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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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At least 991 records · Page 55
All sourcesNASA NTRSDOE OSTI
NASA NTRS2004

Preparation of Proton Exchange Membranes and Lithium Batteries from Melamine-containing Ormosils

Our laboratory has recently reported a series of rodcoil polymers for lithium batteries that display dimensionally stable films with good ionic conductivity. The rod segments consist of rigid linear and branched polyimides and the coil segments are polyethylene oxides (PEO). It has been proposed that good mechanical and transport properties are due to phase separation between the rod and coil segments. It was also observed that increased branching and molecular weight lead to increased conductivity. The following study was undertaken to assess the effects of phase separation in polyalkylene oxides connected by melamine linkages. Melamine was chosen as the linking unit because it provides a branching site, cation binding sites to help ionic transport between polymer chains, and the opportunity for self assembly through hydrogen bonding. Polymers were made by the reaction of cyanuric chloride with a series of amine-terminated alkylene oxides. A linear polymer was first made, followed by reaction of the third site on cyanuric chloride with varying ratios of monofunctional Jeffamine and (3-aminopropyl)triethoxysilane. The lithium trifluoromethane sulfonamide-doped polymers are then crosslinked through a sol-gel process to form free-standing films. Initial results have shown mechanically strong films with lithium conductivities on the order of 2 x 10(exp -5) S/cm at ambient temperature. In a separate study, organically modified silanes (Ormosils) that contain sulfonic acid derivatized melamines have been incorporated into proton exchange membranes. The membranes are made by reaction of the primary amine groups of various ratios of melamine derivative and difunctional Jeffamine (MW = 2000) with the epoxide group of (3-Glycidyloxypropyl)trimethoxysilane. The films were then cross-linked through a sol-gel process. Resulting sulfuric acid doped films are strong, flexible, and have proton conductivities on the order of 2 x l0(exp -2) S/cm (120 C, 25% relative humidity). Our best results have been observed when films contain 60% PEO and 40% sulfonated melamine.

Tigelaar, Dean M.↗
DOE OSTI2024

4 V Na Solid State Batteries Enabled by a Scalable Sodium Metal Oxyhalide Solid Electrolyte

All-solid-state sodium batteries (ASSSBs) are viable candidates for large scale energy storage that could vie with lithium. Ductile solid catholytes for such cells that can be prepared without extensive ball milling and directly paired with high voltage sodium cathodes are lacking, however. We report a new amorphous fast Na-ion conducting metal oxychloride that meets these criteria, synthesized through a scalable and low-cost route based on a spontaneous solid-state reaction with simple short mixing and 100 °C annealing. It has an ionic conductivity of 1.2 mS·cm–1 and low activation energy of 0.31 eV. Due to its dual O2–/Cl– framework, it exhibits a high anodic potential of 4 V vs Na+/Na and good chemical/electrochemical compatibility with high voltage sodium cathode materials. ASSSBs consisting of the oxychloride solid electrolyte paired with a high voltage P2–Na2/3Ni1/3Mn2/3O2 cathode showed stable long-term cycling with a 4.0 V vs Na3Sn cutoff potential and even to 4.3 V.

solid-state electrolyte, solid-state batteries, Nu↗
DOE OSTI2025

Fast-Charging Li-Ion Battery Enabled by an Acetonitrile-Based Electrolyte

Fast charging remains a critical challenge for current-generation lithium-ion batteries (LIBs), particularly in electric vehicle applications. Here, in this study, we present a highly conductive electrolyte formulation based on a ternary solvent system consisting of acetonitrile (AN), fluoroethylene carbonate (FEC), and ethylene carbonate (EC), combined with a tailored additive, lithium difluoro­(oxalato)­borate (LiDFOB). This electrolyte demonstrates significantly enhanced ionic conductivity and a higher Li + transference number, enabling accelerated Li + transport kinetics. The synergistic effect of the solvents and the additive promotes the formation of a robust, low-resistance, inorganic-rich solid-electrolyte-interphase (SEI) that effectively passivates the graphite surface and suppresses AN decomposition. As a result, the electrolyte substantially reduces internal cell resistance and overpotential, both of which are critical for reliable fast charging. These findings highlight the essential role of rational electrolyte design in addressing the limitations of fast-charging LIBs.

Wu, Dezhen [Argonne National Laboratory (ANL), Arg↗
DOE OSTI2025

Machine-Learning-Guided Insights into Solid-Electrolyte Interphase Conductivity: Are Amorphous Lithium Fluorophosphates the Key?

Despite decades of study, the identity of the dominant Li + -conducting phase within the inorganic SEI of Li-ion batteries remains unresolved. While the mosaic model describes LiF/Li 2 O/Li 2 CO 3 nanocrystallites within a disordered matrix, these crystalline phases inherently offer limited ionic conductivity. Growing evidence suggests that interfaces, grain boundaries, and amorphous phases may instead host the primary fast-ion pathways. Using diffusion-based generative structure prediction and machine-learning interatomic potentials (MLIPs), we investigate lithium difluorophosphate (LiPO 2 F 2 ), a key mixed-anion decomposition product of phosphorus- and fluorine-containing electrolytes. We identify a stable crystalline polymorph and demonstrate that the amorphous counterpart is conductive, with projected room-temperature σ ≈ 0.18 mS cm –1 and E a ≈ 0.40 eV. Here, this enhancement stems from structural disorder flattening the Li site-energy landscape and a low formation energy for Li-interstitial defects, which supplies additional mobile carriers. We propose amorphous mixed-anion Li-P-O-F phases as a promising conducting medium in the SEI, offering a specific target for engineering improved battery interfaces.

Zhong, Peichen [University of California, Berkeley↗
DOE OSTI2023

Fuel cell and electrolyzer hotbox module using conductive zirconia stacks

Modular pressurized hotbox for use and substitution in a variety of pressurized electrochemical applications to include reversible solid oxide electrolyzer and fuel cells, energy storage systems, renewable fuel production, solid-state hydrogen pumping and liquefaction, and oxygen transport membranes. This is enabled by mixed electronic and ionic conducting compositions of vanadia-yttria and vanadia-calcia stabilized zirconia and a dry powder method of manufacture for ceramic core stacks.

McLarty, Dustin↗
DOE OSTI2020

Alignment of Polarization against an Electric Field in van der Waals Ferroelectrics

Polarization in ferroelectrics can be switched in the direction of an applied electric field by dipole reorientation, enabling numerous applications and fundamental phenomena. In this study, we demonstrate that, in the van der Waals (vdW) layered ferrielectric Cu In P 2 S 6 , a unique mechanism exists where polarization aligns against the direction of the applied electric field, seemingly in violation of the fundamental properties of a dipolar solid. The mechanism is the result of the electric field driving the Cu atoms unidirectionally across the vdW gaps, which is distinctively different from dipole reorientation. The crossing of Cu atoms is the fundamental process of ionic conductivity, yet it is compatible with the existence of polarization. These phenomena are confirmed by nanoscale imaging and spectroscopy of ferroelectric capacitors, coupled with dynamic density-functional-theory simulations. The symbiotic relationship of ferroelectric and ionic phenomena enables alternative approaches to control polarization and necessitates a change in perspective on nucleation, domain-wall dynamics, and other ferroelectric and electromechanical characteristics in material systems where ionic and ferroelectric phenomena manifest.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2011

Ionic liquids and ionic liquid acids with high temperature stability for fuel cell and other high temperature applications, method of making and cell employing same

Disclosed are developments in high temperature fuel cells including ionic liquids with high temperature stability and the storage of inorganic acids as di-anion salts of low volatility. The formation of ionically conducting liquids of this type having conductivities of unprecedented magnitude for non-aqueous systems is described. The stability of the di-anion configuration is shown to play a role in the high performance of the non-corrosive proton-transfer ionic liquids as high temperature fuel cell electrolytes. Performance of simple H.sub.2(g) electrolyte/O.sub.2(g) fuel cells with the new electrolytes is described. Superior performance both at ambient temperature and temperatures up to and above 200.degree. C. are achieved. Both neutral proton transfer salts and the acid salts with HSO.sup.-.sub.4 anions, give good results, the bisulphate case being particularly good at low temperatures and very high temperatures. The performance of all electrolytes is improved by the addition of a small amount of involatile base of pK.sub.a value intermediate between those of the acid and base that make the bulk electrolyte. The preferred case is the imidazole-doped ethylammonium hydrogensulfate which yields behavior superior in all respects to that of the industry standard phosphoric acid electrolyte.

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

Enhancing the capacitive performance of microporous materials with protic ionic liquids

Classical density functional theory (cDFT) is used to investigate the electrosorption of protic ionic liquids in porous electrodes within the framework of a coarse-grained model. The purpose of this study is to clarify the capacitive behavior of protic ionic liquids in confined geometry. Previous studies have indicated that thermodynamic properties (e.g., capacitance, phase behavior and ionic conductivity) are influenced by the composition of the acid-base system and show asymmetry between acid dominant versus base dominant compositions. Here, we find that the electric double layer capacitance can be significantly improved by using protic ionic liquids compared to its aprotic counterpart through optimization of the mixture composition (i.e., the ratio of acid to base). We demonstrate the influence of pore size and applied voltage on the capacitance performance of protic ionic liquids and provide insight into microscopic understanding of ion and solvent distributions inside micropores.

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

On-Demand Designing of Cathode Internal Surface Architecture for Dramatic Enhancement of SOFC Performance and Durability

This project is aimed to design and modify the internal surfaces of porous composite cathode from currently commercially viable Solid Oxide Fuel Cells (SOFCs), using additive manufacturing process of Atomic Layer Deposition (ALD). The material systems being investigated are commercial composite electrodes complex three-dimensional topographies. In term of the chemistry of the ALD layer applied on the internal surface of the porous cathode, this project has employed commercially relevant electrolyte, electrocatalyst and noble metal materials set. Such materials are fully compatible with the commercial fuel cells, and this project has developed special nanostructure on the surface of the commercial composite cathodes. The formation of the designed nanoarchitecture on the surface of SOFC cathode has been achieved through precise control of ALD parameters and their effect on overall cell performance and resultant electrochemical reaction mechanism of cathodes has been investigated through full cell electrochemical performance testing and nanostructure characterization by transmission electron microscopy (TEM). Under the support of this award, following has been achieved: (1). For cathode materials in solid oxide fuel cells (SOFCs), such as perovskite mixed conductor La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-x (LSCF), cation surface segregation and consequently losing conductivity and active sites for the oxygen reduction reaction (ORR) are problematic. To mitigate the cation segregation and enhance SOFC durability, further decorating the internal backbone surface using the desired electrocatalysts could be a promoting approach. Commonly, the cation segregation such as Sr is very volatile, so the effective surface decoration is ideally conformal. Nevertheless, the conformal surface coating would inevitably alter the ORR pathways that initially take place on the surface of the backbone. To reveal the impact of the conformal coating on both the catalytic activity and the conductivity of the cathode, the unary electrocatalyst of Pt or CoO x , was applied to the LSCF/SDC composite electrode of inherently functional SOFCs, respectively. Both ALD coating layers evolve strong interaction with the LSCF composite cathode. Upon operations, the Pt coating layer remains conformal on LSCF grain surfaces but turns into discrete particles on SDC grain surfaces. Meanwhile, CoO x conformal coating grows to be the discrete nanograins on both the LSCF and SDC grains. ALD coating of the cathode alone reduces the ohmic resistance up to 28 % for the entire cells. The increased conductivity induced by the ALD coating of Pt or CoO x is ascribed to different mechanisms. For the inherent functional SOFCs, the present study presents a novel and feasible approach to apply a conformal, dense coating layer on the surface of a mixed conductor, simultaneously increasing the conductivity and durability of the SOFC cathode. (2). High resistance of the oxygen electrode still significantly hinders the state-of-the-art Solid Oxide Fuel Cells (SOFCs). In particular, for an oxygen electrode consisting of mixed electronic and ionic conductors, such as perovskite lanthanum strontium cobalt ferrite (LSCF), it deteriorates due to its low chemical stability of the grain surface. Such degradation is often associated with the segregation of cations. To prevent the cation surface segregation and its resultant perovskite phase decomposition, we demonstrate a conformal ultra-thin (7-10 nm) surface heterogeneous coating layer consisting of subjacent discrete Pt nanoparticles capped with a superjacent fully dense conformal CoO x layer. The performance studies indicate the ALD coating reduces the cell series resistance by up to 40 %. The conformal CoO x layer consists of randomly orientated but single-layered nanograins, with high-density intergranular and surface grain boundaries serving as the electrochemical reaction sites and facilitating mass transport. The conformal coating layer appears to have successfully suppressed the Sr outward diffusion and confined the Sr enriched layer to a ~ 2 nm interface perovskite phase between the coating layer and the LSCF grain surface. Moreover, this ultra-thin Sr enriched perovskite layer presumably possesses high oxygen vacancy and high ionic conductivity and further imposes tensile strain to the LSCF grain surfaces. With the combination of a conformal CoO x nanoionics, Sr enriched layer, and its strained interface, the ALD coating induced surface layer is estimated to have a conductivity of ~ 1.27x10 4 S/cm, which is over two orders magnitude of that from LSCF at 750 ºC.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2018

The Application of Poly(3-hexylthiophene-2,5-diyl) as a Protective Coating for High Rate Cathode Materials

Poly (3-hexylthiophene-2,5-diyl) (P3HT), a conducting polymer studied extensively for its optoelectronic devices, offers a number of advantageous properties when used as a conductive binder for lithium-ion battery cathode materials. By mixing with carbon nanotubes (CNT), P3HTCNT serves as a surface coating for the cathode material LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA). Oxidation of the P3HT enables high electronic and ionic conductivity to be achieved over the potential range where the NCA is electrochemically active. In addition to the conductivity benefits from electrochemical doping, the P3HT-CNT coating suppresses electrolyte breakdown, thus inhibiting growth of the solid electrolyte interphase (SEI) layer and preventing intergranular cracking in the NCA particles. In conclusion, The use of the P3HT-CNT binder system leads to improved cycling for NCA at high power density with capacities of 80 mAh g -1 obtained after 1000 cycles at 16C, a value that is 4 times greater than what is achieved in the control electrode.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Porin-Inspired Ionomers with sub-nm Gated Ion Channels for High Ion Conductivity and Selectivity (Final Project Report (2026))

The physiological functions of living systems heavily rely on biological ion channels, whose malfunction can lead to disease. These channels enable selective and regulated transport of water, ions, or small molecules across membranes. Analogously, ionomers used in energy conversion and storage technologies govern ion transport within membrane separators and catalyst binder layers. This DOE Office of Science Early CAREER project aimed to achieve molecular-level control over ionic conductivity and ion permselectivity by translating the functionalities of biological, gated ion channels into a novel class of ion-conducting polymers (ionomers) incorporating macrocyclic calix[4]arene-based repeat units. The overarching goal was to establish fundamental design principles and elucidate proton conduction mechanisms through strategic design of macrocyclic calix[4]arene-containing ionomers, with close relevance to energy conversion and storage devices, including proton exchange membrane fuel cells (PEMFCs). The project leveraged sub-nm-sized macrocyclic pores to facilitate exceptionally fast ion transport (beneficial to addressing sluggish ORR kinetics of PEMFC electrodes) and achieve functionalities of ionic diodes under applied electrochemical fields, beneficial for selective transport/separation.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Structural origin of disorder-induced ion conduction in NaFePO 4 cathode materials

Diffusion in NaFePO 4 can be enhanced through amorphization. Based on computations using DFT and machine learning potentials, we ascribe this phenomenon to the formation of less constrained Na-ion environments upon disordering. Most modern battery technologies depend on solid-state crystalline cathode materials. However, some of these materials are constrained by the low ionic conductivity of their most stable phases. An example of this is maricite (NaFePO 4 ). Interestingly, experiments have shown that maricite can improve its rate capability through disordering (amorphization). However, experimental characterization of amorphous cathode materials remains a major challenge, hindering a clear understanding of the structural origin of the disorder-induced improvement in sodium-ion mobility. To address this, we here employ molecular dynamics simulations by first training a machine learning potential for NaFePO 4 based on the atomic cluster expansion approach and a batch active learning potential parameterization scheme. This potential is then applied to explore the structural and dynamical properties of NaFePO 4 glasses as cathode materials. Specifically, we investigate the effect of glass structure on sodium-ion diffusion, revealing the relative influences of short-range and medium-range order features. We find significant heterogeneity in sodium-ion diffusivity in the glass, with fast-conducting ions residing in less constrained atomic environments with fewer P and Fe neighbors. These more mobile ions are also surrounded by larger ring-type structures. Overall, the results and developed approach present promising avenues for developing high-performance glassy cathodes for next-generation batteries.

Christensen, Rasmus↗
DOE OSTI2023

Boosting the interfacial superionic conduction of halide solid electrolytes for all-solid-state batteries

Designing highly conductive and (electro)chemical stable inorganic solid electrolytes using cost-effective materials is crucial for developing all-solid-state batteries. Here, we report halide nanocomposite solid electrolytes (HNSEs) ZrO 2 (-ACl)-A 2 ZrCl 6 (A = Li or Na) that demonstrate improved ionic conductivities at 30 °C, from 0.40 to 1.3 mS cm -1 and from 0.011 to 0.11 mS cm -1 for Li + and Na + , respectively, compared to A 2 ZrCl 6 , and improved compatibility with sulfide solid electrolytes. The mechanochemical method employing Li 2 O for the HNSEs synthesis enables the formation of nanostructured networks that promote interfacial superionic conduction. Via density functional theory calculations combined with synchrotron X-ray and 6 Li nuclear magnetic resonance measurements and analyses, we demonstrate that interfacial oxygen-substituted compounds are responsible for the boosted interfacial conduction mechanism. Compared to state-of-the-art Li 2 ZrCl 6 , the fluorinated ZrO 2 -2Li 2 ZrCl 5 F HNSE shows improved high-voltage stability and interfacial compatibility with Li 6 PS 5 Cl and layered lithium transition metal oxide-based positive electrodes without detrimentally affecting Li + conductivity. We also report the assembly and testing of a Li-In||LiNi 0.88 Co 0.11 Mn 0.01 O 2 all-solid-state lab-scale cell operating at 30 °C and 70 MPa and capable of delivering a specific discharge of 115 mAh g -1 after almost 2000 cycles at 400 mA g -1 .

36 MATERIALS SCIENCE↗
DOE OSTI2019

A high temperature instrument for consecutive measurements of thermal conductivity, electrical conductivity, and Seebeck coefficient

A device for measuring a plurality of material properties is designed to include accurate sensors configured to consecutively obtain thermal conductivity, electrical conductivity, and Seebeck coefficient of a single sample while maintaining a vacuum or inert gas environment. Four major design factors are confirmed as sample-heat spreader mismatch, radiation losses, parasitic losses, and sample surface temperature variance. The design is analyzed using finite element methods for high temperature ranges up to 1000°C as well as ultra-high temperatures up to 2500°C. A temperature uncertainty of 0.46% was estimated for a sample with cold and hot sides at 905.1 and 908.5°C, respectively. The uncertainty at 1000°C was calculated to be 0.7% for a ΔT of 5°C between the hot and cold sides. The thermal conductivity uncertainty was calculated to be -8.6% at ~900°C for a case with radiative gains, and +8.2% at ~1000°C for a case with radiative losses, indicating the sensitivity of the measurement to the temperature of the thermal guard in relation to the heat spreader and sample temperature. Lower limits of -17 and -13% error in thermal conductivity measurements were estimated at the ultra-high temperature of ~2500°C for a single-stage and double-stage radiation shield, respectively. Lastly, it is noted that this design is not limited to electro-thermal characterization and will enable measurement of ionic conductivity and surface temperatures of energy materials under realistic operating conditions in extreme temperature environments.

47 OTHER INSTRUMENTATION↗
DOE OSTI2015

Strongly enhanced oxygen ion transport through samarium-doped CeO 2 nanopillars in nanocomposite films

Enhancement of oxygen ion conductivity in oxides is important for low-temperature (<500 °C) operation of solid oxide fuel cells, sensors and other ionotronic devices. While huge ion conductivity has been demonstrated in planar heterostructure films, there has been considerable debate over the origin of the conductivity enhancement, in part because of the difficulties of probing buried ion transport channels. Here we create a practical geometry for device miniaturization, consisting of highly crystalline micrometre-thick vertical nanocolumns of Sm-doped CeO 2 embedded in supporting matrices of SrTiO 3 . The ionic conductivity is higher by one order of magnitude than plain Sm-doped CeO 2 films. By using scanning probe microscopy, we show that the fast ion-conducting channels are not exclusively restricted to the interface but also are localized at the Sm-doped CeO 2 nanopillars. This work offers a pathway to realize spatially localized fast ion transport in oxides of micrometre thickness.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2018

Stability and conductivity of cation- and anion-substituted LiBH 4 -based solid-state electrolytes

The high-temperature phase of LiBH 4 (HT-LiBH 4 ) exhibits a promisingly high lithium ion conductivity but is unstable at room temperature. We use density functional theory (DFT) calculations to investigate the stabilization effect of halogen and alkali cation/anion substitutions on HT-LiBH 4 as well the underlying mechanism for the high lithium ion conductivity. We find that increasing the substituent concentration enhances the stabilization of HT-LiBH 4 (i.e., the DFT energy difference between the low- and high-temperature forms of substituted LiBH 4 is reduced). Cation/anion substitution also leads to a higher Li defect (vacancy, interstitial, and Frenkel) formation energy, thereby reducing the Li defect (vacancy, interstitial, and Frenkel) concentrations. Using DFT migration barriers input into kinetic Monte Carlo simulations and the Materials INTerface (MINT) framework, here we calculate the room-temperature lithium ion conductivities for Li(BH 4 ) 1-x I x (x = 0.25 and 0.5) and Li 1-y K y BH 4 (y = 0.25). Our calculations suggest that the lower I concentration leads to a higher lithium ion conductivity of 5.7 x10 -3 S/cm compared with that of Li(BH 4 ) 0.5 I 0.5 (4.2 ×10 -5 S/cm) because of the formation of more Li-related defects. Based on our findings, we suggest that the stabilization of HT-LiBH 4 -based lithium ion conductors can be controlled by carefully tuning the cation/anion substituent concentrations to maximize the lithium ionic conductivities of the specific system.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Structural effects of composition tuning in A-site disordered perovskite La0.5Li0.5−xMxTiO3 (M = Na, K) nanorods for fast interfacial transport for solid composite electrolyte design

Polymer-ceramic composite electrolytes (CPE) have emerged as promising replacements for currently used liquid organic electrolytes, which pose as safety hazards, in Li-ion batteries. Limits in conductivity enhancement in CPEs is often attributed to a high resistance for Li-ion transport along the interface due to the incompatibility of the polymer and ceramic phases. A clear understanding of the interfacial structure and how this impacts interfacial Li-ion transport is needed in order to efficiently design a CPE with optimal ionic conductivity. In this study, density functional theory (DFT) calculations, in conjunction with scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS), are used to unveil the bulk and surface structure of La0.5Li0.5−xMxTiO3 (M = Na, K) (LMTO) nanorods, a newly-reported ceramic system with promising applications in CPEs, and the LMTO interactions with the poly(lithium sulfonyl (trifluoromethane sulfonyl)imide methacrylate) (p(MTFSILi)) polymerized ionic liquid. Substitution of lithium for sodium and potassium onto the A-site perovskite lattice is shown to increase the stability of the preferred pseudocubic perovskite phase because of their increased cation size which allows them to reduce the TiO6 octahedral rotations in the bulk and at the surface. STEM and EELS results show that LMTO nanorods with differing compositions have Ti-enriched (110)-oriented surfaces. Increased sodium and potassium compositions in LMTO is also shown using the DFT calculations to weaken the binding of the lithium atom to the MTFSI unit when LiMTFSI is adsorbed to the LMTO surface. This weakening of lithium binding to the polymer at the LMTO interface indicates that the lithium mobility is increased, correlating to an increase in interfacial Li-ion transport. Overall, this work provides insights into how to tune the interfacial interactions between the polymer (p(MTFSI)) and ceramic (LMTO) for optimal CPE design.

Shepard, Lauren B [Pennsylvania State University, ↗
DOE OSTI2021

Layered Heterostructure Ionogel Electrolytes for High‐Performance Solid‐State Lithium‐Ion Batteries

Abstract Ionogel electrolytes based on ionic liquids and gelling matrices offer several advantages for solid‐state lithium‐ion batteries, including nonflammability, wide processing compatibility, and favorable electrochemical and thermal properties. However, the absence of ionic liquids that are concurrently stable at low and high potentials constrains the electrochemical windows of ionogel electrolytes and thus their high‐energy‐density applications. Here, ionogel electrolytes with a layered heterostructure are introduced, combining high‐potential (anodic stability: >5 V vs Li/Li + ) and low‐potential (cathodic stability: <0 V vs Li/Li + ) imidazolium ionic liquids in a hexagonal boron nitride nanoplatelet matrix. These layered heterostructure ionogel electrolytes lead to extended electrochemical windows, while preserving high ionic conductivity (>1 mS cm −1 at room temperature). Using the layered heterostructure ionogel electrolytes, full‐cell solid‐state lithium‐ion batteries with a nickel manganese cobalt oxide cathode and a graphite anode are demonstrated, exhibiting voltages that are unachievable with either the high‐potential or low‐potential ionic liquid alone. Compared to ionogel electrolytes based on mixed ionic liquids, the layered heterostructure ionogel electrolytes enable higher stability operation of full‐cell lithium‐ion batteries, resulting in significantly enhanced cycling performance.

Hyun, Woo Jin↗