Ionic Conductivity Properties Research Articles

Quasi-Solid-State Lithium-Sulfur Batteries Consist of Super P – Sulfur Composite Cathode

Lithium-Sulfur (Li-S) batteries stand out to be one of the most promising candidates to meet the current energy storage requirement, with its natural abundance of materials, high theoretical capacity of 1672 mAhg-1, high energy density of 2600 Whkg-1, and low cost and lower environmental impact. Sulfur itself (S8), Li2S2 and Li2S formed during the discharge process, are electrical insulators and hence reduce the active material utilization and the electronic conductivity of the cathode affecting the battery performance. Combining of Carbon Super P (SP) with sulfur in cathode formulation is used to overcome these issues. In Liquid electrolyte batteries, polysulfides formed while charging and discharging, easily dissolve in liquid electrolyte and the resulting polysulfide shuttling leads to poor coulombic efficiency and cyclability. Liquid electrolytes used in the conventional Li-S batteries are easy to flow and become flammable. Further, Lithium dendrites piercing through separator causing short circuit paths leads to safety concerns. Replacement of the liquid electrolyte by a solid-state electrolyte (SSE) proves to be a strategy to overcome above mentioned issues. Sulfide based solid electrolytes have received greater attention due to their higher ionic conductivity, compatible interface with sulfur-based cathodes, and lower grain boundary resistance. Novel Li6PS5F0.5Cl0.5 due to its remarkable ionic conductivity of 3.5 x 10-4 S cm-1 makes it an excellent candidate for use in a Li-S solid state battery. However, the interface between SSEs and cathodes has become a challenge to be addressed in all solid-state Li-S batteries due to the rigidity of the participating surfaces. A hybrid electrolyte containing of SSE coupled with a small amount of ionic liquid at the interface, has been employed to improve the interface contact of the SSE with the electrodes.Cathode formulation consisting of sulfur as the active material, Super P as the conductive carbon black, acetylene carbon black as conductive carbon additive, with water based carboxymethyl cellulose (CMC) solution and Styrene butadiene rubber (SBR) as the binder was successfully developed. Thermo gravimetric analysis (TGA) studies of the cathode were carried out by the thermo gravimetric analyzer TA 2050 under N2 gas flow of 100 ml/min. Cathode surface morphology was characterized using the Field emission gun scanning electron microscope (FEI), TESCAN scanning electron microscope with energy dispersive X-ray spectroscopy (EDAX). Using a solvent-based process, Li6PS5F0.5Cl0.5 and Li6PS5F0.5Cl2 SSE were synthesized via the introduction of LiF into the argyrodite crystal structure, which enhances both the ionic conductivity and interface-stabilizing properties of the SSE. Relevant Ionic Liquids (IL) were prepared using Lithium bis(trifluoromethyl sulfonyl)imide (LiTFSI) as salt, with premixed pyrrolidinium bis(trifluoromethyl sulfonyl)imide (PYR) as solvent and 1,3-dioxolane (DOL) as diluent.SP-S cathode with 0.70 mgcm-2 sulfur loading was punched into disks of 2.0 cm2. SSE was pressed into 150 mg pellets using a stainless-steel tank. During the assembly, SSE was wetted with total of 40 μl of IL (LiTFSI dissolved in PYR and DOL solution) from both ends using a micropipette. 2032 type coin cells of Quasi-solid-state Li-S batteries (QSSLSB) consisting of SP-S based composite cathodes, Li anodes and novel Li6PS5F0.5Cl0.5 SSE were tested with an ionic liquid wetting both electrode-SSE interfaces. All the QSSLSB were cycled at 30 °C between 1.0 V and 2.8 V using an 8 channel Arbin battery testing system.Effect of IL dilution, co-solvent amount, LiTFSI concentration and C rate at which the batteries are tested, were systematically studied and optimized to develop a QSSLSB with higher capacity retention and cyclability. Optimum batteries had initial discharge capacity >1100 mAh/g and discharge capacity >400 mAh/g after 100 cycles at the C rate of C/10 with a significant coulombic efficiency. 40 μl of LiTFSI (2M) dissolved in PYR:DOL(1:1) IL was found to be optimum for high performance QSSEBs with low sulfur loading of 0.7 mg/cm2. From the C rate performance study QSSEBs have shown improved stability with the higher current rates. Next, cathodes with higher sulfur loading were studied and for sulfur loading > 4 mgcm-2, initial discharge capacity >950 mAh/g and 400 mAh/g after 60 cycles at C/20 rate were achieved with 40 μl of IL consisting of LiTFSI (3M) dissolved in PYR:DOL(1:3) for the SSE Li6PS5F0.5Cl2. Further testing is underway to improve the performance at high C rate for higher loading by incorporating SSE in the cathode to realize QSSLSB with higher capacity with improved cycle retention.

Doped superior garnet electrolyte toward all-solid-state Li metal batteries

Li7La3Zr2O12 (LLZO) garnets are one of the most promising solid electrolytes for next generation all-solid-state Li metal batteries due to their high ionic conductivities, chemical stabilities to metallic lithium and wide electrochemical window. Single and co-doped LLZO with Ga, Al, Nb were prepared by solid state reaction and sintered under oxygen atmosphere. Lithium ion conduction properties were investigated through electrochemical impedance spectroscopy in the temperature range of −25 °C–45 °C. Among the doped compositions, Ga doped single phase cubic LLZO shows the highest ionic conductivity of 1.49 × 10−3 S/cm at room temperature and activation energy of 0.27eV, which is one of the best results reported in literature so far in terms of doped garnet structured LLZO. All single or co-doped LLZO samples exhibit low electronic conduction which are 4–5 orders of magnitude lower than their corresponding ionic conductivities. Ga-doped garnet LLZO of high ionic conductivity and negligible electronic conduction makes it a superior solid electrolyte for all-solid-state Li metal batteries.

High Performance Carbon Fiber Structural Batteries Using Cellulose Nanocrystal Reinforced Polymer Electrolyte.

In recent years, structural batteries have received great attention for future automotive application in which a load-bearing car panel is used as an energy storage. However, based on the current advances, achieving both high ionic conductivity and mechanical performance has remained a challenge. To address this challenge, this study introduces a cellulose nanocrystal (CNC) reinforced structural battery electrolyte (CSBE) consisting of CNC, triethylene glycol dimethyl ether (TriG) electrolyte containing a quasi-solid additive, e.g., cyclohexanedimethanol (CHDM), in a vinyl ester polymer. This green and renewable CSBE electrolyte system was in situ polymerized via reaction induced phase transition to form a high performance multidimensional channel electrolyte to be used in structural carbon fiber-based battery fabrication. The effect of various concentrations of CNC on the electrolyte ionic conductivity and mechanical properties was obtained in their relation to intermolecular interactions, interpreted by FTIR, Raman, Li NMR results. Compared to the neat SBE system, the optimized CSBE nanocomposite containing 2 wt % CNC shows a remarkable ionic conductivity of 1.1 × 10-3 S cm-1 at 30 °C, which reveals ∼300% improvement, alongside higher thermal stability. Based on the FTIR, Raman, Li NMR results, the content of CNC in the CSBE structure plays a crucial role not only in the formation of cellulose network skeleton but also in physical interaction with polymer matrix, providing an efficient Li+ pathway through the electrolyte matrix. The carbon fiber composite was fabricated by 2 wt % CNC reinforced SBE electrolyte to evaluate as a battery half-cell. The results demonstrated that by addition of 2 wt % CNC into SBE system, 7.6% and 33.9% improvements were achieved in specific capacity at 0.33 C and tensile strength, respectively, implying outstanding potential of ion conduction and mechanical load transfer between the carbon fibers and the electrolyte.

Optimization of Ionogel Polymer Electrolytes Composition for Their Best Performance in Electric Double Layer Capacitor

AbstractThe application of a gel polymer electrolyte (GPE) in electrochemical devices such as batteries, electrochemical double layer capacitors (EDLCs), and others is a known topic in the literature. However, GPE with improved ionic conductivity and better mechanical properties are highly desired. In this work, ionogel polymer electrolytes (IGPEs) were synthesized by photopolymerization of a mixture of monomers: aliphatic urethane diacrylate, 1,3,5‐triallyl‐1,3,5‐triazine‐2,4,6(1H,3H,5H)‐trione, trimethylolpropane triacrylate, pentaerythritol tetrakis(3‐mercaptopropionate) in 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide (EMImNTf2). The influence of the monomer ratio on the ionic conductivity and mechanical properties of IGPEs was studied. A mathematical model was used to optimize the composition to obtain ionogel with the best compromise between investigated properties. The optimal composition was synthesized and used in EDLC, characterized by higher volumetric capacity, power, and energy density. To the best of our knowledge, this is the first publication that demonstrates the application of optimization methods for the preparation of IGPEs.

Buffering Volume Change in Solid-State Battery Composite Cathodes with CO2-Derived Block Polycarbonate Ethers.

Polymers designed with a specific combination of electrochemical, mechanical, and chemical properties could help overcome challenges limiting practical all-solid-state batteries for high-performance next-generation energy storage devices. In composite cathodes, comprising active cathode material, inorganic solid electrolyte, and carbon, battery longevity is limited by active particle volume changes occurring on charge/discharge. To overcome this, impractical high pressures are applied to maintain interfacial contact. Herein, block polymers designed to address these issues combine ionic conductivity, electrochemical stability, and suitable elastomeric mechanical properties, including adhesion. The block polymers have “hard-soft-hard”, ABA, block structures, where the soft “B” block is poly(ethylene oxide) (PEO), known to promote ionic conductivity, and the hard “A” block is a CO2-derived polycarbonate, poly(4-vinyl cyclohexene oxide carbonate), which provides mechanical rigidity and enhances oxidative stability. ABA block polymers featuring controllable PEO and polycarbonate lengths are straightforwardly prepared using hydroxyl telechelic PEO as a macroinitiator for CO2/epoxide ring-opening copolymerization and a well-controlled Mg(II)Co(II) catalyst. The influence of block polymer composition upon electrochemical and mechanical properties is investigated, with phosphonic acid functionalities being installed in the polycarbonate domains for adhesive properties. Three lead polymer materials are identified; these materials show an ambient ionic conductivity of 10 –4 S cm–1, lithium-ion transport (tLi+ 0.3–0.62), oxidative stability (>4 V vs Li+/Li), and elastomeric or plastomer properties (G′ 0.1–67 MPa). The best block polymers are used in composite cathodes with LiNi0.8Mn0.1Co0.1O2 active material and Li6PS5Cl solid electrolyte–the resulting solid-state batteries demonstrate greater capacity retention than equivalent cells featuring no polymer or commercial polyelectrolytes.

Effects of different glass formers on Li2S–P2S5–MS2(M = Si, Ge, Sn) chalcogenide solid‐state electrolytes

AbstractChalcogenide solid‐state electrolytes (SSEs) have been receiving growing attentions due to their high ionic conductivity and suitable mechanic properties, especially the Li2S–P2S5systems incorporated with a second glass network formers (Si, Ge, Sn, and so on) besides P. Although the ionic conductivities are generally enhanced with the second glass network formers, the comprehensive effects of different glass formers on other properties, including electrochemical, cycling, and air stability, remain elusive. To acquire deeper understanding, herein, three common but representative glass network formers (SiS2, GeS2, and SnS2) were introduced into Li2S–P2S5, and their individual effects were investigated systematically. The results of multiscale characterizations before and after lithium stripping/plating cycling confirmed that the introduction of metal cations (Ge, Sn) generally leads to worse electrochemical stability and shorter cycle life of these SSEs toward lithium metal compared with SSEs with nonmetal cation (Si) modification. However, the air stability is related to the binding energy of M–S (M = Si, Ge, Sn), which is consistent with the hard base soft acid theory. This work provides valuable understanding for designing pragmatic Li2S–P2S5–MS2‐based SSEs with high electrochemistry, cycling, and air stability.

Printing of self-healable gelatin conductors engineered for improving physical and electrical functions: Exploring potential application in soft actuators and sensors

Significant efforts have been devoted to developing dielectric elastomer actuators owing to their mechanical flexibilities, silent operation, and muscle-like performances. However, it still remains a challenge to demonstrate the actuators that maintain function when subjected to damage because most soft materials constituting such devices are vulnerable to mechanical stresses during repeated operation. Here, self-healable electrodes suitable for dielectric elastomer actuators were prepared from an eco-friendly gelatin-based composite including conductive ions and hydrogen bonds. Electrohydrodynamic printing was used to reproducibly fabricate a custom-made electrode with desired geometry. The printed gelatin-based electrodes were attached onto elastomers to fabricate dielectric elastomer actuators. The devices exhibited good actuator operation and, owing to the self-healing capability of the gelatin-based electrodes, almost fully recovered their performances with an efficiency of up to 96.8% even after the electrodes were damaged. Furthermore, the potential application of the gelatin-based electrode was explored by using them as a strain sensor; this sensor showed a sensitive dependence of electrical resistance on external joint movements. We believe this work provides a useful guideline for designing self-healable conductive composites that can be effectively used to make printed actuators and sensors endowed with good ionic conductivity and useful mechanical properties.

Atomistic modeling of LiF microstructure ionic conductivity and its influence on nucleation and plating

The formation and degradation of the solid electrolyte interphase (SEI) and its underlying transport properties play an essential role in the overall performance of lithium-ion batteries. This paper presents classical molecular dynamics studies on polycrystalline inorganic lithium fluoride (LiF) layers to model and predict the SEI transport properties. The ionic conductivity is obtained from the lithium-ion diffusivity in polycrystalline structures of LiF using the Nernst-Einstein relation. The predicted molecular dynamics data are used in a continuum scale phase-field model to evaluate the plating kinetics under fast charging conditions. The analysis emphasizes that the SEI ionic conductivity properties impact the plating dynamics, where SEI's low ion conductivity value is prone to large plating and subsequent capacity degradation. The combination of atomic and continuum scale studies shown herein lays a foundation to tune in SEI transport properties to decrease the amount of lithium plating and improve the performance of fast-charging batteries.

Biodegradable and highly conductive polymeric blend based on the latex of Calotropis gigantea as solid electrolyte in energy storage applications

A blend polymer based on the latex of the South-Asian giant milkweed Calotropis gigantea (CGL) combined with poly (vinylidene fluoride)-co-hexafluoropropylene (PVDF-HFP) at a mass ratio of 1:1 without the addition of doping salts was synthesized via solution casting to prepare an ionic conductive film. The morphology, crystalline state, vibrational and thermal properties of the film were investigated by Scanning electron microscopy, X-ray diffraction, Fourier Transform infrared spectroscopy (FTIR), Thermal gravimetric analysis (TGA) and Differential scanning calorimetry (DSC). The ionic conductivity and transport properties were investigated by using electrochemical impedance spectroscopy (EIS) Technique. Due the highest ionic conductivity at room temperature (2.7 x 10−2 S/cm), all-solid-state electrolyte was assembled using the prepared polymer film and a comparative study was conducted with respect to 1M H2SO4 liquid electrolyte, regarding the specific capacitance and the electrical properties. The results demonstrate that the fabricated all-solid-state supercapacitor using PVDF-HFP/CGL blend polymer film as electrolyte matches the performance of the liquid electrolyte.

Main‐chain liquid‐crystalline polymers bearing different anion

ABSTRACT In this paper, d-camphoryl chloride, terephthaloyl chloride, hydroquinone and 2,3-dibromosuccinyl chloride were used as raw materials to synthesise the main-chain liquid crystalline polymers by condensation polymerisation. A series of main-chain ionic liquid crystalline polymers with triphenylphosphine as the cationic group were successfully prepared by grafting triphenylphosphine onto the liquid crystalline polymer. By characterisation, we found that the main chain ionic liquid crystal polymer containing quaternary phosphonium ions had low glass transition temperature, high ionic conductivity and strong antibacterial properties. The quaternary phosphonium ions-containing main-chain ionic liquid-crystalline polymers show Smectic A phase, and the main-chain liquid crystalline polymers show nematic phase. The antibacterial experiments showed that the quaternary phosphonium ions-containing main-chain ionic liquid-crystalline polymers had good antibacterial properties, and the antibacterial ability of the polymer was also enhanced with the increase of phosphorus content. In addition, the orientation structure of liquid crystal also had a significant influence on its antibacterial properties.

Design of co-continuous structure of cellulose/PAA-based alkaline solid polyelectrolyte for flexible zinc-air battery

In order to prepare high ionic conductivity and robust mechanical properties of alkaline solid polyelectrolyte (ASPE) for applications in flexible wearable devices, a co-continuous structure membrane was designed using in-situ polymerization to introduce cross-linked polyacrylic acid (N-PAA) into the cellulose network constructed by regenerated degreasing cotton (RDC). The resultant ASPE membrane showed high ionic conductivity (430 mS·cm−1 at 25 °C), strong mechanical properties, and excellent alkaline stabilities, proving the viability of cellulose for use in energy storage systems. Surprisingly, the sandwich-shaped zinc-air battery assembled using RDC/N-PAA/KOH membranes as electrolytes exhibits superior values of cycling stability, discharge time, specific capacity (731.5 mAh·g−1), peak power density (40.25 mW·cm−2), and mechanical flexibility. Even under bending conditions, the zinc-air batteries still possess stable energy supply performance, suggesting this novel solid polyelectrolyte has promising application for wearable technology.

Rapid self‐healing and adhesion nanocomposite physical hydrogels based on dynamic coordination bond

AbstractIn this work, we developed a simple one‐pot strategy to prepare the self‐healing and adhesion nanocomposite hydrogel without crosslinking agent. The metal coordination bond between carboxyl group and Al3+ and the electrostatic interaction between carboxylate cellulose nanofibers (CNF) and quaternary ammonium xylan (QAX) had a positive influence on the mechanical strength of nanocomposite hydrogel, in which the maximum tensile strength and elongation at break of composite hydrogel were 31.1 kPa and 2971%, respectively. Meanwhile, the nanocomposite hydrogel exhibited rapid self‐healing properties, and the healing efficiency reached 95% within 2 h. In addition, the nanocomposite hydrogel possessed adhesion and could adhere to different materials. The hydrogel can detect the changes of human skin during the movement due to its ionic conductivity properties caused by addition of Al3+. We expect that this strategy may enrich the applications of biomass hydrogels in the field of wearable devices.

A cation-dipole-reinforced elastic polymer electrolyte enabling long-cycling quasi-solid-state lithium metal batteries

The application of ionic liquids (IL) in polymer electrolytes represents a safer alternative to the currently used organic solvents in lithium batteries due to their nonflammability and thermal stability. However, as a plasticizer, it is generally agreed that the introduction of ionic liquid usually leads to a trade-off between ion transport and mechanical properties of polymer electrolyte. Here we report the synthesis of an IL-embedded polymer electrolyte with both high ionic conductivity (2.77 × 10−4 S cm−1 at room temperature) and excellent mechanical properties (high tensile strength up to 11.4 MPa and excellent stretchability of 387% elongation at break) achieved by strong ion–dipole interactions between polymer electrolyte components, which was unveiled by the DFT calculation. Moreover, this polymer electrolyte also exhibits nonflammability, good thermal stability and the ability to recover reversibly from applied stress, i.e., excellent elasticity. This highly viscoelastic polymer electrolyte enables tight interfacial contact and good adaptability with electrodes for stable lithium stripping/plating for 2000 h under a current density of 0.1 mA cm−2. By coupling with this polymer electrolyte, the LiFePO4/Li cells exhibit outstanding cycling stability at room temperature as well as the reliability under extreme environmental temperature or being abused.

Comonomer-Tuned Gel Electrolyte Enables Ultralong Cycle Life of Solid-State Lithium Metal Batteries.

Rechargeable lithium metal batteries (LMBs) are considered the "holy grail" of energy storage systems. Unfortunately, uncontrollable dendritic lithium growth inherent in these batteries has prevented their practical applications. The benefits of solid-state electrolyte for LMBs are limited due to the common compromise between ionic conductivity and mechanical property. This work proposes a mechanism for simultaneous improvement in ionic conductivity and mechanical strength of gel polymer electrolyte (GPE) which is based on tunable cross-linked polymer network through adjusting monomer ratios. With increasing bisphenol A ethoxylate dimethacrylate (E2BADMA) and poly(ethylene glycol) diacrylate (PEGDA) mass ratios in GPE precursors, the formed polymer network experienced a composition evolution from a 3D cross-linked mono PEGDA network to triple PEGDA, E2BADMA, and PEGDA/E2BADMA networks and then to dual E2BADMA and PEGDA/E2BADMA networks, accompanied by the increase in both storage modulus (from 6 to 37 MPa) and ionic conductivity (from 0.06 to 0.44 mS cm-1). As a result, the E2BADMA/PEGDA mass ratio of 2:1 facilitates the successful fabrication of a dual-network-supported GPE (PEEPL-12) with a mechanical strength of 37 MPa and superior electrochemical properties (a high ionic conductivity of 0.44 mS cm-1 and a wide electrochemical stability window of 4.85 V vs Li/Li+). Such polymer electrolyte-based symmetric lithium metal batteries delivered a long cycle life (2000 h at 0.1 mA cm-2 and 0.1 mAh cm-2), and the Li|PEEPL-12|LiFePO4 cell delivered a high capacity of 140 mAh g-1 at the 100th cycle at the current density of 0.1 C (1 C = 170 mAh g-1). A more thorough investigation indicated the formation of a stable solid electrolyte interphase layer on a lithium metal anode. These extraordinary features open up a venue for fabrication of advanced polymer electrolyte for long-cycle-life lithium metal batteries.

Revealing Fast Cu-Ion Transport and Enhanced Conductivity at the CuInP2S6-In4/3P2S6 Heterointerface.

Van der Waals layered ferroelectrics, such as CuInP2S6 (CIPS), offer a versatile platform for miniaturization of ferroelectric device technologies. Control of the targeted composition and kinetics of CIPS synthesis enables the formation of stable self-assembled heterostructures of ferroelectric CIPS and nonferroelectric In4/3P2S6 (IPS). Here, we use quantitative scanning probe microscopy methods combined with density functional theory (DFT) to explore in detail the nanoscale variability in dynamic functional properties of the CIPS-IPS heterostructure. We report evidence of fast ionic transport which mediates an appreciable out-of-plane electromechanical response of the CIPS surface in the paraelectric phase. Further, we map the nanoscale dielectric and ionic conductivity properties as we thermally stimulate the ferroelectric-paraelectric phase transition, recovering the local dielectric behavior during this phase transition. Finally, aided by DFT, we reveal a substantial and tunable conductivity enhancement at the CIPS/IPS interface, indicating the possibility of engineering its interfacial properties for next generation device applications.

Solvate ionic liquid-based ionogels for lithium metal batteries over a wide temperature range

Ionogels for lithium metal batteries are usually obtained by immobilization of lithium salt-containing ionic liquids using linear polymers as gelator, which are thermally unstable and lack of adhesion. Meanwhile, the two-cation (ionic liquid cation and lithium ion) competition results in low lithium-ion transference number. In this work, we designed novel ionogels by in situ UV radiation-induced chemically crosslinked polymerization of butyl acrylate in a solvate ionic liquid ([Li(G4)][TFSI]) without additional lithium salt. The obtained ionogels (IG-m/n, m/n is the weight ratio between butyl acrylate and solvate ionic liquid) exhibit nonflammability, favorable thermal and mechanical features, high ionic conductivity, wide electrochemical window, and interestingly adhesive ability that provides an intimate contact with the Li anode. Consequently, one of the ionogels, IG-1/2, owing to its optimized adhesion, ionic conductivity, and mechanical property, could endow the as-fabricated Li|IG-1/2|LiFePO4 cells with high cyclability and Coulombic efficiency at room temperature, 90 °C, and 150 °C.

In-situ polymerized polyacrylamide/magnesium phosphate cement electrolyte for structural supercapacitor

Organic/inorganic composite electrolytes can effectively avoid contradictory relationship between ionic conductivity and mechanical properties as well as poor interfacial contact of electrode/solid electrolyte. However, direct mixing of organic/inorganic materials leads to low dosage and poor dispersion of polymers owing to macromolecular chains. Herein, we firstly prepare polyacrylamide/magnesium phosphate cement (PAM/MPC) electrolytes via in-situ polymerization during cement hydration. The weight average molecular weight of polymerized PAM in MPC paste is around 1500 with high concentrated degree of molecular weight distribution. As the dosage of acrylamide (AM) increases to 40 %, polymerized PAM completely interpenetrates into MPC matrix. The composite electrolyte possesses the optimum multifunctionality with ionic conductivity of 54 mS cm−1 and compressive strength of 30.2 MPa, corresponding structural supercapacitor (SSC) can obtain high specific capacitance of 32.0 F g−1 and energy density of 4.4 Wh kg−1. With the lowest equivalent series resistance, the resulted SSC with 10 % AM exhibits the best energy storage properties with energy density of 5.4 Wh kg−1 and power density of 1600 W kg−1. Hopefully, SSC via in-suit polymerization in MPC paste can be integrated with solar panels to generate and store energy in building structures.

Adamantane-based block poly(arylene ether sulfone)s as anion exchange membranes

Current anion exchange membranes (AEMs) for fuel cells suffer from low ionic conductivity and poor mechanical property. Herein, we introduce adamantane groups onto the block poly(arylene ether sulfone)s backbone to form the selected comb-shaped structure. The structure-property relationships of the AEMs are investigated by varying the ratio of the hydrophobic to hydrophilic segments. The bulk rigid adamantane group can restrain the swelling of the AEMs thus enhancing the mechanical properties and expand the spacing between the hydrophilic/hydrophobic segments of the polymer chains to promote the formation of microphase separation morphology. Consequently, as characterized by atomic force microscope (AFM) and transmission electron microscopy (TEM), the resulting membranes show well-defined microphase separation between the hydrophilic/hydrophobic segments, resulting in high ionic conductivity range from 27.4 to 90.2 mS cm −1 over a temperature range of 30–80 °C. At the same time, the membranes present ultralow swelling ratio with the levels from 1.6% to 6.1% at 30 °C and from 6.8% to 12.7% at 80 °C, respectively, and thus excellent mechanical properties with the tensile strength as high as 11.52 MPa and elongation at break of 29.28%. The excellent comprehensive properties grant the prepared AEMs bright future for fuel cells. • A series of adamantane-based block poly(arylene ether sulfone)s AEMs was prepared. • Influence of hydrophobic chain segments on AEMs' properties and morphology was studied. • The AEMs showed well-defined microphase separation between the hydrophilic/hydrophobic segments. • The AEMs showed high hydroxide conductivity in the range of 27.4–90.2 mS cm −1 .

Low-viscosity quaternary ammonium-based ionic liquid electrolytes for lithium air batteries

• Ionic liquids are investigated as an electrolyte for Li-air batteries. • Low-viscosity ionic liquids with reduced molecular weight are synthesized. • High stability with a lithium metal electrode is demonstrated. Ionic liquids (ILs) have attracted significant attention as candidates for Li-air battery electrolyte solvents owing to their novel properties, such as non-volatility and low reactivity with lithium metal anodes. However, the main drawback of IL-based electrolytes is their high viscosity, which results in poor battery capacity and conductivity. In this study, we synthesized low-viscosity ILs with reduced molecular weights using the side-chain shortening method. In particular, the IL: trimethyl ethoxymethyl ammonium bis(fluoromethylsulfonyl)imide (N111(1O2) FSI), has a lower viscosity (111.4 cP) than that of the electrochemically stable reference material, diethylmethyl (2-methoxyethyl) ammonium bis(fluoromethylsulfonyl)imide (DEME FSI; viscosity of 131.1cP). The use of the optimal IL, N111(1O2) FSI, resulted in an initial capacity 3.75 times higher than that obtained using DEME FSI in the cell test. The chemical stability of N111(1O2) FSI with lithium metal was confirmed by microstructure analysis of the lithium surface. The physicochemical properties, such as viscosity, ionic conductivity, melting point, and electrochemical properties, were thoroughly characterized.

2-HYDROXYETHYL CELLULOSE-AMMONIUM THIOCYANATE SOLID BIOPOLYMER ELECTROLYTES: IONIC CONDUCTIVITY AND DIELECTRIC STUDIES

There is demand for application of polymer materials in electrochemical devices, especially natural polymers, because of their superiority in mechanical integrity, affordability and biodegradability. In this work, solid biopolymer electrolyte (SBEs) comprising 2-hydroxyethyl cellulose (2-HEC) doped with different weight percentage of ammonium thiocyanate, NH4SCN (0 – 44 wt.%) were prepared using a facile solution casting technique. The effects of NH4SCN on ionic conductivity and dielectric properties of SBEs were investigated using electrochemical impedance spectroscopy (EIS). The ionic conductivity recorded at room temperature showed massive improvement for pure 2-HEC from the value of 5.93 x 10-8 S cm-1 to 1.16 ×10-4 S cm-1, comprising 36 wt.% NH4SCN. Meanwhile, at elevated temperatures, the ionic conductivity revealed the Arrhenius behaviour, where it increased proportional to the temperatures. In addition, by introducing NH4SCN content as a proton donor, it also effectively reduced the activation energy of the SBEs, which further support enhancing the ionic conductivity. In dielectric permittivity study, the εr and εi increased as the NH4SCN content increased, revealing the non-Debye dependency of the SBEs, which indicates that the SBEs are ionic conductors. The addition of the optimum value of NH4SCN content showed good characteristic for electrochemical devices applications.