bluuebunny/crossref_metadata_2025_split huggingface dataset:
3D Modelling of the Transport Phenomena in a Parallel-Plate Electrodeionization Reactor through CFD
Authors: Enciso Rubi , Rodríguez-Torres Israel 
Published: February 2020

CFD has been used as a useful tool for the description of the phenomena occurring in electrochemical reactors. The present research studies the electrodeionization process from a 3D perspective, coupling the convection, diffusion and migration phenomena involved in the electrodeionization process using COMSOL Multiphysics and a validation of the simulation process is obtained using Digital Image Analysis and Electrodeionization experiments.
The used reactor is a parallel plate reactor, previously used for an electrodialysis process with good results, the total volume of each of the 4 compartments ( one for diluted-treated solution, one for the concentrated-waste solution and two electrodic rinses to close the electrical circuit) is of about 19.2 mL. The diluted compartment is filled with IRA-67 ion exchange resin ( 0.5-0.75 mm of diameter) previously conditioned and hydrated. The treated solution is a 20 ppm fluoride solution from NaF and was pumped into de diluted and concentrated compartments at a velocity that allowed a one minute Time of Residence.
The simulation was carried out with a 3D model of the reactor using its real measures, only the diluted and concentrated compartments were modelled. The flow of the solution in the concentrated compartment was considered as laminar and in the diluted compartment ( filled with ion exchange resin) a Brinkman-Darcy condition was applied. Nerst-Planck equations were used to describe the transport of the ionic species in the compartments and the flow through a ion exchange membrane.
The results show a good flow distribution,as well as a good ion transport. The simulations, confirmed the experimental results. The analized data is very similar in flow distribution and mass transport in the compartments. The results were analized in a quantitative and qualitative form. The validation of this simulated results will allow the improvement of some problematic zones in the reactor and the methodology developed can be useful to other electrochemical reactors.
(Invited) Water Transport Along Si/Si Direct Wafer Bonding Interfaces
Authors: Rieutord François , Tardif Samuel , Nikitskiy Ivan , Fournel Frank , Tedjini Marwan , Larrey Vincent , Bridoux Claudine , Morales Christophe , Landru Didier , Kononchuk Oleg 
Published: February 2020

Direct bonding interfaces exhibit, before annealing, a narrow density gap due to the contact interactions of facing surface asperities and their incomplete compression. This gap makes a narrow channel (width<1nm) along which water is able to move. This is evidenced clearly from the defect distribution in Si/Si hydrophilic bonding showing clearly a rim of defects whose extent is related to the kinetics of water penetration [1]. A simple model of capillary flow has been used in a first attempt to describe the kinetics of water penetration [2] under such very high confinement but this model fails to reproduce some of the experimental observations as e.g. the increase of wetting front width with penetration length, or the water distribution in case of reversed flow. We shall describe these experimental results, recording kinetics of water flow under varying amplitude and direction of chemical potential gradients (e.g. relative humidity) and different temperatures. These experiments allow a direct test of the dependence of flow kinetics with various parameters such as viscosity and surface energies.
Finally we shall establish from basic principles the equation of propagation, which is shown to be a porous medium equation type [3]:
∂ρ/∂t= D/2ρ0 ∂2ρ
2
/∂x2

where ρ is the interface areal density of water and D a constant “diffusion” coefficient depending on the wetting characteristics of the surface , the geometry of the gap and the water viscosity. Solutions of this equation will be given with boundary conditions corresponding to the wafer bonding interface situation. They exhibit features intermediate between sharp water front propagation (as described by Lucas-Washburn type of models) and diffusion equation, in agreement with experiments.

REFERENCES

[1] M. Tedjini et al. Appl. Phys. Lett. 109, 111603 (2016)
[2] F. Rieutord,et al ECS Trans. 2016
volume 75(
9) ,
163-167

[3] J. L. Vazquez, The Porous Medium Equation: Mathematical Theory, Clarendon Press Oxford (2007)
Modification of Carbon/Electrolyte Interface for Electrochemical Capacitor Improvement
Authors: Frackowiak Elzbieta , Slesinski Adam , Fic Krzysztof 
Published: February 2020

Electrochemical capacitor (EC) parameters are affected by the amount of charge reversibly accumulated at electrode/electrolyte interface, electrode material, type of electrolyte and its electrochemical stability as well as cell construction. It has been proved that asymmetric configuration, i.e., various electrode materials for positive and negative electrodes or hybrid configuration where different charge storage mechanism is utilised on both electrodes can bring a significant capacitor enhancement. Both approaches, it means typical electrostatic attraction of ions on various electrode materials and pseudocapacitive phenomena originating from electrode materials and/or electrolyte have been considered.
Carbon electrode surface has been modified by the ammonia adsorption. Dry and wet preliminary oxidation as well as thermal treatment of carbon materials have been realized for more efficient ammonia trapping into pores. A detailed analysis of nitrogen functionalities and carbon texture was performed. Donor-acceptor nature of modified carbon allows a capacitor voltage to be extended. The equilibria state and protective layers formed at the carbon/electrolyte interface give the possibility to reach operating capacitor voltage of 1.8 V. This unique but simple strategy enables a self-controlled pH gradient within the capacitor system. It is assumed that bulk of electrolyte has a neutral character (lithium sulfate) whereas both electrode interfaces (+) and (-) indicate acidic and basic character, respectively. Expected gradient of pH between positive and negative electrode is at least 6. Excellent reversibility during long-term galvanostatic cycling (10 000 cycles) and floating has been confirmed. Furthermore, this configuration eliminates the need for physical separation of ions (such as an ion-exchange membrane) to decelerate their mixing and improves the power density of the device.
Another approach for capacitor operation improvement is selection of suitable ions at electrode/electrolyte interface considering their ‘hard’ and ‘soft’ character.
Insights into Electrochemical Capacitors Ageing at Different Voltage/Current Conditions
Authors: Fic Krzysztof , Piwek Justyna , Platek Anetta , Frackowiak Elzbieta 
Published: February 2020

Electrochemical capacitors (ECs) are high-power energy storage devices able to operate for thousands of cycles. Nevertheless, their calendar and cycle life is limited, especially when high voltage is applied. On the other hand, that parameter (voltage, U) significantly increases their energy values according to the equation E=0.5CU2. Therefore, there is a particular need for the understanding of ageing and performance fade reasons in order to prolong supercapacitor operation.
Herein, the effect of ageing-related phenomena in water-based ECs is widely studied. LiNO3 at various concentrations (1M and 5M) was utilized. According to the ageing criteria (IEC 62391-1) AC/AC systems were cycled at elevated voltages (1.5-1.7V) using floating test until 20% of initial capacitance fade. It has been observed that voltage increase by 0.1V interval results in a shortening of the operation time for about 50%, reflected by resistance increase and distorted voltammetry response. However, the utilization of highly concentrated LiNO3 solution (5M) extends the electrochemical performance from 206h recorded for 1M LiNO3 to 312h. In order to insightfully describe ageing phenomena, physicochemical carbon properties were monitored by post-mortem approach. It has been observed that remarkable SBET decrease is observed on positive electrode only. The higher voltage applied the lower SBET surface area of positive electrode, whatever the electrolyte concentration. TPD studies provided more the information about the surface of the AC electrode. Essentially, the oxidation of positive electrode was higher than the negative one Moreover, it is predicted that negative electrode suffers from some morphological transformations rather than surface functionality changes, likely caused by hydrogen evolution.
It seems that p
ost-mortem approach which involves diversity of physio-chemical techniques can be definitely treated as an insightful approach for ageing research in the real capacitor system.
(Invited) Appearance of High Mobility Carriers in Strained Epitaxial Germanium
Authors: Myronov Maksym 
Published: February 2020

Carrier mobility is one of the most important parameters of any semiconductor material, determining its suitability for applications in a large variety of electronic devices including field effect transistors (FETs). Bulk or 3D, Germanium (Ge), with its very high intrinsic hole and electron mobilities of 1900 and 3900 cm2V-1s-1 at room temperature, respectively, is the most promising candidate material to replace Si channels in future complementary metal oxide semiconductor (CMOS) devices. When one or more of the dimensions of a solid are reduced sufficiently to nanometer range, its physicochemical characteristics notably depart from those of the bulk solid. With reduction in size, novel electrical, mechanical, chemical, magnetic, and optical properties can be introduced. The resulting structure is then called a low-dimensional structure or system.
Biaxial compressive strain in nm scale thick Ge epilayer narrows its band gap and causes the appearance of a quantum well (QW) in the valence band. Holes confined in the strained Ge QW form a two-dimensional hole gas (2DHG) and have an increased mobility due both to their lower effective mass and reduced scattering factors in this material system. During the recent years a major breakthrough have been achieved in enhancement of carrier mobility in strained epitaxial Ge grown on a standard Si(001) substrate. Extremely high room- and low-temperature 2DHG mobilities of up to 4,500 cm2V-1s-1 and 1,500,000 cm2V-1s-1, respectively, have been demonstrated. These hole mobilities are the highest not only among the group-IV Si, SiGe, Ge, SiC and Diamond semiconductors, but also among p-type III–V, II–VI and emerging 2D materials.
The 2DHG mobilities in strained Ge are already sufficiently high to fabricate sub-100 nm electronic devices and demonstrate ballistic transport therein at or around room temperature. This material will be an excellent platform for scientists to discover new quantum phenomena and applications.
(Invited) Catalytic Chemical Vapor Deposition Technology for Low Temperature Processing of Thin Film Transistors
Authors: Hong Wan-Shick 
Published: February 2020

For bendable and wearable device applications, it is necessary to ensure a sufficiently low processing temperature, usually one that is lower than the glass transition temperature of ordinary plastic sheets. However, it is very challenging to obtain inorganic thin films that contain an acceptable level of electronic defects at such a low temperature. Various attempts have been made to improve the electrical characteristics of the low temperature films, but most of the efforts slowed down the deposition rate considerably.
Catalytic chemical vapor deposition technique (Cat-CVD) has been known for its versatility and advantages such as a fast film growth rate and a high efficiency of gas utilization. These assets, combined with the absence of the atomic-scale damage caused by the bombardment of the charged particles, make this method attractive to applications in low temperature processing of the thin film transistors. Although this technique is still struggling to overcome several obstacles on its way to industrial implementation, it is a powerful research tool that can shed a light not just to finding interesting phenomena when various combinations of process parameters are tried, but also to understanding the behavior of radicals and atoms on the low temperature surfaces.
In this presentation, models of film growth in the catalytic chemical deposition process are discussed, and recent studies, including a surface pre-treatment, on applications to thin film transistors are surveyed.
(Invited) Development of Ultra-Wide Bandgap Amorphous Oxide Semiconductors for Future Electronics
Authors: Kim Junghwan , Hosono Hideo 
Published: February 2020

Over a decade, amorphous oxide semiconductors (AOSs) have been significantly developed. And, they are already employed in flat panel displays (FPDs), including LCDs and OLED displays. However, a longstanding issue such as bias-stress, illumination stress, e.g. NBS, NBIS, PBS, is not yet fully resolved. While, transparent or flexible electronics, recently, attract much attention for next generation. To realize practical transparent or flexible electronics, stability of conventional AOSs should be improved much than now. For instabilities of AOSs, many phenomenalistic cases have been reported, but their origins and mechanisms have not been theoretically elucidated. But, it is clear that all instabilities result from external factors such as illumination, hydrogen diffusion, humidity and electrical bias. Thus, it can be said that the material with less sensitivities to a variety of external factors exhibits higher stability.
We recently demonstrated a highly photo-stable TFT consisting of an ultra-wide bandgap AOS (UWB-AOS) based on a-GaOx [1-3]. The UWB-AOS has a low sensitivity against visible light due to its very wide optical bandgap of ~4.0 eV. However, a wider bandgap AOSs tend to have low mobility or difficulty in doping electrons. As shown in Fig. 1, the AOSs comprising the cations of relatively large principle quantum number have a relatively high mobility of >20 cm2/Vs. However, they have a narrow band gap (Eg) of ~2.5 eV. Therefore, a widening the Eg by decreasing only the valence band maximum (VBM) level would be the best approach to obtain high-performance UWB-AOSs.
Details, including the relation between electronic structures and stabilities, will be presented at the conference.

References

[1] J. Kim el al., SID Symposium Digest of Technical Papers 47 (2016) 951.
[2] J. Kim et al., NPG Asia Materials 9.3 (2017) e359.
[3] J. Kim et al., Active-Matrix Flatpanel Displays and Devices (AM-FPD), 2017 24th International Workshop on. IEEE, 2017.

Figure 1
(Invited) Printed Poly-Si TFTs on Paper for Beyond Plastic Electronics
Authors: Ishihara Ryoichi , Trifunovic Miki , Sberna Paolo , Shimoda Tatsuya 
Published: February 2020

Solution process has received many attentions in recent years because of low-cost manufacturability of flexible electronic devices owing to the additive process. Organic and metal-oxide semiconductors can be printed at low-temperature however carrier mobility and reliability of TFTs using those materials are still much inferior than those for silicon. Silicon as the base material, on the other hand, has advantages in terms of high-mobilities for the both of electron and holes, chemical and electrical stability, and low-power consumption by CMOS circuit configuration.
Silicon can be printed using liquid silicon ink, which is a mixture of polymerized cyclopentasilane (CPS) and a solvent [1]. However, low-temperature formation and fabrication of polycrystalline-Si (poly-Si) and transistors on top of low-cost flexible substrates, such as paper, were outstanding challenges.
In this paper, we review a novel method that forms poly-Si patterns directly on paper using the same liquid silicon with doctor-blade coating and local irradiation of excimer-laser with room temperature process [2]. We review also the process and electrical properties of poly-Si TFTs fabricated on the paper [3]. Both p- and n-channel poly-Si TFTs were fabricated directly on top of paper with field-effect mobilities of 6.2 cm2/Vs and 2.0 cm2/Vs, respectively. Owing to the low-cost, biodegradable nature of paper, and superior electrical performance and reliability and biocompatibility of silicon, this technique will break-though the printed electronics by enabling applications such as fast printed electronics that are inexpensive, fully-recyclable, biodegradable and even edible.
[1] T. Shimoda, et al., “Solution-processed silicon films and transistors” Nature 440, 783-786 (2006).
[2] M. Trifunovic, T. Shimoda and R. Ishihara, “Solution-processed polycrystalline silicon on paper”, Appl. Phys. Lett. 106, 163502 (2015)
[3] M Trifunovic, PM Sberna, T Shimoda, R Ishihara, “Solution-based polycrystalline silicon transistors produced on a paper substrate”, npj Flexible Electronics 1 (1), 12 (2017)
Tailoring Electrolyte Specifications for Graphite/NMC811-Based Lithium Ion Batteries
Authors: Beltrop Kolja , Klein Sven , Nölle Roman , Qi Xin , Winter Martin , Placke Tobias 
Published: February 2020

In order to increase the energy density of lithium-ion batteries (LIB) one promising approach is rooted in the increase of the nickel content in layered oxide cathode materials (LiNixMnyCo1-x-yO2, x ≥ 0.6, LiNMC) for an application as positive electrode due to the high specific discharge capacity at moderate upper cutoff voltages below 4.4 V vs. Li/Li+.[1, 2] However, the insufficient cycling stability as well as significant safety concerns restricted this material class from industrial application so far. For that reason, new electrolyte compositions including specifically designed additives are of great importance to enable a sufficient electrochemical performance of Ni-rich NCM materials.[3]
In this work, we introduce a low molecular weight, low cost and non-toxic chemical compound as electrolyte additive for the application in graphite/LiNi0.8Mn0.1Co0.1O2 (NMC811) cells.[4] The addition of only 0.5 wt.% of the additive into the control electrolyte (1M LiPF6 in EC / EMC 3:7, by weight) significantly increases the reversible capacity as well as the 1st cycle Coulombic efficiency (CE) improving the capacity retention of the standard full cell system between 2.8 - 4.3 V. Irreversible lithium loss in the negative electrode was found to be the predominant factor for the full cell capacity fade and the poor cycling performance of the control electrolyte. Inductively coupled plasma-mass spectrometry (ICP-MS) and X-ray photoelectron spectroscopy (XPS) analysis reveals the contribution of the electrolyte additive in the solid electrolyte interface (SEI) formation on the negative electrode as well as in the cathode electrolyte interface (CEI) formation on the positive electrode. As a result, less active lithium loss during cycling is present in the additive containing electrolyte which leads to an impressive increase in capacity retention of 77%. In addition, a comprehensive performance study of state of the art electrolyte additives such as triphenylphosphine (TPP), vinylene carbonate (VC) and diphenyl carbonate (DPC) is presented and compared to the invented electrolyte additive, demonstrating the outstanding working ability of this compound in graphite/NMC811 cells. To the best of our knowledge the presented cycling results outperform the so far reported electrolyte additives in the field.

Reference:

[1] J. Kasnatscheew, M. Evertz, R. Kloepsch, B. Streipert, R. Wagner, I. Cekic Laskovic, M. Winter, Energy Technology, 5 (2017) 1670-1679.
[2] H.-J. Noh, S. Youn, C.S. Yoon, Y.-K. Sun, Journal of Power Sources, 233 (2013) 121-130.
[3] A.M. Haregewoin, A.S. Wotango, B.J. Hwang, Energy & Environmental Science, 9 (2016) 1955-1988.
[4] K. Beltrop, S. Klein, R. Nölle, A. Wilken, J.J. Lee, J. Reiter, L. Tao, C. Liang, M. Winter, X. Qi, T. Placke, Chemistry of Materials, (2018), submitted.

Figure 1
(Invited) Tuning Ion Mobility in Solid Electrolytes Via Lattice Disorder
Authors: Kim Kwangnam , Siegel Donald J 
Published: February 2020

Historically, the ionic conductivity of solids has been insufficient to supplant liquid electrolytes in battery applications. Very recently, however, a small number of solids with ionic conductivities comparable to that of liquids have been identified. The discovery of these fast ion conductors has advanced the prospects for realizing solid-state batteries. Nevertheless, additional study of these materials has, in essentially all cases, unearthed other shortcomings (stability, Li penetration, etc.), suggesting that the discovery of alternative solid electrolytes (SE) remains an important pursuit.
A fundamental question in the identification of new SEs is ‘what chemical/mechanical/structural features promote high ion mobility?’ We hypothesize that lattice disorder represents one such feature. The anti-perovskites (AP) present an ideal venue to explore the connection between disorder and ion mobility: the degree of disorder in the APs can be systematically tuned via atom substitution, yet the relative simplicity of the structure allows for a comprehensive characterization of ion migration pathways.
Here, we systematically probe the connection between ionic mobility and lattice disorder across a series of 24 model APs. Our calculations reveal that ‘disorder tuning’ provides a pathway to higher ionic conductivity. More specifically, a strong correlation is observed between the degree of lattice disorder and the minimum migration barrier for percolating ion migration: compounds with the largest disorder exhibit the lowest barriers for ion migration, independent of the migration mechanism (vacancy or interstitial). At the same time, the energetic spread between the largest and smallest migration barriers for a given compound increases with increasing disorder. Nevertheless, a higher degree of disorder also correlates with diminished thermodynamic stability, signaling a tradeoff with ionic mobility. Thus, realizing higher mobility will benefit from the development of strategies to kinetically stabilize disordered phases.