bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Material and Process Optimization for the Scale-up of Printed OTFT on Printing Pilot Line
Authors: Charbonneau Micael
Published: February 2020

This paper introduce the PICTIC Printing Pilot line and related activities for the development of printed electronic. In particular, through Collaborative Project and internal Development, CEA-LITEN and partners have been working on the transfer and scale-up of OTFT Circuits from Lab to Printing Pilot Line (GEN1). The paper will present the Materials, Tools and Characterization Protocols that have been co-developed at CEA-LITEN with partners from the ATLASS European Project. Material strategy and inks developed for robust printing capability and the engraving technologies engineered for the downscaling of printed pattern down to 150 µm and beyond will be presented. We will discuss characterization protocols set-up to tune inks and process recipes and introduce the Automated Inspection Tools developed to support the yield and TRL improvement. Electrical performances of OTFT fabricated on GEN1 pilot line will be also presented (µ > 2cm²/V/s; Vt~ 4.5 V) together with statistics on foils (>100TFTs) and possible track of improvement for résolution and electrical performance scaling will be presented.

Figure 1
Thin Film FETs on Flexible Substrates: a Case for Biosensing Application
Authors: Pasha Syed Khalid , Mujawar Mubarak A , Sonawane Apurva , Bhansali Shekhar
Published: February 2020

Thin film transistors have been explored for biosensing applications due to their simplicity, fast reaction times and low cost. The fabrication of thin film transistors on flexible substrates open up new avenues for wearable electronic sensors for personal health monitoring. In this study, we investigate the fabrication and characterization of a Zinc Oxide based thin film transistor on a flexible substrate for biosensing application. Oxide based semiconductors have advantages such as deposition at low temperatures, better smoothness and a great potential to be used on a roll to roll fabrication for flexible applications. Zinc oxide (ZnO) serves as an ideal substrate for binding bio-recognition molecules viz., antibodies, Aptamers, enzymes, microorganisms etc. This binding is facilitated by the difference in the isoelectric points of the bio-receptor molecules (~5) and Zinc oxide (~9). Using this peculiarity, we designed back-gated bio-functionalized field effect transistors (FETs) for linker-free and label-free detection of biomarkers. The transistors were fabricated using Atomic layer deposition and sputtering techniques on a polyimide substrate. Polyimide is a stable polymer which has been used in electronic industry as a flexible substrate for various applications. The high temperature stability combined with excellent adhesion to different materials renders it a suitable substrate for this investigation. After fabrication, the transistors were characterized for their electrical parameters and material properties. The channel of the TFT was fictionalized by immobilizing antibodies that were specific to Cortisol on top of it. Cortisol is an important corticosteroid that is produced in humans by the adrenal cortex in the adrenal gland. It has been associated with maintaining healthy bodily functions and is often cited as a biomarker for quantification of stress. It is often released in response to stress and low blood glucose levels. It has been associated with several other important bodily functions and is considered as one the most important biomarkers for detecting stress. Cortisol solution was dispensed on the fictionalized FETs and the source-drain current was measured. The binding of cortisol to the immobilized antibodies causes a change in the charge transfer characteristics of the gate and thus modifies the gate voltage. This change manifests in the form of a change in drain current of the FET. Accordingly, the source-drain current is related to the change in cortisol levels of the samples exposed to the sensor.
Molecular Dynamics Study Investigating the Interface between Nanoparticles and Matrix in Composite Materials
Authors: De Nicola Antonio
Published: February 2020

Polymer composites attract large attention for their industrial use because of their unique features. The preparation of equilibrated melts of long entangled chains in the presence of a solid

nanoparticle in molecular dynamics simulations is a very difficult task due to the slow relaxation time. We present a coarse-grained (CG) model suitable for polymer nanocomposites which combines Iterative Boltzmann-Inversion derived polymer models, the hybrid particle-field representation of non-bonded interactions, and a convenient description of a solid nanoparticle suitable for hybrid particle-field models. The proposed approach is applied to test simulations of well characterized polystyrene-silica nanocomposites models. Finally, procedures for an efficient relaxation of pure polymer melts and interphase structures of large molecular weight nanocomposites are proposed.
Thermal Conductivity Improvement of Fiber Orientation Control By Sheet Folding Method
Authors: Saito Takushi , Ihara Satoshi , Kawaguchi Tatsuya , Satoh Isao
Published: February 2020

In this study, a method improving the thermal conductivity in the sample thickness direction by secondary processing of an intermediate sheet in which carbon fibers were oriented in one direction was proposed. Moreover, the effectiveness of the proposed method was experimentally investigated. When fillers having a large aspect ratio such as carbon fibers are added to the polymer matrix, the thermal conductivity of the composites is largely influenced by the filler orientation. Therefore, it is necessary to orient the filler in the out-plane direction to effectively improve the thermal conductivity in the thickness direction of thermal conductive film or sheet. In the experiment, a zigzag shape was given to the intermediate sheet, and a sample with a thickness of 1 mm was obtained by folding the intermediate sheet. As a result, the thermal conductivity in the sheet thickness direction measured by the laser flash method became five times larger than that of the initial sample, the intermediate sheet.
Evaluation of Internal Morphology and Mechanical Properties of ABS/PMMA Blend
Authors: Ueda Tsubasa , Kurose Takashi , Nagasawa Motonobu , Umahara Makoto , Morioka Kazuo , Iwata Jun , Ito Hiroshi
Published: February 2020

Glazing materials represented by glass substitutes used in various amusement products (e.g., arcade) are required to have high surface hardness and ductile properties. The brittle material has the high surface hardness but it is easy to break. However, the ductile material is inferior in scratch resistance. Therefore, polymer blend material composed of high hardness material in the surface layer and a ductile material in the core part is desired because of its properties with anti-scratching and a high impact resistance. In this study, we conducted a fundamental study on material development using advanced melt mixing process of the blending system between poly(acrylonitrile-butadiene-styrene) copolymer (ABS) with the high toughness and poly(methyl methacrylate) (PMMA) having high surface hardness. The ABS/PMMA blends were prepared by conventional twin-screw melt kneading extruder (L/D = 25) and the advanced octa-screw melt kneading extruder (L/D = 180) at 230 ℃ with the rotational speed of 100 rpm. The amount of PMMA in the blends was 20 wt%. In Figure 1, the observation result of SEM images reveals that PMMA domain was dispersed in ABS matrix. The smaller domain size with higher dispersibility of PMMA can be obtained by octa-screw melt kneading extruder (500 nm) compared with twin-screw melt kneading extruder (1-2 µm) process, due to the effect of higher L/D of the octa-screw kneading extruder. The enhance of dispersibility and the decrease in domain size of PMMA has the resulted in the enhancement of the mechanical properties of the ABS/PMMA blend such as the bending modulus and bending stress, surface modulus, and pullout load of the nail. In addition, the relationship between the bending modulus and pullout the load of nail was reasonably clarified.

Figure 1
Interface of Hydrated Perfluorosulfonic Acid Electrolyte and Platinum Catalyst: Dissipative Particle Dynamics Simulation Model
Authors: Tajima Nobuo , Nara Jun , Yamasaki Takahiro , Ozawa Taku , Nitta Hiroya , Ohata Kosuke , Ohno Takahisa
Published: February 2020

Polymer electrolyte fuel cells (PEFC) are expected to be used widely in the future as a non-polluting power source in various applications. PEFC applications are only limited currently however, as PEFCs are still not competitive with existing power sources in energy efficiency and cost. One of the most popular forms of PEFC are composed of an electrolyte of hydrated perfluorosulfonic acid (PFSA), and carbon based electrodes that support small catalyst particles (typically Pt) on the surface. The global performance of PEFC of this type is governed by the rate of red-ox reactions on the catalyst surface, which are affected by molecular level dynamics of fuel, oxidants, and protons in the electrolyte near the catalyst surface. We need deeper understanding on this interfacial structures for new insights into the mechanisms that control the electrochemical surface processes. Several structure models have been proposed for the bulk electrolyte, while only little is understood as to its structure near the catalyst surface so far.

In this study, to investigate the interfacial system of hydrated PFSA and platinum surface, we constructed models of this system for dissipative particle dynamics (DPD) simulations. DPD simulation is a kind of coarse-grained simulation which is used to study mesoscopic systems, typically consisting of macromolecules like polymers and biomolecules. We coarse grained the simulation system with DPD particles corresponding to PFSA segments A-C (see Fig.1), those grouping four water molecules (denoted as W), and those grouping ~8 platinum atoms (Pt). The catalyst surface was represented by a fixed slab of the Pt particles forming a simple lattice. We used soft potentials constructed via quantum chemical calculations by Okuwaki et al. [1] for interactions of DPD particles A-C and W; while we newly constructed soft potentials for the interactions of Pt with other DPD particles by analyzing their affinities via all-atom classical MD simulations for some small systems. For these all-atom MD simulations, we derived some intermolecular potential functions by first principles calculations. Details of our DPD simulations as well as the interaction model constructions will be presented in the conference session (a snapshot is displayed in Fig. 2).

A portion of this research was supported by MEXT within the priority issue 6 of the FLAGSHIP2020 project (Project ID: hp160226, hp170253,hp180187).

[1] K. Okuwaki et al., JSAP spring meeting (2016) 20a-W323-6.

Figure 1
Effects of Post Deposition Annealing Ambient on Interfacial and Electrical Properties of HfO2/Ge3N4 Gate Stacks on Ge Mos Devices
Authors: Mallem Kumar , Dutta Subhajit , S.V Jagadeesh Chandra , Yi Junsin
Published: February 2020

We report the effects of post deposition annealing (PDA) ambient O2 and FG gas on interfacial and electrical properties of HfO2 gate dielectric on nitrided Ge. The morphological studies of the dielectric, interface quality and chemical composition of the HfO2/Ge3N4/Ge were studied from X-ray diffraction (XRD), High-resolution transmission electron microscopy image (HRTEM) and X-ray photoelectron spectroscopy (XPS) respectively. Experimental results of O2 annealed devices exhibit improved interfacial and electrical characteristics such as high dielectric constant (~19.50), high capacitance (1.24 nF), small EOT (1.74 nm), Dit (3.18x1010 cm2 eV-1), oxide charges (Qeff 2.60x1012 eV-1) and gate leakage currents in the order nA (0.5x10-9 A/cm-2) as compared with FG annealing devices. The Fowler−Nordheim (F−N) tunnelling current conduction mechanism was also verified. Therefore, these results are evidence for the O2 gas PDA improves the interfacial and electrical properties of HfO2/Ge3N4/Ge MOS devices as compared with FG annealing.
Highly Directional Deposition of Oriented Nanoscale Semiconductor Structures with Phototropic Control
Authors: Meier Madeline Claire , Carim Azhar I , Yalamanchili Sisir , Thompson Jonathan R , Atwater Harry A , Lewis Nathan S
Published: February 2020

Semiconducting chalcogen films consisting of high-fidelity, periodic nanoscale elements displaying significant structural anistotropy were deposited using a light-guided electroplating technique without any lithographic processing. The direction of the material growth with respect to the substrate was controlled by manipulating the light propagation vector. Thus, the morphological determination of the structures was guided in the same manner as the growth of sunflowers and palm trees are guided by the sun, natural phototropism. Additional morphological complexity was generated by combining the use of inclined illumination with a series of defined polarization and wavelength inputs which allowed variation of the feature anisotropy, in-plane and out-of-plane orientation, spacing, and periodicity. The optical control of the morphological determination was a consequence of light scattering and a spontaneous optimization of the interfacial light absorption during deposition. These fundamental processes were simulated using a finite-difference time domain method to model the light-matter interactions and a Monte Carlo method for mass addition. The results of the simulation successfully reproduced the experimentally observed morphologies, affirming that the light response was a fully optically-induced phenomenon. The underlying optical basis was further investigated using a simplified light scattering model that corroborated the magnitude and direction of the empirically-observed phototropic responses.
Effect of Pinholes in Electrolyte on Re-Oxidation Resistance of the Anode-Supported Solid Oxide Fuel Cells
Authors: Kumada Keigo , Sumi Hirofumi , Sato Kazuhisa , Hashida Toshiyuki
Published: February 2020

In this study, assuming the case of fuel starvation (e.g. high utilization of fuel), the stop of fuel gas supply under SOFCs (solid oxide fuel cells) operating condition that caused leakage of oxygen into the pinholes and re-oxidation of the anode substrate. At that time, OCV (open circuit voltage) was maintained in the case of pinhole free electrolyte. But, when there are many pinholes in the electrolyte, the OCV has fallen because an airflow through the pinholes and then directly burning fuel that caused increase of the oxygen partial pressure at the anode side. In this experiment, air supply was continued while the fuel supply was stopped. Therefore, the oxygen partial pressure at the cathode side is considered to be constant that enable the OCV to convert the oxygen partial pressure at the anode side by using the Nernst equation. To consider the oxygen partial pressure change in the cell’s anode side with time as an accumulated oxygen permeation curve, it could be found oxygen transmission rate (OTR). This value depends on the number and size of pinholes, thus OTR could be used as an index of the oxidation resistance in SOFCs.
(Invited) Proton Conductivity Enhancement in Polymer Thin Films By Molecular Orientation and Organized Structure
Authors: Nagao Yuki
Published: February 2020

Highly proton-conductive polymers have long attracted the attention of researchers for use in energy conversion, sensors, catalysts, and other applications. From the viewpoint of scientific history of creating highly proton-conductive polymers, one fundamental approach is based on the strategy of phase-segregated structures with strong acid groups.[1-3] Protons are considered to be transported through the hydrophilic parts.

In the recent polymer research fields, taking advantage of the interface extends the molecular design such as the oriented structure and organized structure for the highly proton conductive materials. Matsui et al. showed anisotropic proton conductivity in Langmuir–Blodgett thin films with well-defined lamellar structures [4]. Proton conductivity is enhanced by the formation of 2D hydrogen-bonding networks in multilayer nanosheets [5, 6].

In this presentation, the author demonstrates a new approach to enhance the proton conductivity of the polymer thin films using an interface that can modify the degrees of freedom for a polymer structure through interaction between the substrate surface and polymers.[7-12] The interface can modify the degrees of freedom for polymer structures through interaction for functional groups, wettability, and surface charge between the substrate surface and polymers. Some proton-conductive polymers exhibit an oriented structure determined by an IR p-polarized multiple angle incidence resolution spectrometry (pMAIRS) [13]. Their oriented thin films show unique proton transport properties compared to those of non-oriented samples.

References

[1] K.D. Kreuer, J. Membr. Sci., 185 (2001) 29-39.

[2] M.A. Hickner, H. Ghassemi, Y.S. Kim, B.R. Einsla, J.E. McGrath, Chem. Rev., 104 (2004) 4587-4611.

[3] T.J. Peckham, S. Holdcroft, Adv. Mater., 22 (2010) 4667-4690.

[4] T. Sato, Y. Hayasaka, M. Mitsuishi, T. Miyashita, S. Nagano, J. Matsui, Langmuir, 31 (2015) 5174-5180.

[5] T. Sato, M. Tsukamoto, S. Yamamoto, M. Mitsuishi, T. Miyashita, S. Nagano, J. Matsui, Langmuir, 33 (2017) 12897-12902.

[6] J. Matsui, H. Miyata, Y. Hanaoka, T. Miyashita, ACS Appl. Mater. Inter., 3 (2011) 1394-1397.

[7] Y. Nagao, Langmuir, 33 (2017) 12547-12558.

[8] Y. Ono, R. Goto, M. Hara, S. Nagano, T. Abe, Y. Nagao, Macromolecules, 51 (2018) 3351-3359.

[9] K. Krishnan, H. Iwatsuki, M. Hara, S. Nagano, Y. Nagao, J. Mater. Chem. A, 2 (2014) 6895-6903.

[10] K. Krishnan, H. Iwatsuki, M. Hara, S. Nagano, Y. Nagao, J. Phys. Chem. C, 119 (2015) 21767-21774.

[11] Y. Nagao, J. Phys. Chem. C, 117 (2013) 3294-3297.

[12] Y. Nagao, J. Matsui, T. Abe, H. Hiramatsu, H. Yamamoto, T. Miyashita, N. Sata, H. Yugami, Langmuir, 29 (2013) 6798-6804.

[13] T. Hasegawa, Anal. Chem., 79 (2007) 4385-4389.
Molecular Dynamics Simulations of Li+ Desolvation in Electric Double Layer at the Lithium Ion Battery Graphitic Anode Interface
Authors: Aoyagi Koutarou , Otani Minoru
Published: February 2020

The use of lithium-ion (Li-ion) batteries to power hybrid, plug-in hybrid, and electrical vehicles in recent years calls for greater battery charge/discharge rate and cycle life than their applications in electric devices. These properties are largely caused by the phenomenon in the interphase of electrode and electrolyte. For the battery charge/discharge rate, the process of Li+ desolvation in the interphase and intercalation to graphitic anode are key factors. However, there are various hypotheses about Li+ desolvation and it has still not been clarified. Detailed understanding of the interphase can accelerate the development of Li-ion battery. In this work, to gain an understanding of the electrolyte structure in the interphase, atomistic molecular dynamics simulations of the electrode/electrolyte interphase at a constant voltage were performed and Li+ desolvation process were observed.

We utilize a modified version LAMMPS code implemented the novel computational approach to carry out the simulation of the electrolyte in the presence of electrodes and applied voltage. The approach for treating the model of battery interface held at a constant potential, which has necessity to calculate the nonperiodic cell in the surface normal direction, is based on effective screening medium (ESM) method [Otani and Sugino, Phys. Rev. B 73, 115407 (2006)]. The Poisson equation is solved with the help of the green’s function technique. The electrostatic potential V(z) was solved as following equation, V(z) = -∑q
i|z
i-z|/2ε
0
S
0, where ε
0 is the permittivity of vacuum, S
0 is electrode’s surface area, and q
i is the charge of ith atom. If a potential difference V is applied across the two electrodes, then the charges are induced on each electrode surface to be V(z
le) - V(z
re) = V, where z
le is the z of left side electrode surface and z
re is right one.

Prepared simulation model is the box with two edge plane of graphitic electrodes separated by an electrolyte which consists of 1M LiPF6 / ethylene carbonate (EC) / ethyl methyl carbonate (EMC) 30:70. The interelectrode spacing is 8nm. We confirmed it is enough to describe the Electric double layer (EDL) of each electrodes with utilizing ESM-RISM method [Nishihara and Otani, Phys. Rev. B 96, 115429 (2017)].

The simulation of 2ns at 298K was carried out in the constant NVT ensemble with applied voltage of constant 20V. The reason why excess voltage was applied is to get the interphase structure with EDL in short timescale simulation. We observed the dynamics of electrolyte in the interphase of graphitic anode. Then we found that EMC solvate Li+ until the end, and desolvation of EC occur by force of the own dipole facing to the electric field. It was suggested that the desolvation of EC is faster than that of EMC in the EDL. We also calculated dielectric spectrums of solvents on the surface for confirming existence of solvent’s dynamics in EDL by experiment.

Figure 1
The Electrochemical Conversion of Carbon Dioxide on Cu−Ni Stacked Bilayer Electrodes
Authors: Yoshihara Naoki , Saito Hiroki , Noda Masaru
Published: February 2020

The electrochemical reduction of carbon dioxide (CO2) has gained popularity as a novel technique to realize a sustainable carbon cycle owing to improvements in power generation using renewable energy sources, such as solar and wind energy [1−2]. Recent progress of CO2 conversion utilizing the crystalline copper surfaces offers a promising approach to produce the useful hydrocarbon products.

In our previous works, we demonstrated the fabrication of the single-crystal copper membranes by sputtering copper onto the specific support substrates, such as c-plane sapphire (Al2O3) and magnesium oxide (MgO). The electrochemical reduction of CO2 on these copper surfaces was produced selective hydrocarbons as compared with the commercially available copper plates [3]. In addition, these sputtered single-crystal copper membranes have been successfully peeled away from the support substrates, and thus it is able to fabricate repeatedly onto the identical support substrate [4]. The electrochemical reduction of CO2 on these crystalline copper electrodes is an effective route toward the practical use of the CO2 conversion process, however this methodology of homogeneous copper membrane deposition is essential to the complicated process.

On the other hand, it has been demonstrated that the electrochemical reduction of CO2 to hydrocarbon on a copper surface is due to moderate surface adsorption of a carbonate intermediate by theoretically calculations [5]. Binary metal electrodes, such as copper and another metal, are expected to allow to the carbonate intermediate to adsorb to the appropriate surface and achieve the more effective CO2 conversion to hydrocarbon production as compared with pristine copper electrodes. In this work, we study the electrochemical conversion of CO2 on Cu−Ni stacked bilayer electrodes. Hydrocarbon emissions for the electrochemical reduction of CO2 were strongly dependent on the amount of nickel deposited on the copper electrodes. However, excess deposition of nickel on the copper electrodes suppressed the CO2 conversion. This is suggested that the surface adsorption of the carbonate intermediate is improved on the Cu−Ni stacked bilayer electrodes, compared with pristine copper electrodes, due to the interactions between copper and nickel. Additionally, we also show the selectivity of the hydrocarbon products formed via CO2 conversion on the Cu−Ni stacked bilayer electrodes in terms of the crystal structure underneath the copper electrodes.

Reference

[1] Y. Hori et al., J. Mol. Catal. A Chem., 199, 39–47 (2003).

[2] K. J. P. Schouten et al., ACS Catal., 3(6), 1292–1295 (2013).

[3] N. Yoshihara et al., ECS Trans., 66(24), 83-89 (2015).

[4] N. Yoshihara et al., ECS Trans., 75(43), 33-38 (2017).

[5] A. A. Peterson et al., J. Phys. Chem. Lett., 3, 251−258 (2012).
(Invited) Conductive Biopolymers for Selective Metal-Devoid Electrocatalysis
Authors: Coskun Halime , Stadler Philipp
Published: February 2020

Electrocatalysis can be useful in energy conversion, in particular for the production of synthetic fuels from renewable energy. However, this requires catalytic conductors, which sustain the reaction conditions that foremost occur in aqueous solution. Conducting polymers represent a chemically robust but conductive materials class that could be harnessed for aqueous electrocatalytic processes in order to facilitate the important reactions steps to electrosynthesize fuels.

In terms of CO2 reduction this has been demonstrated by using a conducting form of polydopamine.(1–3) This system no than other incorporates a richly functionalized backbone able to attach CO2 and electro-reduce to formate efficiently. We shed light on the relevant electro-activation of the incorporated functional themes in the biopolymer and compare this mechanisms to similarly efficient inorganic catalysts. We find that it is the actual nature of the incorporated theme that significantly influences its final selectivity. Such tunability enables the tailoring of selective and highly active catalytic surfaces from organic-functional matter. The functionalzed organic catalysts rely on different reaction mechanisms than state-of-the-art metal-based systems and possibly can be optimized as future sustainable contenders for metal-based electrocatalysts.

H. Coskun et al., Chemical vapor deposition - based synthesis of conductive polydopamine thin-films. Thin Solid Films. 645, 320–325 (2018).

X. Zheng et al., Sulfur-Modulated Tin Sites Enable Highly Selective Electrochemical Reduction of CO2 to Formate. Joule (2017), doi:10.1016/j.joule.2017.09.014.

H. Coskun et al., Biofunctionalized conductive polymers enable efficient CO2 electroreduction. Sci. Adv.
3, e1700686 (2017).
(Invited) Imperceptible Electronic Sensor Foils
Authors: Kaltenbrunner Martin
Published: February 2020

Electronics of tomorrow will be imperceptible and will form a seamless link between soft, living beings and the digital world. Exploring the fundamental physics, mechanical form factors, and materials required to meet the needs of this new generation of soft electronics is driving multidisciplinary research worldwide. Weight, flexibility and conformability are pivotal for future wearable, soft and stretchable electronics to proliferate. The abilities to be imperceptible, epidermal, transient and self-healing are fueling the vision of autonomous smart appliances to be embedded everywhere, on textiles, on our skin, and even in our body.

We here introduce a technology platform for the development of large-area, ultrathin and lightweight electronic and photonic devices, including solar cells[1,2], light emitting diodes[3]and photodetectors[4], active-matrix touch panels[5], implantable organic electronics, imperceptible electronic wraps and “sixth-sense” magnetoception[6]in electronic skins. Air stable perovskite solar cells, only 3 µm thick, endure extreme mechanical deformation and have an unprecedented power output per weight of 23 W/g. Highly flexible, stretchable organic light emitting diodes are combined with photodetectors for on-skin photonics and pulse oximetry. E-skins with GMR-based magnetic field sensors equip the wearer with an unfamiliar sense that enables perceiving of and navigating in magnetic fields. These large area sensor networks build the framework for sensor skins that are not only highly flexible but become highly stretchable when combined with engineered soft materials such as elastomers, shape memory polymers or hydrogels. We show mobile health monitoring systems, smart, tissue-like electronics and soft machines that utilize tough hydrogels[7]as soft robots, generators and adaptive lenses.

References

[1] Kaltenbrunner et al, Nature Communications 3:770, 1-7 (2012)

[2] Kaltenbrunner et al, Nature Materials 14, 1032-1039 (2015)

[3] White et al, Nature Photonics 7,811–816 (2013)

[4] Yokota et al, Science Advances 2:e1501856 (2016)

[5] Kaltenbrunner et al, Nature 499, 458-464 (2013)

[6]GSC Bermúdez et al, Science Advances 4:eaao2623, (2018)

[7] Wirthl et al, Science Advances 3:e1700053, (2017)
Na+ Ion Transport in Glassy Electrolytes for Solid-State Sodium Ion Batteries: A Reactive Molecular Dynamics Study
Authors: Dive Aniruddha Mukund , Banerjee Soumik
Published: February 2020

All solid-state sodium ion battery is a promising technology for electrical grid energy storage. The low ionic conductivity of solid-state electrolytes is a major challenge towards commercialization of solid-state sodium ion batteries. Sulfide glasses are potential electrolytes possessing excellent ionic conductivity at room temperature for high performance sodium ion batteries. Understanding the Na+ ion transport in these glasses is critical towards developing novel electrolytes for these all solid-state sodium batteries. In-situ characterization of Na+ ion transport through experiments is extremely challenging. Molecular dynamics (MD) simulations offer an economical route for investigating the local structure of these glasses as well as Na+ ion transport mechanisms. Classical MD simulations employ empirical forcefields to define pairwise interactions between constituent ions in these glasses. These empirical forcefields captures the short-range order accurately, but cannot capture the medium-range order. Additionally, these empirical forcefields are not to account for the complex chemistry in sulfide glasses makes it extremely challenging to model these glasses. While ab initio MD simulations are able to overcome these limitations, the maximum system size that can be realistically modeled using ab initio MD is limited (400-500 atoms) and cannot account for the bulk properties of these glasses.

Reactive force fields, such as ReaxFF, provide an effective route to accurately capture bond breakage and formation, while simulating considerably large systems (~ 100,000 atoms). These reactive force fields (ReaxFF) are based on bond-order formalism in conjunction with charge equilibration scheme. ReaxFF can more accurately capture the complex electrode-electrolyte interfacial reactions as compared to both classical and ab initio MD. Understanding these interfacial reactions is extremely crucial in developing a stable interface for high performance sodium ion batteries. ReaxFF forcefields are highly system specific and need to be parameterized for an individual system.

In the present study, we employed Monte Carlo Force Fields (MCFF) optimizer to parameterize ReaxFF for x Na2S – (1-x) SiS2 glasses. We utilized ReaxFF for Li/Al/Si/O as a starting forcefield which was expanded for the x Na2S – (1-x) SiS2 glasses. Parameterization was performed by fitting against formation energies, atomic configurations and charge distributions for a range of representative clusters and equations of state obtained through DFT calculations. The parameterized reactive forcefields were validated by comparing the pair distribution functions (PDF’s) obtained through MD simulations to those obtained through X-ray scattering experiments. Na+ ion transport was investigated in these glasses characterizing the changes in the local structure with composition. Interfacial reactions between pure sodium metal and glassy electrolyte were further analyzed using these parameterized forcefields.
Lithium Ion Batteries and Next Generation Energy Storage Technology - Adoption to Aircraft and Aerospace
Authors: Brewer Roger Alan
Published: February 2020

Lithium ion batteries provide a high energy to weight ratio making the technology attractive for aircraft and aerospace applications. Introducing lithium ion battery technology, as with other types of battery chemistries, can prove challenging for a variety of reasons. As electrical load demands for aircraft increase controlling and harnessing high energy dense solutions will become more critical.

The presentation will begin with a basic introduction of lithium ion battery chemistry and evolve into a discussion on the role various aspects play in safely implementing lithium ion batteries on aircraft including the key design drivers and issues that influence system safety. The presentation will also cover key operational modes, applied to aircraft in general, that can drive risk and effect a prudent power system design (cell overheating, voltage “sag” below minimums at low temperatures, etc.) in the integration of battery technologies to an aircraft. Battery design features and attributes that relate to typical operating modes in an airborne platform will also be discussed in some detail.

The presentation will next evolve into a narrative on next generation energy storage technologies and supercapacitors (electric double layer devices) and their potential role in evolving airborne applications. Implementation of higher surge supportable energy storage designs, again driven by considerations at cold temperature conditions, will also be discussed. Energy and power density "road mapping targets" for evolving applications will be highlighted along with issues that influence nominal values including, but not limited to, operating temperature (cold and hot temperature extremes) typical of battery installations in harsher Aerospace environments. An illustration will be provided in the presentation of what the ideal aircraft battery looks like including the ability to float on an unregulated aircraft bus (without Batter Management Electronics) with large voltage swings, ripple content as well as other “nice to haves” (including higher packaged battery system Whrs and kilo-Watts per kilo gram than existing). A final summary will wrap up the discussion with an overview of the presentation material.
Free Standing Nitrogen Deficient Carbon Nitride Oxygen Electrodes for Metal-Air Batteries
Authors: Wagh Nayantara , Shinde Sambhaji S , Kim Dong-Hyung , Lee Jung-Ho
Published: February 2020

Designing highly active, long-life durable bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is urgently required for bringing future renewable energy conversion and storage devices. However, poor conductivity and resulting serious irreversible capacity loss were pronounced for carbon nitride due to its high nitrogen content. Herein, one-dimensional (1D) nitrogen deficient g-C3N4 microtubes based electrocatalysts were fabricated using thermal polymerization of melamine-cyanuric acid complex precursors, followed by denitriding technology to reduce the nitrogen. The resultant ND-g-C3N4 exhibited outstanding bifunctional ORR/OER performances with overpotential of ~ 0.9 V comparable to the commercial noble metal catalysts (such as Pt/C & RuO2). This excellent catalytic performance was attributed to unique one-dimensional tubular structure having abundant active sites, high electrical conductivity, and efficient mass transport in the frameworks. The obtained bifunctional catalysts displayed the outstanding Zn-air battery performance for 400 h stability at 10 mA cm-2 with fast rate capability, open circuit potential of 1.48 V, and high power density of 230 mW cm-2. The outstanding electrochemical performances evidently stimulate the application of g-C3N4 materials in the energy storage devices.
Modeling the Effect of the Operating Temperature on the Performance of a Zinc/Bromine Flow Battery
Authors: Lee Dongcheul , Koo Boram , Lee Jaewoo , Shin Chee Burm
Published: February 2020

The zinc/bromine (Zn/Br2) flow battery is an attractive rechargeable system for energy storage because of its inherent chemical simplicity, high degree of electrochemical reversibility at the electrodes, good energy density, and abundant low-cost materials. Because the performance of a Zn/Br2 flow battery depends strongly on the operating temperature, it is important to develop a mathematical model to predict the performance of the battery as a function of the operating temperature in order to estimate such quantities as current efficiency and conversion per pass. This information can be used to design both of bench and production scale cells and to select the operating conditions for optimum performance.

In this work, a method of modeling the dependence of the charge and discharge curves of a Zn/Br2 flow battery on its operating temperature is presented. This work adopts a simple modeling approach by considering Ohm’s law and charge conservation on the electrodes based on the simplified polarization characteristics of the electrodes. To accommodate the temperature dependence, the key modeling parameters are expressed as the functions of temperature based on the well-known principles of the Arrhenius equation of chemical kinetics and the Nernst equation of electrochemical thermodynamics. The model is validated by comparing the modeling results with the experimental measurements.
Electroless Synthesis Approach for Cu2o-CuO Nanowires/Whiskers on C-Felt for Lithium Ion Battery Anode Materials
Authors: Watson Venroy George , Haynes Zion , Yeboah Yaw D. , Weatherspoon Mark H. , Zheng Jim P , Kalu Egwu Eric
Published: February 2020

Lithium ion batteries (LIBs) have dominated the energy storage industry with carbon as the main anode material and also one of the limiting factors for improved capacity performance. With this widespread use of carbon as the anode, there is a need to evaluate other anode materials to improve LIB performance. Alternatives such as transition metal oxides are promising candidates [1, 2]. One such material with higher capacity than graphite anode material is copper oxide (674 mAh/g) [3,4]. Despite the positive attribute of copper oxide anode materials, pulverization and low-cost feasible fabrication method remain some of the issues impeding its application commercially in LIBs. It is well known that high surface area thin films and small particles reduce volume change and pulverization. As such we engineered copper oxide anode fabrication via use of electroless encapsulation technique. Conductive, porous, mesh-like, and free-standing carbon cloth that is lithium active was coated with very thin copper films electrolessly and oxidized by annealing at 150 and 300OC in air, respectively. These yielded 150-Cu2O-CuO@C-Cloth and 300-Cu2O-CuO@C-Cloth materials that are binder-free and free-standing without the support of a current collector. SEM and XRD revealed the presence of the Cu2O-CuO whiskers. The C-Cloth, 150-Cu2O-CuO@C-Cloth and 300-Cu2O-CuO@C-Cloth materials were used as electrodes in LIBs and the lithiation capacities at first cycle were 300 mAh/g, 450 mAh/g and 510 mAh/g, respectively. Our results indicate that our synthesis approach is feasible to obtain lithium storing anode materials for LIBs.

Figure 1 shows the 1st cycle discharge capacities of C-Cloth, 150 Cu2O-CuO@C-Cloth and 300 Cu2O-CuO@C-Cloth materials when used as electrodes in LIBs.

REFERENCES

Ding, J. S. Chen and X. W. Lou, Adv. Funct. Mater., 2011, 21, 4120–4125.

Liang, H. Hu, H. Park, C. Xiao, S. Ding, U. Paik and X. W. Lou, Energy Environ. Sci., 2015, 8, 1707–1711.

Kim, S. Kim, S. Han, D. Kwak, E. Hwang, D. Kim, G. Lee, H. Choe and K. Park, J. Mater. Chem. A, 2015, 3, 23003–23010.

Zhu , D. Chao, J. Sun , I. Bacho, Z. Fan,C. Ng, X. Xia, H. Huang, H. Zhang, Z. Shen , G. Ding, and H. Fan, Adv. Mater. Interfaces 2014, 1400499-1400505.

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Design of High Voltage All-Solid-State Batteries Based on Sulfide Electrolytes
Authors: Fitzhugh William , Li Xin
Published: February 2020

Ceramic sulfide solid-electrolytes are amongst the most promising materials for enabling solid-state lithium ion batteries. With ionic conductivities that can meet or exceed liquid-electrolytes, such ceramic sulfides are limited in practice chiefly by a narrow electrochemical stability window of approximately 1.7-2.1 V vs Lithium metal. In addition, ceramic sulfides are frequently plagued by interfacial reactions when combined with common electrode active materials. In this talk, methods for the stabilization of both the bulk electrochemical decompositions and the interfacial reactions will be discussed. Solid-state cells stable up to 5V, including layered Li-Co-O and spinel Li-Mn-Ni-O, will be presented and the stabilization mechanisms will be discussed from a detailed theoretical perspective.

Ceramic sulfides are known substantially swell during electrochemical decay. Such swelling has been shown to provide a viable means by which to stabilize electrochemical decomposition in lithium ion batteries[1]. Evidence and theoretical understanding of stability window expansion as the result of mechanical constriction will be discussed for both Li10GeP2S12 and Li10SiP2S12 systems. Further discussion on the impact of interfaces will focus on our novel high-throughput computational schema[2], which has enabled the evaluation of nearly 70,000 material DFT calculation for interfacial stability with Li10SiP2S12. These new computational methods found over 2,000 high-voltage coating materials that are electrochemically inert against Li10SiP2S12 at standard cathode voltages.

The culmination of these approaches, mechanical bulk stabilization combined with interfacial coating layers, is the design of solid-state full cells with high voltage stability and good cyclability. The principal focus of this talk will be a discussion on the theoretical underpinnings of these methods and a comparison with experimental data.

[1] Fan Wu*, William Fitzhugh*, Luhan Ye, Jiaxin Ning, Xin Li. Advanced Sulfide Solid Electrolyte by Core-Shell Structural Design. Nature Communications, (9), 4037 (2018).

[2] William Fitzhugh*, Fan Wu*, Wenye Deng, Pengfei Qi, Luhan Ye, Xin Li. A High-Throughput Search for Functionally Stable Interfaces in Sulfide Solid-State Lithium Ion Conductors. Advanced Energy Materials. Under review.
Choline Chloride-Urea Deep Eutectic Solvent As Promising Electrolyte for Zinc Ion Batteries
Authors: Kao-Ian Wathanyu , Kheawhom Soorathep
Published: February 2020

Zinc-ion batteries (ZIBs) have received increasing attention due to their safety, environmental friendliness, cost-effectiveness. Though aqueous-based ZIBs show great promise, their critical challenges involve zinc anode corrosion and passivation, and dendritic zinc formation during recharge. We reported the application of biocompatible, nonaqueous, and low-cost electrolyte based on choline chloride/urea deep eutectic solvent for rechargeable ZIBs (δ-MnO2 intercalation cathode). The behavior of zinc anode stripping and deposition in the electrolyte, as well as intercalation into the δ-MnO2 cathode, were investigated. The results revealed that the fabricated battery exhibited good electrochemical performance with the maximum specific capacity of 170 mAh/g. Besides, the system showed reversible plating/stripping of zinc without dendrite formation and zinc anode passivation. Hence, the results confirmed the reversible intercalation of zinc into the δ-MnO2 cathode. The proposed electrolyte shows good promise for Zn/δ-MnO2 battery system.

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Highly Concentrated Aqueous Gel Electrolytes for Diverse Battery Applications
Authors: Cresce Arthur v. , Eidson Nicolas Thierry , Xu Kang C.
Published: February 2020

The development of aqueous solutions containing comparatively high amounts of dissolved salts has brought water, an unlikely solvent, into the ongoing development of new battery chemistries. Aqueous electrolytes have the advantage of being inherently non-flammable materials, while demonstrating high cation transference number behavior and cation conductivity in the range of 1-10 mS/cm2 in the case of Li+. As a reaction medium, highly concentrated aqueous electrolytes allow for polymerization reactions such as radical polymerization to occur, and it has been demonstrated that the kinetics of these reactions are fast enough to allow rapid processing into films of solid gel electrolytes. While lithium ion batteries were one of the first applications of aqueous gel electrolytes, we have synthesized gel electrolytes for the increasingly popular sodium and zinc systems as well. This talk will focus on the kinetics of polymerization of various radicalized monomers, the formation and properties of the solid gels that result, and the electrochemical behavior and application tree that follow using the new electrolyte materials.
Use of Polarization Curves to Determine Kinetics Parameters in K–O2 batteries
Authors: Gourdin Gerald , Xiao Neng , Wu Yiying
Published: February 2020

Metal–O2 batteries have shown great potential as energy storage devices and are foreseen as one of the potential successors to lithium ion batteries. Unlike either batteries or fuel cells, however, metal-O2 batteries form an insoluble product that diminishes cathode capacity. Cathode capacity is related to the electrochemically-accessible surface area and product accumulation results in a loss of that surface area, which then contributes to the total overpotential during discharge. While typically used to determine the effect of varying load levels on the performance of energy producing devices (i.e. batteries, fuel cells), polarization, or current-potential, measurements are also an indirect measure of the different energy losses that contribute to the total overpotential associated with a particular redox process. Each region of the curve is affected by a specific overpotential that is dominant within a certain potential range. Polarization curves therefore allow for the determination of certain properties that are important for understanding and improving the performance of electrochemical energy devices.

As shown in Figure 1, the short steep, but curving, slope at the start of the current-potential curve is attributed to the activation overpotential, which is the energy required to overcome the potential barrier associated with the discharge reaction. The overpotential responsible for the long sloping line is attributed to the ohmic resistance, which is dominated by electrolyte resistance. Finally, the limiting current—sharp decline in the cell potential at higher current densities—is generally attributed to mass-transfer limitations. Using derived analytical expressions, essential kinetic parameters have been determined for fuel cells from the data obtained from polarization analyses.1,2

Proceeding from that previous work involving fuel cells, analytical expressions were derived that can be applied to the data obtained from polarization analyses of metal-O2 batteries. Due to the unique single-electron redox process (K+ + O2 + e− → KO2) in the cathode (oxygen) electrode, the K–O2 superoxide battery provided an ideal case for developing and evaluating those expressions.3,4 Polarization analyses were performed on K–O2 batteries and the data obtained was evaluated using the derived expressions to determine kinetic values essential to the operation and performance of the K–O2 battery.

References

1. A. A. Kulikovsky, J. Electrochem. Soc., 161, F263–F270 (2014).

2. J. Bockris and A. Reddy, in Modern Electrochemistry 2B - Electrodics in Chemistry, | John O'M. Bockris | Springer,, p. 1789–1901 (2000).

3. N. Xiao, X. Ren, W. D. McCulloch, G. Gourdin, and Y. Wu, Acc. Chem. Res., 51, 2335–2343 (2018).

4. W. D. McCulloch, N. Xiao, G. Gourdin, and Y. Wu, Chem-Eur J, 53, 3225 (2018).

Figure 1. Polarization Curve. Typical polarization curve from K–O2 battery

Figure 1