bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermodynamics and Kinetics of Lithium Dendrite Growth
Authors: Jana Aniruddha , Woo Sang Inn , Vikrant Karra Suryanaryana , García R. Edwin 
Published: February 2020

Lithium metal anodes are a promising choice to achieve high energy density compared to current graphite anodes. However, lithium whisker growth (dendrites) during battery charging poses a major safety and performance concern for both lithium metal batteries, and overcharging of presently used graphite anodes in lithium-ion batteries. The present understanding of lithium electrodeposit growth is largely based on the Diffusion Limited Aggregation theory that results in a tip-controlled growth of fractal or dendritic structures. However, lithium electrodeposits have been reported in scientific literature to grow from the base at low current densities [1,2,3], that cannot be explained solely by electrodeposition kinetics. In this work, the mechanisms of lithium growth on anodes are analyzed assessing the combined contribution of electrochemical and mechanical driving forces. Physical mechanisms for tip-controlled and base-controlled growth modes are developed based on a thermodynamically consistent formulation, and have been validated based on the available scientific literature. Analytical and numerical solutions are discussed.
References:
[1] F. Orsini, A. D. Pasquier, B. Beaudouin, J. M. Tarascon, M. Trentin, N. Langenhuizen, E. D. Beer, and P. Notten. "In situ SEM study of the interfaces in plastic lithium cells." J. Power Sources 81 (1999) 918-921.
[2] O. Crowther, A.C. West, “Effect of Electrolyte Composition on Lithium Dendrite Growth.” J. Electrochem. Soc., 155 (2008) 806-811
[3] P. Bai, J. Li, F. R. Brushett, M. Z. Bazant. “Transition of lithium growth mechanisms in liquid electrolytes.” Energy Environ. Sci. 9 (2016) 3221-3229
Intercalation Cathodes for Rechargeable Aluminum-Ion Batteries
Authors: Jadhav Ankur , Messinger Robert J. 
Published: February 2020

Rechargeable aluminum batteries have been a topic of great interest as aluminum metal has a high volumetric capacity and is the most abundant metal in the earth’s crust. However, few crystalline materials have been shown to reversibly intercalate aluminum ions into their structures. Recently, it has been shown that aluminum ions can reversibly intercalate/de-intercalate into the Chevrel Mo6S8 phase and the spinel Mn2O4 compound. However, the intercalation mechanisms are not well understood, particularly for the spinel Mn2O4, in part due to poor capacity retention and slow solid-state diffusion of the highly charged tri-valent aluminum ions within these crystalline structures. Better understanding of the intercalation mechanism of aluminum ions into these materials, including the dynamics and populations of aluminum ions, is important for the design and optimization of next-generation intercalation electrodes for aluminum batteries.
Our research has focused on these intercalation electrode materials for use in aluminum batteries with AlCl3/[EMIm]Cl ionic liquid electrolyte to study the intercalation process of aluminum ions into crystalline host structures. Cyclic voltammetry was performed at low scan rates to identify oxidation and reduction peaks corresponding to different intercalation sites during the charge-discharge process. Galvanostatic cycling was performed to observe capacity retention at different current densities. Ex situ multi-dimensional solid-state 27Al magic-angle-spinning (MAS) NMR spectroscopy was used to observe changes in the populations and local environments of the aluminum ions, as well as their dynamics. X-ray diffraction and electron microscopy were also used to analyze structural changes in the cathode materials as a function of state-of-charge. Our studies shed light on the intercalation mechanisms of aluminum ions in crystalline transition metal oxide and sulfide host structures.
Evaluation on Catalytic Activity of Bi2-XRu2O7-Z Nano-Particles for Oxygen Reduction and Evolution By Titanium Disk Method
Authors: Sakurai Yuki , Kawaguchi Kenji , Hirose Yutaka , Nishiyama Hiroshi , Nakanishi Shinji , Iba Hideki , Morimitsu Masatsugu 
Published: February 2020

A metal hydride (MH)/air secondary battery uses oxygen in air as the active mass of the positive electrode, and the positive electrode’s reactions are oxygen reduction during discharge and oxygen evolution during charge. We have been developing the bi-functional catalysts for these reactions, one of which is a pyrochlore type oxide, Bi2-xRu2O7-z nano-particles, obtained by co-precipitation method. The catalytic activity of such bi-functional catalysts for the oxygen reactions has been investigated with rotating disk electrode (RDE) method and the substrate of the RDE electrode used in alkaline solutions is normally graphite or glassy carbon disk on which the catalyst particles are loaded with ionomers or PTFE. However, such conditions are difficult to eliminate the influence of the carbon substrate, ionomers, or PTFE on the catalytic activity. In this paper, we present a novel method to evaluate the catalytic activity of Bi2-xRu2O7-z nano-particles using RDE method in which the substrate was a titanium disk and the results on the specific activity of Bi2-xRu2O7-z catalysts for ORR and OER at different oxide amount on titanium disk.
Bi2-xRu2O7-z particles were prepared by co-precipitation method which was carried out by the calcination of the precipitates obtained by adding excess NaOH solutions into the metal salt solution containing Bi(III) and Ru(III). The obtained particles were loaded on a titanium disk by dropping the solution prepared by dispersing the oxide particles in distilled water under ultrasonic agitation. No binder and no ion exchange resin were used for this preparation. The oxide loaded titanium disk was analyzed by SEM and used as the working electrode for oxygen reduction and evolution. The concentration of KOH solution at 0.1 mol/L was used at 25 oC. The electrolyte was bubbled with oxygen or nitrogen to measure the net oxygen reduction current. The specific activity of the oxide catalyst was evaluated by the currents normalized with the amount of the loaded catalyst, i
w, or the double layer charge, i
c.
The polarization curves with the oxide loaded titanium disk at different amounts of oxide were measured, and the results indicated that oxygen evolution current increased with increasing the weight of catalyst, while the specific activities, iC and iW, was unchanged with the loaded oxide amount, suggesting that the double layer charge and the catalyst’s amount are linear to the active surface area for oxygen evolution. Although the oxygen reduction current also increased with increasing the weight of catalyst, the specific activity, iW, decreased with increasing catalyst’s weight, which implies that the inner site of catalyst’s layer hardly works for the sites of oxygen reduction under the condition that the active species is only dissolved O2. More detail results will be presented in this paper.
High-Power, Low-Corrosion Aluminum-Air Battery
Authors: Hopkins Brandon James , Hart Douglas P. 
Published: February 2020

Aluminum-air (Al-air) batteries are promising candidates for use in electric vehicles due to their high pack-level energy densities and to the abundance, recyclability, lightweight, low cost, and three-electron-redox properties of aluminum. Severe capacity fade during open-circuit conditions, however, has limited Al-air commercialization for over 50 years. Open-circuit capacity fade is caused by corrosion wherein the aluminum anode reacts with water from the aqueous electrolyte. Existing strategies to mitigate open-circuit corrosion, however, generally lead to reduced powers and energy densities. Optimized aqueous systems that use anode alloying and or electrolyte additives achieve high powers (500 mW cm-2) and energy densities (4 kWh kg-Al-1) but suffer from unacceptably high open-circuit corrosion currents (10 mA cm-2). In contrast, gel electrolyte systems yield low powers (91.1 mW cm-2) and energy densities (1.2 kWh kg-Al-1) but achieve no long-term open-circuit corrosion. Here we present a high-power (433 mW cm-2), energy-dense (3.9 kWh kg-Al-1) Al-air battery that experiences no long-term open-circuit corrosion.
Open-circuit corrosion can be stopped with no discernible effect to closed-circuit performance by displacing the aqueous electrolyte with a non-conducting liquid oil. When the battery is in closed-circuit conditions, the aqueous electrolyte can effectively displace the oil due to the natural and designed underwater oleophobic properties of the anode and cathode—the oil beads up and is flushed out by the electrolyte. The figure shows measured anode corrosion via hydrogen collection before and after the electrolyte has been displaced by oil and suggests that long-term open-circuit corrosion is completely stopped. We estimate that an Al-air vehicle battery pack with the proposed corrosion mitigation system could achieve energy densities of 222 Wh-kg-1 (2x that of Li-ion vehicle packs) and 183 Wh-L-1 (comparable to Li-ion vehicle packs) at costs as low as 18 US$-kWh-1 (33x less than Li-ion packs). We anticipate that our findings will further enable the use of aluminum as a critical element for energy storage.

Figure 1
(Invited) Ion Intercalation and High Temperature Behavior of 2D Materials
Authors: Hu Liangbing 
Published: February 2020

I will discuss our recent progress on engineering of 2D materials, with a focus on metal ion intercalation and ultra-high temperature treatment (up to 3000-3500K). We developed a nano-battery platform that allows in situ measurement of optical, electrical and structure changes of 2D materials during ion intercalations. We used the nano-battery setup to investigate various properties of 2D materials upon ion intercalation, including Li+, Na+ and K+. Dramatic increases in both transmittance and conductivity were reported, which leads to the highest figure of merit (FOM) for transparent conductor applications. We also extended the knowledge to printed reduced graphene oxide network toward large-scale applications. In a separated topic, I will discuss our effort in the past three years on high temperature material behavior for reduced graphene oxide (RGO) networks. High-temperature stability of RGO networks allows us to uniquely engineer them for a range of emerging applications, such as 3D printed rapid heaters and highly conductive RGO paper as lightweight battery current collectors.

Keywords: Ion intercalation, Optoelectronics, Nano batteries, 2D materials, 3000K, 3D printing, High conductivity
[1] Chen, Y.; Fu, K.; Zhu, S.; Luo, W.; Wang, Y.; Li, Y.; Hitz, E.; Yao, Y.; Dai, J.; Wan, J.; Danner, V.; Li, T.; Hu, L.* Reduced Graphene Oxide Films With An Ultra-High Conductivity as Li-ion Battery Current Collectors, Nano Letter, Accepted
[2]Yao, Y.; Fu, K.; Yan, C.; Dai, J.; Chen, Y.; Wang, Y.; Zhang, B.; Hitz, E.; Hu, L.* 3D Printable High-Temperature and High-Rate Heaters, ACS Nano, Accepted
[3] Bao, W.; Pickel, A.; Zhang, Q.; Chen, Y.; Yao, Y.; Wan, J.; Fu, Kun.; Wang, Y.; Dai, J.; Zhu, H.; Drew, D.; Fuhrer, M.; Dames, Chris.; Hu, L. Flexible, High Temperature, Planar Lighting with Large Scale Printable Nanocarbon Paper, Advanced Materials, Accepted, Front Inside Cover.
[4] Lacey, S.; Wan, J.; Wald Cresce, A.; Russell, S.; Dai, J.; Bao, W.; Xu, K.; Hu, L. Atomic Force Microscopy Studies on Molybdenum Disulfide Flakes as Sodium-Ion Anodes, Nano Letters, 2015, 15, 1018.
[5] Wan, J.; Gu, F.; Bao, W.; Dai, J.; Shen, F.; Luo, W.; Han, X.; Urban, D.; Hu, L. Sodium-ion Intercalated Transparent Conductors with Printed Reduced Graphene Oxide Networks, Nano Letter, 2015, 15, 3763
[6] Wan, J.; Bao, W.; Liu, Y.; Dai, J.; Shen, F.; Zhou, L.; Cai, X.; Urban, D.; Li, Y.; Juangjohann, K.; Fuhrer, M.; Hu, L. In Situ Investigations of Li-MoS2 with Planar Batteries, Advanced Energy Materials, 2014, 1, 1401742.
[7] Bao, W.; Wan, J.; Han, X.; Cai, X.; Zhu, H.; Kim, D.; Ma, D.; Munday, J.; Drew, D.; Fuhrer, M.; Hu, L. Approaching the Limits of Transparency and Conductivity in Graphitic Materials through Lithium Intercalation, Nature Communications, 2014, 5, 4224.
(Invited) SURMOFs and CCNCs As Novel Tuneable Materials for Electronic Devices and Applications
Authors: Redel Engelbert 
Published: February 2020

Here we present a particularly interesting class of surface-anchored (metal-organic frameworks andcoordination network compounds) materials SURMOFs and (conductive coordination network compounds) CCNCs for the fabrication e.g. of 1D (Photonic Band Gap) PBG materials [1,2] as optical sensors, low-k dielectric thin films [3],optoelectronic/electrochromic switchable coatings/devices [4] microelectronic devices, e.g. RRAM devices [5] or Hybrid-Materials NPs@SURMOFs for future artificial Light-Harnessing (LH) assemblies and photocatalysts.[6]
Since these materials are highly porous and the size of their pores are highly adjustable, they can be further functionalized and further tailor to electrically load and unload small ions (optoelectronic applications) or act as photon traps, which are able to efficiently absorb, transport and harness light energy over an artificial LH antenna array.[7] An outlook will be given for highly conductive and porous CCNCs thin film materials as well as further electronic characterization of SURMOFs and CCNCs.

References

[1] J. Liu, E. Redel, S. Walheim, Z. Wang, V. Oberst, J. Liu, S. Heissler, A. Welle, M. Moosmann, T. Scherer, M. Bruns, H. Gliemann, C. Woell Chemistry of Materials (ACS) 2015, 27, 1991-1996.
[2] J. P. Best, J. Michler, J. Liu, Z. Wang, M. Tsotsalas, X. Maeder, S. Roese, V. Oberst, J. Liu, S. Walheim, H. Gliemann, P. G. Weidler, E. Redel and C. Woell Appl. Phys. Lett. 2015, 107, 101902.
[3] E. Redel, Z. Wang, S. Walheim, J. Liu, H. Gliemann, C. Woell, App. Physics Lett. 2013, 103, 091903 [4] J. Liu, W. Zhou, S. Walheim, Z. Wang, P. Lindemann, S. Heissler, J. Liu, P. G. Weidler, T. Schimmel, C. Woell, E. Redel Optics Express (OSA) 2015, 23, 13725-13733.
[5] Z. Wang, D. Nminibapiel, P. Shrestha, J. Liu, K. P. Cheung, W. Guo, P. G. Weidler, H. Baumgart, C. Woell, E. Redel (Back Cover Issue 1/02 2016) ChemNanoMat (Wiley-VCH) 2016, 2, 67-73.
[6] W. Guo, C. Zhi, C. Yang, T. Neumann, C. Kuebel, W. Wenzel, A. Welle, W. Pfleging, O. Shekhah, C. Woell, E. Redel Nanoscale (RSC) 2016, 8, 6468-6472.
[7] J. Liu, W. Zhou, J. Liu, I. Howard, G. Kilibarda, S. Schlabach, D. Couprey, M. Addicoat, S. Yoneda, Y. Tsutsui, T. Sakurai, S. Seki, Z. Wang, P. Lindemann, E. Redel, T. Heine, C. Woell *VIP ≡ Very Important Paper (Angewandte Front Cover Issue 2015-54/25) Angewandte Chemie International Edition (Wiley-VCH) 2015, 54, 7441-7445.
(Invited) Hyperbolic Metamaterials and Their Imaging, Lasing, Sensing Applications
Authors: Rho Junsuk 
Published: February 2020

Metamaterials, artificially structured nanomaterials, have enabled unprecedented phenomena such as negative refraction. However, despite the great and promising science, making practical devices based on metamaterials have been one of the most important issues due to the difficulty in fabrication. In this abstract, I will discuss recent development of scalable large-scale nanofabrication efforts to make practical metamaterials-based devices. The example is realizing a super-resolution imaging device of wafer-scale hyperlens, which is the first experimental demonstration of near- to far-field imaging of biological living objects at visible light with resolution beyond the diffraction limit in two lateral dimensions. With proposed hyperlens array, we show the first bio-sample imaging experimental result of super-resolution imaging on hyperlenses by combining to conventional microscopy system for imaging biomolecules. Hippocampal neuron cells are imaged by visible light through the hyperlens array with resolution down to 150 nm, beyond the diffraction limit. The super-resolution imaging result of neuron at sub-diffraction size shows that hyperlens can be used as a useful imaging tools in biology, pathology, medical science and nanotechnology. If time allows, I will discuss recent applications of hyperbolic metamaterials such as nanoscale cavity far beyond diffraction limit and sensing biomolecular matters. Also, such a unique fabrication techniques mentioned in this talk will provide the opportunity to achieve practical metamaterial devices as the significant step making nanoscience to nanotechnology.

Figure 1
Comprehensive Modeling and Simulation of the Effects of Surface Defects on Graphene Chemical Sensors
Authors: Lowenberger Aaron , Li Qiliang 
Published: February 2020

Chemical sensors are ubiquitous in the world, with important and broad applications in medicine, industrial process monitoring, automotive and aerospace applications, and the military. Due to its unique electrical properties and an ideal two-dimensional structure, graphene shows great promise as a highly sensitive, low noise sensor material. In this work, we report the results of comprehensive first-principles simulation and modeling of the electrostatic response of graphene when exposed to multiple chemical vapors, including hexane, tetrahydrofuran, toluene, and acetone. The effects of different graphene surface defects, such as vacancy defects, hydrogen defects, oxygen defects and hydroxyl group defects on graphene conduction have been explored, including how these defects affect the response of graphene when exposed to each of the studied chemical vapors. The simulation results were analyzed and compared with experimental data with a focus on understanding the physics and kinetics of the adsorption and desorption of gas molecules on the graphene surface. The results of this modeling study of surface defects on graphene sensors is very important for understanding how to engineer advanced chemical vapor sensors for increased sensitivity and selectivity.
(Invited) SiC MOSFET Reliability and Implications for Qualification Testing
Authors: Lelis Aivars , Green Ron , Habersat Dan 
Published: February 2020

There are a number of potential reliability issues associated with SiC power MOSFETs, including threshold-voltage stability, gate-oxide reliability, body-diode robustness, short-circuit current robustness, and radiation effects. This talk is primarily focused on threshold-voltage stability and the need for an improved test method to unambiguously separate out good devices from bad ones. Threshold-voltage stability is affected primarily by active charge traps in the near-interfacial region of the insulating gate oxide. Their close proximity to the semiconductor interface leads to a strong time dependence in the direct-tunneling mechanism in response to changes in gate bias. This time dependence is not properly accounted for in the existing test methods for assessing high-temperature gate-bias (HTGB) effects, which allow temporary removal of bias during cool down and significant un-biased delay (up to 96 hours) before the post-stress measurements are performed. However, this delay, introduced to accommodate the practical constraints of industrial testing, renders this test practically meaningless due to the significant recovery that occurs in the charge states of the near-interfacial oxide traps. This difficulty can be overcome by reapplying the gate bias for a brief period of time before measuring. Details of the nature of the near-interfacial oxide traps will be discussed, including their activation energy. All this work will be presented within the context of standards development within JEDEC, and a new SiC power-devices qualification working group.
GaN Lateral High Voltage Photoconductive Semiconductor Switches
Authors: Koehler Andrew D. , Nath Anindya , Khachatrian Ani , Anderson Travis J , Tadjer Marko J. , Mastro Michael A , Hite Jennifer K , Buchner Stephen , Hobart Karl D , Kub Francis J 
Published: February 2020

Wide bandgap GaN photoconductive semiconductor switches (PCSSs) have gained recent attention due to high critical electric field strength and high electron saturation velocity to provide high power ultrafast devices. To reduce leakage currents, PCSSs have previously been demonstrated on semi-insulating GaN achieved by Fe compensation doping. However, Fe is known to have strong memory effects, which can redistribute Fe into subsequent films, as well as a narrow window of acceptable doping levels. PCSSs with fast response time are required for applications requiring high repetition rates. C-doped GaN is used to reduce leakage current and improve the photocurrent of lateral PCSSs. The C-doping is performed by simply tuning the growth parameters, such as temperature, pressure and III/V ratio and creates shallow accepter levels, compensating any unintentional n-type doping. In this work, we demonstrate high voltage GaN:C PCSSs with fast response times measured using a picosecond pulsed laser and high breakdown voltages, over 4000 V, measured in a vacuum probe station.
(Invited) Ultrawide Bandgap β-Ga2O3 Thin Films: Growths, Properties and Devices
Authors: Rafique Subrina , Han Lu , Zhao Hongping 
Published: February 2020

Ultrawide bandgap (UWBG) gallium oxide (Ga2O3) represents an emerging semiconductor material with excellent chemical and thermal stability up to 1400 oC. It has a band gap of 4.5-4.9 eV, much higher than that of the GaN (3.4 eV) and 4H-SiC (3.2 eV). It exhibits high transparency in the deep ultraviolet (DUV) and visible wavelength region due to its very large bandgap. The monoclinic b-phase Ga2O3 represents the thermodynamically stable crystal among the known five phases (α, β, γ, δ, ε). The breakdown field of β-Ga2O3 is estimated to be 8 MV/cm, which is about three times larger than that of 4H-SiC and GaN. These unique properties make β-Ga2O3 a promising candidate for high power electronic device and solar blind photodetector applications. More advantageously, single crystal β-Ga2O3 substrates can be synthesized by scalable and low cost melting based growth techniques such as edge-defined film-fed growth (EFG), floating zone (FZ) and czochralski methods. For β-Ga2O3 thin film synthesis, both molecular beam epitaxy (MBE) and metalorganic vapor phase epitaxy (MOVPE) have been demonstrated to produce high quality and controllable doping films but with slow growth rates (2-10 nm/min). Halide vapor phase epitaxy (HVPE) using chloride precursors was demonstrated to grow β-Ga2O3 films with fast growth rates (>5 μm/hr). Recently, we have developed a low pressure chemical vapor deposition (LPCVD) method to grow high quality β-Ga2O3 thin films on both native Ga2O3and c-sapphire substrates with controllable doping and fast growth rates up to 10 μm/hr.
In this talk, we present a study on the defects in β-Ga2O3 thin films grown via LPCVD. The β-Ga2O3 thin films were grown on native β-Ga2O3 substrates and sapphire substrates using high purity gallium and oxygen as the precursors, and argon (Ar) as the carrier gas. The growth temperature ranged between 850 ˚C and 950 ˚C. The β-Ga2O3 thin films were characterized by using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). FESEM images were taken with Helios 650. High resolution transmission electron microscopy (HRTEM) images and selected-area electron diffraction (SAED) were taken using a FEI Tecnai F30 at 300 kV. Bright field, dark field, combined with two-beam condition TEM were used to characterize the defects in the as-grown films. From our studies, β-Ga2O3 thin films grown on (010), (001) and (-201) β-Ga2O3 substrates have shown different growth rates as well as different properties of interfacial defects. Improved LPCVD growths to suppress defects in β-Ga2O3thin films grown on different substrates will be discussed. Room temperature Hall measurements will be performed to understand the dependence of carrier transport on defects.
In summary, the fundamental defect studies are performed on β-Ga2O3 thin films grown via LPCVD on Ga2O3 and sapphire substrates. The results from this study are important knowledge for power device applications.