Fundamental Transport Properties Research Articles

Identification of the conductivity type of single-walled carbon nanotubes via dual-modulation dielectric force microscopy.

The conductivity type is one of the most fundamental transport properties of semiconductors, which is usually identified by fabricating the field-effect transistor, the Hall-effect device, etc. However, it is challenging to obtain an Ohmic contact if the sample is down to nanometer-scale because of the small size and intrinsic heterogeneity. Noncontact dielectric force microscopy (DFM) can identify the conductivity type of the sample by applying a DC gate voltage to the tip, which is effective in tuning the accumulation or depletion of charge carriers. Here, we further developed a dual-modulation DFM, which simplified the conductivity type identification from multiple scan times under different DC gate voltages to a single scan under an AC gate voltage. Taking single-walled carbon nanotubes as testing samples, the semiconducting-type sample exhibits a more significant charge carrier accumulation/depletion under each half-period of the AC gate voltage than the metallic-type sample due to the stronger rectification effect. The charge carrier accumulation or depletion of the p-type sample is opposite to that of the n-type sample at the same half-period of the AC gate voltage because of the reversed charge carrier type.

Height-modulating horizontal transport of dust particles in a dusty plasma ratchet

Dust particles are often electrostatically trapped and levitated within the non-electroneutral region of a sheath. The fascinating transport phenomena of dust particles strongly depend on the plasma parameters surrounding them within the sheath, whereas, that are quite difficult to obtain, leading to an unclear understanding of particle transport mechanisms. Here, we demonstrate a tunable horizontal transport of micron-sized dust particles by precisely manipulating their vertically suspended heights in an asymmetric ratchet sheath by designing dusty plasma ratchet. A collection of dust particles serves as micro-probes to detect the height-dependent transport properties and the feature of the sheath. Two methods are employed to lift or reduce the suspended heights of dust particles while maintaining the sheath unchanged. As the suspended heights of dust particles vary, their directional transport changes accordingly, including a flow reversal. A two-dimensional model of the ratchet sheath depicts the nonlinear distributions of plasma parameters and reveals that these unexpected transport phenomena can be attributed to the dependence of the electric ratchet potential and the resulting non-equilibrium net ion drag force on the suspended heights of dust particles. Our combined experimental and theoretical study provides insights into the fundamental transport properties of dust particles in an asymmetrical sheath.

Giant Spin-Orbit Induced Magnon Nonreciprocity in Ultrathin Ferromagnets.

The propagation characteristics of fermionic and bosonic quasiparticles determine the fundamental transport properties of solids and are of great technological relevance for designing logic devices. In particular, nonreciprocity, which describes that a quasiparticle flows preferably along a certain direction of a symmetry path, is an essential requirement to realize logic architectures, e.g., switches, diodes, transistors, etc. Here we introduce a mechanism, which leads to giant nonreciprocity of ultrafast terahertz magnons in ferromagnetic films with a large spin-orbit coupling. The mechanism is based on the competition between the exchange and spin-orbit scattering. We anticipate that the effect can be used to excite nonreciprocal or even unidirectional magnons in a large class of ultrathin films and nanostructures grown on substrates with a large spin-orbit coupling.

Lattice thermal conductivity of β-, α- and κ- Ga2O3: a first-principles computational study

The thermal transport properties of Ga2O3 in different phases remain inadequately explored. We employ first-principles calculations and the phonon Boltzmann equation to systematically study the lattice thermal conductivity of β-, α- and κ-Ga2O3. Our results reveal that κ-Ga2O3 exhibits pronounced phonon anharmonicity due to its complex polyhedral configurations and weak bonding, resulting in significantly lower lattice thermal conductivity compared to β- and α-Ga2O3. This work provides critical knowledge of the fundamental phonon thermal transport properties of different-phase Ga2O3, as well as helpful guidance for the thermal design of Ga2O3-based high-power devices.

Understanding Charge, Mass, and Heat Transfer in Fuel Cells for Transport Applications – Insights from the Camelot Project

Proton Exchange Membrane Fuel Cells (PEMFCs) are a promising solution for zero-emission vehicle propulsion owing to their high energy density, low operating temperature, and high efficiency. The overall aim of the CAMELOT project is to improve the power density of fuel cells by understanding the limitations on the performance of state-of-the-art (SoA) and beyond SoA PEMFC membrane electrode assemblies (MEAs). To achieve this, the CAMELOT project has diagnosed the fundamental transport properties that limit performance of these MEAs and materials. Not only has the CAMELOT project produced MEAs with features that have the potential to enable disruptive performance increases but have further developed leading open-source models to enable accurate simulations validated through experimental work. In-depth parametrisation of fuel cell components through extensive ex-situ and in-situ characterisation has been performed to provide input to the modelling activities. The two major modelling advances achieved by the CAMELOT project are i) the improvement of water uptake and transport models, especially concerning ultra-thin PEMs, and ii) extending a leading open-source model (FAST-FC) to enable accurate simulation of beyond SoA fuel cell performance and voltage loss breakdown. CAMELOT has developed a series of beyond-SoA fuel cell components to ensure that the modelling inputs are representative of SoA component properties. A series of membranes with varying thicknesses were prepared and a range of ex-situ experiments were carried out to gather water uptake and permeability properties for the water transport models. Additional in-situ electrochemical characterisation was carried out on a series of catalyst coated membranes (CCMs) to extract important properties of the catalyst and membrane components as inputs to improve the physics-based fuel cell performance model.Significant results from the project to be highlighted in this presentation include the development of a water transport model with improved description of water uptake and transport in thin ionomeric layers, the development of a predictive modelling framework from which we can identify the most important material parameters to tune to reach our MEA performance targets of 2.7 A/cm2 at >0.67 V with total catalyst loadings <0.08 mgPt/cm2, the development of ultrathin (< 10 µm) proton exchange membranes and ultra-low loading cathode catalyst loadings (0.08 mgPt/cm2), the development of catalyst coated membranes (CCMs) with in-plane catalyst and ionomer gradients, and extensive in-situ fuel cell characterization of the SoA CAMELOT CCMs/MEAs.The CAMELOT project has received funding from the Fuel Cells and Hydrogen 2 Joint Undertaking (now Clean Hydrogen Partnership) under grant agreement No 875155. This Joint Undertaking receives support from the European Union’s Horizon 2020 Research and Innovation program, Hydrogen Europe and Hydrogen Europe Research.

Localized Study of the CCM with Graded Ionomer and Catalyst Loading across the X-Y and Z Directions Using Current Scan Shunt

In project CAMELOT, it is aimed to diagnose the fundamental transport properties that limit performance in state-of-the-art (SoA) and prototype beyond-SoA Membrane Electrode Assembly (MEA)s and materials. To accomplish this goal, a series of in-situ characterization methods are used to create correlations between the observed performance, voltage loss breakdowns at the cell level, and the fundamental material property characteristics of the MEA and MEA materials. To accomplish this goal, thin Catalyst Coated Membrane (CCM) with low Pt loading is used as target study material; and the logic for using thinner layers in each of the MEA components is clear: thinner constituent layers (membrane, catalyst layers, microporous layers (MPL), gas diffusion layers (GDL)) means shorter transport distances for protons, oxygen, hydrogen and electrons and should thus reduce the associated transport losses. Thin‐layer X‐Y and Z direction graded catalyst layers are developed in project CAMELOT to optimize porosity, ionomer content and catalyst loading across the X‐Y and Z directions of the CCM. For the X‐Y direction CAMELOT matches the catalyst layer composition to the conditions at different locations within the flow field. For example, the porosity and ionomer content of the catalyst layer near the outlet of the flow field should be tuned for significantly wetter conditions than at the flow field inlet. For Z direction CAMELOT matches the catalyst layer composition to the conditions of the membrane and the GDL layer. The goal is to ensure that at each point in the active area, the catalysts can operate as close to their maximum (kinetically limited) performance as possible by minimizing mass transport limitations under the conditions that prevail at the different locations. For example, the porosity and ionomer content of the catalyst layer near the outlet of the flow field should be tuned for significantly wetter conditions than at the flow field inlet. Current Scan Shunt (CSS) is used as a convenient tool to measure real-time current density and temperature distribution within the fuel cell in situ operando, to analyze the cell behavior depending on the components and the direction of the grading catalyst layer on the developed CCMs. The experimental work will later be supplemented by a theoretical analysis carried out in the modelling work and, together, the modelling and experimental analysis can be used to construct a complete picture of correlated relationships between the MEA structure and properties and the associated voltage loss causes of the performance limitations for current SoA materials.

Fluorinated Battery Electrolytes for Low Temperature Cycling

Lithium-ion batteries often see dramatic capacity losses when cycling at low temperatures, due to sluggish lithium transport within the bulk electrolyte and at the electrode-electrolyte interfaces. The development of new battery electrolytes with enhanced lithium-ion conductivity and improved interfacial transfer at low temperatures is needed to improve the overall stability and wide operating range performance of batteries. Koura has developed fluorinated materials for lithium-ion electrolytes with improved stability and safety properties, and in this study their efficacy in batteries under low temperature conditions is investigated and compared to conventional electrolytes. Fundamental transport properties such as lithium transference number, conductivity, and viscosity are reviewed. Cycling and rate performance across a range of temperatures from -20°C to 45°C are also investigated, and interfacial properties are assessed. By combining analyses of the bulk electrolyte properties, interfacial electrochemistry, and performance data at several temperatures, a comprehensive picture of the effect of electrolyte on low and wide temperature performance is developed. Experimental results show that several of Koura’s fluorinated materials can improve low temperature cycling performance, and key considerations in optimizing electrolyte properties and composition for low temperature performance are discussed.

(Invited) Gallium Oxides Devices for Grid-Scale Power Electronics and High Power Switched Mode RF Amplifiers

Within a decade of the first demonstration of a MESFET device, monoclinic β-Ga2O3 (Ga2O3) devices have made incredible progress in breakdown voltages, power device figure of merit and high-speed performance. It has emerged as a promising ultra-widebandgap semiconductor for next generation power, GHz switching and RF applications. In this talk, we will present an overview of our studies on fundamental transport properties, kilovolt class power MOSFETs and aggressively scaled RF devices. The large bandgap of Ga2O3 leads to a high critical field strength. This high field strength in combination with demonstrated room temperature mobility and calculated electron velocity leads to a higher Baliga’s Figure of Merit (BFoM) and Johnston Figure of Merit (JFoM) than current commercially available widebandgap technologies. Additionally, the large bandgap also enables high temperature operation and radiation hardness making it attractive for space applications such as Mars and Venus missions.In the first part, we will discuss the deep insights gained from the first-principles based transport calculations in Ga2O3. We will discuss the limits to low field mobility, saturation velocities and impact ionization coefficients. The impact of the plasmon-phonon coupling on the phonon limited transport will be discussed. We will present the experimental signatures of plasmon-phonon coupling and anti-screening behavior in ionic gated accumulation layers.Next, I will describe our work on the lateral MOSFETs with improved field plate design and beyond-kV breakdown. Temperature dependent analysis and device simulation suggest an extrinsic breakdown mechanism outside the channel. A simple and yet effective SU-8 polymer passivation technology was developed that results in significant improvement in breakdown voltages. The higher field strength of the SU-8 polymer enables a significant increase in breakdown voltage to 8 kVs in lateral MOSFETs. However, these devices show a high Ron, which is due to the depletion caused by RIE of the channel. We will present the use of ultra-high vacuum annealing techniques to improve the on-resistance of the devices still maintaining the multi-kilo-volt rating of the devices.Due to its high JFoM, Ga2O3 is a potential candidate for high power density RF amplifiers. We will also present the performance advancement that can be obtained in RF power performance using Ga2O3 technology. We will present the challenges in the technology and potential solutions. We will present the experimental DC and pulsed measurements on laterally scaled MOSFETs with 100 nm gate length. Severe DC-RF dispersion was observed which is attributed to the RIE damage and surface states on the oxide. Passivation of the devices shows reduced current collapse. Using aggressive gate lengths and gate-source spacing scaling, (AlxGa1-x)2O3/Ga2O3 heterostructure FETs were fabricated that show record high RF performance. The device transconductance was limited by the regrowth interface resistance. Ex-situ silicon nitride passivation was shown to be effective to reduce DC-RF dispersion. Recently, thin channel MOSFETs with deep-sub-micron gate lengths and source/drain regrowth have demonstrated devices with simultaneously low on resistance, high frequency, high voltages.

Structural, electronic, optical, and thermoelectric studies on Zintl SrCd2Pn2 (Pn=P/As) compounds for solar cell applications: A First Principle Approach

Strontium-based Zintl materials SrCd2Pn2 (Pn = P/As) have been investigated here for their thermoelectric applications. The fundamental structural, optoelectronics and transport properties of Zintl SrCd2Pn2 (Pn = P/As) compounds were determined by employing the full potential linearized augmented plane wave approach (FP-LAPW). The formation and dynamical stabilities have been confirmed by formation energy and phonon dispersion studies. The established band structures using the modified Becke–Johnson potential (mBJ) reveals a direct energy bandgap (Eg) of 1.58 eV and 1.15 eV for SrCd2P2 and SrCd2As2, respectively. The DOS spectra disclose Pn(P/As) states are present in the valence band while Sr states are present in the conduction band. The optical features of the compounds were analyzed from dielectric constants, refractive index, extinction coefficient, and energy loss function against photon energy (eV) up to 30 eV. We observed that the material absorption by falling the light is fascinating in the visible region, revealing a viable choice for optoelectronics application. We evaluated transport properties like the Seebeck coefficient, electrical and thermal conductivity, power factor versus temperature, carrier concentration, and chemical potential with the classical Boltzmann transport theory. The computed Seebeck coefficients for SrCd2P2 and SrCd2As2 are found to be equal to 242μVK−1 and 239 μVK−1 at 300 K and 255 μVK−1, 257 μVK−1at 1200 K. The highest values of the power factor obtained at 1200 K are 5.88 × 1011 W/K2m.s, 5.21 × 1011W/K2m.s for SrCd2P2 and SrCd2As2, respectively. The tremendous optoelectronic characteristic and outstanding power factor values predicted this group could be favorable for uses in solar and thermoelectric uses.

Terahertz Electromodulation Spectroscopy for Characterizing Electronic Transport in Organic Semiconductor Thin Films

Terahertz (THz) spectroscopy is a well-established tool for measuring the high-frequency conductance of inorganic semiconductors. Its application to organic semiconductors, however, is challenging, because of the low carrier mobilities in organic materials, which rarely exceed 10cm2/Vs. Furthermore, low charge carrier densities in organic field-effect devices lead to sheet conductivities that are often far-below the detection limits of conventional THz techniques. In this contribution, we present the application of THz electromodulation spectroscopy for characterizing charge transport in organic semiconductors. Pulses of THz radiation are transmitted through organic field-effect devices and are time-resolved by electro-optic sampling. A differential transmission signal is obtained by modulating the gate voltage of the devices. This controls charge injection into the semiconductors, where the charge carriers reduce the THz transmission by their Drude response. Advantageous is that a nearly noise-free differential transmission can be obtained. Furthermore, electromodulation allows to sense specifically either injected electrons or holes. Because the method exclusively probes transport of mobile carriers, it provides access to fundamental transport properties, which are difficult to access with conventional characterization methods, such as conductance measurements of organic field-effect transistors. The outstanding property that a relative differential signal is measured allows to obtain charge carrier mobilities with high reliability. Mobilities as small as 1cm2/Vs can be probed, which makes THz electromodulation spectroscopy an attractive tool for studying charge transport in most technologically relevant organic semiconductors.

Anisotropic magnetoelectric transport in AgCrSe2 single crystals

AgCrSe2, a quasi-two-dimensional material, is famous for its superionic conducting. Here, it is confirmed that the anisotropic behaviors exist in the magnetic, electronic, and magneto-transport properties of the AgCrSe2 single crystal. A field induced phase transition causes asymmetrical antiferromagnetic states in the μ0H//ab plane and the c axis, which correspond to the positive/negative magnetoresistances in two directions, respectively. Below ∼32 K, a spin flop is manifested with a magnetic field of about 4 T, according to the field dependent electoral resistance. The anisotropic behaviors are ascribed to the quasi-two-dimensional structure and also to the unstable Ag+ ions and the puckered honeycomb lattice of Cr3+ ions. This research reveals fundamental transport properties in AgCrSe2 single crystals and can be explored further in superionic conductor engineering.

Reorientation of Crystalline Block Copolymer Membranes by Phospholipid Hybridization

Block copolymer (BCP) self-assembly and crystallization determine their fundamental mechanical, optical, and transport properties. Multiple physical and chemical routes to control BCP self-assembly have been developed over the years. In contrast, modulating the crystallization behavior, particularly crystallite size and orientation, has received considerably less attention. This paper underpins that 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) phospholipid additives enable precise control of BCP crystallization via a combination of interfacial and confinement effects. The assembly and crystallization behavior of methoxy-poly(ethylene glycol)-b-poly(ε-caprolactone) (mPEG-b-PCL) hybridized with DPPC was elucidated in solid-supported dry-film forms. mPEG-b-PCL/DPPC hybrid films coassemble into multilamellar structures with BCP and lipid domains stacked in registry across the film thickness. With small amounts of DPPC (3 wt %), mPEG-b-PCL/DPPC hybrid films unexpectedly exhibit nonadditive thermal conductivity, reaching ∼0.1 W m–1 K–1, a value considerably lower than pure BCP or DPPC films. Hybridization alters DPPC chain packing and induces specific PCL crystallite orientation at the nanoscale. PCL chains on the folding plane of an orthorhombic lattice optimize molecular interactions with vertically aligned DPPC alkyl chains by orienting PCL crystallites at a 20° tilt. These results enable new applications of polymeric systems in which switchable crystallization routes are used to tune heat transport.

Multiscale modeling of the dynamical conductivity of self-assembled nanoparticle networks: Numerical simulations vs analytical models

Impedance spectroscopy experiments are able to reveal the fundamental charge transport properties of a wide variety of complex disordered and nano-structured materials provided that appropriate modeling tools are used. In this paper, we present a numerical simulation-based approach to model the dynamical conductivity of networks formed by self-assembled metal nanoparticles. Inter-particle nano-resistance and nano-capacitance are implemented at the nano-scale assuming inter-particle charge transfer and accumulation mechanisms that can be adapted depending on the nature of the nano-particles and the surrounding medium. The actual positions and spatial arrangements of the nanoparticles within the network are taken into consideration, allowing the attributes of percolating conducting routes to be extracted, classified, and compared in terms of path conductance and statistical distribution of path lengths. Our findings are contrasted to those obtained using analytic models, which are commonly used, but rely on strong assumptions about the electric properties of the conducting paths. We address these assumptions and show that in the case of weakly disordered systems, there is a general agreement between numerical simulations and analytic modeling-based approaches. In the case of disordered networks where the nano-particle size and position fluctuations are included, we show that the path length distribution is frequency-dependent and can differ significantly from the lognormal distribution usually assumed in the analytic models. The impedance of individual pathways may be extracted from the numerical simulations; we discovered that the conductance and susceptance of a specific path are frequency-dependent and inversely proportional to the path length only in ordered networks. Strong scattering of conductance values is caused by disorder effects. The developed numerical approach is generic and applies to most nano-devices where charge transport relies on percolation; it allows to bridge the gap between the nano-scale and micro-scale electric characteristics and, thus, permits a deeper understanding of the charge transport properties of nano-structured materials.

Excellent Long‐Range Charge‐Carrier Mobility in 2D Perovskites

AbstractThe use of layered, 2D perovskites can improve the stability of metal halide perovskite thin films and devices. However, the charge carrier transport properties in layered perovskites are still not fully understood. Here, the sum of the electron and hole mobilities (Σμ) in thin films of the 2D perovskite PEA2PbI4, through transient electronically contacted nanosecond‐to‐millisecond photoconductivity measurements, which are sensitive to long‐time, long‐range (micrometer length scale) transport processes is investigated. After careful analysis, accounting for both early‐time recombination and the evolution of the exciton‐to‐free‐carrier population, a long‐range mobility of 8.0 +/− 0.6 cm2 (V s)–1, which is ten times greater than the long‐range mobility of a comparable 3D material FA0.9Cs0.1PbI3 is determined. These values are compared to ultra‐fast transient time‐resolved THz photoconductivity measurements, which are sensitive to early‐time, shorter‐range (tens of nm length scale) mobilities. Mobilities of 8 and 45 cm2 (V s)–1 in the case of the PEA2PbI4 and FA0.9Cs0.1PbI3, respectively, are obtained. This previously unreported concurrence between the long‐range and short‐range mobility in a 2D material indicates that the polycrystalline thin films already have single‐crystal‐like qualities. Hence, their fundamental charge carrier transport properties should aid device performance.

Self-Absorption Analysis of Perovskite-Based Luminescent Solar Concentrators

Luminescent solar concentrators (LSCs) are considered promising in their application as building-integrated photovoltaics (BIPVs). However, they suffer from low performance, especially in large-area devices. One of the key issues is the self-absorption of the luminophores. In this report, we focus on the study of self-absorption in perovskite-based LSCs. Perovskite nanocrystals (NCs) are emerging luminophores for LSCs. Studying the self-absorption of perovskite NCs is beneficial to understanding fundamental photon transport properties in perovskite-based LSCs. We analyzed and quantified self-absorption properties of perovskite NCs in an LSC with the dimensions of 6 in × 6 in × 1/4 in (152.4 mm × 152.4 mm × 6.35 mm) using three approaches (i.e., limited illumination, laser excitation, and regional measurements). The results showed that a significant number of self-absorption events occurred within a distance of 2 in (50.8 mm), and the photo surface escape due to the repeated self-absorption was the dominant energy loss mechanism.

1D topological systems for next-generation electronics

1D topological systems for next-generation electronics

Mechanically robust hydrophobized double network hydrogels and their fundamental salt transport properties

AbstractWater swollen polymer networks are attractive for applications ranging from tissue regeneration to water purification. For water purification, charged polymers provide excellent ion separation properties. However, many ion exchange membranes (IEMs) are brittle, necessitating the use of thick support materials that ultimately decrease throughput. To this end, novel double network hydrogels (DNHs) with variable water content are prepared and characterized in terms of mechanical and ion transport properties to evaluate their potential utility as tough membrane materials. The first network contains fixed anionic charges, while the other is comprised of a copolymer with varied ratios of hydrophobic ethyl acrylate (EA) and hydrophilic dimethyl acrylamide (DMA) repeat units. Characterization of freestanding DNH films reveals a reduction in water content from 88 to 53 wt% and a simultaneous increase in ultimate stress and strain by ~3.5× and ~4.5×, respectively, for 95%/5% EA/DMA, relative to 100% DMA. Fundamental salt transport properties relevant to water purification, including permeability, solubility, and diffusivity, are measured and systematically compared with conventional membrane materials to inform the development of DNHs for membrane applications. The ability to simultaneously reduce water content and increase mechanical integrity highlights the potential of DNHs as a synthetic platform for future membrane applications.

Determination of coordination form of tungsten ion in molten alkali chloride by electrochemical method

The results of the coordination form of low-concentration ions in molten salt have great reference significance for exploring the electrolysis reaction mechanism. Given the low concentration of tungsten ions after the electrochemical dissolution of tungsten carbide, this can be difficult to judge the coordination form of tungsten ions through spectral characterization. This paper will struggle to tackle the problem by comparing the electrochemical behaviors of tungsten ions from the electrochemical dissolution of tungsten carbide and NaCl–KCl–2 wt% Na2WO4 melt. The electrochemical method had been investigated as a mean to understand the fundamental thermodynamic and mass transport properties of tungsten ions. The apparent standard potentials of oxidation and reduction couple at several temperatures were calculated by using a proposed new method. The diffusion coefficients of tungsten ions were determined. It can be concluded that the tungsten ions in the molten salt after tungsten carbide electrolysis were simple ions without coordinating anions by comparing the dynamics and thermodynamic calculation results of the two systems. The developed simulation boxes can serve as a verification for further theoretical investigations of the coordination form of tungsten ion groups at molecular scale. The results of this work provide necessary knowledge for the development methods to determine the dynamics and thermodynamic properties and coordination forms of metal ions.

Study on empirical models of isobaric heat capacities and conductivities for ammonium salt-based DESs

In this research, a comparative evaluation of empirical models for the fundamental transport properties of DESs is presented. The detailed knowledge about the properties of DESs is critically important to rationally extend the utilization of DESs. The accurate information about these properties plays a vital role in transferring the laboratory scale applications to large industrial scale. In this regard, the ammonium salt-based 5 DESs were synthesized to study empirical models for conductivities within the temperature range of 298.15 to 323.15 K. The experimental isobaric heat capacity data of 17 ammonium salt-based DESs covering 326-data points with a temperature range of 293.15 to 353.15 K were collected from the open literature. Six models including group contribution – mass connectivity index (GC-MCI) and artificial neural network (ANN) were applied for modeling and predicting heat capacities. The GC-MCI and ANN showed good agreement with the experimental data. The error values of the GC-MCI model (R2 = 0.9863), and AAD = 2.25%) and ANN model (R2 = 0.9982 and AAD = 0.55%) were calculated. Three models were employed for studying conductivities of DESs. Results for conductivities show that the 4-parameters GH model gave low deviation (R2 = 0.9984 and AAD = 2.63%) compared to VFT (R2 = 0.9950 and AAD = 3.11%) and ARH (R2 = 0.9942 and AAD = 5.30%).

Understanding Chemical Crossover in Redox Flow Batteries Via Quantitative Structure-Property Relationship Modelling

The understanding of anode and cathode chemical crossover in redox flow batteries (RFBs) is imperative to crossover mitigation and the development of high-performing RFBs for green energy storage. This may be accomplished through investigating the fundamental transport properties of chemical crossover in redox flow batteries (RFBs) through the discovery of quantitative structure-property relationships (QSPRs) by developing predictive multivariate linear regression (MLR) models. Through the isolation of steric and electronic molecular parameters that impede chemical crossover in RFBs, these parameters may be successfully tuned to rationally design electrolyte species that are crossover resistant. This approach effectively mitigates one of the predominate mechanisms of RFB degradation, thereby addressing a large hurdle to their successful commercialization. Herein, we demonstrate the process of model development and present our findings toward achieving crossover resistant electrolytes and tuning molecule-separator interactions to further enhance whole system crossover resistance.