bluuebunny/crossref_metadata_2025 huggingface dataset:
Solid State Ion Conductors to Enable Low Temperature Molten Sodium Batteries
Authors: Spoerke Erik D. , Peretti Amanda , Gross Martha M. , Percival Stephen , Small Leo J. , Hill Ryan , Cheng Yang-Tse
Published: May 2020

Molten sodium batteries show clear promise for safe, long-lifetime grid-scale energy storage, and there is growing expectation that they may be able to impact a host of energy storage areas, ranging from vehicle electrification to industrial applications. Key to the successful development and implementation of these technologies, though, are 1) reducing the traditionally high operating temperature of these batteries and 2) identifying robust, zero-crossover solid state separators that will perform effectively at these reduced temperatures. Traditional molten sodium batteries, such as sodium-sulfur and sodium-nickel chloride (ZEBRA), operate near 300°C, where ceramic separators, such as β”-Al2O3 have high ionic conductivity, but these high temperature systems can be cost-prohibitive. Here, we discuss a significant deviation from these chemistries and materials in a sodium-iodide (NaI) battery that utilizes a molten sodium anode and a sodium iodide-based molten salt catholyte, operating at drastically reduced temperatures near 100°C. NaSICON (Na Super Ion CONducting) separators show promise as effective ceramic separators in lab-scale demonstrations of this battery chemistry, but challenges to cost, widespread availability of the material, electrochemical compatibility, and mechanical stability of the ceramic have motivated the search for new sodium ion conducting separator materials and designs. We will describe not only critical synthetic considerations, but also important benefits and shortcomings of NaSICON separators for use in this specific battery chemistry. Importantly, we will describe recent efforts build on the promise of NaSICON materials, exploring new composite materials and hybrid structures that meet strenuous demands of ionic conductivity, chemical compatibility, and mechanical robustness for separators in low temperature sodium batteries. Innovative designs that take advantage of controlled particle morphology and organization in polymer-ceramic composites, for example, promise improved mechanical durability and effective ionic conductance in low cost, highly processable systems. Understanding the critical relationships between material composition, microstructure, and electrochemical performance of these emerging materials will be central to the successful development of a new generation of solid-state ion conductors and the realization of effective low temperature molten sodium batteries.

Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
(Invited) Understanding Chemical, Mechanical and Thermal Stability of NCA in Polymer Solid-State Batteries
Authors: Besli Muenir Mustafa , Metzger Michael , Hellstrom Sondra , Usubelli Camille , Liu Yijin , Nordlund Dennis , Doeff Marca M , Christensen Jake , Kuppan Saravanan
Published: May 2020

The structural integrity and chemical stability of layered Ni-rich oxide cathode materials are influential factors that critically affect the performance and reliability of lithium batteries. Prolonged battery operation often involves repeated phase transitions, buildup of mechanical stresses, which could result in chemical and mechanical changes in cathodes. Chemo-thermo-mechanical interplay can cause performance degradation through various processes. Here we systematically investigate such complex chemomechanical and chemothermal interplays over a wide range of length scales within the hierarchically structured polymer solid-state batteries. This presentation will discuss our understanding of 1) The formation of mesoscale cracks and corresponding state of charge (SOC) inhomogeneity within secondary NCA particle cycled in solid polymer batteries1 2) Thermal decomposition, fracture (intergranular and intragranular), and mesopores formation due to oxygen evolution in delithiated Li0.30NCA particles upon heating2 3) long-term chemothermal stability of delithiated Li0.30NCA at relevant operating conditions of polymer solid-state batteries.3

Our investigation provides a fundamental understanding of chemo-thermo-mechanical breakdown of the NCA in solid-state polymer batteries.

Reference :

1. Besli, M. M. et al. Mesoscale Chemomechanical Interplay of the LiNi0.8Co0.15Al0.05O2 Cathode in Solid-State Polymer Batteries. Chem. Mater.
31, 491–501 (2019).

2. Besli, M. M. et al. Thermally-driven mesopore formation and oxygen release in delithiated NCA cathode particles. J. Mater. Chem. A
7, 12593–12603 (2019).

3. Besli, M. M. et al. Long-Term Chemothermal Stability of Delithiated NCA in Polymer Solid-State Batteries. J. Mater. Chem. A 11–13 (2019) doi:10.1039/c9ta11103d.
Gel Polymer Electrolyte Made of an Amorphous Polyacrylonitrile-Based Elastomer
Authors: Verdier Nina , Lepage David , Zidani Ramzi , Prébé Arnaud , Ayme-Perrot David , Pellerin Christian , Dollé Mickael , Rochefort Dominic
Published: May 2020

Lithium-ion batteries (LiBs) are a mature technology which has attracted much attention over the last three decades with the development of portable devices. With the increasing number of LiBs and their use in electric vehicles, there are persistent efforts to enhance their safety by identifying suitable substitutes for liquid non-aqueous electrolytes, which are highly flammable, volatile, and can cause leakage. To this end, gel polymer electrolytes (GPEs) represent a promising alternative. To be suitable in applications and maximize ionic conductivity, polymers must meet specific requirements, the most important ones being a low glass transition temperature (Tg) and a low crystallinity, as ions move faster in amorphous phase. Moreover, these polymers need to be electrochemically stable and provide mechanical resistance as well as flexibility to the GPE. To increase the conductivity, polymers with polar functional groups that can dissolve salts are required. Several polymers, like PEO or PAN have already been studied but one limitation is their high Tg (above ambient temperature) as well as a high crystallinity which make them brittle and limit the ionic conductivity.

To circumvent this limitation, we studied an amorphous polymer based on acrylonitrile monomers. This elastomer, HNBR (Hydrogenated Nitrile Butadiene Rubber), was previously studied by our group and was shown to be thermally cross-linkable, leading to a polymer chemically resistant to electrolytes and electrochemically stable over a wide potential range. Hence, we propose to investigate thermally cross-linked HNBRs to gain a better understanding on the effect of interactions between polar nitrile functions and lithium ions and finally use this system as a GPE for Li-ion battery. To do so, a three-component system comprising HNBR:solvent:LiTFSI was studied to pinpoint the correct ratio to provide the GPE with competitive conductivity. Infrared spectroscopy was used to shed light on the interactions between nitriles and lithium ions while PFG-NMR was utilized to obtain spin-lattice relaxation times (T1) and diffusion coefficients of 7Li and 19F for various HNBR-based GPEs. These results were correlated to EIS measurements and among the GPEs tested, those composed of 2M LiTFSI in propylene carbonate and HNBR with an acrylonitrile content of 50% are the most promising. This study highlights the benefits of high acrylonitrile content in the polymer and the use of a solvent with moderate donor number to promote interactions between nitriles and Li+.
(Invited) Localized High Concentration Electrolytes for Li Metal and Li Ion Batteries
Authors: Cao Xia , Xu Wu , Zhang Ji-Guang
Published: May 2020

It is well known that a stable and high efficiency Li metal anode (LMA) is critical for rechargeable Li metal batteries (LMBs). Although LMA is kinetically unstable with non-aqueous electrolyte, Localized High Concentration Electrolytes (LHCEs) can largely minimize the side reaction between LMA and electrolyte, therefore enable a dynamically stable LMA for long term cycling of li metal batteries. In this work, we report a series of LHCEs we developed recently that are highly stable with both LMA and high voltage cathode such as Ni rich LiNixCoyMn1-x-yO2 (x ≥ 0.6), LiCoO2 etc. These LHCEs not only exhibit the advantage of high concentration electrolyte, but also exhibit low viscosity, low cost of the low concentration electrolytes. Furthermore, these electrolytes can be tailored to be non-flammable and stable at low temperature. With appropriate additives, these LHCEs can also largely improve the stability of Si based Li ion batteries. The excellent performance of these batteries are mainly due to the formation of inorganic rich (such as LiF and Li2O) solid electrolyte interphase (SEI) on LMA and cathode electrolyte interphase (CEI) in these electrolytes. The monolithic solid electrolyte interphase (SEI) generated in some of these electrolytes is largely different with those of mosaic- or multilayer-type SEIs reported before. These electrolytes not only can improve the stability of LMA, but also greatly suppresses the phase transformation (from layer structure to rock salt) of the cathode and prevent dissolution of transition metal element in bulk cathode. Therefore, excellent cell performances in terms of long-term cycling stability and high rate capability is realized in high voltage LMBs together with reduced safety concerns. The fundamental mechanism behind the stability of these electrolytes to both LMA and high voltage cathode will also be discussed.
Indigo As Single Additive in Liquid Electrolyte for Lithium Metal Batteries
Authors: Mallet Charlotte , Rochon Sylviane , Zaghib Karim
Published: May 2020

Rechargeable lithium ion batteries (LIBs) have been successfully developed and widely used to power today’s portable electronic devices. The long term success in electric vehicles and energy storage system relies on rising the energy density, low temperature efficiency, safety and increased cycle life.

In parallel, lithium metal batteries (LMBs), described as a system with Li0 as anode and metal oxide as cathode (NMC, LFP, LMO) are arising as aim of research for a plethora of groups. Lithium metal anode is considered as ideal anode due to high theoretical capacity (3860 mAhg-1), lower negative electrochemical potential and lower density (0.534 g.cm-3).1 Researchers used complex liquid electrolyte (ionic liquid, etc.) systems in order to avoid lithium dendrite and degradation, conventional liquid electrolyte (LiPF6, carbonate solvants) degraded faster than expected, and consequently, generated cells fading. Therefore conventional liquid electrolyte in such cell was not used.

Use organic additive in electrolyte and/or electrodes is considered as one of the most economical and effective’s approaches for solved many problems as cited previously. The additive can interact with electrolyte or anode to prevent degradation or enhanced cell performances.

This presentation will outline commercial organic compounds: Indigo and his derivatives use as single additive in NMC/Li batteries with conventional liquid electrolyte, which considerably increased the cycle life of Li metal batteries. Dyes such Indigoïd contain electron density donor (-NH-) and acceptor (-C=O) groups linked by conjugated bonds, which participate to their versatile electrochemical properties.

Used as additive in cathode materials or electrolyte, indigo modified the electrode structure and changed the composition of the Li-ions battery electrolyte and solid electrolyte interface (SEI) on lithium metal.

1.Zhang, H., Eshetu, G.G.,Judez, X., Li, C., Armand, M., Angew. Chem. Int. Ed. 2018, 57, 15002-15027

Figure 1
Interface Modification between Li3PS4 Electrolyte and Li Metal Using Molten Salt Electrolyte Based on Alkali Bis(fluorosulfonyl)Imides
Authors: Li Qin , Cao Yi , Gao Yunzhi
Published: May 2020

All-solid-state lithium batteries employing sulfide solid electrolyte hold high promise to replace traditional liquid-electrolyte lithium ion batteries due to their high safety[1]. However, the formation of Li dendrites which would lead to short-circuiting of batteries is a serious issue that hinders its successful practical application[2]. Introduction of an interlayer by ex-situ or in-situ formation between a Li metal and sulfide solid electrolyte is a well-known method intended to reduce the interfacial resistance and suppress the dendrite growth inside all-solid-state batteries. Here, we applied molten salts which possess excellent electrolyte properties[3] to modify the electrolyte/anode interface. Symmetric cells of Li3PS4 electrolytes with the binary eutectic mixture of LiFSI-KFSI exhibited better Li dissolution-deposition performance and enabled operation at high current density (2.98 mA cm−2, 100 ℃) without short-circuiting. The higher interface energy of in-situ formed LiF derived from the reaction of LiFSI/KFSI and Li metal as well as the excellent electrolyte properties of the LiFSI-KFSI eutectic mixture lead to the enhanced electrochemical performance. These results indicate that interface modiﬁcation is promising strategy to achieve all-solid-state batteries with high energy densities.

[1]Xu R, Han F, Ji X, et al. Interface engineering of sulfide electrolytes for all-solid-state lithium batteries[J]. Nano energy, 2018, 53: 958-966.

[2]Han F, Yue J, Zhu X, et al. Suppressing Li dendrite formation in Li2S‐P2S5 solid electrolyte by LiI incorporation[J]. Advanced Energy Materials, 2018, 8(18): 1703644.

[3]Xu F, Liu C, Feng W, et al. Molten salt of lithium bis (fluorosulfonyl) imide (LiFSI)-potassium bis (fluorosulfonyl) imide (KFSI) as electrolyte for the natural graphite/LiFePO4 lithium-ion cell[J]. Electrochimica Acta, 2014, 135: 217-223.

Figure 1
Can a “Bad” Salt be a Good Salt for Li Metal Batteries?
Authors: Dumaz Philippe , Sergent Nicolas , Pagnier Thierry , Benayad Anass , Lécuyer Margaud , Deschamps Marc , Bouchet Renaud
Published: May 2020

Ethylene oxides (EO) based electrolytes are commonly used for their relatively good stability face to lithium metal. These ethers allow a good dissociation and solvation of lithium salts such as the commonly used LiTFSI salt. However, the EO/LiTFSI complexes if they show quite good conductivities, their transport numbers are quite low, and the TFSi anions do not give very good Solid electrolyte interphases (SEI) which implies quite poor performance vs lithium metal anodes. By replacing the salt by LiNO3, we observed an outstanding improvement in the cyclability of symmetrical Li cells, even at rather high current density (i. e. above 1 mAcm-2). To understand this improvement, we first compared the ionic transport properties of LiNO3 versus LiTFSI salt in small glymes (molar mass = 240 g / mol). At 40°C, PEG laden with 1M LiNO3 present an ionic conductivity one order of magnitude lower than LiTFSI, but the Li+ transport number is very high at 0,87. From ab initio calculation, Raman spectroscopy and NMR, we demonstrate that LiNO3 is only partially dissociated and tends to form dimers (or more) with lithium ion. These anionic complexes are not very mobile, which explains the lower conductivity and higher lithium ion transport number cationic conduction. Then, by mean of XPS and EIS, the composition and electrical properties of the SEI formed on lithium metal were obtained and compared. Finally, the lithium electrodeposits morphologies were characterized by X-Ray micro-tomography and SEM, allowing us to have all the cards in hand to explain the far better performance of the LiNO3 salt vs LiTFSI salt.
A Simple Way to Stabilize Li and Na Metallic Electrodes Surfaces
Authors: Roch Marlene , Davoisne Carine , Fleutot Benoit , Dedryvère Rémi , Morcrette Mathieu
Published: May 2020

Post Li-ion technologies such as Li-air, lithium sulphur or all-solid-state batteries have in common the use of lithium metal as negative electrode. Known from decades, dissolution and deposition of lithium induce the growth of inactive lithium moss or more critically the dendritic growth that can lead to short circuit phenomenon. Therefore, researchers try to tackle this problem by adding functional layers at the Li surface that may generate an improvement in capacity, lifetime and performances at high current rates.

There are different ways to protect lithium such as ALD inorganic coating1,2, grafting of organic materials3,4,5, polymers6 or deposition of inorganic alloys7,8. In this work, by dip coating (a simple and cheap process) a lithium foil into a solution of glyme with phosphorus trichloride (DME-PCl3), we succeeded in obtaining a thin and protective phosphorus-based layer.

Through electrochemical characterization techniques (EIS, GITT in 2 or 3 electrodes) and surface characterization techniques (SEM, and more importantly XPS), we were able to determine its morphology and chemical composition, its influence on the lithium plating and stripping processes and the mechanism of lithium diffusion through the protective layer. Cycling results in lithium symmetric cells but also full cells (Li-ion, Li-S) will be presented.

Finally, since our results were very promising with lithium, we extended this type of protection to sodium since the reactivity of this metal with electrolyte is ever more pronounced. With the same methodology, we will demonstrate that our protection nicely improves the use of Na metal in liquid cells.

1 A. C. Kozen and al., Next-generation lithium metal anode engineering via Atomic Layer Deposition, acsnano, 2015, 9, 6, 5884-5892

2 C-F Lin, and al., ALD protection of Li-metal anode surfaces – Quantifying and preventing chemical and electrochemical corrosion in organic solvent, Adv. Mater. Interfaces, 2016, 3, 1600426

3 F. Marchioni and al., Protection of lithium metal surfaces using chlorosilanes, Langmuir, 2007, 23, 11598 - 11602

4 S. Neuhold and al., Effect of surface preparation and R-group size on the stabilization of lithium metal anode with silanes, Journal of Power Sources, 2012, 206, 295 -300

5 S. Neuhold and al., Enhancement in cycle life of metallic lithium electrodes protected with Fp-silanes, Journal of Power Sources, 2014, 254, 241-248

6 Y. Liu and al., Lithium-coated polymeric matrix as a minimum volume-change and dentrite-free lithium metal anode, Nature communications, 2016, 7, 10992

7 X. Liang and al., A facile surface chemistry route to a stabilized lithium metal anode, Nature Energy, 2017, 2, 17119

8 L-L. Kong and al., Lithium-Magnesium alloy as a stable anode for Lithium-sulfur battery, Adv. Funct. Mater., 2019, 29, 1808756

9 L. Lin and al., Lithium phosphide/lithium chloride coating on lithium for advanced lithium metal anode, J. Mater. Chem. A, 2018, 6, 15859
(Invited) Advancement of Low Temperature Ceramic Synthesis for Solid State Battery Components and Cells – a Personal Love Story
Authors: Rupp Jennifer L.M.
Published: May 2020

Next generation of energy storage devices may largely benefit from fast and solid Li+ ceramic electrolyte conductors to allow for safe and efficient batteries and fast data calculation. For those applications, the ability of Li-oxides to be processed as thin film structures and with high control over Lithiation and phases at low temperature is of essence to control conductivity. Through this presentation we review the field from a new angle, not only focused on the classics such as Li-ionic transport and electrochemical stability window for Li-solid state battery electrolytes, but focusing on opportunities and challenges routes in thermal and ceramic processing of the components and their assemblies with electrodes. Also, we will carefully review and give perspectives on the role of solid state battery ceramic strategies for the electrolyte on the electrode interfaces and towards charge transfer and vs. current densities. In other words, it will be a little ceramicist (own) love story on the good and the evil we can design by smart ceramic design at the interfaces originating by the very first choices made in the electrolyte ceramic structure and material design. In the second part of the talk we will discuss new opportunities on low temperature processing of solid state electrolyte ceramics that do not technically require “classic sintering” and avoid prior particle calcination; instead demonstrating opportunities to use liquid based direct densification routes and vacuum techniques to design solid electrolytes and grafting interfaces to new hybrid and solid state battery prototypes targeted at processing below 700C for all parts. Collectively, the insights on solid state energy storage provide evidence for the functionalities that those Li-solid state material designs can have for cost and mass manufacturable solid state and hybrid battery prototypes.

References:

1. A Low Ride on Processing Temperature for a Fast Li Conduction in Garnet Solid State Battery Films

R Pfenninger, M. Struzik, I Garbayo, E Stilp , JLM Rupp, Nature Energy, 4, 475–4832019, 2019

2. Lithium-Containing Thin Films

JLM Rupp, R Pfenninger, M. Struzik, A Nenning, I Garbayo, US 62/718,838 (2018)

3. Methods of Fabricating Thin Films Comprising Lithium-Containing Materials

JLM Rupp, R Pfenninger, M. Struzik, A Nenning, I Garbayo, US 62/718,842 (2018)

4. Glass-Type Polyamorphism in Li-Garnet Thin Film Solid State Battery Conductors

I Garbayo, M Struzik, WJ Bowman, R Pfenninger, JLM Rupp, Advanced Energy Materials, 1702265 (2018)

5. Solid-state Electrolyte and Method of Manufacture Thereof.

ZD Hood, Y Zhu, L Miara, JLM Rupp. US 62/713,366 (2018)

6. Solution-Processed Solid-state Electrolyte and Method of Manufacture Thereof.

Y Zhu, ZD Hood, L Miara, JLM Rupp US 62/713,428 (2018)
Stabilizing Anode-Free Lithium Batteries Via External Thermal Gradients
Authors: Atkinson Robert W. , Kingston Todd A. , Carter Rachel , Love Corey T.
Published: May 2020

Temperature is known to have a profound impact on battery electrochemistry and performance due to the strong temperature-dependence of kinetics and diffusion. However, the role of temperature on battery behavior has mostly been considered in the case of an isothermal cell. Though active thermal management systems for batteries strive to maintain isothermal control, localized thermal gradients can still develop within individual cells, which can significantly influence local electrochemistry. For this reason, it is important to understand the consequences and also the potential benefits of non-uniform temperature distribution across batteries.

Thermal gradients have been applied to lithium symmetric cells to significantly improve performance and stability. The direction of an interelectrode thermal gradient governs lithium plating morphology and dictates whether unstable, one-dimensional Li electroplating or stable, homogeneous electroplating occurs (1). With a warm positive electrode (40°C) and a cold negative electrode (0°C) (negative thermal gradient) we observe unstable cell behavior, extensive side reactions between Li and the electrolyte, and internal shorting. Reversing these temperatures so that the negative electrode is warmer than the positive electrode (a “positive” thermal gradient) decreases overpotentials, minimizes deleterious side reactions between Li and the electrolyte, and encourages long cycle life. Additionally, a positive thermal gradient stabilizes high-rate plating and stripping (1), showing promise for enabling fast-charging in lithium metal batteries.

This presentation will discuss the impact of thermal gradients on stabilizing lithium plating and stripping and its application for improving long-term cycle life in anode-free lithium metal batteries. First, we will use symmetric Li metal coin cells to investigate the roles of thermal gradient magnitude and electrode temperatures on lithium plating stability. After identifying optimal thermal conditions for highly reversible Li plating and stripping, we will apply this thermal gradient to an anode-free full cell with LiFePO4 cathode to confirm its benefit on long-term cycling in a practical cell. Operando techniques, such as optical microscopy and internal thermal sensing, as well as post mortem materials characterization, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy, will be used to describe and characterize cell behavior in the presence of an applied thermal gradient.

References

1. R. W. Atkinson III, R. Carter and C. T. Love, Energy Storage Materials, 22, 18 (2019).
Efficient Simulation of 2D Models for Microstructure Evolution in Lithium-Metal Batteries
Authors: Jang Taejin , Uppaluri Maitri , Subramanian Venkat R.
Published: May 2020

The lithium-metal batteries are receiving great attention as one of the most promising candidates of next-generation batteries.1 While the Li-ion batteries use graphite to intercalate lithium, lithium-metal batteries do not need extra components except lithium plate itself and it is significantly advantageous in the specific capacity. On the other hand, the surface property of lithium metal anode greatly affects the performance of the battery and increases the dendrite growth and “dead” lithium over the cycle.2 Therefore, understanding the behavior of lithium-metal anode during the cycle is critical to mitigate the safety issue and enhance the overall performance of the battery.

In this talk, we first analyzed a previous one and two-dimensional model for Li-ion to lithium-metal battery under different geometry and rates.3 Different approaches for simulation are compared and preliminary results for microstructure evolution will be presented.

Acknowledgments

This research was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the US Department of Energy (DoE) through the Advanced Battery Materials Research Program (Battery500 Consortium) and Texas Materials Institute at the University of Texas at Austin.

References

1. C. Niu, H. Pan, W. Xu, J. Xiao, J.-G. Zhang, L. Luo, C. Wang, D. Mei, J. Meng, X. Wang, Z. Liu, L. Mai, and Jun Liu, Nature Nanotechnology, 14 594-602 (2019).

2. H. Sano, H. Sakaebe, H. Senoh, and H. Matsumoteo, J. Electrochem. Soc., 161 A1236-A1240 (2014)

3. M. Tang, P. Albertus, and J. Newman, J. Electrochem. Soc.,
156 A390-A399 (2009).
Effect of Additives on Rechargeable NCA/Graphite 18650 Li-Ion Batteries
Authors: Duriyasart Farkfun , Amnuaymucha Nontawan , Sawangphruk Montree
Published: May 2020

Electrolyte additive is one of the most important parts in the development of stable Lithium-ion batteries (LIBs) with high efficiency and durability. In particular, a commonly used nickel cobalt aluminum (NCA) cathode with graphite anode battery is receiving growing interest from their high specific energy (275 mAhg-1), long life span, and good energy density. However, Ni-rich cathode material trends to suffer from the unstable solid electrolyte interface (SEI) layer on the anode, leading to capacity fading after charge-discharge cycles. Among several parameters affecting on the SEI formation, electrolyte additive is a crucial and practical factor capable of being optimized in a large-scale battery production process. In this work, vinyl carbonate (VC) and fluoroethylene carbonate (FEC) were used as additives in an electrolyte of 1 M LiPF6 in a mixed solvent system consisting ethylene carbonate (EC), Ethylene methyl carbonate (EMC), and dimethyl carbonate (DMC) at a volumetric ratio of 1:1:1. The effect of each additive on the creation of SEI structure and its further effect on the battery cycle stability was investigated. A systematic study of additive contents in the control electrolyte showed that the highest coulombic efficiency of the NCA/graphite battery was achieved when 2wt% VC was used, while an optimum FEC content can be up to 4wt%. The combination of VC and FEC at different ratios were also studied and their synergistic effect on the battery performances was revealed by SEI investigation.
Interface Engineering of Sulfide-Based All-Solid-State Lithium Batteries
Authors: Wang Changhong , Huang Huan , Sun Andy Xueliang
Published: May 2020

All-solid-state lithium batteries (ASSLBs) have gained intensive attention worldwide because of their intrinsic safety and potential high energy density.1 As a critical component in ASSLBs, various solid-state electrolytes have been extensively studied over the past decade. So far, the ionic conductivity of solid-state electrolytes, particularly sulfide electrolytes (SEs, i.e. Li10GeP2S12) is close to that of conventional liquid electrolytes. However, the electrochemical performance of SE-based ASSLBs is hindered by the large interfacial resistance between electrodes and sulfide electrolytes. The underlying reasons are detrimental interfacial reactions and insufficient solid-solid contact between electrodes and SEs in ASSLBs.2 In our research, taking the advantages of atomic/molecular layer deposition techniques, an interfacial layer with designed functionalities can be conformably interposed between the electrodes and solid-state sulfide electrolytes, aiming at overcoming the interfacial resistance. At the anode interface, a artifical solid electrolyte interphase (SEI) has been engineered to suppress the interfacial rections and lithium dendrite growth, sucessfully enabling the use of Li metal in SE-based ASSLBs.3 At the cathode interface, a dual-shell interfacial nanostructure was rationally designed, in which the inner shell LiNbO3 suppressing the interfacial reactions, while the outer shell Li10GeP2S12 providing an intimate electrode-electrolyte contact.4 As a result, the dual-shell strucutured LGPS@LNO@LCO cathode exhibits a high initial specific capacity of 125.8 mAh.g-1 (1.35 mAh.cm-2) with an initial Coulombic efficiency of 90.4% at 0.1 C and 87.7 mAh.g-1 even at 1C. Furthermore, a plastic crystal electrolyte has been developed, which can simultaneously suppress the interfacial reactions and lithium dendrite growth in ASSLBs.5 The above work not only demonstrates various strategies to enable high-energy-density ASSLBs but also provides new insights into the interfacial challenges of ASSLBs.

References:

1. Y. Zhao, K. Zheng and X. Sun, Joule, 2018, 1-22.

2. C. Wang, Q. Sun, Y. Liu, Y. Zhao, X. Li, X. Lin, M. N. Banis, M. Li, W. Li, K. R. Adair, D. Wang, J. Liang, R. Li, L. Zhang, R. Yang, S. Lu and X. Sun, Nano Energy, 2018, 48, 35-43.

3. C. Wang, Y. Zhao, Q. Sun, X. Li, Y. Liu, J. Liang, X. Li, X. Lin, R. Li, K. R. Adair, L. Zhang, R. Yang, S. Lu and X. Sun, Nano Energy, 2018, 53, 168-174.

4. C. Wang, X. Li, Y. Zhao, M. N. Banis, J. Liang, X. Li, Y. Sun, K. R. Adair, Q. Sun, Y. Liu, F. Zhao, S. Deng, X. Lin, R. Li, Y. Hu, T.-K. Sham, H. Huang, L. Zhang, R. Yang, S. Lu and X. Sun, Small Methods, 2019, 1900261, doi:10.1002/smtd.201900261.

5. C. Wang, K. R. Adair, J. Liang, X. Li, Y. Sun, X. Li, J. Wang, Q. Sun, F. Zhao, X. Lin, R. Li, H. Huang, L. Zhang, R. Yang, S. Lu and X. Sun, Adv. Funct. Mater., 2019, 1900392, DOI:10.1002/adfm.201900392.

Figure 1
(Invited) Electron Transport in Bulk and 2DEGs in beta-Ga2O3 and kV Class Laterals Device in beta-Ga2O3
Authors: Ghosh Krishnendu , Zhang Ke , Vaidya Abhishek , Sharma Ankit , Kumar Avinash , Singisetti Uttam
Published: May 2020

Monoclinic beta-Ga2O3 and (AlxGa1-x)2O3 alloys are an emerging ultra-widebandgap semiconductor system for next generation power, GHz power switching and RF applications. In this talk, we will present the low field and high field transport simulations in Ga2O3 using first-principles calculations. Density functional theory calculations is used to get the band structure. The density functional perturbation theory is used to understand the lattice dynamics and identify the infrared (IR) active and Raman active phonon modes. Electron-phonon scattering rates are calculated Boltzmann transport equation is solved to calculate the low field mobility, velocity-field profiles and the impact ionization coefficients. The effect of dynamic screening on the electron mobility is evaluated in a two-dimensional electron gas (2-DEG) system in (AlxGa1-x)2O3/Ga2O3 heterostructures.

We will also report the Ga2O3 based power and RF devices. MOSFETs with spin-doping source/drain and n+ ohmic capped layers will be presented. kV breakdown voltages are seen with the devices limited by extrinsic breakdown. Temperature dependent characteristics show potential for high temperature applications.
(Invited) Radiation Effects on the Self-Heating of AlGaN/GaN High Electron Mobility Transistors
Authors: Choi Sukwon
Published: May 2020

Gallium nitride (GaN) has emerged as one of the most attractive wide bandgap materials for near-future electronics technology, specifically for applications that require high-power and high-frequency devices. The spontaneous and piezoelectric polarization of GaN utilized in AlGaN/GaN high electron mobility transistors (HEMT), provides significantly low ON-resistance due to the formation of a two-dimensional electron gas (2-DEG) channel at the AlGaN/GaN heterointerface without any intentional doping. The fact that these devices do not rely upon dopants to carry the current, in conjunction with superior material property of GaN, makes AlGaN/GaN HEMTs perfect candidates for deep space applications. However, the high voltage operation and the inherently low ON-resistance in AlGaN/GaN HEMTs result in extremely high power densities. Consequently, intense self-heating deteriorates device performance and more importantly, reliability.

In order to counter the potential thermal problems associated with these device technologies for deep space applications, it is necessary to advance the knowledge of device irradiation and its effect on self-heating, material interfaces, and properties of constituent materials. To achieve this goal, a set of AlGaN/GaN HEMTs were irradiated with a proton flux at an energy level of 1 MeV at a fluence of 2x1015/cm2. Diverse optical thermography techniques including infrared thermography, thermoreflectance thermal imaging, and micro-Raman spectroscopy were used to quantify the effect of radiation on the device temperature distribution. It was observed that, as compared to pre-irradiated devices, irradiated devices show a 40% higher device peak temperature under identical power dissipation (5 W/mm). To understand the contributing factors behind the observations (and the resulting deterioration of device mean-time-to-failure), the device material stack and transmission line measurement (TLM) structures were analyzed further. Steady-state thermoreflectance (SSTR) measurement, standard electrical characterization, and 3D coupled electro-thermal modeling were performed to capture changes in the thermal conductivity, interfacial thermal boundary resistance, ohmic contact resistance, and sheet resistivity of the devices. This comprehensive study will support the exploitation of the full potential of GaN electronics for deep space and other applications that require radiation hardness.
Anti-Corrosion Layer Embedded Top Cathode for Semi-Transparent Perovskite Solar Cells
Authors: Lan Shuai , Seok Hae-Jun , KIM Han-Ki
Published: May 2020

Power conversion efficiency (PCE) of perovskite solar cells (PSCs) has exceeded 25%, which is comparable to that of silicon solar cells and makes PSCs promising candidates for the next generation photovoltaics. However, their commercialization is still seriously hindered by the low device stability. Besides the well-known thermal and chemical factors, another major cause of the instability is the interaction of top metal electrodes with the Iodine-containing compounds decomposed from perovskite absorber layers. Both these volatile compounds and metal atoms can diffuse towards each other through hole transport layers and consequently lead to the degradation of device performance. In order to resolve this problem, an anti-corrosion layer against undesired mass transport is required to be inserted between the metal electrode and the perovskite absorber layer. Molybdenum is intrinsically resistant to the corrosive reaction of Mo to MoI3 because of its higher Metal-Metal bonding energy (435.5 kJ/mol) than Metal-Iodine bonding energy (266.9 kJ/mol). Besides, it has also been proven that Mo is stable against metal atom diffusion into perovskite by theory analysis. In this work, Mo was chosen to act as the anti-corrosion layer embedded in Oxide/Metal/Oxide (OMO) transparent cathodes for inverted semi-transparent PSCs. Bottom indium zinc tin oxide (IZTO) layers with a thickness of 30nm were fabricated via facing target sputtering using a low power before the deposition of magnetron sputtered Mo to protect organic layers from sputter damage. The electrical and optical characteristics of IZTO/Mo/IZTO (IMI) transparent electrodes were analyzed with dependence on Mo thickness and top IZTO thickness. Inverted semi-transparent PSCs integrated with the optimized IMI top cathode were assembled, in which the diffusion of iodine ions and metal atoms were more efficiently blocked compared to the reference device without a Mo anti-corrosion layer.
Electrospun Composite TiO2 Fibers for Color Tuning in Electrochromic Devices
Authors: Eyovge Cavit , Susarrey Arce Arturo , Gardeniers Johannes G.E.
Published: May 2020

Engineering one-dimensional (1D) nanostructures with multiple components can unlock properties that are not attainable by single elements alone. Herein, we use coaxial electrospinning for the synthesis of non-woven webs nanofibers with different metal(oxide) nanoparticles (NPs), i.e. silver (Ag), gold (Au), and copper oxide (CuO). The approach includes the structuring of nanofibers with an average diameter of 198.7±21.5 nm comprised of mesoporous TiO2 nanopowders mixed with metal(oxide) NPs to enable color tuning upon the application of an electrical potential. The nanofiber composites are supported on a fluorine-doped tin oxide (FTO) glass substrate and assembled in an electrochromic device in a half-cell configuration. It is observed that the color attained can be altered by changing the NP composition; such that Ag shows a black-brown color, Au yields dark blue, and CuO leads to a dark green color under negative bias. Fast color switching (<10 seconds) is possible per each TiO2 nanofiber/NP configuration. This is attributed to the faster kinetics of electrospun nanofibers in redox reactions gained by the high surface area to volume ratio. Band-gap deployment of the nanofiber composites is also observed, depending on the synthesized TiO2 nanofibers the band gap can be modulated between 2.76 to 3.01 eV allowing fine-color tuning upon EC cycles between ±2V. The rational design of the composite nanofibers is confirmed chemically, structurally and optically. The experiments show that material functionalities like color tuning are achievable with the use of metal(oxide) NPs. These findings can pave a new path for the rational design of nanofiber materials with applications in smart colored windows.
Remote-Type Quantum Dot Lens-Based LEDs Fabricated with Stereolithagraphy 3D Printing
Authors: Jung Nian-Ting , Ho Shih-Jung , Chen Hsueh-Shih
Published: May 2020

Quantum dots (QDs) have a great potential for next generation luminescence materials due to their unique properties, e.g., size-tunable bandgap, high luminescence quantum yield (QY) and narrow emission bandwidth. Thus, a wide-color-gamut display can be realized by introducing QDs in QD light-emitting diode application (QD-LED) instead of traditional phosphors. It has been found that photo and thermal oxidation can cause degradation of QDs.1 In the present study, a remote-type QD-LED in the structure of a QD color-convertor lens, prepared with stereolithagraphy (STL) 3D printing, on a blue InGaN chip has been presented. Different from traditionally fused-deposition-modeling (FDM) 3D printing, STL has advantages of fast forming process, direct laser curing without post-thermal curing, more intricate details and smooth surface. Comparing the reliability of QD-lens-based QD-LED with that of on-chip-package-type one, the QD lens are about 3.14 times longer in T50 and 78% lower in decaying rate than that of on-chip-package one after 528 h operated at 20 mA. A better reliability of the QD lens is attributed to smaller thermal and photo doses compared with those QDs in the on-chip package. The remote QD lens-based QD-LEDs are promising in lighting and display applications.

1. C. Huang, C. W. Yeh, G. H. Chen, M. C. Liu, and H. S. Chen, ACS Appl. Mater. Interfaces,
11, 2516 (2018).

Figure 1
Study of Graphene-like Indium Phosphide
Authors: Gorbenko Vitaliy Ivanovich
Published: May 2020

The semiconductor compounds in a state of graphene-like structure are the interesting object for both fundamental studies and technology. The two-dimensional material have unique electronic, structural, chemical and physical properties that plays a significant role for technology of new devices. Therefore the obtaining of various properties of that graphene-like materials and the understanding of the nature of chemical interaction with various species are important. In this work for the geometry optimisation graphene-like structure of indium phosphide the GAMESS program package [1] have been used. The electronic properties of g-InP has been obtained by ABINIT program package [2].

Such species as hydrogen, oxygen and carbon are a part of many natural compositions of the environment. In this work the preferred adsorption sites for the H, O and C adatoms have been defined through the potential-energy profiles of its interacting with g-InP sheet.

All ab initio calculations reported in this work were carried out using the Hartree-Fock method of GAMESS program package. The GAMESS was run on computers cluster of V.M.Glushkov Institute of Cybernetics of NAS of Ukraine [3]. Both STO-3G and 3-21G Pople style basis sets were used for C, H and O atoms. The g-InP sheet has been presented by cluster model with 48 In-atoms and 48 P-atoms in the hexagonal cells and 24 hydrogen atoms on the cluster perimeter. In the atomic-force probe technique the atom-probe (H, O or C) is moving above the surface of sheet on fixed distance without any optimization of its geometry. As a result the potential-energy (PE) profiles of interaction of the various atoms-probe with g-InP sheet have been obtained.

[1] Gordon M.S., Schmidt M.W. // in "Theory and Applications of Computational Chemistry: the first forty years" by ed. C.E.Dykstra. - Elsevier, Amsterdam, 2005, p.1167-1189.

[2] https://docs.abinit.org/topics/features/

[3] http://www.icyb.kiev.ua/s/189/ua/klaster_ik.html

Figure 1
Experimental and Modeling Results for Dislocation Sidewall Gettering in ZnSSe/GaAs (001)
Authors: Raphael Johanna , Kujofsa Tedi , Ayers John E
Published: May 2020

Dislocation sidewall gettering (DSG) is an important method for the removal of device-compromising defects from optoelectronic devices such as detectors and light-emitting diodes. DSG involves the patterned epitaxy or post-growth patterning and annealing, and allows misfit dislocations to elongate until they are captured by image forces at sidewalls. Despite this physical understanding of the process, practical application of DSG has often been guided by empirical studies due to the scarcity of modeling studies. In this work we apply a detailed model for lattice relaxation and dislocation dynamics to DSG in heteroepitaxial ZnSSe/GaAs (001), considering the effects of thickness, composition, growth temperature, and annealing, and we compare modeling and experimental results for this material system.
Threading Dislocation Dynamics in ZnSSe Strained-Layer Superlattices
Authors: Raphael Johanna , Kujofsa Tedi , Ayers John E
Published: May 2020

Strained-layer superlattices (SLSs) have been used extensively to modify the threading dislocation behavior in metamorphic semiconductor device structures, and have even been utilized as “dislocation filters.” However, up to the present time the application of SLSs in metamorphic structures has been impeded by the lack of detailed physical models for their behavior. In this work we apply a “weaving and jogging” model for dislocation interactions in ZnSSe SLSs to study their expected behavior and the dependence on the SLS design (placement, compositions, thicknesses, and growth conditions). Based on this study we make recommendations for the use of SLSs in the modification of threading dislocation behavior in ZnSSe/GaAs (001) device structures.
Comparison of Nonlinear Grading Approaches for ZnSSe/GaAs (001) Heterostructrures
Authors: Ayers John E , Kujofsa Tedi
Published: May 2020

Compositional grading is commonly used to accommodate the lattice mismatch in metamorphic semiconductor device structures. Although linearly-graded or linear step-graded approaches are commonly used, there are experimental and theoretical grounds for the expectation that nonlinearly-graded buffer layers could offer advantages in the control of dislocations or strain. In this work we have conducted a detailed modeling study of nonlinearly-graded buffer layers in ZnSSe/GaAs (001) heterostructures to better understand the dislocation dynamics and defect behavior in such nonlinear buffers, and we make comparisons to the well-known case of linear grading.
The Effect of Polymeric Binders in the Sulfur Cathode on the Cycling Performance for Lithium-Sulfur Batteries
Authors: Eom Ji-Yong , Kim Seong In , Lee Da-Yeon , Kang Ji-Hoon
Published: May 2020

Recently, great advance of the Li-S battery technology enables its penetration to the power source of the mid- and large-sized devices, which require high energy and power density that cannot be achieved in the Li-ion battery. While the most successful sulfur cathode could be designed by the optimization of the composite structure with carbonaceous materials, the binder system has been recently considered another important factor because the electrode structure of the sulfur cathode suffers huge structural change during the repeated electrochemical cycles. We studied the structural and electrochemical performance of the sulfur cathodes prepared by two different binders, the water-soluble SBR/CMC mixture binder and the traditional PVdF binder. The enhanced battery performance was observed in the SBR/CMC-based electrode and its origin was investigated by post mortem analysis about the electrodes, which confirmed the better mechanical integrity in the electrode compared with the PVdF-based electrode.