Sub-ambient Temperatures Research Articles

Zeolite Catalysis: Water Can Dramatically Increase or Suppress Alkane C–H Bond Activation

Zeolite-catalyzed alkane C–H bond activation reactions carried out at room temperature, low pressure, and low reagent loadings demonstrate that water can act either to increase or to suppress the observed reaction rates. Isobutane-d10 undergoes hydrogen/deuterium exchange with the acidic zeolite HZSM-5 at subambient temperatures, as first reported by us (Truitt et al. J. Am. Chem. Soc. 2004, 126, 11144 and Truitt et al. J. Am. Chem. Soc. 2006, 128, 1847). New experiments demonstrate that the C–H bond activation chemistry is very sensitive to the presence of water. Isobutane reaction rate constants increase by an order of magnitude at water loadings in the range of ≤1 water molecule per catalyst active site relative to the dry catalyst. Conversely, water loadings greater than about 1–3 water molecules per active site retard isobutane reaction. In situ solid-state NMR data show that water molecules and isobutane molecules are simultaneously proximate to the catalyst active site. These results indicate that water can be an active participant in reactions involving hydrophobic molecules in solid acid catalysts, possibly via transition state stabilization, as long as the water concentration is essentially stoichiometric. Such conditions exist in well-known catalytic reactions, e.g., methanol-to-hydrocarbon chemistries, since stoichiometric water is a first-formed byproduct.

Lithium plating in lithium-ion batteries at sub-ambient temperatures investigated by in situ neutron diffraction

Lithium plating in commercial LiNi1/3Mn1/3Co1/3O2/graphite cells at sub-ambient temperatures is studied by neutron diffraction at Stress-Spec, MLZ. Li plating uses part of the active lithium in the cell and competes with the intercalation of lithium into graphite. As a result, the degree of graphite lithiation during and after charge is lower. Comparison of graphite lithiation after a C/5 charging cycle fast enough to expect a considerable amount of Li plating with a much slower C/30 reference cycle reveals a lower degree of graphite lithiation in the first case; neutron diffraction shows less LiC6 and more LiC12 is present. If the cell is subjected to a 20 h rest period after charge, a gradual transformation of remaining LiC12 to LiC6 can be observed, indicating Li diffusion into the graphite. During the rest period after the C/5 charging cycle, the degree of graphite lithiation can be estimated to increase by 17%, indicating at least 17% of the active lithium is plated. Data collected during discharge immediately after C/5 charging give further evidence of the presence and amount of metallic lithium: in this case 19% of discharge capacity originates from the oxidation of metallic lithium. Also, lithium oxidation can be directly related to the high voltage plateau observed during discharge in case of lithium plating.

Vapor Pressure of Triethyl and Tri-n-Propyl Phosphates and Diethyl Malonate

Triethyl phosphate (TEPO, CAS No. 78-40-0), tri-n-propyl phosphate (TPPO, CAS No. 513-08-6), and diethyl malonate (DEM, CAS No. 105-53-3) are of considerable interest to the chemical defense community as nontoxic simulants for toxic chemical warfare agents. Vapor pressure data have been measured for TEPO at T = (271.25 to 480.15) K, for TPPO at T = (263.15 to 527.61) K, and for DEM at T = (265.15 to 471.25) K using a variety of standard methods that have been modified as necessary. The new data extend the range of vapor pressure data previously reported in the literature for each of the title compounds to subambient temperatures and to lower pressures by approximately 3 orders of magnitude for TEPO, 5 orders of magnitude for TPPO, and 1 order of magnitude for DEM. Vapor pressure data and derived properties, including volatility and temperature-dependent heats of vaporization are reported for TEPO, TPPO, and DEM along with comparisons to chemical warfare agent materials.

Character of transitions causing the physicochemical aging of a sapric histosol

Physicochemical aging of soil organic matter is assured by the dynamic character of weak interactions stabilizing its supramolecular structure. However, aging is difficult to monitor, due to low organic matter content in most soils and relatively large time constants. In order to overcome those problems, a model soil, sapric histosol, was exposed to the accelerated aging after a short heating event to 110 °C, and its thermal characteristics were monitored over several months. Classical and temperature modulated differential scanning calorimetry, microcalorimetry and solid-state NMR were used to elucidate the character of involved transitions. The heating event caused separation of an initially broad transition into two processes; a melting, which showed almost no response on the previous heating and a step transition, which is associated with the disruption of water molecule bridges (WaMB) between molecular segments of organic matter. Both processes are preceded by a preparatory phase, starting at subambient temperatures, in which aliphatic domains probably recrystallize and water molecules condensate forming WaMB stabilizing the physical structure of sapric histosol. The aliphatic moieties showed a particular behavior reflected in higher imperfection in crystallite structure upon slow cooling, which was attributed to their interaction with surrounding porous and heterogeneous structures. The results show that soil organic matter aging, considered as a natural process driven by thermodynamic principles, is caused by successive development of WaMB. This is potentially accompanied by recrystallization of aliphatic structures and both processes lead to higher physicochemical stability of soil organic matter.

Structural and ambient/sub-ambient temperature magnetic properties of Er-substituted cobalt-ferrites synthesized by sol-gel assisted auto-combustion method

Er-substituted cobalt-ferrites CoFe2−xErxO4 (0 ≤ x ≤ 0.04) were synthesized by sol-gel assisted auto-combustion method. The precursor powders were calcined at 673–873 K for 4 h, subsequently pressed into pellets and sintered at 1273 K for 4 h. X-ray diffraction (XRD) confirmed the presence of the spinel phase for all the compositions and, additional orthoferrite phase for higher compositions (x = 0.03 and 0.04). The XRD spectra and the Transmission Electron Microscopy micrographs indicate that the nanocrystalline particulates of the Er-substituted cobalt ferrites have crystallite size of ∼120–200 nm. The magnetization curves show an increase in saturation magnetization (MS) and coercivity (HC) for Er-substituted cobalt-ferrites at sub-ambient temperatures. MS for CoFe2O4, CoFe0.99Er0.01O4, CoFe0.98Er0.02O4, and CoFe0.97Er0.03O4 peak at 89.7 Am2/kg, 89.3 Am2/kg, 88.8 Am2/kg, and 87.1 Am2/kg, respectively, at a sub-ambient temperature of ∼150 K. HC substantially increases with decrease in temperature for all the compositions, while it peaks at x = 0.01−0.02 at all temperatures. The combination of Er content—x ∼ 0.02 and the temperature—∼5 K provides the maximum HC ∼ 984 kA/m. Er-substituted cobalt-ferrites have higher cubic anisotropy constant, K1, compared to pure cobalt-ferrite at ambient/sub-ambient temperatures. K1 gradually increases for all compositions in the temperature decreasing from 300 to 100 K. While K1 peaks at ∼150 K for pure cobalt-ferrite, it peaks at ∼50 K for CoFe0.99Er0.01O4, CoFe0.98Er0.02O4, and CoFe0.96Er0.04O4. The MS (∼88.7 Am2/kg), at 5 K, for Er substituted cobalt-ferrite is close to the highest values reported for Sm and Gd substituted cobalt-ferrites. The MS (∼83.5 Am2/kg) at 300 K for Er-substituted cobalt-ferrite is the highest among the lanthanide series element substituted cobalt-ferrites. The HC (at 5 K) for Er substituted cobalt-ferrite is close to the highest values observed for La, Ce, Nd, Sm, and Gd substituted cobalt-ferrites.

Equilibrium Partitioning of Di-ethylene Glycol Monomethyl Ether (DiEGME) between Fuel and Aqueous Phases at Sub-Ambient Temperatures

Improved understanding of the effect of temperature and concentration on the equilibrium partitioning of Fuel System Icing Inhibitor (FSII) additive between fuel and aqueous phases can assist in identifying required dose concentrations for safe aircraft operability. A novel experimental system was designed and used to quantify the equilibrium partitioning of the currently approved FSII, di-ethylene glycol monomethyl ether (DiEGME), under conditions relevant to actual aircraft fuel system operation. This included temperatures from ambient to −47 °C, total water contents from 130 to 560 ppmV, and initial FSII concentrations from 100 to 1500 ppmV. The partitioning of DiEGME was a strong function of temperature, exhibiting nonideal solution behavior. For a constant temperature, the resulting phase partitioning was independent of initial FSII and total water concentrations, with a single equilibrium correlation established. FSII partitioning into the aqueous phase increased with both decreasing temperature and initial FSII dose concentration in the fuel. The overall behavior was attributed to hydrophilic interactions between the glycol ether and water, which become more favored at lower temperatures and concentrations. The behavior is consistent with that expected based on the effect of temperature and concentration on the corresponding FSII activity coefficients in each phase, and has previously been observed for analogous glycol ethers. Based on the partitioning behavior, very low concentrations of FSII are expected to be sufficient to prevent water solidification to temperatures below the specification freeze point of the fuel.

Innovative High Performing Metal Organic Framework (MOF)-Laden Composite Polymer Electrolytes for All Solid State Lithium Batteries

The unique properties such as high single cell working potential, energy density, long cycle life, etc., have identified secondary Li–ion batteries as the ultimate power source for portable electronic devices such as laptop computers, cellular phones, digital cameras, etc. However, their possible widespread penetration into the large-scale hybrid electric vehicle (HEV) and plug-in HEV markets can be realized only when substantial improvements such as low cost, sustainability, safety, high rate capability and long calendar life are achieved.The advancement in lithium battery technology relies mainly upon replacement of the conventional liquid electrolyte by an advanced solid polymer electrolyte. In order to achieve this goal, many lithium-conducting polymeric networks have been prepared and characterized. Among the polymer hosts explored so far, poly(ethylene oxide) - PEO has been indeed the most extensively studied system [1]. Unfortunately, solid polymer electrolytes comprising a polymer host and a lithium salt (e.g., PEO + LiClO4) exhibit low ionic conductivity at ambient and sub-ambient temperatures. Numerous attempts have been made to enhance the ionic conductivity of PEO-based electrolytes; one of the most common ways is the addition of low molecular weight liquid plasticizers like ethylene carbonate, propylene carbonate, etc. The addition of plasticizers, despite ameliorating the ionic conductivity, it adversely deteriorates the mechanical integrity and safety; moreover, side reactions with lithium metal eventually occur.Recently, new interesting structures have been described in the literature as metal organic frameworks (MOFs) [2]. Generally speaking, they are microporous solids consisting of an infinite network of metal centres (or inorganic clusters) bridged by simple organic linkers through metal–ligand coordination bonds. MOFs are widely used in catalysis, sensors, ion exchange, gas storage, purification, separation and sequestration; they are also used in optoelectronics to improve both electronic and proton conductivity. Nevertheless, to the best of our knowledge, so far no attempt has been made on the development of PEO-based composite polymer electrolytes (CPEs) encompassing an ad hoc synthesized Al-BTC (aluminium benzenetricarboxylate, see Fig. 1) MOF and a proper lithium salt showing an enhanced ionic conductivity of more than two order of magnitude at low temperature and excellent stability towards lithium metal even after a prolonged storage time. The obtained metal organic frameworks and macromolecular composite networks are thoroughly characterized from the structural, morphological and physico-chemical viewpoint of and, for the first time, an excellent long-term electrochemical behaviour in a lab-scale LiFePO4/CPE/Li cell is demonstrated (noteworthy stable even at low 50 °C), thus accounting for the development of high performing, safe all-solid-state lithium batteries. Even though lots of literature data are available on ceramic based fillers, the studies based on MOF encompassed polymer electrolytes are truly interesting due to its tailor-making capability and the broad spectrum of opportunities and possibilities it can bring. If very well-tuned, the MOF based fillers will be a true promising candidate and a vital ingredient which can enforce the intrusion of polymer electrolytes into the huge market of lithium-based batteries. [1] E. Quartarone, P. Mustarelli, Chem. Soc. Rev., 2011, 40, 2525.[2] M. Eddaoudi, H. Li, O.M. Yaghi, J. Am. Chem. Soc., 2000, 122, 1391

Effects of sorbent materials on the cryofocusing analysis of gaseous reduced sulphur compounds

The relative performance of different sorbent materials employed in the cryofocusing (e.g. in cold trap (CT) unit) stage was investigated at sub-ambient temperature by the thermal desorption (TD)–gas chromatography (GC)–pulsed flame photometric detector. To this end, the TD-based calibration of five reduced sulphur compounds (RSC: H 2S, CH 3SH, CS 2, DMS and DMDS) and SO 2 was carried out via the Peltier cooling system with five types of sorbent combinations such as two single-bed (Tenax TA and Silica gel) plus three multibed types (a combination of either two from the following three sorbents: Tenax TA, Silica gel and Carbopack B). Relative performance of each of all five CT options, if evaluated in terms of response factors for each compound, demonstrated that each CT composition acts as an important criterion to distinguish detection properties between light and heavy sulphur species. Although the relative response of H 2S and CH 3SH was systematically distinguishable between the CT types, that of SO 2 was the most complicated to interpret. According to this study, the two CT types consisting of Carbopack B and Silica gel (CS-0.4 and CS-0.6) were the optimum choices for sulphur gas analysis in terms of basic QA parameters (sensitivity, reproducibility and linearity).

Evaluation of Reactive Absorption of Ethylene over Ethane Using Copper Metal Solution through AspenPlus Reactive Absorption–Regeneration Model

Traditionally, olefin/paraffin separations are carried out using cryogenic distillation. The close relative volatility, subambient temperatures and high pressures required in cryogenic distillation make the cryogenic distillation an energy-intensive and capital-intensive separation scheme. Significant energy savings could potentially be realized if a nondistillation separation could prefractionate the olefins from the paraffins for more optimum placement in the downstream distillation unit or eventually completely replace the need for distillation. Reactive absorption with metal species carried in a solvent is one of the techniques that use a transition metal to selectively bind the olefin through formation of an olefin–metal π-complex. An experimental investigation into the selective absorption of ethylene over ethane using a novel copper metal solution containing aniline–CuCl–NMP was reported in the literature [Reine, Travis; Olefin/Paraffin Separation by Reactive Absorption. PhD Thesis, University of Texas at Austin, 2004]. The present work makes use of this work and models this reactive absorption–regeneration in AspenPlus for the selective absorption of ethylene over ethane using aniline–CuCl–NMP solution. The Aspen model predicted the experimental results for ethylene recovery and selectivity at varied liquid-to-gas ratios in reasonable agreement with the experimental results from the literature. The model can be used for a scale-up purpose and can also be extended for selective absorption of higher olefin/paraffin systems. It is also possible to use the simulation approach presented here to guide the research in this area, potentially reducing the energy consumption for the production of these key products.

CO2 Capture by Cold Membrane Operation

Air Liquide is developing a cost effective hybrid CO2 capture process based on sub-ambient temperature operation of a hollow fiber membrane in combination with cryogenic separation. These membranes, when operated at temperatures below -20˚C, show two to four times increase in CO2/N2 selectivity with minimal CO2 permeance loss compared to ambient temperature values. Long term (6 month) bench-scale testing with CO2/N2 mixtures at sub-ambient conditions has verified the enhanced separation performance seen at lab scale translated to commercial membrane modules [1,2].A relatively high CO2 capture rate is required to drive down the cost per tonne of captured CO2 as it valorizes the cost of the flue gas pre-treatment and compression prior to the membrane unit. However, as the CO2 recovery increases, the productivity of the membrane module decreases, thereby driving up the membrane system capital cost. The main reason for this is a “pinch effect”: the CO2 driving partial pressure differential across the membrane decreases as CO2 recovery proceeds. Computational fluid dynamics modelling shows that this effect can be partially off-set by a sweep operation where a small fraction (<5%) of the N2- enriched retentate gas is fed into the permeate chamber. Experimental measurements were made with a commercial 12” membrane module, as a function of CO2 recovery, in both sweep and non-sweep (baseline) mode. At the desired 90% CO2 recovery level, sweep operation resulted in 30% higher membrane productivity with negligible effect on permeate purity. This would result in 30% lower membrane system cost with negligible change in specific energy for CO2 capture.Bench-scale process optimization work with synthetic CO2/N2 mixtures is currently being performed within Air Liquide's Delaware Research & Technology Center, USA; this will be followed by field testing at the National Carbon Capture Center (Wilsonville, Alabama, USA) with pre-treated flue gas from air-fired coal combustion.

Effect of composition on the properties of PEM based on polybenzimidazole and poly(vinylidene fluoride) blends

Inadequate performance, short term durability and high cost of polymer electrolyte membrane (PEM) are the major roadblocks that need to be resolved for successful commercialization of high temperature PEM fuel cell. In this report, we investigated the viability of previously developed miscible blend membranes of polybenzimidazole and poly (vinylidene fluoride) (PBI/PVDF), as potential PEMs. In addition, we have carried out several advanced analytical techniques such as dynamic mechanical analysis (DMA), 13C CP-MAS solid state NMR (SS-NMR) and wide-angle X-Ray diffraction (WAXD) to prove the miscible behavior of the polymer pair. Sub-ambient temperature DMA studies confirmed the miscible behavior of PBI/PVDF blends at different compositions based on single Tg criterion. SS-NMR and WAXD showed the presence of interactions between the functional groups of the polymers and their dependence on blend composition. Thermogravimetric analysis of phosphoric acid (PA) doped and undoped blend membranes confirmed the improved thermal stability of the membranes compared to neat PBI. The membranes exhibited excellent oxidative stability than pristine PBI membrane. The swelling ratio and volume after dipping in PA was found to be significantly low in the blend membranes owing to the hydrophobic nature of PVDF. Among the blends prepared, 90/10 and 75/25 membranes showed higher proton conductivity than PBI, attributed in part, to electronegativity of fluorine and crystallinity of PBI in PA that activate proton transport. The results demonstrated the potential usefulness of the blend membranes as PEM in fuel cell.

Effects of heat on new and aged polyamide 6,6 textiles during pest eradication

Abstract Subjecting artefacts to raised (58 °C) or lowered (−30 °C) temperatures in order to combat the problem of pest infestations is common practice within the museum and heritage sector. However, concerns have been raised by the conservation profession about applying temperature based pest treatments to polyamide 6,6, due to the changes in thermal properties known to occur over the range of temperatures in question. Unaged and artificially aged polyamide 6,6 fibres were subjected to creep/recovery experiments using dynamic mechanical analysis at temperatures ranging from 58 °C to −30 °C. These experiments were carried out on loaded samples to determine whether textile material would suffer deterioration if treated whilst hanging under load, for example on a mannequin. Samples were analysed before and after loading by attenuated total reflectance Fourier-transform infrared spectroscopy, differential scanning calorimetry and tensile testing to investigate the chemical and physical alterations in the polyamide 6,6 fabric subject to treatment. Samples loaded at room temperature exhibited permanent contraction, attributed to strain induced crystallization. For both the unaged and aged samples at elevated temperatures the samples underwent permanent deformation. Samples treated at sub-ambient temperatures recovered to their original length during the recovery section of the creep test, although some structural alterations were evident during subsequent analysis. The results suggest that the low temperature treatments of polyamide artefacts, particularly in the presence of stress, are preferable.

Thermodynamic study of selected monoterpenes II

A thermodynamic study of selected monoterpenes, (−)-borneol, (−)-camphor, (±)-camphene, and (+)-fenchone is presented in this work. The vapor pressure measurements were performed using the static method over the environmentally important temperature range from (238 to 308)K. Heat capacities of condensed phases were measured by Tian–Calvet calorimetry in the temperature interval from (258 to 355)K. The phase behavior was investigated by differential scanning calorimetry (DSC) from subambient temperatures up to the fusion temperatures. The thermodynamic properties in the ideal-gas state were calculated by combining statistical thermodynamic and density functional theory (DFT) calculations. Calculated ideal-gas heat capacities and experimental data for vapor pressures and condensed phase heat capacities were treated simultaneously to obtain a consistent thermodynamic description.

Evidence of low temperature relaxation and hopping in ion conducting polymer blend

Abstract We report sub-ambient dielectric relaxation and ion migration phenomena in a blend type solid polymer electrolyte based on PEO-PDMS-LiPF 6 . X-ray diffraction and scanning electron microscopy results indicate a possibility of blending between the two polymer components. It also confirmed the complexation between polymer blend and salt. Dielectric behavior of the blend electrolytes exhibits a dispersive response with clear evidence of α-relaxation at ambient and sub-ambient (30 °C to − 30 °C) temperatures. This has further been corroborated by clear relaxation peak in the modulus spectra that changes its position from lower to higher side on the frequency scale with rise in temperature irrespective of salt concentration. It is also noted that the electrolytes having higher salt concentration (O/Li ~ 10) exhibit long range ion migration in the low frequency limits (≤ 10 5 Hz) followed by short range ion migration in high frequency range (≥ 10 5 Hz). The latter occurs via hopping of charge carriers under thermal activation. Evidence of temperature dependent relaxation time distribution has also been noted. The dynamics of charge transport is dependent on salt concentration. Higher the salt concentration, faster is the transport process.

ChemInform Abstract: Advances in Low Temperature Gas‐Phase Kinetics

AbstractReview: 147 refs.

Resolving Individual Solute Levels of AA6061 through Multiple Sub-Ambient Temperatures Thermoelectric Power Measurements

This work concentrates on assessment of the TEP change of AA6061 during isothermal aging at 177 °C and the following interrupted aging at 65 °C. The results show that the TEP is sensitive to follow the microstructural changes undergone during all aging stages. Multiple sub-ambient temperature dependences TEP of binary Al-X alloys as well as the AA6061 subjected to the above mentioned heat treatments were undertaken. The solute level of individual element of the alloy, particularly those contributing to the clustering/precipitation, can be extracted and evaluated.

Resolving Individual Solute Levels of AA6061 through Multiple Sub-Ambient Temperatures Thermoelectric Power Measurements

Resolving Individual Solute Levels of AA6061 through Multiple Sub-Ambient Temperatures Thermoelectric Power Measurements

Modeling dendrite growth during lithium electrodeposition at sub-ambient temperature

Increased propensity for dendritic lithium electrodeposition during sub-ambient temperature operation has been widely reported in lithium battery systems, yet is not fully understood. In the present paper, a mathematical model is developed to quantify the dendritic growth rate during lithium electrodeposition at sub-ambient temperature. This model builds on a diffusion–reaction framework presented recently by Akolkar [J. Power Sources 232 (2013) 23–28]. Using a steady-state diffusion model with a concentration-dependent diffusion coefficient, the lithium-ion concentration depletion in the stagnant Nernst diffusion boundary layer near the lithium surface is modeled. A surface electrochemical reaction model is then employed to correlate the lithium concentration depletion to the dendrite growth rate. Temperature effects on the lithium-ion transport and its electrochemical surface reaction are incorporated in the model via an Arrhenius-type temperature-dependence of the diffusion coefficient and the apparent charge transfer coefficient. It is shown that lowering the system temperature has the effect of increasing the lithium-ion diffusion resistance and decreasing the surface film thickness – conditions favorable for the formation of dendrites during lithium electrodeposition.

Molecular Shape Selectivity for Polycyclic Aromatic Compounds on a Core–Shell Octadecylsilica Stationary Phase at Subambient Column Temperatures

Molecular shape selectivity for polycyclic aromatic compounds on a core–shell-type octadecylsilica (ODS) phase at subambient column temperatures was studied in reversed-phase liquid chromatography. The plate height on the core–shell ODS column was relatively stable at subambient column temperatures when compared with that of a conventional ODS column. In order to compare the sample diffusivities in the conventional and core–shell ODS columns, van Deemter plots were prepared. The plate height of the core–shell column was significantly lower than that of conventional column, suggesting an advantageous feature of the core–shell-type stationary phase especially at a high flowrate of the mobile phase. An enhanced molecular shape recognition capability of the core–shell ODS phase was also confirmed at subambient column temperature. The result could be consistent with an improved shape selectivity as normally observed on conventional ODS phases at low temperatures, however, the enhanced molecular shape recognition capability of the core–shell phase enables a good separation between benz[a]anthracene and chrysene at subambient column temperatures. Similar improved shape selectivities for terphenyl isomers were also confirmed on the core–shell phase.

Exploring low temperature Li+ ion conducting plastic battery electrolyte

We report blend-based plastic polymer electrolyte (i.e., polyethylene oxide (PEO)–polydimethyl siloxane (PDMS)–lithium hexafluorophosphate (LiPF6)) with substantial improvement in DC conductivity at ambient and subambient temperatures when compared with literature reports. Conductivity variation with salt concentration, investigated within ±30 °C range, indicates an optimum conductivity of 5.6 × 10−5 S cm−1 at 30 °C for O/Li ~10 with a further lowering by one order at 0 °C and it remains unaltered at −10 °C. Enhanced conductivity in this blend electrolyte, though lower than two copolymer counterparts, is attributed to very low glass transition temperatures of the host polymers. X-ray diffraction (XRD) and scanning electron microscopy (SEM) suggest an effective blending between the two polymers with an effective interaction between the Li salt and the blend polymer matrix. Raman spectroscopy results indicated that cation (Li+) coordination occurs at the C=O site in PEO out of the two electron-rich sites (i.e., CO and Si–O–Si) in the PEO–PDMS blend. The blend electrolytes are predominantly ionic (t ion ~97 %).