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At least 793 records · Page 44
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Ion Transport and Crystal Rotation in Plastic Crystal Electrolytes Under Applied Electric Fields

Organic ionic plastic crystal electrolytes, containing a plastic crystal and lithium salt, offer a potential balance between mechanical and electrochemical properties for solid state lithium-ion battery electrolytes. These electrolytes contain multiple mobile ionic species (three or four), resulting in complex transport mechanisms which have not yet been established. Plastic crystals are defined by long-range positional order and short-range rotational disorder. It is therefore necessary to quantify changes in the local crystal structure of the electrolyte as current flows through it. Herein, we examine the electrochemical properties of pyrrolidinium-based plastic crystal electrolytes containing lithium salt and zwitterion additives, including measurements of current fraction and limiting current. We obtain species-specific insight into electrolyte transport using pulsed-field gradient nuclear magnetic resonance spectroscopy and find that, while the zwitterion additive increases ionic conductivity, it decreases lithium diffusivity with respect to other ionic components. With operando spatiotemporally resolved wide-angle X-ray scattering we observe location-specific crystal rotations due to the passage of ionic current. In conclusion, we posit that reducing energy dissipation due to rotation is essential for using plastic crystal electrolytes in practical applications.

Yap, Kyra M. K. [University of California, Berkele↗
DOE OSTI2016

Relationship between Ion Dissociation, Melt Morphology, and Electrochemical Performance of Lithium and Magnesium Single-Ion Conducting Block Copolymers

Single-ion conducting block copolymers, such as poly(ethylene oxide)-b-poly[(styrene-4-sulfonyltrifluoromethylsulfonyl)imide lithium] (PEO-P[(STFSI)Li]), represent an exciting new class of materials capable of improving the performance of solid-state batteries with metal anodes. In this work, we report on the synthesis and characterization of a matched set of lithiated (PEO-P[(STFSI)Li]) and magnesiated (PEO-P[(STFSI) 2 Mg]) single-ion conducting diblock copolymers. We measure the temperature dependence of ionic conductivity, and through analysis using the Vogel-Tamman-Fulcher (VTF) relation, demonstrate that ion dissociation is significantly lower for all PEO-P[(STFSI) 2 Mg] samples when compared to their PEO-P[(STFSI)Li] counterparts. The VTF parameter characterizing the activation barrier to ion hopping was similar for both cations, but the VTF prefactor that reflects effective charge carrier concentration was higher in the lithiated samples by an order of magnitude. We study the melt morphology of the single-ion conducting block copolymers using temperature-dependent X-ray scattering and use the mean-field theory of Leibler to extract the effective Flory-Huggins interaction parameter (χ) for PEO/P[(STFSI)Li] and PEO/P[(STFSI) 2 Mg] from the X-ray scattering data. Lastly, we demonstrate a linear relationship between the charge-concentration-related VTF parameter and the parameter quantifying the enthalpic contribution to χ. It is evident that ion dissociation and block copolymer thermodynamics are intimately coupled; ion dissociation in these systems suppresses microphase separation.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Functionalization of Cathode–Electrolyte Interface with Ionic Liquids for High-Performance Quasi-Solid-State Lithium–Sulfur Batteries: A Low-Sulfur Loading Study

We introduce a quasi-solid-state electrolyte lithium-sulfur (Li–S) battery (QSSEB) based on a novel Li-argyrodite solid-state electrolyte (SSE), Super P–Sulfur cathode, and Li-anode. The cathode was prepared using a water-based carboxymethyl cellulose (CMC) solution and styrene butadiene rubber (SBR) as the binder while Li6PS5F0.5Cl0.5 SSE was synthesized using a solvent-based process, via the introduction of LiF into the argyrodite crystal structure, which enhances both the ionic conductivity and interface-stabilizing properties of the SSE. Ionic liquids (IL) were prepared using lithium bis(trifluoromethyl sulfonyl)imide (LiTFSI) as the salt, with pre-mixed pyrrolidinium bis(trifluoromethyl sulfonyl)imide (PYR) as solvent and 1,3-dioxolane (DOL) as diluent, and they were used to wet the SSE–electrode interfaces. The effect of IL dilution, the co-solvent amount, the LiTFSI concentration, the C rate at which the batteries are tested and the effect of the introduction of SSE in the cathode, were systematically studied and optimized to develop a QSSEB with higher capacity retention and cyclability. Interfacial reactions occurring at the cathode–SSE interface during cycling were also investigated using electrochemical impedance spectroscopy, cyclic voltammetry, and X-ray photoelectron spectroscopy supported by ab initio molecular dynamics simulations. This work offers a new insight into the intimate interfacial contacts between the SSE and carbon–sulfur cathodes, which are critical for improving the electrochemical performance of quasi-solid-state lithium–sulfur batteries.

25 ENERGY STORAGE↗
DOE OSTI2020

Mechanically robust and superior conductive n-type polymer binders for high-performance micro-silicon anodes in lithium-ion batteries

Compared with nanostructured silicon (Si), the Si microparticle (SiMP) has more commercial prospects due to its low cost. However, SiMPs suffer from unavoidable fracture during electrochemical cycling owing to their significant volume change. Here we develop a series of novel n-type conductive polymer binders (CPBs) for SiMP anodes in lithium-ion batteries owing to their superior properties. Extraordinary electrochemical performance of cells with such unique binders could be achieved, which is because these designed polymers contain electron-withdrawing oxadiazole ring groups and easily ionizable sulfonate polar groups, exhibiting excellent ionic conductivity, outstanding wettability to the electrolyte, and improved electronic conductivity after doping. Moreover, the coexistence of rigid and flexible chains enables them to have exceptional strength and ductility. Besides, a unique electrochromic approach has been utilized to investigate the energy gap of the CPBs in n-doping states. The ionic and electronic conductivities of prepared CPBs in an eigenstate and n-doping state have been systematically studied by the electrochemical method, filling the current research gap in this field. Due to the high conductivity of b-POD, the capacity of SiMPs (4200 mA h g –1 ) can be almost entirely released during the first cycle of discharge, while the SiMP anodes prepared with the PAALi or CMC binder show a much lower initial capacity. Here, the high conductivity of b-POD also endows it with better cycling performance than non-conductive binders especially at high current densities, demonstrating its excellent fast-charging ability. More essentially, this work provides polymer binders without any intricate structural designs to obtain high-performance SiMP batteries, significantly enhancing their practical applications.

25 ENERGY STORAGE↗
DOE OSTI2016

Perpendicularly Aligned, Anion Conducting Nanochannels in Block Copolymer Electrolyte Films

Connecting structure and morphology to bulk transport properties, such as ionic conductivity, in nanostructured polymer electrolyte materials is a difficult proposition because of the challenge to precisely and accurately control order and the orientation of the ionic domains in such polymeric films. In this work, poly(styrene-block-2-vinylpyridine) (PSbP2VP) block copolymers were assembled perpendicularly to a substrate surface over large areas through chemical surface modification at the substrate and utilizing a versatile solvent vapor annealing (SVA) technique. After block copolymer assembly, a novel chemical vapor infiltration reaction (CVIR) technique selectively converted the 2-vinylpyridine block to 2-vinyl n-methylpyridinium (NMP+ X-) groups, which are anion charge carriers. The prepared block copolymer electrolytes maintained their orientation and ordered nanostructure upon the selective introduction of ion moieties into the P2VP block and post ion-exchange to other counterion forms (X- = chloride, hydroxide, etc.). The prepared block copolymer electrolyte films demonstrated high chloride ion conductivities, 45 mS cm(-1) at 20 degrees C in deionized water, the highest chloride ion conductivity for anion conducting polymer electrolyte films. Additionally, straight-line lamellae of block copolymer electrolytes were realized using chemoepitaxy and density multiplication. The devised scheme allowed for precise and accurate control of orientation of ionic domains in nanostructured polymer electrolyte films and enables a platform for future studies that examines the relationship between polymer electrolyte structure and ion transport.

Arges, Christopher G.↗
DOE OSTI2024

Facilitating Ionic and Electronic Conduction in Radical Polymers through Controlled Assembly

The major objectives, research performed, and significant results associated with this effort agree with the originally proposed work. That is, we have made significant advances in terms of both the experimental and computational thrusts of this effort, and these key results have allowed for us to have significant impact in the materials chemistry community. As is usual, this has led to even greater tangible product generation in the final year of the work relative to the first two years. Importantly, we have observed that the materials created under this effort have promising electronic and ionic conductivity properties along these lines, and we have developed the initial structure-property-performance relationships that offer future promise for these open-shell materials in advanced energy applications. One metric that represents this success is the number of publications that appear in notable journals regarding the work performed. Additionally, the team has been invited to present at many conferences of leading societies and at top academic institutions due to the work associated with this award. Finally, we anticipate that this will be of interest to multiple communities in the materials chemistry realm, and they will have broader impact into related technologies as well.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Polymer–Ceramic Composite Electrolytes for Lithium Batteries: A Comparison between the Single-Ion-Conducting Polymer Matrix and Its Counterpart

Single-ion-conducting polymer electrolytes are attractive to use in lithium batteries as the transference number of the lithium cation approaches unity. This helps prevent concentration gradients across the electrolyte, which can result in dendrite formation. The addition of ceramic particles to polymer electrolytes at high loadings can increase the mechanical strength of the polymer, which can also help suppress dendrite formation. Here, a single-ion-conducting polymer electrolyte is blended with lithium-conducting oxide ceramic particles to make a composite electrolyte. This electrolyte is studied in comparison to a composite electrolyte containing freely dissolved lithium salt. It is found that the addition of ceramic particles to the single-ion-conducting polymer can result in increased cation dissociation and consequent increased ionic conductivity. The electrolytes are cycled in lithium symmetrical cells, and it is found that the ceramic-containing electrolytes show increased interfacial stability with the lithium metal compared to the pristine polymer electrolytes. Our findings shed light on how to optimize the polymer host chemistry to form composite electrolytes that can meet the challenging requirements to stabilize the lithium metal anode.

25 ENERGY STORAGE↗
DOE OSTI2015

New ionic liquids based on complexation of dipropylsulfide and AlCl3 for electrochodeposition of aluminum

A new kind of ionic liquid based on complexation of dipropyl sulfide (DPS) and AlCl 3 has been prepared. The equivalent concentration of AlCl3 in the ionic liquid is as high as 2.3 M. More importantly, it is highly fluidic and exhibits an ambient ionic conductivity of 1.25 x 10 -4 S cm -1 . This new ionic liquid can be successfully used as an electrolyte for electrodeposition of aluminum.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Secondary electron emission measurements from imidazolium-based ionic liquids

The electron-induced secondary electron emission (SEE) yields of imidazolium-based ionic liquids are presented for primary electron beam energies between 30 and 1000 eV. These results are important for understanding plasma synthesis of nanoparticles in plasma discharges with an ionic liquid electrode. Due to their low vapor pressure and high conductivity, ionic liquids can produce metal nanoparticles in low-pressure plasmas through reduction of dissolved metal salts. In this work, the low vapor pressure of ionic liquids is exploited to directly measure SEE yields by bombarding the liquid with electrons and measuring the resulting currents. The ionic liquids studied are [BMIM][Ac], [EMIM][Ac], and [BMIM][BF 4 ]. The SEE yields vary significantly over the energy range, with maximum yields of around 2 at 200 eV for [BMIM][Ac] and [EMIM][Ac], and 1.8 at 250 eV for [BMIM][BF 4 ]. Molecular orbital calculations indicate that the acetate anion is the likely electron donor for [BMIM][Ac] and [EMIM][Ac], while in [BMIM][BF 4 ], the electrons likely originate from the [BMIM] + cation. The differences in SEE yields are attributed to varying ionization potentials and molecular structures of the ionic liquids. These findings are essential for accurate modeling of plasma discharges and understanding SEE mechanisms in ionic liquids.

ionic liquids↗
DOE OSTI2015

Electronically Conductive Vanadate Glasses for Resistive Plate Chamber Particle Detectors

Particle detectors are constantly being built and refitted with new technology to improve the spatial resolution, radiation hardness, and speed at which the detector can capture particle events. One of the most crucial components of a modern collider experiment is the hadron calorimeter. One of the proposed improvements on future hadron calorimeters is to utilize resistive plate chambers (RPCs). They provide the spatial and energy resolution as well as could provide speed and radiation hardness. RPCs depend on manufacturing electrically conductive glasses that are mechanically strong, durable, radiation resistant, and not ionically conductive. To achieve such requirements, vanadate glasses were developed as alternatives to current prototypes which use soda lime silicate glasses. The conductivity, oxidation states of vanadium, radiation hardness, as well as the prototype performance, were tested on vanadate glasses. The prototype tests show that using 0.40ZnO−0.40TeO 2 −0.20V 2 O 5 can improve the RPC detector rate up to 100 times.

Johnson, Nicole↗
DOE OSTI2025

Tailoring the structural durability and proton conductivity of electrolytes for highly fuel-flexible and reversible ceramic cells

A durable and high ionic conducting electrolyte is critical for achieving fuel-flexible and reversible protonic ceramic cells (PCCs) at reduced temperatures since the developed electrolyte materials are vulnerable to steam, CO 2 , or coking deterioration. Here, we report a fast-conducting electrolyte material BaZr 0.06 Ce 0.7 Y 0.06 Yb 0.06 Hf 0.06 Gd 0.06 O 3−δ (BZCYYbHG), demonstrating excellent durability against CO 2 and H 2 O under the realistic electrolysis operations, and a high conductivity of 0.017 S cm −1 at 550 °C for lowering the PCC operating temperature. Further, density functional theory calculations indicate that the higher configurational entropy of mixing at the B-site cations slightly reduces the hydrogen adsorption energy, suggesting a higher incorporation rate of protons or hydrogen atoms into the electrolyte bulk. Ultimately, single cells with the BZCYYbHG electrolyte deliver peak power densities of 1.39, 1.12, and 0.7 W cm −2 in H 2 , NH 3 , and wet CH 4 at 550 °C with promising durability. In addition, the PCCs achieve a current density of −1.61 A cm −2 at 1.3 V and 550 °C with a high faradaic efficiency of 91.3% at −0.5 A cm −2 , enabling stable operations in steam electrolysis mode under humid air (30% H 2 O), wet air containing CO 2 (up to 10%), and reversible cycling.

25 ENERGY STORAGE↗
DOE OSTI2015

Fuel cell components and systems having carbon-containing electrically-conductive hollow fibers

A method, according to one embodiment, includes acquiring a structure having an ionically-conductive, electrically-resistive electrolyte/separator layer covering an inner or outer surface of a carbon-containing electrically-conductive hollow fiber and a catalyst along one side thereof, adding an anode that extends along at least part of a length of the structure, and adding a cathode that extends along at least part of the length of the structure, the cathode being on an opposite side of the hollow fiber as the anode.

25 ENERGY STORAGE↗
DOE OSTI2018

Mechanisms of adhesion degradation at the photovoltiac module's cell metallization-encapsulant interface

Adhesion measurements and chemical characterization of the encapsulant/silver metallization interface of a photovoltaic (PV) module through temperature, humidity, and voltage bias exposures were conducted. Results demonstrate two independent degradation mechanisms: (a) with voltage bias, the ionic conduction of Na + ions through the encapsulant results in the formation of sodium silicate at the silver metallization surface, thereby weakening that interface and (b) with moisture ingress, dissociation of the silane bonding to silver in the silver oxide similarly weakens this interface resulting in significantly lower debond energies.

14 SOLAR ENERGY↗
DOE OSTI2025

Critical role of polymer-ceramic ion exchange for high conductivity composite electrolytes

Polymer-ceramic composites offer a path to enhance the transport and mechanical properties of solid electrolytes. However, an in-depth understanding of the extent and role of ion transport along and across polymer-ceramic interfaces in these systems is lacking. We have recently shown that Li-conducting Li 0.11 Na 0.24 K 0.02 La 0.43 TiO 2.82 (LMTO) nanorods can be prepared by a molten flux method, and the addition of 30–50 weight (wt.)% LMTO to a bis[(trifluoromethyl)sulfonyl]imide-vinyl ethylene carbonate-based single-ion conducting (SIC) polymer electrolyte leads to a two-fold enhancement in Li-ion conductivity, from 1.4 to 3.0 × 10 −5 S/cm at 30 °C. In the present study, we use NMR methods to identify the Li-ion transport pathways and determine the timescale of chemical exchange between the SIC polymer and LMTO ceramic components. Tracer exchange NMR indicates preferential transport through the polymer or polymer-interfacial regions, and exchange spectroscopy (EXSY) and a new isotope exchange method reveal negligible Li exchange between the SIC polymer and LMTO ceramic up to several days. Here, LMTO nanorods act as a passive filler. Our results further highlight that significant (e.g., 10- or 100-fold) conductivity enhancements in composite electrolytes can only be achieved 1) with ionically-conductive fillers, and 2) when both the ceramic and polymer components actively participate in long-range transport. For this, fast interfacial ion exchange is needed. In conclusion, this leads us to introduce a critical interfacial ion exchange time to evaluate whether a filler actively contributes to conduction in a composite electrolyte, and screen for promising polymer-ceramic pairings to accelerate the development of high conductivity solid electrolytes.

Battery, Solid electrolyte↗
DOE OSTI2016

Morphology-enhanced conductivity in dry ionic liquids

The size polarity and tail stiffness of amphiphilic ionic liquid molecules can be tailored to obtain 3D continuous ionic channels possessing isotropic conductivities.

catalysis (homogeneous), solar (photovoltaic), bio↗
DOE OSTI2021

Decoupling Conductivity and Solubility in Electrolytes Using Microemulsions

Redox flow batteries have recently received considerable attention as possible large-scale energy storage devices, but their low energy density has inhibited widespread application. In this work, a novel strategy of decoupling conductivity and solubility of electrolytes using microemulsion is put forward to enhance ionic conduction of non-aqueous electrolytes, increase the selectivity of active species, improve the battery voltage, and eventually achieve the possibility of high energy density. We report a study of the electrochemistry of ferrocene in single phase Tween® 20/1-butanol/H 2 O/toluene microemulsion system at 20 °C. At low and intermediate surfactant to water weight ratios (<0.5/0.5), the voltammogram exhibits reversible electrochemical behavior, while at high surfactant levels the curves show lower levels of reversibility. The latter voltammograms have a form typically associated with high resistance in solution, consistent with a gradual transition in microstructure as surfactant levels increase. This change in structure is supported by correlations with conductivity results based on the literature. The voltammograms show little evidence of anomalies in double layer capacitance or electrode "blocking" by droplets, suggesting that the electron transfer is indeed occurring in a facile manner between the electrode and the ferrocene inside the oil phase.

25 ENERGY STORAGE↗
DOE OSTI2022

Highly Loaded Sulfur Cathode, Coated Separator and Gel Electrolyte for High Rate Li-Sulfur Batteries

As one of DOE Battery 500 Seedling projects, Cornell University and EIC Labs investigated and developed i) highly loaded sulfur cathodes (> 3 mg/cm 2 ), ii) hybrid separators, and iii) gel ceramic electrolytes (GCE) to mitigate the low rate capability, shuttling effect and limited cycle life in high performance Li-Sulfur batteries. Scalable nanomanufacturing processes such as air-controlled electrospray (ACES) and gas-assisted electrospinning (GAES) have been utilized to develop directly deposited electrodes and polymer/ceramic hybrid separators. First, in the development of highly loaded cathodes, alternating layers of sulfur impregnated mesoporous carbon and graphene were fabricated via ACES and the resulting layered cathodes and coated separators exhibit higher capacity and capacity retention (about 1,000 mAh/g capacity with less than 0.02% fade/cycles) than single layer cathode or cathode prepared by conventional slurry cast. Alternating layer approach via ACES has been applied to high loading systems (3 - 5 mg S/cm 2 ), demonstrating the potential to increase sulfur utilization and capacity retention. We have also incorporated iron oxides (Fe 3 O 4 ) into S/mesoporous carbon/graphene cathodes to enhance sulfur utilization and mitigation of polysulfide shuttling. and the effect of Fe 3 O 4 in mesoporous carbon and Gr is highly pronounced at high C rates of 1C and 2C cycling performance. To further improve the cathodes at high rates, graphene nanoribbons (GNR) which can promote ion transport were incorporated in the cathode, resulting in 550 mAh/g at 5C/5C rates. Hybrid Li-ion/Li-S cathodes has also been explored to better engage unreacted polysulfides during charge/discharge. S/LFP hybrid cathodes offer higher sulfur utilization and enhanced rate capability, as well as higher areal loading. This study suggests inclusion of iron phosphide (Fe2P) which can chemically interact with polysulfides can further enhance sulfur utilization and mitigation of soluble polysulfides at high rates. Secondly, in the development of hybrid separators, we first employed graphene coating on the commercial polyolefin separators, which exhibits higher capability, better capacity retention and enhanced rate capability. To improve the rate capability with enhanced safety features such as thermal stability and nonflammability, we developed polymer/ceramic hybrids based on thermally stable polyimide (PI) and room temperature curable ceramic precursors such as organopolysilazane (OPSZ) or polysilsesquioxanes (PSSQ), which exhibit no shrinkages up to 300 ºC and non-flammability. To improve mechanical properties and electrochemical stability, polybenzimidazole (PBI) and alumina have been incorporated in polymer/ceramic hybrid separator, replacing PI and OPSZ/PSSQ, respectively. Finally, the gel ceramic electrolyte (GCE) based on ceramic cross linkers have been applied to make Li-S cells even safer and also to mitigate the polysulfide shuttling further. The resulting gel ceramic electrolyte offers improved capacity retention and rate capability, and also effectively mitigates polysulfide shuttling which was also confirmed by modeling. Inclusion of high ion conducting additives into GCE together with polymer/ceramic hybrid separators exhibit the higher ionic conductivity than liquid electrolyte with commercial polyolefin separator. We demonstrated that the developed highly loaded sulfur cathodes, polymer/ceramic hybrid separators and gel ceramic electrolyte can effectively mitigate the low rate capability, shuttling effect and limited cycle life in high performance Li-Sulfur batteries with improved safety.

25 ENERGY STORAGE↗