that alumina precursors infiltrate both polymer templates four times more efficiently than zinc oxide precursors. Using the quartz crystal microbalance (QCM) technique, we provide a comprehensive study on the room temperature accessibility to water and ethanol of pores in block copolymers (BCPs) and porous polymer templates using polystyrene-block-poly-4-vinyl pyridine (PS75-b-P4VP25) and polymers of intrinsic microporosity (PIM-1), polymer templates modified by swelling, and porous inorganic coatings such as AlO x and ZnO synthesized by SIS using such templates. Importantly, we demonstrate that no structural damage occurs in inorganic nanoporous AlO x and ZnO coatings synthesized via infiltration of the polymer templates during the water freezing/melting cycling tests, suggesting excellent mechanical stability of the coatings, even though the hardness of the inorganic nanoporous coating is affected by the polymer and precursor selections. We show that the hardness of the coatings is further improved by their annealing at 900 °C for 1 h, though for all the cases except ZnO obtained using the BCP template, this annealing has a negligible effect on the porosity of the material, as is confirmed by the consistency in the optical characteristics. These findings unravel new potential for the materials being used across various environment and temperature conditions.

36 MATERIALS SCIENCE↗
DOE OSTI2021

3D printing of lignin: Challenges, opportunities and roads onward

Abstract As the second most abundant biopolymer on earth, and as a resource recently becoming more available in separated and purified form on an industrial scale due to the development of new isolation technologies, lignin has a key role to play in transitioning our material industry towards sustainability. Additive manufacturing (AM), the most efficient‐material processing technology to date, has likewise made great strides to promote sustainable industrial solutions to our needs in engineered products. Bringing lignin research to AM has prompted the emergence of the nascent “lignin 3D printing” field. This review presents the recent state of art of this promising field and highlights its challenges and opportunities. Following a review of the industrial availability, molecular attributes, and associated properties of technical lignins, we review R&D efforts at implementing lignin systems in extrusion‐based and stereolithography (SLA) printing technologies. Doing so underlines the adage of lignin research that “all lignins are not created equal,” and stresses the opportunity nested in this chemical diversity created mostly by differences in isolation conditions to molecularly select and tune the attributes of technical lignin systems towards desirable properties, be it by modification or polymer blending. Considering the AM design process in its entirety, we finally propose onward routes to bring the full potential to this emerging field. We hope that this review can help promote the unique value and overdue industrial role of lignin in sustainable engineered materials and products.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Impact of Ionic Liquid on Lithium Ion Battery with a Solid Poly(Ionic Liquid) Pentablock Terpolymer as Electrolyte and Separator

In this work, a ternary blend solid polymer electrolyte (SPE) consisting of a poly(ionic liquid) (PIL) multiblock polymer, lithium salt, and ionic liquid (IL) was investigated with the goal of understanding the influence of IL concentration on ion transport mechanisms and electrochemical stability. The physical, transport, mechanical, morphological, and electrochemical properties of the ternary blend SPE were systematically investigated as a function of IL concentration (r = [IL]/[PIL] mole ratio between 0.1 and 0.7). The results indicate that with increasing IL concentration, the continuous conductive domain increases along with the polymer chain segmental mobility, as well as facilitate ionic conductivity, while the mechanical modulus exhibits a percolation threshold (from 52.17 MPa to 0.55 MPa at r = 0.2 to 0.3). Surprisingly, at higher IL concentrations, there is a reduction in the lithium cation mobility (i.e., 9.3 × 10-12 m2 s-1 versus 3.8 × 10-12 m2 s-1 for r = 0.2 versus r = 0.5, respectively) as evidenced by pulsed-field gradient nuclear magnetic resonance (PFG-NMR), which coincides with an increased overpotential (i.e., 50 mV versus 150 mV for r = 0.2 versus r = 0.5, respectively) evidenced by lithium metal stripping and plating. This work provides valuable insights into the impact of IL on lithium ion conducting PIL block polymers, which may enable the design of new SPEs with both high ionic conductivity and improved stability for the future lithium ion batteries.

Chen, Tzu-Ling↗