Wide Temperature Range Research Articles

Entropy‐Driven Hydrated Eutectic Electrolytes with Diverse Solvation Configurations for All‐Temperature Zn‐ion Batteries

AbstractBatteries always encounter uncontrollable failure or performance decay under extreme temperature environments, which is largely limited by the properties of electrolytes. Herein, an entropy‐driven hydrated eutectic electrolyte (HEE) with diverse solvation configurations is proposed to expand the operating temperature range of Zn‐ion batteries. The HEE possesses over 40 types of Zn2+ solvation structure with uniform distribution, contributing to its much higher solvation configurational entropy compared to the conventional aqueous counterpart (only 6 types). These effectively promote its anti‐freezing ability under ultralow temperatures, with a high ionic conductivity of 0.42 mS cm−1 even at a low temperature of −40 °C. Moreover, the entropy‐driven property can simultaneously enhance the thermal stability under a high temperature over +140 °C. Therefore, the HEE can enable full cells stably working over a wide temperature range of −40~+80 °C, performing over 1500 cycles with 100 % capacity retention at −40 °C and 1000 cycles with ~72 % capacity retention at +80 °C. This inspiring concept of entropy‐driven electrolyte with quantized solvation configurational entropy value has charming potential for designing future special batteries with excellent adaptability towards extreme temperature environments.

Molecule Design for Non-Aqueous Wide-Temperature Electrolytes via the Intelligentized Screening Method.

Operating a lithium-ion battery (LIB) in a wide temperature range is essential for ensuring a stable electricity supply amidst fluctuating temperatures caused by climate or terrain changes. Electrolyte plays a pivotal role in determining the temperature durability of batteries. However, specialized electrolytes designed for either low or high temperatures typically possess distinct features. Therefore, wide-temperature electrolytes (WTEs) are necessary as they encompass a combination of diverse properties, which complicates the clear instruction of WTE design. Here we represent an artificial intelligence (Al)-assisted workflow of WTE design through stepwise parameterizations and calculations. Linear mono-nitriles are identified as ideal wide-liquidus-range solvents that can "softly" solvate lithium ions by weak interactions. In addition, the explainable modules revealed the halogenoid similarity of cyanide as fluorine on the electrolyte properties (e.g. boiling point and dielectric constant). With the further introduction of an ether bond, 3-methoxypropionitrile (MPN) has been eventually determined as a main electrolyte solvent, enabling the battery operation from -60 to 120 °C. Particularly, a LiCoO2/Li cell using the proposed WTE can realize stable cycling with capacity retention reaching 72.3 % after 50 cycles under a high temperature of 100 °C.

Molecule Design for Non‐Aqueous Wide‐Temperature Electrolytes via the Intelligentized Screening Method

AbstractOperating a lithium‐ion battery (LIB) in a wide temperature range is essential for ensuring a stable electricity supply amidst fluctuating temperatures caused by climate or terrain changes. Electrolyte plays a pivotal role in determining the temperature durability of batteries. However, specialized electrolytes designed for either low or high temperatures typically possess distinct features. Therefore, wide‐temperature electrolytes (WTEs) are necessary as they encompass a combination of diverse properties, which complicates the clear instruction of WTE design. Here we represent an artificial intelligence (Al)‐assisted workflow of WTE design through stepwise parameterizations and calculations. Linear mono‐nitriles are identified as ideal wide‐liquidus‐range solvents that can “softly” solvate lithium ions by weak interactions. In addition, the explainable modules revealed the halogenoid similarity of cyanide as fluorine on the electrolyte properties (e.g. boiling point and dielectric constant). With the further introduction of an ether bond, 3‐methoxypropionitrile (MPN) has been eventually determined as a main electrolyte solvent, enabling the battery operation from −60 to 120 °C. Particularly, a LiCoO2/Li cell using the proposed WTE can realize stable cycling with capacity retention reaching 72.3 % after 50 cycles under a high temperature of 100 °C.

Enhancement of Low Temperature Superionic Conductivity by Suppression of Li Site Ordering in Li7Si2-xGexS7I.

Ge4+ substitution into the recently discovered superionic conductor Li7Si2S7I is demonstrated by synthesis of Li7Si2-xGexS7I, where x≤1.2. The anion packing and tetrahedral silicon location of Li7Si2S7I are retained upon substitution. Single crystal X-ray diffraction shows that substitution of larger Ge4+ for Si4+ expands the unit cell volume and further increases Li+ site disorder, such that Li7Si0.88Ge1.12S7I has one Li+ site more (sixteen in total) than Li7Si2S7I. The ionic conductivity of Li7Si0.8Ge1.2S7I (x=1.2) at 303 K is 1.02(3)×10-2 S cm-1 with low activation energies for Li+ transport demonstrated over a wide temperature range by AC impedance and 7Li NMR spectroscopy. All sixteen Li+ sites remain occupied to temperatures as low as 30 K in Li7Si0.88Ge1.12S7I as a result of the structural expansion. This differs from Li7Si2S7I, where the partial Li+ site ordering observed below room temperature reduces the ionic conductivity. The suppression of Li+ site depopulation by Ge4+ substitution retains the high mobility to temperatures as low as 200 K, yielding low temperature performance comparable with state-of-the-art Li+ ion conducting materials.

Enhancement of Low Temperature Superionic Conductivity by Suppression of Li Site Ordering in Li7Si2–xGexS7I

AbstractGe4+ substitution into the recently discovered superionic conductor Li7Si2S7I is demonstrated by synthesis of Li7Si2–xGexS7I, where x≤1.2. The anion packing and tetrahedral silicon location of Li7Si2S7I are retained upon substitution. Single crystal X‐ray diffraction shows that substitution of larger Ge4+ for Si4+ expands the unit cell volume and further increases Li+ site disorder, such that Li7Si0.88Ge1.12S7I has one Li+ site more (sixteen in total) than Li7Si2S7I. The ionic conductivity of Li7Si0.8Ge1.2S7I (x=1.2) at 303 K is 1.02(3)×10−2 S cm−1 with low activation energies for Li+ transport demonstrated over a wide temperature range by AC impedance and 7Li NMR spectroscopy. All sixteen Li+ sites remain occupied to temperatures as low as 30 K in Li7Si0.88Ge1.12S7I as a result of the structural expansion. This differs from Li7Si2S7I, where the partial Li+ site ordering observed below room temperature reduces the ionic conductivity. The suppression of Li+ site depopulation by Ge4+ substitution retains the high mobility to temperatures as low as 200 K, yielding low temperature performance comparable with state‐of‐the‐art Li+ ion conducting materials.

A prediction model of brittle crack arrest toughness in TMCP heavy plates

Micro-alloyed low carbon MnCrNiCuMo steels were proposed to produce heavy plates with a maximum thickness of 100 mm. An integrated industrial route including a thermo-mechanical control process (TMCP) based on a study on continuous cooling transformation was applied in industrial production. Comprehensive mechanical properties tests including the measurement on resistance against crack initiation using crack tip opening displacement (CTOD) approach were conducted. Large scale wide-plate temperature gradient double tension (DT) technique was employed to evaluate the crack arrest toughness Kca in the heavy plates under different conditions. Nil-ductility transition temperature (NDTT) was also tested across the entire thickness section of the plates. The results showed that heavy steel plates were qualified being brittle crack arrest (BCA) products at EH47 grade with yield strength high than 460 MPa. High crack initiation toughness was exhibited by both Charpy-V notch impact property and CTOD values. Crack arrest toughness at −10 °C greater than 253 MPa √m was achieved in a plate even with thickness of 100 mm. The mean value of crack arrest toughness at different temperature measured by the DT approach can be indexed by the highest NDTT in the interior section of the heavy plates leading to an empirical prediction model. Further, fracture mechanics based master curve approach was used to statistically predict crack arrest toughness distribution over a wide range of temperatures showing improved predictability over the empirical model and an existing model in the literature.

Magnetocaloric properties of Nd-doped Gd5Si4 microparticles and nanopowders

Abstract The preparation of materials with enhanced magnetocaloric properties is crucial for magnetic refrigeration. In this study, Nd-doped Gd5Si4 microparticles and nanomaterials were synthesized using the reduction-diffusion method. The impact of Nd doping with varying compositions on the structure and entropy change properties of the materials was investigated. The Curie temperatures of both the micron and nanosized materials ranged from 190 to 210 K, which were lower than previously reported values. The micron-sized samples doped with 1% Nd exhibited superior magnetocaloric properties, demonstrating a maximum entropy change of 4.98 J·kg-1·K-1 at 5 T over a wide temperature range of approximately 70 K, with an entropy change exceeding 4 J·kg-1 ·K-1. Conversely, the nanomaterials had broader entropy change peaks but lower values. All the samples exhibited a second-order phase transition, as confirmed by Arrott plots.

The impact of the environment of use on the behavior of polychlorinated (vinyl chloride).

Polymers are omnipresent in our daily life thanks to their low production cost and their ease of implementation, which makes thermoplastics more usable in supplying drinking water, distributing cold and hot water, and transporting hot corrosive fluids and industrial chemicals, including inorganic acids. The material of our study is chlorinated polyvinyl chloride (CPVC); it has better thermal insulation and a wide operating temperature range. This paper deals with the impact of thermal aging over time on the behavior of CPVC by performing two types of tests according to ISO 15877 (EN ISO 15877) two types of tests; the first is thermal aging (Fig.1) at a temperature of 95°C and a pressure of 10 bars for periods of up to 2000h and the second test exposure of the pipeline to pressure until bursting. On the basis of the test results, we can predict the rupture of the pipeline and thus avoid the dangerous accidents due to the bursting under the effect of the pressure and the high temperature; by using the results of this study, the inspectors change CPVC structures at the right time, neither too early when the part is still in good condition nor too late after failure; this will be very useful to save water and money and of course save the environment.

The surface chemistry of the atomic layer deposition of ruthenium on aluminum and tantalum oxide surfaces

The surface chemistry of Ru atomic layer deposition (ALD) processes based on the use of tris(2,2,6,6-tetramethyl-3,5-heptanedionato)ruthenium(III) (Ru(tmhd)3) and either molecular oxygen or atomic hydrogen on aluminum oxide films was characterized by a combination of surface-sensitive techniques. The thermal decomposition of the Ru metalorganic precursor was determined, by using a combination of reflection-absorption infrared spectroscopy (RAIRS), temperature programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS), to start below 400 K and to take place in a stepwise fashion over a wide range of temperatures. Gas-phase products from this chemistry include 2,2,6,6-tetramethyl-3,5-heptanedione (the protonated ligand, Htmhd; in a TPD peak at 520 K), isobutene (540 K; indicating the fragmentation of the organic ligands), and other products from isomerization and/or aldol condensation (650 and 730 K). This chemistry is accompanied by the reduction of the Ru3+ ions in two stages, involving the loss of some of their ligands and their direct bonding to the substrate first (between 500 and 600 K) and a full reduction to a metallic state later on (600–700 K). ALD cycles using either molecular oxygen or atomic hydrogen resulted in the slow build-up of Ru on the surface, but the co-deposition of carbon could not be avoided, at least in the initial cycles, while the alumina surface was still exposed. With O2, the Ru atoms alternate between partially-oxidized (after the O2 exposures) and zero-valent (after the Ru(tmhd)3 doses) states, and some Ru loss in the form of the volatile RuO4 oxide was seen after the second half of the ALD cycles; neither the Ru oxidation state alternation nor the elimination of some Ru from the surface were observed when using H·. The deposited Ru was determined, by combining results from angle-resolved XPS (ARXPS) and low-energy ion scattering (LEIS) experiments, to grow as 3D nanoparticles rather than as a layer-by-layer 2D film, presumably because the Ru precursor preferentially adsorbs (and decomposes more cleanly) on the metal surface. A discussion is provided of the implications of these results for the design of ALD processes.

A Dual-Focus Workflow for Simultaneously Engineering High Activity and Thermal Stability in Methyl Parathion Hydrolase.

Industrial fermentation applications typically require enzymes that exhibit high stability and activity at high temperatures. However, efforts to simultaneously improve these properties are usually limited by a trade-off between stability and activity. This report describes a computational strategy to enhance both activity and thermal stability of the mesophilic organophosphate-degrading enzyme, methyl parathion hydrolase (MPH). To predict hotspot mutation sites, we assembled a library of features associated with the target properties for each residue and then prioritized candidate sites by hierarchical clustering. Subsequent in silico screening with multiple algorithms to simulate selective pressures yielded a subset of 23 candidate mutations. Iterative parallel screening of mutations that improved thermal stability and activity yielded, MPHase-m5b, which exhibited 13.3 °C higher Tm and 4.2 times higher catalytic activity than wild-type (WT) MPH over a wide temperature range. Systematic analysis of crystal structures, molecular dynamics (MD) simulations, and Quantum Mechanics/Molecular Mechanics (QM/MM) calculations revealed a wider entrance to the active site that increased substrate access with an extensive network of interactions outside the active site that reinforced αβ/βα sandwich architecture to improve thermal stability. This study thus provides an advanced, rational design framework to improve efficiency in engineering highly active, thermostable biocatalysts for industrial applications.

Highly matched electrode for all-solid-state sodium-ion fiber hybrid supercapacitor with wide temperature and high energy density

In order to solve the kinetic mismatch problem of hybrid supercapacitors, a simple and effective assembly technology for wide temperature all-solid-state sodium-ion fiber hybrid supercapacitor is proposed based on anode and cathode with optimal volume capacity ratio and complementary potential windows. Ti3C2Tx fiber anode is produced by wet spinning in acetic acid bath. It reveals an excellent volume capacity of 406 F cm−3, good cycle stability of 90 % retention in 1 M NaClO4 electrolyte, high conductivity of 3303 S cm−1, and tensile strength of 80 MPa. NaV3O8/rGO (NVO/rGO) fiber cathode is obtained by wet spinning and hydrothermal treating, exhibiting high matched volumetric capacitance and improved rate performance. Moreover, a wide temperature all-solid-state sodium-ion fiber hybrid supercapacitor (PVA EGHG NVO/rGO//Ti3C2Tx AFSIC) is assembled using polyvinyl alcohol ethylene glycol hydrogel (PVA EGHG) as separator and electrolyte. The AFSIC shows an outstanding volumetric specific capacitance of 76 F cm−3 at 0.1 A cm−3, and a maximum volumetric energy density of 30.6 mWh cm−3 at a power density of 83.2 mW cm−3. In addition, it can be bend to diverse degrees without significant change in its electrochemical performance. In addition, the AFSIC exhibites exceptional capacitance and outstanding flexibility in a wide temperature range of −40 to 60 °C, showing that the PVA EGHG NVO/rGO//Ti3C2Tx AFSIC has wide prospect in the area of wearable electronic components.

Effect of the Temperature on the Performance and Dynamic Behavior of HfO2-Based Rram Devices

Over the past decades, the demand for semiconductor memory devices has been steadily increasing, and is currently experiencing an unprecedented boost due to the development and expansion of artificial intelligence. Among emerging high-density non-volatile memories, resistive random-access memory (RRAM) is one of the best recourses for all kind of applications, such as neuromorphic computing or hardware security [1]. Although many materials have been evaluated for RRAM development, some of them with excellent results, HfO2 is one of the established materials in CMOS domain due to its compatibility with standard materials and processes [2].The main goal of this work is to study the switching capability and stability of HfO2-based RRAMs, as well as to explore their ability in the field of analogue applications, by analyzing the evolution of the resistance states that allow multilevel control. Indeed, analogue operation is a key point for achieving electronic neural synapses in neuromorphic systems, with synaptic weight information encoded in the different resistance states. This research has been carried out over a wide temperature range, between 40 and 340 K, as we are interested in testing the extent to which performance is maintained or modified, with a view to designing neuromorphic circuits that are also suitable in the low-temperature realm. We aim to prove that these simple, fast, high integration density structures can also be used in circuits designed for specific applications, such as aerospace systems.The RRAM devices studied in this work are TiN/Ti/8 nm-HfO2/TiN metal-insulator-metal (MIM) capacitors. Dielectric layers were atomic layer deposited (ALD). It has been demonstrated that the Ti coat in the top electrode acts as a scavenger that absorbs oxygen atoms from the HfO2 layer, and facilitates the creation of conductive filaments of oxygen vacancies [3]. In fact, the oxygen reservoir capability of Ti is well known, as it is able to attract and release oxygen atoms from or to the HfO2 layer during the RRAM operation [4]. The clustering of vacancies extends through the entire thickness of the oxide and, after an electroformig step, it joins the upper and lower electrodes and the device reaches the low resistance state (LRS). By applying adequate electrical signals, the filaments can be partially dissolved, which brings the device into the high-resistance state (HRS), with lower current values. The set process brings the device to the LRS state, while the reset one brings it to the HRS. The dependence of electrical conductivity on external applied electrical excitation allows triggering the device between the both states in a non-volatile manner [5].The experimental equipment used consisted of a Keithley 4200-SCS semiconductor parameter analyzer and a Lake Shore cryogenic probe station. Fig.1 shows current-voltage cycles measured at different temperatures; the averages values at each temperature, both in logarithmic and linear scale, are also shown. The functional window increases as temperature decreases.The evolutions of set and reset voltage values with temperature are depicted in Fig.2, whereas the current values (measured at 0.1 V) corresponding to the LRS and HRS can be seen in Fig.3. LRS resistance decreases as temperature increases, in agreement with semiconductor behaviour, probably due to a hopping conduction mechanism. Both set and reset voltages decrease as temperature increases; the reset process is smoother at high temperatures. The reduction in reset voltage variability as temperature increases is very notable.Finally, Fig. 4 shows a picture of the transient behaviour; in the right panel of the same figure, the amplitudes of the current transients in the reset state have been included in the external loop.To sum up, the resistive switching phenomena is studied in a wide temperature range. The LRS shows semiconducting behavior with temperature, most likely related to a hopping conduction mechanism. Switching voltages decrease as temperature increases, with a notable reduction in reset voltage variability. An excellent control of intermediate resistance state is shown through current transients at several voltages in the reset process.REFERENCES[1] M. Asif et al., Materials Today Electronics 1, 100004 (2022).[2] S. Slesazeck et al., Nanotechnology 30, 352003 (2019).[3] Z. Fang et al., IEEE Electron Device Letters 35, 9, 912-914 (2014).[4] H. Y. Lee et al., IEEE Electron Device Letters 31, 1, 44-46 (2010).[5] D. J. Wouters et al., Proceedings of the IEEE 103, 8, 1274-1288 (2015). Figure 1

Liquid Binary and Ternary Electrolytes Mixtures for Low-Temperature Sulfurized Carbon Batteries

Active sulfurized carbon (SC) has been proposed as promising alternative to enable sulfur as the next generation cathode material due its ability to confine sulfur and suppresses polysulfide shuttling. Pragmatic cell performance of SC electrodes needs to extend over a wide range of temperatures from -20 °C to 60 °C. Low-temperature performance of SC cells is mainly limited by electrolyte wettability, ionic mobility between the electrodes, and the nature of the formed solid electrolyte interphase. In this work we have utilized electrolyte binary and ternary mixtures based on carbonates, ethers, and fluorinated solvents to enhance the SC cell discharge performance up to -20 °C. To understand the effects of electrolyte mixtures in the cell performance we have utilized electrochemical impedance spectroscopy (EIS) as a function of temperature and voltage. The lower cell resistance translates into a higher rate capability, cyclability, and low-temperature performance. Based on the EIS response and its spectra deconvolution we proposed an apparent electrical equivalent circuit that permits the elucidation of resistance elements and their magnitude such as the ohmic, electron charge transfer, surface film, and mass transport resistance to provide a phenomenological understanding on how the mixtures can enhance the electrochemical performance. Furthermore, differential capacity analysis and Hybrid Pulse Power Characterization (HPPC), are utilized to support the characterization. Finally, best performance electrolyte mixtures were utilized to build >0.5 Ah pouch cells for testing at low temperatures, discharge rates, and pressure conditions.

Theoretical Study on the Dynamics of Lithium-Ion Transport in PPS-Based Polymer Electrolytes

The development of solid-state lithium-ion batteries (LIBs) is a key advancement in energy storage technology. Solid electrolytes are important in this development because they are safer and more stable than liquid electrolytes, and they have higher energy density. Among the various types of solid electrolytes, Polyphenylene Sulfide (PPS)-based solid-state polymer electrolytes (SPEs) are notable for their ability to conduct ions as well as liquid electrolytes across a wide range of temperatures. This ability is particularly important because other solid polymer electrolytes, like those based on polyethylene oxide (PEO), struggle with ion conduction at different temperatures. PPS-based SPEs are different because their ion transport does not depend on the movement of the polymer chains, which means their ion conduction remains steady from high to low temperatures.The previous study conducted a series of first-principle calculations, revealing that the introduction of neutral molecules, referred to as agent molecules, can significantly enhance the movement of lithium ions within a solid matrix when these are mixed with lithium salts. This is because the intermolecular interactions within a binary system comprising an agent molecule and lithium salt are governed by a strong bond formation between lithium and oxygen atoms. When these agent molecules are introduced, they replace the anionic species around lithium in the salts, leading to a weakened Coulomb force between lithium and oxygen. This reduction is essential for rapid lithium-ion movement through the easy separation of lithium salts and the subsequent generation of ion-hopping sites characterized as lithium-free oxygen cages. According to the previous study, the strategic selection of neutral molecules with functional groups that bolster chemical resonance is imperative. Such molecules have been identified as promising candidates for agent molecules.Our study builds upon previous research by directly incorporating PPS polymers into our computational simulations. We utilized molecular dynamics and quantum mechanics to examine the role of neutral molecules in PPS in facilitating lithium-ion mobility. We parameterized our system with quantum mechanics calculations, which were crucial in informing our molecular dynamics simulations. Using VASP program for interaction assessment and LAMMPS program for energy and structure analysis, we refined our models to understand the interactions between PPS polymers, Li+ ions, TFSI- ions, and Chloranil molecules. Our simulations explored the structural dynamics and the effects of fillers and PPS polymer layers on ion transport.Our work enhances the basic understanding of SPEs and helps in the creation of new lithium-ion batteries that perform better and are safer. We've pinpointed important factors that control how lithium ions move in PPS-based electrolytes, laying the groundwork for future improvements in solid-state electrolytes and leading to lithium-ion batteries that are more effective and safer.Reference:[1] Jiwon Yu, Myungsuk Lee, Yeonseo Kim, Hyung-Kyu Lim, Jonghyun Chae, Gyeong S. Hwang, Sangheon Lee, “Agent molecule modulated low-temperature activation of solid-state lithium-ion transport for polymer electrolytes”, Journal of Power Sources 505, 229917 (2021).

High-Valence Ion Doped Compositionally Partitioned Li[Ni0.78Co0.10Mn0.12]O2 Cathode for Advanced Lithium-Ion Batteries

Numerous approaches have been employed to reduce the intrinsic instability of Ni-rich cathodes. Among them, the introduction of concentration gradient (CG), i.e., a strategy to protect the labile Ni-enriched compartment with a chemically protective Mn-rich shell, has proven successful in commercial applications.1 However, because the segmentation of transition metal (TM) constituents and the formation of unique geometric configurations are characteristics inherited from the CG hydroxide precursor; it is crucial to select the optimal calcination temperature and precisely control it.2 Excessive thermal energy input can result in concentration planarization because the CG of the hydroxide precursor is intrinsically susceptible to the interdiffusion of TM elements during lithiation. Moreover, the immoderate coarsening of the primary particles can eliminate the advantageous features of the CG design by producing equiaxed primary particles.2 In this study, we propose a strategy that can effectively ameliorate the deterioration of Ni-rich CG cathodes resulting from excessive thermal energy input and remarkably improve their electrochemical cycling performance. It was revealed that a trace amount of tungsten incorporation during the cathode calcination can effectively mitigate the high-temperature-induced cathode degeneration and maintain outstanding product quality over a wide range of temperatures. Thus, the proposed strategy opens new avenues for the facile synthesis of long-life Ni-rich CG cathodes. Reference s : [1] Y.-K. Sun, S.-T. Myung, B.-C. Park, J. Prakash, I. Belharouak, K. Amine, Nat. Mater. 8 (2009) 320-324.[2] G.-T. Park, H.-H. Ryu, T.-C. Noh, G.-C. Kang, Y.-K. Sun, Mater. Today 52 (2022) 9-18.

(Invited) Electrolyte Design for Wide-Temperature Lithium Batteries

Improving the wide temperature performance of rechargeable batteries is vital to the operation of electronics and vehicles in extreme environments, where systems capable of higher energy, high-rate discharge and long cycling are in short supply. In this talk, we will show electrolyte designs to achieve high-energy density and stable cycling performance in wide temperature range, especially in extremely low-temperature environment. We will use a few examples, including ester- and ether-based electrolyte with different concentrations to showcase the critical role of solvation and desolvation in determining the charge-transfer kinetics at low-temperature. We will also discuss the role of solvation structure in shaping interfacial stability in different cathode and anode systems. These fundamental understanding may provide viable design strategies for high energy density and long-life batteries for both high and extremely low temperatures such as rechargeable Li metal batteries using both high-Ni oxide and sulfur cathodes.

Thin-Film Embedded Sensors for Battery Health Monitoring

Hybrid or all-electric aircraft are being developed as the next generation of aircraft to both allow new forms of aviation and decrease environmental impact. Since these types of aircraft are based on high-capacity battery technology, safe operation of these batteries becomes increasingly important. In particular, the potential for battery failure due to uncontrolled chemical reactions resulting in thermal runaway, catastrophic failure, and battery fires must be addressed in order for such battery technology to have the level of safety needed for standard aviation implementation. Efforts to ensure battery safety often involve engineering solutions that seek to contain rather than prevent such events by early detection. Such approaches increase the system weight and decrease the power per unit mass provided by the battery system. Existing methods for measuring battery parameters to determine the battery state-of-health are limited. These methods include electrical measurements of the cell current and/or voltage output as well as temperature measurements taken externally on the cell surface. Such external temperature measurements are limited in their ability to provide early warning of impending battery failure. In response, an effort to develop sensors operating internal to battery for health monitoring has been ongoing in the NASA Sensor-based Prognostics to Avoid Runaway Reactions & Catastrophic Ignition (SPARRCI) project [1]. The basic approach associated with this sensor work is the deposition of thin film sensors on the battery separator located between the anode and cathode of the battery. These thin film sensors are then monitored to determine changes in battery parameters and health. Microfabrication techniques are employed to minimize the overall impact of the sensors on battery operation through the implementation of sensors with minimal size, weight, and power consumption. The thickness of the films, which are fabricated through physical vapor deposition (sputtering), are on the order of thousands of angstroms and can have minimal surface area. Thin film sensors for system health management have been implemented for a many decades on complex components for aerospace applications [2,3]. However, the application of thin films of this type on a battery separator for internal battery monitoring applications has not previously been demonstrated to our knowledge. This paper describes the development of sensors for the internal battery monitoring through the use of thin film sensor technology. Thin metal films were successfully deposited on a battery separator polymer material with good adherence and electrical continuity. Multiple types of sensors have been deposited, as well as lead connections from the sensor to the edge of the separator material. The ability of these thin film sensors immersed in electrolyte to perform multiple types of battery parameter measurements has been demonstrated. For example, a multiparameter sensor system measured multiple properties simultaneously inside of a pouch cell over a wide temperature range. Further, real time measurement of interior temperature changes in a battery pouch cell with an integrated interior temperature sensor was demonstrated. These changes include detecting a fault in the battery (shorting) in situ with rapid response time (less than a minute) corresponding to a more limited response by a temperature sensor mounted externally. Other aspects of monitoring battery health were also explored, such as real-time measurement of simulated dendrite growth/metal deposition by sensor on separator material demonstrated. Future efforts will include improvements in the durability of the sensor structure to allow introduction of the approach into standard battery fabrication techniques. Overall, this work is a step forward in providing a method to prevent catastrophic battery failures and provide a foundation for safer, lighter, and higher energy batteries for the electric aircraft industry.[1] B. DeMattia, Daniel Perey, John Lawson, and Gary Hunter, “Advanced Battery Health Approaches for Electric Aircraft”, Energy & Mobility Technology, Systems, and Value Chain Conference & Expo, Cleveland, OH, Sept. 23, 2023.[2] John D. Wrbanek, and Gustave C. Fralick, “Thin Film Physical Sensor Instrumentation Research and Development at NASA Glenn Research Center”, 52nd International Instrumentation Symposium Cleveland, OH, May 2006, NASA TM-2006-214395[3] Lawrence G. Matus (2015) “Instrumentation for Aerospace Applications: Electronic-Based Technologies”, Journal of Aerospace Engineering 26 (2) https://doi.org/10.1061/(ASCE)AS.1943-5525.0000302

A new method to calculate and predict thermodynamic properties of nonpolar, polar and quantum fluids at high temperatures

As the only known equation of state (EOS) with the rigid theoretical foundation, the virial equation of state (VEOS) can be reliable enough to describe real-gas imperfection for low-to-moderate densities when truncated after the second or third virial coefficient. In our previous work, on the basis of the corresponding state principle, the generalized second and third virial coefficient models were proposed for nonpolar, polar and quantum fluids in a wide temperature range. In this work, combined with the ideal heat capacities, the high-temperature performance of the truncated VEOSs was evaluated on derived thermodynamic properties including speed of sound, isobaric heat capacity, entropy and internal energy. The criterion for being “valid” is defined as 1% relative deviation from the multiparameter EOSs, and this work presents the valid density and pressure regions of the truncated VEOSs for the derived thermodynamic properties. The truncated VEOSs have valid densities of the saturated densities below the critical temperatures, and have valid densities that tend to be constant beyond the critical temperatures. The SRK EOS is chosen as the representative of generalized EOSs. By the comparisons with the SRK EOS, the truncated VEOSs show the advantage in stability and universality. The truncated VEOSs can give a reliable extrapolation with wide applicable pressure ranges at high temperatures for nonpolar, polar and quantum fluids. The applicable density regions of the truncated VEOSs for derived thermodynamic properties are recommended to be the valid density regions of the pvT property. The applicable temperature ranges of the truncated VEOSs for derived thermodynamic properties are determined by the temperature ranges of the available ideal heat capacity data.

(Invited) Energy Storage in Ti3C2T x MXene in a Wide Temperature Range

Pseudocapacitors have the potential to achieve high energy and high power density simultaneously, a holy grail for electrochemical energy storage. MXene-based pseudocapacitors have made major progress in the last decade, achieving better energy and power density than carbon supercapacitors using the double-layer charge storage mechanism. However, one obstacle facing pseudocapacitors is their shorter lifetime. In MXene-based pseudocapacitors, which showed up to 500,000 cycles lifetime in aqueous electrolyte at room temperature, this concern is pronounced particularly at high temperatures due to the limited stability of the active material in aqueous solutions. This work shows that Ti3C2T x MXene electrodes in 5 M H2SO4 possess excellent rate capabilities from -50 °C to 100 °C but also a sufficient lifetime at 70 °C when using a float test holding at -0.9 V vs. Hg/Hg2SO4. Post-mortem characterization using X-ray photoelectron spectroscopy and Raman spectroscopy showed negligible signs of oxidation in the bulk of the film. This work suggests sufficient stability of Ti3C2T x MXene as a negative electrode in protic aqueous electrolytes across a wide temperature range rooted in thermodynamics, making it promising for pseudocapacitor energy storage.

Influence of Temperature on the Nucleation and Adsorption Kinetic Mechanisms for Copper Corrosion

Copper is a valuable catalyst that is widely used in electrochemical devices, particularly in the generation of clean, renewable energy and the CO2 reduction reaction (CO2RR). Gaining insight into the fundamentals of corrosion/deposition of Cu in an electrochemical cell can aid in the design of more durable and efficient devices. To take advantage of the capabilities of Cu and comprehend the broader impacts, it is crucial to understand the kinetics of nucleation and adsorption mechanisms and conduct a thorough investigation of the underlying principles. Here, we utilize a model system with Cu underpotential deposition (UPD) on an Au(111) electrode surface in sulfuric acid electrolyte and investigate the impact of temperature change on the kinetics of Cu corrosion/deposition. The Transient technique, chronoamperometry, is employed to differentiate and illustrate the effects of the nucleation process and adsorption of ions. At temperatures below 20°C, peaks indicate the nucleation and adsorption processes can be identified individually. At temperatures 20°C and above, more adsorption characteristics are seen which may be due to the interactions between less-ordered monolayers at the interface, further demonstrated by the loss of nucleation characteristics. Electrochemical devices operate across a wider temperature range in practical uses. The aim of this study is to examine and quantify the influence of temperature on the nucleation and adsorption mechanisms for the kinetics of Cu in order to optimize the durability of Cu-containing electrochemical devices.