bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation Model of a Prismatic Lithium-Ion-Battery for Temperature Propagation in the Cell after a Short Term Thermal Stress
Authors: Bohn Pamina , Liebig Gerd , Vasic Stanislav , Komsiyska Lidiya , Wittstock Gunther 
Published: February 2020

For several years lithium-ion batteries have been commercially used in portable devices such as camcorders, laptop computers and cell phones. Battery lifetime plays only a minor role in such applications due to rapid product innovation and strong competition. However, the increasing demand for lithium-ion batteries for automotive traction applications requires drastic increase in battery life-time and safety.[1] The majority of the existing life-time and performance prognoses are based on accelerated aging tests at elevated temperatures such as 40 °C, since the temperature plays a crucial role on the battery performance, safety and life-time.
However automotive lithium-ion cells must endure multiple production processes during the fabrication of a high-end traction battery system, such as contact welding, where the cells are exposed to elevated temperatures for a short period of time.[2] Up to date there is little information on the temperature propagation within the cell during the short-term thermal stress and also the influence of such short period thermal stress on the cell performance and cyclic ability.
For a better understanding of the temperature propagation in the cell, a simulation model based on the thermal material characteristics of a prismatic Li-NiMnCoO2 cell was created in COMSOL Multiphysics®. The thermal characteristics of the battery components are experimentally determined using Laser Flash Analysis (LFA) and Differential Scanning Calorimetry (DSC). In order to validate the modeling approach in this work, we built an experimental setup to measure the temperature propagation within a dummy cell. This dummy cell includes a carbonate solution as electrolyte, yet without a lithium salt.
After validating the model is used to describe the temperature propagation after a short-term temperature stress on automotive lithium-ion cells. Furthermore, it’s possible to predict the temperature propagation in the cell with this simulation model, after the short-term stress on different positions on the cell casing surface and at different SOC’s.
[1] J. Vetter, P. Novák, M.R. Wagner, C. Veit, K.-C. Möller, J.O. Besenhard,M. Winter, M. Wohlfahrt-Mehrens, C. Vogler, A. Hammouche; Ageing mechanisms in lithium-ion batteries. J. Power Sources 147 (2005) 269–281
[2] M. Yoshio, R.J. Brodd, A. Kozawa; Lithium-Ion Batteries, Science and Technologies; Springer (2009)
Model Based Dynamic Optimization Strategies for Lithium-Ion Batteries
Authors: Sonawane Dayaram , Suthar Bharatkumar , Pathak Manan , Santhanagopalan Shriram , Subramanian Venkat 
Published: February 2020

Accurate estimation of battery internal states i.e. state of charge (SOC), state of health (SOH) and battery power is of great significance for safe and optimal performance of proactive Battery Management Systems (BMS) (1).
Mathematical models for lithium-ion batteries (2, 3) vary with complexity, computational costs and reliability of predictions. Incorporating more physicochemical phenomena in a model can improve its prediction accuracy but they cannot be directly employed for online control due to their high computational requirements. So, it is important to have reformulated battery models for online control and accurate predictions of internal states. Efforts have been made in past (4), to reformulate battery models to significantly reduce its computational expenses, allowing for real time control and simulation.
In this work, we explored the use of an experimentally validated reformulated pseudo two dimensional model to derive the optimal charging profiles at different temperatures. The two distinct dynamic optimization strategies i.e. simultaneous optimization (5) and control vector parameterization (CVP) (6, 7, 8) to estimate optimal charging current profile for effective use of lithium-ion batteries are evaluated.
Acknowledgements

The work presented herein was funded in part by the Advanced Research Projects Agency – Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000275.

References

V. Pop, H. J. Bergveld, D. Danilov, P. P. L. Regtien and P. H. L. Notten, Battery management systems: accurate state-of-charge indication for battery powered applications, Springer Verlag (2008).

M. Doyle, T. F. Fuller and J. Newman, J. Electrochem. Soc.,140, 1526 (1993).

T. F. Fuller, M. Doyle and J. Newman, J. Electrochem. Soc., 141, 1 (1994).

P. W. C. Northrop, V. Ramadesigan, S. De and V. R. Subramanian, J. Electrochem. Soc., 158, A1461 (2011).

Biegler, L.T. Cervantes, A. M. Wachter, A., Advances in simultaneous strategies for dynamic process optimization, Chemical Engineering Science, 57(4):575-593, (2002).

J. R. Banga, E. Balsa-Canto, E. G. Moles, and A. A. Alonso, Dynamic optimization of bioprocesses: Efficient and robust numerical strategies. Journal of Biotechnology, 117:407–419, (2005).

R. N. Methekar, V. Ramadesigan, R. D. Braatz, and V. R. Subramanian, Optimal charging profile for lithium-ion batteries to maximize energy storage and utilization, ECS Trans, vol. 25, no. 35, pp. 139-146, (2010).

Fathy, Hosam K., Reyer, Julie A., Papalambros Panos Y., and Ulsoy, A. Galip, On the Coupling between the Plant and Controller Optimization Problems, in Proceedings of the ACS, (2001).
First Principles Investigation of Stable LiMn2O4 Surfaces for Lithium-Ion Batteries
Authors: Kim Soo , Aykol Muratahan , Wolverton Chris 
Published: February 2020

The spinel LiMn2O4 (LMO) has been widely studied as a lithium-ion battery cathode to replace the currently-used LiCoO2 materials due to its low cost and fast Li+ diffusivity.[1] However, a severe capacity fading during LMO cycling occurs because of the Mn dissolution, possibly initiating from the cathode surface. Thus, it is essential to completely understand the stable LMO surface structure to overcome current limitations and further to suppress the Mn dissolution in LMO.
In this work, we investigate the effects of surface termination, slab reconstruction, relaxation schemes, magnetic ordering, and different U value for Mn to determine the relative stabilities of the LMO surfaces. We find that it is necessary to relax all atomic positions with symmetry-broken DFT calculations to fully capture the local variation of Mn-O and Li-O polyhedral clusters to obtain the most consistent surface energies. We finally comment on the possible implication of our work on the future surface studies of the mixed-valence transition metal complex oxides such as the LMO system.

Acknowledgement: This work has been supported by Northwestern-Argonne Institute of Science and Engineering (NAISE) and by The Dow Chemical Company.

Reference: [1] R. J. Gummow, A. Kock, M.M. Thackeray, Solid State Ionics
1994, 69, 59.

Figure 1
Long-Term High-Efficient Cus and Cu2s Cathodes for Lithium-Ion Batteries
Authors: Meng Xiangbo , Ren Yang , Sun Chengjun , Elam Jeffrey W 
Published: February 2020

Lithium-ion batteries (LIBs) based on intercalation, such as C/LiCoO2, are dominant in consumer electronics, mainly ascribed to their superiority over their competitors in energy density. To meet our expectations for use in electrical vehicles (EVs), however, LIBs need to further improve their capability in energy density. In this context, intensive investigation has been undertaking for new battery materials of high capacities. A new reactivity concept named “conversion reaction” was first reported with transition metal oxides 1 at the very beginning of the 21st century. Since then, more and more binary compounds were discovered having the similar electrochemical reactions in LIBs, such as metal sulfides, metal fluorides, and metal nitrides 2. In comparison to the intercalation-based materials, the conversion-based materials can generally provide much higher capacities and this makes these new classes of materials important candidates for new battery technologies.
CuS has been regarded as one promising cathode material via conversion reactions, featuring a theoretical capacity of 560 mAh/g, flat discharge plateaus, and good electrical conductivity. In spite of these advantages, CuS was reported with severe capacity fading 3. To circumvent this technical hurdle, Chung and Sohn 4 discovered that narrowing voltage window could help improve cycleability of CuS in LIBs, but CuS still could not sustain long-term high-efficient discharge-charge cycling. In comparison to CuS, there were even fewer studies reported on Cu2S. In this talk, we are going to present our recent progress on both CuS and Cu2S cathodes. We confirmed that a suitable selection on voltage windows is essential for securing reliable cycleability of the CuS and Cu2S cathodes. On the other hand, we found current collectors also have some effects on the LIB cathodes. To explore the underlying mechanism, we applied advanced synchrotron-based techniques of in situ X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) to track time-resolved structural changes of CuS and Cu2S during discharge-charge cycles. Based on all these efforts, we developed a set of conditions for achieving long-term high-efficient CuS (see figure 1) and Cu2S cathodes in LIBs. In addition, the electrochemical characteristics of CuS and Cu2S also will be comparatively discussed. This work is potentially significant for developing next-generation high-energy batteries for EVs.

References:

(1) Poizot, P.; Laruelle, S.; Grugeon, S.; Dupont, L.; Tarascon, J. M. Nature
2000, 407, 496.
(2) Cabana, J.; Monconduit, L.; Larcher, D.; Palacin, M. R. Adv Energy Mater
2010, 22, E170.
(3) Debart, A.; Dupont, L.; Patrice, R.; Tarascon, J. M. Solid State Sciences
2006, 8, 640.
(4) Chung, J. S.; Sohn, H. J. Journal of Power Sources
2002, 108, 226.

Figure 1
Mapping of Ageing Mechanisms in Cylindrical LiFePO4/Graphite Batteries Cycled Under Deep Discharge Steps
Authors: Aguesse Frederic , Sarasketa-Zabala Elixabet , Bekaert Emilie , Lopez Carmen , Kubiak Pierre , Rodriguez-Martinez Lide M 
Published: February 2020

Li-ion batteries are good candidates for electric vehicles and stationary applications due to their high power and energy density. Despite significant improvement over the last decade, lifetime and safety remain major issues for large-scale applications. Thus, a better understanding of factors governing battery lifetime and performance loss is crucial. Various types of Li-ion batteries are commercially available and their characteristics and performance depend strongly on the combination of active materials, cell design and manufacturing process. Therefore, the determination of specific degradation mechanisms and their correlation with cell performances is crucial for working on cell concepts that can meet target lifetimes [1-3].
In this work, cycling performance fade of LiFePO4-based cylindrical batteries is evaluated under deep charge/discharge steps (100% DOD). The cycling conditions were chosen to represent highly demanding condition of operation, which covers the analysis of ageing phenomena under the largest possible operating DOD. Diagnostic evaluation of the ageing mechanisms included in-situ electrochemical measurements, and ex-situ destructive physico-chemical and electrochemical analyses of cell components. A thorough study on the degradation mechanisms in different areas of the battery is realised in order to establish a geometrical mapping of the cell degradation. This allows identifying areas of inhomogeneous degradation along the jelly-roll of the battery. Degradation mechanisms were evaluated by microstructural (SEM) and crystallographic (XRD) analyses. Elemental analysis of the electrode composition was determined by EDS and ICP techniques. The electrochemical performances of selected areas of the harvested electrodes were determined by galvanostatic testing in half-cell configuration. These results were combined with non-destructive cell electrochemical measurements to provide a global view of the main degradation processes.
[1] M. Safari and C. Delacourt, Journal of the Electrochemical Society, 2011. 158(12): p. A1436-A1447.
[2] M. Dubarry and B.Y. Liaw, Journal of Power Sources, 2009. 194(1): p. 541-549.
[3] D.P. Abraham, J. Liu, C.H. Chen, Y.E. Hyung, M. Stoll, N. Elsen, S. MacLaren, R. Twesten, R. Haasch, E. Sammann, I. Petrov, K. Amine, and G. Henriksen, Journal of Power Sources, 2003. 119-121: p. 511-516.
Preparation of Graphite from Fish Scales
Authors: Huang Yaqin , Gao Mengyao , Wang Weikun 
Published: February 2020

Graphite with relatively high specific capacity (372mAh g-1), cycling efficiency and low irreversible charge is nowadays the choice of the lithium-ion batteries [1,2]. In order to improve the electrochemical performance of graphite, many reports focused on the selection of suitable carbon precursors with easy graphitization [3,4]. In this work, fish scale with a layer-by-layer structure inspired us to prepare graphite from it. The advantages are as follows: 1) it is as an abundant food waste; 2) collagen as its main composition has high carbon content (about 50%); 3) the preparation process could be easy. The fish scales have been carbonized at 900℃ with a heating rate of 3℃ min-1 under a flowing N2. The obtained carbon was diluted by acid and then graphited at 2800℃. The BET surface area of the as-prepared fish-scale-based graphite is 5 m2 g-1 and the Raman ID/IG ratio only remains 0.04 (Fig. 1a) which illustrates a low degree of defects and a high degree of crystallinity. The initial discharge specific capacity is 310 mAh g-1 and keeps 300 mAh g-1 with the coulombic efficiency 99.6% after 150 cycles (Fig. 1b). These results state that the fish-scale-based graphite is a promising material for the anode of lithium-ion batteries.
Fig. 1 (a) Raman spectra (514 nm laser) and (b) Cycle performance and corresponding Coulombic efficiency at a current density of 50 mA g-1 for the fish-scale-based graphite.

Acknowledgments

Financial support from the National Natural Science Foundation of China (no.51272017 and 51432003) is gratefully appreciated.
[1] M. Armand and J. -M. Tarascon, Nature, 451, 652 (2008).
[2] N. A. Kaskhedikar and J. Maier, Adv. Mater. , 21, 2664 (2009).
[3] I. Cameán, A. B. García, I. Suelves, J. L. Pinilla, M. J. Lázaro, and R. Moliner, J. Power Sources, 198, 303 (2012).
[4] C. Ma, Y. Zhao, J. Li, Y. Song, J. Shi, Q. Guo, and L. Liu, Carbon, 64, 553 (2013).

Figure 1
(Invited) Record-Performance In(Ga)As MOSFETS Targeting ITRS High-Performance and Low-Power Logic
Authors: Rodwell Mark J , Huang Cheng-Ying , Lee Sanghoon , Chobpattana Varistha , Thibeault Brian , Mitchell William , Stemmer Susanne , Gossard Arthur 
Published: February 2020

We review recent development of In(Ga)As-channel MOSFETs. Low-effective mass InAs and InGaAs channels, combined with thin gate dielectrics, provide high transconductance, but off-state leakage can be high due to band-band and source-drain tunneling currents.
This leakage is reduced through thin 2.5-3nm channels, and through InGaAs or wide-bandgap InP vertical field spacers in the raised, regrown source and drain.
Planar UTB devices with 2.7nm thick strained InAs channels and lightly-doped InGaAs spacers in the raised regrown source and drain provide, at 25nm gate length, record 0.5mA/µm on-current at 100nA/µm off-current (ITRS HP specification) and 500mV VDD. 1 µm gate length FETs show 61mV/decade subthreshold swing at 0.1 Volts VDD. Targeting the ITRS LP specification, we have developed InGaAs-channel MOSFETs with lightly-doped InP wide-bandgap spacer layers in the raised source and drain. At 30nm gate length, these show a minimum 60 pA/µm off-current, approximately 100:1 smaller than a similar device using InGaAs source/drain spacers. A FET using InP spacers, with 45 nm gate length, shows 0.15 mA/µm on-current at 1nA/µm off-current (ITRS GP specification) and 500mV VDD. We will discuss ongoing efforts to further increased on-current and decrease off-current in short-gate-length III-V MOSFETs.
Effect of Design and Rare-Earth Doping of the Structural, Optical, Electrical and Light Emitting Properties of Si-Based Superlattices Developed for Photonic Application
Authors: Khomenkova L. , Pratibha Nalini R. , Labbe Christophe , Carrada Marzia , Portier Xavier , Gourbilleau Fabrice 
Published: February 2020

Nowadays, silicon-based nanostructures attract great attention due to their wide functionality. However, in spite of a lot of efforts forwarded on the investigation of Si-based nanomaterials, additional research is still required in order to design their optical properties for optoelectronic, photovoltaic or memory applications. The structural disorder is one of the main issues that may reduce the efficiency of device operation in the applications area of every nanomaterial.
Undoped and rare-earth (RE) doped Si-rich-SiO2 (SiOx) composite films and multilayers were recently investigated [1-3]. An efficient RE emission was achieved in Er- and, later, Nd-doped SRSO films due to an interaction of RE ions with Si-nanoclusters (Si-ncs). Although, a multilayer (ML) approach offers a precise control of Si-ncs distribution via a tuning of SRSO thickness, RE-doped SRSO-based MLs are not well addressed. This work presents the benefits of ML approach to achieve high efficiency and to control RE emission from Nd-doped SiOx/SiNx-based MLs grown by RF magnetron sputtering. Their properties were studied by means of XRD, TEM, PL and PL excitation methods versus deposition conditions, annealing treatment and ML design (doping, thickness of alternated sublayers (silicon oxide, nitride)). In each type of ML structures, either one or both sublayers were doped with Nd ions to investigate the effect of selective or full doping on PL emission. The results will be summarized and compared with those of Nd-doped SiOx/SiO2 MLs. It will be showed that comparable Nd PL emission can be obtained for both types of ML structures. Besides, fabrication approach allowed the PL emission to be achieved from as-grown samples. However, the highest Nd PL intensity was obtained after an annealing at about 700°C in nitrogen flow, whereas the formation of crystallized Si-ncs occurs at 1000-1100°C. The mechanism of Nd ions' excitation (i.e. an interaction with Si-ncs as well as with matrix defects, if any) will be discussed in details based on PL excitation spectra and PL life-time data. These results reveal potential photonic applications of Nd-doped MLs.
This work was supported by French National Agency (ANR) through DAPHNES project.
1. Pratibha Nalini R., Khomenkova L., Debieu O., Cardin J., Dufour C., Carrada M., Gourbilleau F.,Nanoscale Research Letters, 7, 124 (2012).
2. Cueff S., Labbé C., Khomenkova L., Jambois O., Pellegrino P., Garrido B., Frilay C., Rizk R., Mater. Sci. Eng. B. 177, 725 (2012).
3. E. Talbot, R. Lardé, P. Pareige, L. Khomenkova, K. Hijazi, F. Gourbilleau, Nanoscale research letters 8, p.39 (8 pages) (2013).
Light Emitting Properties of Si-Rich-Si3N4 Films Grown By PECVD Method
Authors: Torchynska Tetyana V. , Casas Espinola Jose Luis , Polupan Georgiy , Vergara Hernandez Erasto , Khomenkova Larysa , Slaoui A 
Published: February 2020

Bandgap engineering of Si-based materials through the control of the distribution of Si nanoclusters’ (Si-ncs) offered future applications of Si-based nanostructured materials in optoelectronics as low-cost, miniaturized, and CMOS-compatible, light-emitting and photovoltaic devices. In the past, most efforts were concentrated on the development of luminescent Si-ncs embedded in SiO2 host. However, its insulating nature remains a barrier for the production of future electrically pumped LEDs and efficient photovoltaic cells. This detrimental aspect can be coped with a medium of higher conductivity and lower band gap, for instance, Si nitride. Tunable room temperature visible light emission from Si-ncs embedded in Si nitride matrices has been recently demonstrated.
Present work deals with the Si-rich Silicon nitride films were grown by PECVD technique on silicon substrates. The film stoichiometry was controlled via variation of NH3/SiH4 ratio from R=0.45 up to 1.0. Thermal treatment was performed at 1100°C for 30min in nitrogen flow to form Si-ncs. To control structural and light emitting properties of the films Raman scattering, X-ray diffraction (XRD), Transmission electron microscopy (TEM) and photoluminescence (PL) methods were used. The evolution of PL spectra with the temperature of measurements from 20 to 300 K was studied also aiming at the determination of the types of optical transitions.
The PL spectra were found to be complex and the shape and magnitude of PL spectra depends on silicon nitride stoichiometry. The increase of gas ratio from R=0.63 to R=1 results in the shift of PL peak position from 1.6 eV up to 2.7 eV. Analysis of the temperature dependence of PL spectra revealed the presence of several PL components with the maxima at 2.9-3.0 eV, 2.5-2.7 eV, 1.9-2.2 eV and 1.8-1.9 eV. The peak position of the former three PL components unchanged with the decrease of temperature of the measurements. This allows describing all these components to the defects of silicon nitride host. At the same time, PL band peaked at 1.8-1.9 eV showed high-energy shift with sample cooling and can be ascribed to the exciton recombination inside Si-ncs. The presence of these latter was confirmed by Raman scattering spectra and TEM images. The nature of light emitting defects in silicon nitride, the mechanism of photoluminescence and the way for the optimization of light emitting properties are discussed.
Pulse Width Modulation for Reducing Pulsed MOS Capacitor Measurement Time
Authors: Safarnezhad Hendijani Mohamad , Zahedi Sayedehgolnaz 
Published: February 2020

Carrier lifetime in silicon is a direct measure of its deep-level defect density. This parameter is therefore widely used for process screening purposes to check for unwanted contaminations such as metallic impurities. The dynamics of semiconductor industry requires the development of novel approaches to reduce the measurement time of commonly established carrier lifetime measurement techniques for more efficient screening in process lines. The pulsed MOS capacitor (MOS-C) is the most popular technique for measuring the generation lifetime (τg
) where τg
is being extracted from the capacitance transient response (C-t) of a MOS capacitor device when pulsed from accumulation into deep-depletion and as it moves from the non-equilibrium deep-depletion into the inversion. Although accurate and easy to implement, the pulsed MOS capacitor takes a long time to accomplish. For clean wafers the time for a single measurement can easily reach several hours. This becomes specifically problematic when the goal is to map the whole wafer area. Many attempts have been made to reduce the lifetime measurement times. The challenge, however, is to maintain the accuracy while trying to reduce the test time. It will showed that by using a dynamic pulse train and exploiting the pulse width, the pulsed MOS-C technique can be implemented not only to reduce the measurement time. If the accumulation pulse in the pulsed MOS technique is applied at a high frequency the device response will become substantially short resulting in a reduced measurement time. Interestingly, this approach will not cause any compromise in the accuracy with which the lifetime is measured. TCAD simulations and experimental results will be presented to show the effect of the accumulating pulse width on the C-t transient of a typical MOS device.