bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extremely Fast Solvers for Newman-Type Models of Li-Ion Cell (dis)Charge
Authors: Korotkin Ivan , Richardson Giles , O'Kane Simon , Foster Jamie M 
Published: May 2020

The Newman model for charge transport within porous electrodes was developed by Newman, Fuller and Doyle in the mid-90s, and has become the standard tool for simulating Li-ion cell (dis)charge. The model is comprised of a system of nonlinear partial differential equations that must, in general, be solved numerically.
The computational costs associated with solving the Newman model, even for a single planar cell, are relatively high; for example, most solvers take several minutes to compute a single discharge curve. This makes its application to computationally expensive problems (such as cell optimisation, parameter estimation or battery pack simulation) problematic. Motivated by the lack of a fast Newman solver in the literature we have developed a new software tool, named DandeLiion. This provides extremely fast code with which to solve the Newman model. It is straightforward to install, comes with concise and clear documentation, is fully parallelisable and free to use. As an example of its power it has the capability of simulating a full discharge curve in less than a second (with fully nonlinear transport and sufficient resolution to compute the solution to several digits of accuracy) which is approximately several hundred times faster than most commercial solvers. In addition, it is equipped with a library of battery chemistries that incorporates models for nonlinear lithium transport and open circuit voltage in most active electrode materials, and for lithium transport and conduction in the most common electrolytes. This gives the user the ability to simulate a wide range of devices designs. It can also be used to simulate realistic drive cycle data.
In order to illustrate the power of this software we perform a thermally coupled simulation in a realistic pouch cell geometry, using DandeLiion to compute the electrochemical discharge of the cell stack in the resulting three-dimensional evolving temperature field. We note that such thermally coupled pack simulations are normally performed using simple equivalent circuit models of the cell, rather than the Newman model, because the computational cost associated with a thermally heterogenous Newman model has, up until now, been too high.
Redox Mediators Degradation By Singlet Oxygen in Lithium Oxygen Batteries
Authors: Kim Hun , Sun Yang-Kook 
Published: May 2020

Non-aqueous lithium-oxygen batteries cycle by forming and decomposing the lithium peroxide to deliver a capacity. During charging, oxidizing the solid insulating lithium peroxide can greatly be facilitated by redox mediators which shuttle electron-holes between the porous substrate and lithium peroxide. Redox mediator stability is thus key for energy efficiency, reversibility, and cycle life. However, the gradual deactivation of redox mediators during repeated cycling has not conclusively been explained. Here, we show that organic redox mediators are predominantly decomposed by singlet oxygen that forms during cycling. Their reaction with superoxide, previously assumed to mainly trigger their degradation, peroxide, and dioxygen, is orders of magnitude slower in comparison. The reduced form of the mediator is markedly more reactive towards singlet oxygen than the oxidized form, from which we derive reaction mechanisms supported by density functional theory calculations. Thus, design of redox mediators considers the stability against singlet oxygen.
References:
1. Kwak, W.-J.; Kim, H.; Jung, H.-G.; Aurbach, D.; Sun, Y.-K. Review—A Comparative Evaluation of Redox Mediators for Li-O 2 Batteries: A Critical Review. J. Electrochem. Soc.
2018, 165, A2274–A2293.
2. Mahne, N.; Schafzahl, B.; Leypold, C.; Leypold, M.; Grumm, S.; Leitgeb, A.; Strohmeier, G. A.; Wilkening, M.; Fontaine, O.; Kramer, D.; et al. Singlet Oxygen Generation as a Major Cause for Parasitic Reactions during Cycling of Aprotic Lithium–Oxygen Batteries. Nat. Energy
2017, 2, 17036.
3. Kwak, W.-J.; Kim, H.; Petit, Y. K.; Leypold, C.; Nguyen, T. T.; Mahne, N.; Redfern, P.; Curtiss, L. A.; Jung, H.-G.; Borisov, S. M.; et al. Deactivation of Redox Mediators in Lithium-Oxygen Batteries by Singlet Oxygen. Nat. Commun.
2019, 10, 1380.
(Invited) Dielectric Science on Today's Devices
Authors: Misra Durgamadhab 
Published: May 2020

Device scaling in CMOS technology has approached to 10nm range and below. The gate dielectric, being the critical constraint, has evolved significantly and requires constant quality improvements in order to keep the proper functioning of the transistors and memory devices. While the transistor has transformed from a planar device to a three-dimensional device to a gate all around device, several new devices such as ferroelectric FETs and negative capacitance FETs have emerged to be integrated into standard CMOS technology. Additionally, many forms of memory devices such as resistive random-access memory (ReRAM) devices and ferroelectric RAM devices are being investigated for possible implementation of artificial intelligence hardware. All these devices use high dielectric constant (high-k) materials in some form or other. The electrical performance in these devices depends on the dielectric deposition process, precise selection of deposition parameters, pre-deposition surface treatments and subsequent thermal budget. In this work we describe the evolution of dielectric science in nanoelectronics.
For logic devices, once the thickness of SiO2 reached the onset of direct tunneling region (<1.5 nm) high-k insulators were introduced to suppress the direct-tunneling leakage current. Because of thermal stability, HfO2-based high-k dielectrics were selected to replace SiO2. To resolve issues like mobility degradation, threshold voltage control and Fermi-level pinning, HfO2-based high-k gate dielectrics was introduced with an interfacial SiO2 layer on silicon devices. Subsequently, higher-k dielectrics are required for transistors performance enhancement to keep up with the scaling without reducing the physical dielectric thickness. It was achieved by controlling the structural phase of HfO2 by doping HfO2 with various metal oxides including ZrO2 as cubic, or tetragonal phase that provides higher-k than amorphous or monoclinic phase. By considering the interface reaction kinetics and thermal budget various atomic layer deposition (ALD) schemes were identified to get a stable dielectric with a robust interface. We will discuss the deposition of Hf1-xZrxO2 or HfAlOx on both silicon and germanium, a higher mobility channel material. The reliability characterization of these dialectics based on dielectric-semiconductor interface will also be discussed.
In ReRAM devices, the resistance change, achieved in a dielectric material between two metal terminals by applying a voltage, is promising for further scaling of memory devices. The switching mechanism in transition metal oxides like HfO2 is, while evolving, based on similar mechanism to soft breakdown, where a conducting filament path is formed due to oxygen vacancy transition/formation. The process is reversed by rupturing the filament. Various dielectric stacks are currently being studied for ReRAM applications. Additionally, ferroelectric characteristics of HfZrO films also derived significant attention recently. Some of the current trends in memory devices involving high-k dielectrics will be discussed.
(Invited) Advanced Transistors for High Frequency Applications
Authors: Parvais Bertrand , Peralagu Uthayasankaran , Vais Abhitosh , Alian AliReza , Witters Liesbet , Mols Yves , Walke Amey , Ingels Mark , Yu Hao , Putcha Vamsi , Khaled Ahmad , Rodriguez Raul , Sibaja-Hernandez Arturo , Yadav Sachin , ElKashlan Rana , Baryshnikova Marina , Mannaert Geert , Alcotte Reynald , Kunert Bernardette , Simoen Eddy , Zhao Ellen , De Jaeger Brice , Fleetwood Daniel , Langer Robert , Zhao Ming , Wambacq Piet , Waldron Niamh , Collaert Nadine 
Published: May 2020

The growing interest for 5G radios pushes technology development towards low-cost and high-performance solutions for operating at microwave and mm-wave. Downscaling CMOS technology has allowed the integration of high-speed transceivers on silicon chips, but high-power amplifiers rely on III-V technologies to deliver the power and efficiency levels required by modern radios.
In this work, we motivate the interest of non-Si technologies to meet 5G requirements, and we explore two routes to enable the fabrication of compound semiconductor devices on a large-scale manufacturable Si platform [1,2]. We provide insight on the potential of these new technologies for the design of advanced front-end modules, including modelling and reliability challenges.
In the first route (Figure 1(a)), we report on Al(Ga,In)N HEMTs, MISHEMTs and MOSFETs integrated on 200 mm Si wafers using Au-free processing in standard Si CMOS tools, and discuss the performance trade-offs, limitations and solutions. State-of-the-art contact resistance of 0.14 Ω.mm is demonstrated for a non-Au, low thermal budget (<600 oC) contact scheme, as well as a high vertical breakdown voltage (VBD) of >300 V. We show that MISHEMTs, which feature the highest field effect mobility (μFE), >2000 cm2/V.s, and the best 1/f noise performance, have the potential to outperform the other device types in terms of device scalability for high frequency operation. The GaN-on-Si substrate optimization for low RF losses and nonlinear distortion is further discussed.
The second route (Figure 1(b)) includes the formation of HBT on Si wafer by selective epitaxy. We demonstrate GaAs/InGaP HBTs grown on a 300 mm Si substrate. A DC current gain of ~112 and breakdown voltage, BVCBO, of 10 V is achieved. The emitter-base and base-collector diodes show an ideality factor of ~1.2 and ~1.4, respectively. This demonstration shows the potential for enabling a hybrid III-V CMOS/ technology for 5G and mm-wave applications, not limited to GaAs but which can also be extended to InGaAs on a 300 mm Si substrate.

Figure 1
(Invited) Junctionless Device Cross-Section: A Key Aspect for Overcoming Boltzmann Tyranny
Authors: Kranti Abhinav , Gupta Manish 
Published: May 2020

The demonstration of higher impact generate rate at relatively lower applied biases in a junctionless transistor (JLT) [1-2] has renewed interest in its device physics, operation and technology downscaling. This phenomenon is particularly interesting as it can lead to an associated steep current switching from off-to-on state with a subthreshold swing lower than 60 mV/decade [3-4]. A 3dimensional tri-gate JLT while offering immunity from short channel effects due increased gate controllability offers an additional degree of freedom apart from gate length and drain bias to tune the impact generation rate. Since JLT is a heavily doped device (figure 1(a)), the cross-section governs the concentration of carriers in the channel available for impact ionization and steep switching. Hence, the cross-section of a 3d JLT is expected to serve as a key facilitator for steep switching.
Figure 1(b) shows the comparison of the 3d simulations exhibiting a sharp increase in current in a JLT with the available experimental data [1]. The default models of TCAD simulation tool [5] were calibrated to ensure a reasonable agreement with published results. Figure 1(c) shows the drain current (I
ds) – gate voltage (V
gs) characteristics of JLT for two different device cross-sections. The lower aspect ratio (AR = 0.2) JLT exhibits a lower subthreshold swing (SS) of 3 mV/decade while a JLT with AR of 1 showcases a conventional SS of 60 mV/decade. As shown in figure 1(d), results clearly indicate that device cross-section of a 3d JLT is crucial for overcoming the Boltzmann tyranny, and should be a crucial component for device design and operation. The research work demonstrates new possibilities through the optimization of 3d cross-section of a JLT for attaining a sharp enhancement of drain current at shorter gate lengths.
References:
[1] C.-W. Lee et al., Applied Physics Letters, 96, 102106, 2010.
[2] S.M. Lee et al., IEEE Trans. Electron Devices, 60, 11, 3856-3861, 2013.
[3] M. Gupta et al., IEEE Trans. Electron Devices, 65, 6, 2406-2412, 2018.
[4] M. Gupta et al., IEEE Trans. Electron Devices, 64, 5, 2061-2066, 2017.
[5] ATLAS User’s Manual, Silvaco.

Figure 1
Enabling Fast Charging Lithium-Ion Batteries through Highly Ordered Laser-Patterned Electrode Design
Authors: Chen Kuan-Hung , Namkoong Min Ji , Goel Vishwas , Yang Chenglin , Mazumder Jyoti , Thornton Katsuyo , Sakamoto Jeff , Dasgupta Neil P. 
Published: May 2020

Current Li-ion battery technology is highly optimized for performance at relatively slow charging rates. However, significant challenges still present for fast charging conditions (< 15-minute charge time). These bottlenecks include large kinetic polarizations, concentration gradients, and Li plating on the anode surface.1 In state-of-the-art Li-ion batteries with high energy densities, the electrodes are relatively thick (> 50 μm), which leads to a tradeoff between energy density and high-power performance. Thicker electrodes with tortuous pathways limit Li-ion transport through the electrode thickness, leading to large electrolyte concentration gradients during cycling. This results in large cell polarizations, which reduce the accessible capacity of the battery. In addition, the electrochemical potential of the graphite anode can become more negative than the thermodynamic potential of Li metal during fast charging, resulting in Li plating. Therefore, to simultaneously achieve fast charging and maintain energy density of Li-ion batteries, new approaches are required to address Li ionic transport limitations through the thick graphite anodes.
In this work, we demonstrate a structural modification of conventional graphite anodes to improve their fast charge capability. This is achieved by introducing laser-patterned vertical channels into post-calendared graphite anodes2. This 3-D electrode architecture consists of a hexagonal close-packed array of vertical channels that serve as linear pathways for rapid ionic diffusion through the electrode thickness, allowing for a more homogeneous flux of Li throughout the volume of the electrode and decreased ionic concentration gradients. As a result, the accessible capacity of the electrode can be significantly improved and Li plating can be minimized during fast charging. Utilizing the 3-D electrode design, we demonstrate significant improvement in capacity fade at 4C (15-minute) and 6C (10-minute) charge rate with industrial-relevant electrode material and loading (3 mAh/cm2 electrode loading in >2Ah pouch cells). This work thus demonstrates the viability of realizing high energy density Li-ion batteries with fast charge capability based on thick electrodes.
References:
1. Ahmed, S. et al. Enabling fast charging e A battery technology gap assessment. J. Power Sources
367, 250 (2017).
2. Kim, Y., Drews, A., Chandrasekaran, R., Miller, T. & Sakamoto, J. Improving Li-ion battery charge rate acceptance through highly-ordered hierarchical electrode design. Ionics
24, 2935 (2018).
Visualization of Internal Potential Distribution in an All-Solid-State Fluoride Shuttle Battery Using Operando Hard X-Ray Photoelectron Spectroscopy
Authors: Kiuchi Hisao , Sakurai Katsutoshi , Okazaki Ken–ichi , Nakanishi Koji , Morita Yoshiyuki , Matsubara Eiichiro , Abe Takeshi 
Published: May 2020

Introduction

Fluoride shuttle battery (FSB), which uses fluoride ions as carrier ions, has attracted much attention as one of the innovative batteries that can theoretically exceed the energy density of conventional lithium-ion batteries. However, there are still few reports on charge/discharge reactions using fluoride ions as carriers[1, 2], and most of the electrode reactions are still unclear. Here we have applied the newly developed operando hard X-ray photoelectron spectroscopy (HAXPES) to a thin film Cu-based all-solid-state FSB, which allows us to observe the bulk-sensitive electronic structure changes in all the components (positive and negative active materials, a solid electrolyte and a current collector) during charge and discharge processes.

Experimental

A Cu positive electrode was deposited on a LaF3 substrate by a DC magnetron sputtering method, and an Au current collector was deposited thereon by the same method. A W current collector for the anode side was deposited on the back side of the LaF3 substrate by the same method. Electrochemical tests were performed with a constant current mode under potential rages from 3.6 V to 2.0 V at 140⁰C. The Au 4f, F 1s, La 3d, Cu 2p
operando HAXPES measurements was performed at BL28XU in SPring-8 during the charge process.

Results and Discussion

Fig. 1 shows the Cu 2p
3/2, F 1s and La 3d
5/2
operando HAXPES spectra at each charge capacity. The Cu 2p
3/2 HAXPES spectra were normalized with a peak intensity of 932.5 eV derived from Cu metal. As charging progressed, new peaks derived from CuF2 appeared at 936.8 eV and 943.0 eV, indicating that Cu converts to CuF2. In the F 1s and La 3d
5/2 HAXPES spectra, a peak shift of approximately 1.4 eV toward the lower binding energy was observed at the beginning of charging. These peak shifts correspond to the sudden increase in the cell voltages at the beginning of charging, indicating that a potential difference is generated between the LaF3 solid electrolyte and Cu positive electrode. As the charging reaction further proceeds, the peak shifts to the lower binding energy as the cell voltage increases in the La 3d
5/2 region, however, a new peak appeared at 684.7 eV to the higher binding energy in the F 1s region, suggesting that F species of CuF2 have been detected. Therefore, we succeeded in capturing the fluorination process of Cu by both Cu 2p and F 1s HAXPES spectra changes and the potential distribution of the all-solid-state FSB using operando HAXPES.

Acknowledgments

This work was supported by the New Energy and Industrial Technology Development Organization (NEDO) under the “Research and Development Initiative for Scientific Innovation of New Generation Batteries 2 (RISING2)”.

References

[1] M. A. Reddy et al., J. Mater. Chem.
21, 17059 (2011).
[2] D. T. Thieu et al., Adv. Funct. Mater.
27, 1701051 (2017).

Figure 1
Study of Solid State Lithium Batteries with a Ceramic Electrolyte
Authors: Dussart Thibaut , Laberty-Robert Christel , Stevens Philippe , Toussaint Gwenaëlle 
Published: May 2020

Solid state lithium batteries are considered as the next generation of batteries due to its potential higher energy density and better safety compared to Li-ion technology[1]. Oxides, sulfides, polymers and polymer/ceramic hybrid materials can be used as lithium ion conducting solid electrolytes, some of which have very good ionic conductivities (up to 10-3 S.cm-1 at 25°C) and good electrochemical stability[2,3].
Li1,3Al0,3Ti1,7(PO4)3 (LATP) is a potential candidate as a solid electrolyte with an ionic conductivity of 1.10-4 S.cm-1 at 25°C. It is stable up to 5V vs Li/Li+ but it is instable in contact with lithium due to the reduction of Ti4+ in Ti3+ [4]. A thin protective layer of a stable lithium ion conducting material is deposited to avoid contact between LATP and Li metal[5]. The LATP solid electrolyte has been synthesized via solid state synthesis and LATP particles exhibit a cubic morphology.
Al doped Li7La3Z2O12 (LLZO), another good candidate for solid electrolyte, displays a high ionic conductivity >10-4 S.cm-1 [6] and an good stability in contact with lithium metal. LLZO synthesized by the Pechini route exhibit a cubic phase with minor impurity of La2Zr2O7.
The main challenge is to control this interphase in order to decrease the interfacial resistance. Different strategies are employed to deposit the lithium such as electrochemical deposition and vapor deposition. Full cells are assembled using different positive electrode compositions and characterized in order to overcome the technological barriers related to this technology.
[1] T. Placke, R. Kloepsch, S. Dühnen, M. Winter, Lithium ion, lithium metal, and alternative rechargeable battery technologies: the odyssey for high energy density, J. Solid State Electrochem. 21 (2017) 1939–1964. doi:10.1007/s10008-017-3610-7.
[2] J. Janek, W.G. Zeier, A solid future for battery development, Nat. Energy. 1 (2016) 1–4. doi:10.1038/nenergy.2016.141.
[3] Y. Zhu, X. He, Y. Mo, Origin of Outstanding Stability in the Lithium Solid Electrolyte Materials: Insights from Thermodynamic Analyses Based on First-Principles Calculations, ACS Appl. Mater. Interfaces. 7 (2015) 23685–23693. doi:10.1021/acsami.5b07517.
[4] P. Hartmann, T. Leichtweiss, M.R. Busche, M. Schneider, M. Reich, J. Sann, P. Adelhelm, J. Janek, Degradation of NASICON-type materials in contact with lithium metal: Formation of mixed conducting interphases (MCI) on solid electrolytes, J. Phys. Chem. C. 117 (2013) 21064–21074. doi:10.1021/jp4051275.
[5] H.S. Kim, Y. Oh, K.H. Kang, J.H. Kim, J. Kim, C.S. Yoon, Characterization of Sputter-Deposited LiCoO 2 Thin Film Grown on NASICON-type Electrolyte for Application in All-Solid-State Rechargeable Lithium Battery, ACS Appl. Mater. Interfaces. 9 (2017) 16063–16070. doi:10.1021/acsami.6b15305.
[6] R. Murugan, V. Thangadurai, W. Weppner, Fast lithium ion conduction in garnet-type Li7La 3Zr2O12, Angew. Chemie - Int. Ed. 46 (2007) 7778–7781. doi:10.1002/anie.200701144.

Figure 1
(Invited) Systematic Study of Electrolyte Components and Their Effects on the Fast Charging of High Energy Density Li-Ion Cells
Authors: Wu Xianyang , Du Zhijia 
Published: May 2020

Energy density, cost and safety are, more than ever, the most significant barriers to overcome in order to increase the wide acceptance of Li-ion batteries (LIBs) in electric vehicles (EVs).1 The U.S. Department of Energy (DOE) has set ultimate goals for battery electric vehicles (BEVs), which include reducing the production cost of the battery pack to $150/kWh, increasing the electrical range of the battery to 300 miles, and decreasing the charging time to 15 minutes or less.2 Increasing electrode thickness, and hence increasing active material loading, is an effective way to achieve these energy density and cost targets.3 The caveat, however, is that thicker electrodes fail during fast charging.
One of the solutions for enabling extreme fast charging while retaining most of the battery energy can be achieved through the significant enhancement of the Li-ion mass-transport in electrolytes such that enough Li ions are available for intercalation in graphite. The mass transport of Li-ions can be evaluated by two macroscopic characteristic values: 1) the Liions ionic conductivity that is related to the total flux of charge carriers, 2) the Liion transference number that is related to the fraction of the total current that is carried by Liions. An electrolyte with both higher Liions conductivity and transference numbers is ideal for higher Liions transport, and hence would be a step toward realizing cells with higher charging rates.
The fast charging performance of high-energy density (NMC811/graphite) Li-ion cells is studied when different electrolytes were used. The effect of electrolyte components and their effect of the electrode materials, electrolytes and electrolyte/electrode interfaces were studied and will be presented.
(1) Needell, Z. A.; et al. Potential for Widespread Electrification of Personal Vehicle Travel in the United States. Nat. Energy
2016, 1 (9).
(2) Howell, D.; et al. Enabling Fast Charging: Enabling Fast Charging: A Technology Gap Assessment. 2017, No. October.
(3) Du, Z.; et al. Understanding Limiting Factors in Thick Electrode Performance as Applied to High Energy Density Li-Ion Batteries. J. Appl. Electrochem.
2017, 47 (3), 405–415.