bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Glass Forming Electrolyte Based on Lithium Glycerolate
Authors: Di Noto Vito , Pagot Gioele , Vezzù Keti , Nale Angeloclaudio , Negro Enrico , Pace Giuseppe 
Published: May 2020

The study of the interplay between structure and conductivity in lithium-conducting electrolytes is a pivotal point for the development of future secondary batteries [1]. The use of Glycerol as a low molecular weight component in electrolytes is particularly interesting due to its glass-forming behavior and low glass transition temperature (-78.5°C). In addition, a high flexibility of the alkyl backbone chain and the well-known capability of oxygen functionalities to coordinate lithium cations make Glycerol very appealing as ion-conducting media as well as building block to obtain hybrid polymer electrolytes [2].
On this basis a family of eleven electrolytes based on Lithium Glycerolate with general formula C3H8-xO3Lix, where 0 ≤ x ≤ 1, is prepared and investigated [3]. In these electrolytes the Glycerolate (C3H8-xO3
x-) component acts as a large and flexible macro-anion which is able to provide a high single-ion conductivity to the material (8.36∙10-5 S∙cm-1 at 20°C and 1.55∙10-2 S∙cm-1 at 150°C for x = 0.25).
Finally, the Glycerol∙∙∙Li+ interactions in these electrolytes are studied on T and x, with a particular reference to the detection of: a) macro-anion coordination sites; and b) the secondary structure of Glycerol chains. Insights on the long-range charge transfer mechanism and Glycerol relaxation events are also discussed.
These studies are carried out by Inductively-Coupled Plasma Atomic Emission Spectroscopy, IR and Raman spectroscopies, DSC, TGA, and Broadband Electrical Spectroscopy.

References

[1] V. Di Noto, S. Lavina, G. A. Giffin, E. Negro, B. Scrosati, Electrochim. Acta 57 (2011) 4-13.
[2] V. Di Noto, M. Vittadello, S. G. Greenbaum, S. Suarez, K. Kano, T. Furukawa, The Journal of Physical Chemistry B 108 (2004) 18832-18844.
[3] G. Pagot, S. Tonello, K. Vezzù, V. Di Noto, Batteries 4 (2018) 41.
(Invited) Solid Halide Electrolytes for All-Solid-State Lithium Ion Batteries
Authors: Asano Tetsuya , Sakaida Masashi , Sakai Akihiro , Miyazaki Akinobu , Hasegawa Shinya 
Published: May 2020

In order to realize all-solid-state batteries (ASSBs) with high energy density and high-rate charging/discharging capability that surpass conventional LIBs, development of solid electrolytes (SEs) is one of the utmost remaining issues. The difficulty is that SEs need to satisfy stringent requirements particularly for large scale applications; not only high ionic conductivity, but also high electrochemical stability, chemical stability, and deformability. However, neither sulfide nor oxide SEs satisfy all these requirements by themselves so far.
Here, we propose that, considering the electronic and chemical nature of halide anions, halide solid electrolytes (HSEs) have potential to satisfy all the above requirements, and demonstrated that HSEs are indeed suited as an SE material for ASSB application [Ref].
The lithium ionic conductivity of cold-pressed powders of the HSEs we developed surpassed 1 mS/cm at room temperature without any additional grain-boundary resistance. Such high ionic conductivity was realized even with close-packed anion sublattices whose ion pathways are unlike those of sulfide or oxide SEs, indicating that the design consideration for ionic conductors varies depeding on the material systems. The bulk-type ASSBs using these new HSE materials exhibited excellent charge/discharge performance with 4 V class cathode active materials without any extra coating; the initial coulomb efficiency over 94% and low interfacial resistance to be less than 10 Ωcm2, indicating high oxidation stability of HSE materials. Moreover, by appropriate selection of cation/anion pairs, electrochemical stability of HSE can be improved so that HSE can work with the anode active materials with Li-metal potential such as graphite.
All these characteristics of halide materials clearly indicate that HSEs are promising candidate for ASSB application, in addition to sulfides and oxides, for large scale deployment.
[Ref] T. Asano et al., Adv. Mater. 2018, 30, 1803075.
A New Method for Measuring Transference Number Using Raman Spectroscopy
Authors: Fawdon Jack , La Mantia Fabio , Pasta Mauro 
Published: May 2020

The successful use of lithium metal as the negative electrode in high-energy density batteries is dependent on the effective suppression of dendritic growth during charging.1 A key electrolyte property for mitigating dendritic growth is the transference number, which describes the movement of one ion in relation to the other ions in solution.2 Traditionally, the agreed method for measuring the transference number has been the Hittorf method,3 but with the requirement of a large volume of electrolyte and the difficulty of separator inclusion, it does not imitate a real battery application. The popular polarisation methods including the so-called Bruce-Vincent method4 and the pure Electrochemical Impedance Spectroscopy method5 addresses this problem by including separators and only using small amounts of electrolyte. However, these methods assume ideality, which can often lead to the incorrect value of transference number especially at high concentrations or using ionic liquid electrolytes.
We propose a new method for measuring the transference number, using Raman Spectroscopy, which closely imitates a real cell by the inclusion of a separator and does not assume ideality. We believe this facile and powerful new experiment is implementable in both academia and industry to understand how novel electrolyte’s transference number is influencing the concentration gradient and also dendrite growth.

References

1. Cheng, X. B., Zhang, R., Zhao, C. Z. & Zhang, Q. Toward Safe Lithium Metal Anode in Rechargeable Batteries: A Review. Chem. Rev.
117, 10403–10473 (2017).
2. Brissot, C., Rosso, M., Chazalviel, J. N. & Lascaud, S. Dendritic growth mechanisms in lithium/polymer cells. J. Power Sources
81, 925–929 (1999).
3. Valoen, L. O. & Reimers, J. N. Transport Properties of LiPF6-Based Li-Ion Battery Electrolytes. J. Electrochem. Soc.
152, A882 (2005).
4. Bruce, P. G. & Vincent, C. A. Steady state current flow in solid binary electrolyte cells. J. Electroanal. Chem.
225, 1–17 (1987).
5. Ravn Sørensen, P. & Jacobsen, T. Conductivity, charge transfer and transport number-an ac-investigation of the polymer electrolyte LiSCN-poly(ethyleneoxide). Electrochim. Acta
27, 1671–1675 (1982).
Garnet-Type Li7La3Zr2O12 / Lithium Metal Interface: Microstructure and Electrochemical Properties in Solid State Batteries
Authors: Schmieg Johannes , Müller Marius , Dierickx Sebastian , Szász Julian , Weber André , Ivers-Tiffée Ellen , Gerthsen Dagmar 
Published: May 2020

All-solid-state lithium ion batteries may overcome safety issues in future energy storage systems, when a non-flammable solid electrolyte instead of a liquid electrolyte is applied. Garnet-type Li7La3Zr2O12 (LLZO) is an encouraging choice due to its high Li+ conductivity and its chemical stability against lithium metal [1]. However, low-resistance LLZO/Li interfaces are deteriorated by incomplete adhesion of lithium metal onto LLZO and by surface contamination [2]. The resulting inhomogeneous distribution of contact areas may be more prone to dendrite formation. Previous studies [3,4] indicate that LLZO/Li interface quality is significantly improved by metallic buffer layers.
In this study, we aim for a reliable preparation of low-resistance interfaces between solid electrolyte and lithium metal. At first, magnetron sputtering is applied to deposit an indium buffer layer of 50 to 500 nm thickness onto the polished and cleaned electrolyte surface. For cell assembly, lithium foil is put on both sides of an In-coated LLZO pellet and the test cell is heated to 220°C in argon atmosphere. After that, microstructure and electrochemical properties of the symmetric cells are analyzed. We improved cross-section sample preparation to inspect the quality of LLZO/In/Li interfaces over hundreds of µm. Scanning electron microscopy (SEM, cf. figure 1) confirms excellent adhesion between lithium and LLZO. We use a dry inert atmosphere during preparation, handling and transfer of our samples to avoid artifacts and sample degradation. The FEI Helios G4 FX microscope enables correlative SEM imaging by simultaneous acquisition of up to four different detector signals for interface topography and material contrast. Local chemical composition at the interface is analyzed by energy dispersive X-ray spectroscopy and electron-beam damage is minimized for SEM imaging by selecting optimum electron energies.
Electrochemical impedance spectroscopy (EIS) followed by data evaluation via the distribution of relaxation times (DRT) and equivalent circuit modelling [5] deliver the proportional contributions of grain, grain boundaries and interfaces to the total impedance of symmetric cells (Li/In/LLZO/In/Li). Interface microstructures and EIS measurements are correlated for samples with different buffer layer characteristics to allow targeted optimization. We compare the pristine state of the test cells to samples that have been cycled with different current densities.

References

[1] S. Ramakumar et al., Progress in Materials Science 88 (2017), 325-411
[2] L. Cheng et al., Physical Chemistry Chemical Physics 16 (2014), 18294
[3] W. Luo et al., Advanced Materials 29 (2017), 1606042
[4] C. Tsai et al., ACS Applied Materials & Interfaces 8 (2016), 10617−10626
[5] P. Braun et al., Journal of Electroceramics 38 (2017), 157-167

Figure 1
High Performance Metal Sulfide Electrode for Lithium Battery
Authors: Kalimuldina Gulnur , Nurpeissova Arailym , Adair Desmond , Bakenov Zhumabay 
Published: May 2020

The energy crisis is reaching its critical point where the actions for its mitigation cannot be postponed any longer. Therefore, urgency for more powerful, more stable energy storage systems is making our society investigate different materials with various configurations. Conducted studies on electrode materials, in general, have shown the essential tendencies besides electrode material itself being morphology, microstructure and chemical composition [1]. One of the promising electrode materials for the next-generation lithium-ion batteries is metal sulfides, as they possess high electronic conductivity and relatively high theoretical capacity than that of LiCoO2. Nowadays, copper sulfide is attracting more researchers due to its wide range of stoichiometric composition (CuxS, x=1-2) and diverse application in energy devices [2]. Extensive studies have demonstrated the possibility for numerous copper sulfide synthesis methods such as hydrothermal and solvothermal methods, melt diffusion, mixed solvents method, chemical deposition, sol-gel method, spray pyrolysis (SP), microwave-assisted growth, chemical vapor transport, template synthesis, and electrodeposition [3,4]. However, all those methods are costly and time-consuming. In this study, is presented a simple and straightforward novel method of preparation of flower-like structured copper sulfide (CuxS) (Fig. 1) with excellent electrochemical properties and cycling stability. Detailed studies of the electrochemical reaction mechanism for the new composition of CuxS phase will be presented.
References
[1] G. Zubiab, R. Dufo-López, M. Carvalho, G. Pasaoglu, Renew. Sust. Energ. Rev., 89 (2018) 292-308.
[2] C. Feng, L. Zhang, Z. Wang, X. Song, K. Sun, F. Wu, G. Liu, J. Power Sources, 269 (2014) 550-555.
[3] G. Kalimuldina, I. Taniguchi, J. Mater. Chem. A, 5 (2017) 6937-6946.
[4] C. Feng, L. Zhang, M. Yang,. X. Song, H. Zhao, Z. Jia, K. Sun, G. Liu, ACS Appl. Mater. Interfaces, 7 (2015), 15726−15734.
Acknowledgements
This work was supported by the projects 091019CRP2114 “Three-Dimensional All Solid State Rechargeable Batteries” and 240919FD3914 “Self-charging rechargeable lithium-ion battery” from Nazarbayev University.

Figure 1
Photo-Electrochemical Etching of Single Crystalline β-Ga2O3 Thin Film
Authors: Choi Yong ha , Bae Jinho , Kim Jihyun 
Published: May 2020

β-Ga2O3 is a next-generation semiconductor material having ultra-wide bandgap energy of 4.8 eV and excellent electrical properties. So it is expected to be suitable for various applications such as power electronics, solar-blind UV photodetectors and gas sensors. However, there are some issues to overcome in order for β-Ga2O3 to be commercialized. Among them, crystal defects are important factor that significantly affects device performance. Defects are formed intrinsically during the growth process, or caused by high-energy plasma ion during dry etching. It has been reported that the electrical characteristics are deteriorated in the device such as MOSFET and MISFET fabricated by inductively coupled plasma etching. Unlike dry etching, which can cause damage by plasma ions, wet etching is a damage-free process that uses a chemical reaction between the target material and etchant. In addition, wet etching may be used for removing defects by using the etching characteristic, which the chemically unstable defect areas are preferentially etched. However, β-Ga2O3 hardly reacts with etchant at room temperature, and has been reported to have etch rate of several tens of nm/min when acid etchant are used at higher than 100 °C.
In our study, we have tried to increase the etch rate of β-Ga2O3 and remove defects effectively by Photo-electrochemical (PEC) etching. PEC etching is a method that promotes the reaction by irradiated light having energy above bandgap and applied external bias. Single crystalline β-Ga2O3 thin films are cleaved in the [100] direction with mechanical force from single crystalline β-Ga2O3 substrate. Ti/Au was deposited to form Ohmic contact with β-Ga2O3 thin films. With the PEC etching method, we could etch at a lower temperature than conventional wet etching. In addition, it was confirmed that the etch rate can be controlled according to the external bias condition. The details of our experiment conditions and results will be presented at the meeting.
(Invited) Characterization of Thermal Effects in Wide Bandgap Semiconductor Materials and Devices
Authors: Graham Samuel , Hopkins Patrick E , Goorsky Mark S. , Khan Asif , Henry Asegun , Doolittle W. Alan , Luo Tengfei , Suga Tadatomo , Mu Fengwen 
Published: May 2020

Wide bandgap electronics made from nitrides (e.g., Gallium Nitride (GaN)) and oxides (e.g., Gallium Oxide (Ga2O3)) are currently under development due to their potential to create some of the most advanced RF and power electronic devices in the world. However, the thermal response of these devices under applied electric fields can create large power densities (RF and power electronics) that must be understood. For many of these devices, the electrothermal response plays a strong role in both the acceptable operation or long-term failure and reliability of the devices. Thus, tools that can help elucidate these responses and provide a method to help design better devices is of critical need for this field.
In this talk we will discuss advancements in thermal characterization techniques that have allowed new insights into electrothermal behavior in GaN and Ga2O3 materials and devices. Specifically, a focus on the role of device architecture and material processing will be addressed. For GaN and Ga2O3 RF and power electronics, the role of thermal interfaces in the heat dissipation of both lateral and vertical device architectures will be discussed. We will cover aspects of semiconductor-semiconductor as well as metal-semiconductor interfaces and their roles in device thermal management. A highlight will be the use of plasma activated bonding to provide ultralow thermal resistance interfaces that allow for heterogenous integration of nitrides and oxides with high thermal conductivity substrates. Finally, we will discuss the implications of these effects on device behavior through experiments and modeling.
Fabrication and Characterisation of Silicide/3C-SiC/Si Contacts for Schottky Barrier Diode Application
Authors: Cherkaoui Karim , Duane Russell , Ward Peter , Blake Alan 
Published: May 2020

Silicon carbide is a wide band gap semiconductor which presents excellent physical properties such as a high critical electric field strength which enables the realisation of efficient power devices [1]. The cubic silicon carbide (3C-SiC) polytype has been less investigated than the more popular hexagonal structure 4H-SiC. 3C-SiC has the advantage that it can be epitaxially grown on Si by chemical vapour deposition (CVD) [2] and presents properties suitable for achieving cost effective SiC power devices in the range 650V to 1200V. These 3C-SiC/Si substrates offer a promising alternative to the costly hexagonal SiC (4H-SiC) wafers and can also be used as template for the epitaxy of cubic GaN [3]. However, the presence of the Si substrate does limit the temperature available to anneal out the implantation damage generated by some device processing sequences.
This work investigates the properties of metal silicides as a potential Schottky contacts for high blocking voltage 3C-SiC/Si Schottky barrier diodes (SBDs). For this study, Ti and Pt silicide contacts are formed on the (100)3C-SiC surface. The influence of the silicide formation temperature (500oC-650oC) on the contact electrical properties is investigated in detail. Current voltage (I-V) and capacitance voltage characteristics (C-V) are used to evaluate the reverse leakage current and extract the Schottky barrier height as well as the concentration of electrically active dopants in the N type 3C-SiC/Si. The Pt silicide Schottky contact is found to present higher energy barrier height than the Ti silicide Schottky contact and this trend was confirmed by the associated improved reverse current in the Pt Schottky. This is a promising result as it suggests that the reverse leakage is not dominated by the stacking faults inherent to this material. Temperature dependent I-V characteristics are measured and compared to theoretical I-V curves to explore the mechanisms responsible of the reverse leakage. The effort towards high blocking voltage final SBD device requires excellent PN junction edge termination. In this work, to avoid the damage caused by Al ion implantation, the electrical properties of 3C-SiC/Si PN junction diodes fabricated by epitaxy of P type 3C-SiC layers on N type 3C-SiC/Si substrates are also investigated. The reverse current mechanisms in the PN junction and the Schottky are compared and the suitability of the PN for device termination is discussed.
[1] Kimoto, T., Cooper, J.A. Fundamentals of Silicon Carbide Technology: Growth, Characterization, Devices and Applications, Wiley, (2014)
[2] A. Severino, C. Locke, R. Anzalone, et al., ECS Transactions, 35 (6), 99 (2011)
[3] Okumura, H., Ohta, K., Feuillet, G., et al. Journal of Crystal Growth, 178 (1-2), 113, (1997)
Rapidly Thinning Silicon Carbide By Anodization
Authors: Kuo Stanley Ken-Hua , Jian Bill Po-Yen , Li Wen-Shuo , Hwang Yean-Ren , Lee Benjamin T. -H. 
Published: May 2020

SiC is a semiconductor material used to fabricate electronic devices that can operate under severe conditions, such as high temperatures, and which have some advantages over silicon-based devices (for example, high frequency and high power). The hardness of SiC is quite high (Mohs=9.5) and strong chemically inert, making it difficult be thinned. Up to now, since the majority carriers of n-type SiC are electrons, its application is more extensive, but it is also more difficult to thin. An effective etching method is by the reactive ion etching (RIE) method, which may produce satisfactory results in a smooth surface. In addition, according to reports, an efficiently etching processing can be performed by a high temperature (>700 C) molten alkali metal hydroxide (for example, NaOH). However, the equipment cost, operation convenience and thinning speed of these etching approaches are not as well as electrochemical etching, i.e., anodization. However, n-type SiC is very difficult to be anodized because of the lack of electric holes which are the key species for etching. In our report, we used a wafer bonding processing to form a temporary p-n junction by jointing to a p-type silicon, so that minority carriers, electric holes, in the mated p-type silicon can easily transfer to the SiC surface via a bias, resulting in a HF-based electrochemical etching. By the processing, the n-type SiC can be quickly thinned. After thinning, the p-type silicon subatrate can be easily removed without the chemical contamination on the thinned SiC substrate.
Figure: The anodized surface of n-type SiC.

Figure 1
(Invited) Selective Area Etching and Doping of GaN for Power Electronics
Authors: Li Bingjun , Wang Sizhen , Han Jung 
Published: May 2020

Gallium Nitride (GaN)-based devices are very attractive candidates for next-generation high-power applications, due to the intrinsic material properties. However, the lack of selective-area doping technique in GaN greatly limits the design flexibility and device performance. Implant or diffusion of dopants into GaN are currently being pursued. Additionally, attempts of selective-area etching by reactive-ion etching (RIE) followed by regrowth doping have been reported by many groups; most of them reported defective electronic interfaces with very leakage characteristics. It was determined that the presence of highly energy ions, reactive chlorine species, and ultraviolet photons in RIE tend to generate both surface and sub-surface damages. Here, we report an alternative method of selective-area etching to overcome this barrier. Tertiarybutylchloride (TBCl) is employed as an in-situ chemical etchant of GaN in MOCVD to create smooth trenches, and to remove plasma etching-generated damages on the surface. Regrowth is performed right after the TBCl etching without breaking the vacuum. Several key issues that will be discussed include 1) the exploration of etching parameter space, 2) comparisons among continuous, RIE-etched, and TBCl-etched regrown PN diodes, 3) selective area etching and doping, 4) nanoscale characterization of selective area doping by scanning probes and atomic probe topography (APT), and 5) the implication of anisotropy in selective area regrowth.
This work is supported by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000871 as part of the PNDIODES program managed by Dr. Isik Kizilyalli.