bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Halide-Free Flourinated Alkoxyaluminate Electrolytes for Mg and Ca Ion Batteries
Authors: Arnold Craig B.
Published: February 2020

Magnesium-ion batteries are one of the most researched multivalent-ion chemistries because of the ability to use energy-dense metallic magnesium anodes, which have a higher volumetric energy density compared to metallic lithium. One of the key limiting factors in bringing these batteries to fruition has been the development of suitable electrolytes that enable the reversible deposition of magnesium metal with high coulombic efficiency, high conductivity, and practical oxidative stability on non-noble metal surfaces. With few exceptions, the tenacious oxide layer on magnesium metal has limited the scope of research to halide ion-based electrolytes, which help activate the electrode surface but also limit the working voltage window considerably and can cause pitting and corrosion to parts commonly used in coin cells. Here we discuss our efforts at developing new halide-free magnesium ion and calcium-ion electrolytes based on fluoroalkoxyaluminate anions synthesized via a facile and scalable method. Our results for Mg show a large voltage window on stainless steel and aluminum (4-5 V vs. Mg), high conductivity (comparable with lithium ion electrolytes), and near unity Coulombic efficiency. Using a combination of x-ray photoelectron spectroscopy and energy-dispersive x-ray spectroscopy, we analyze how electrolyte composition affects surface structures and elemental makeup of both the magnesium anode and deposits on the counterelectrode over multiple plating/stripping cycles. Flourinated alkoxyaluminate electrolytes represent a new class of halide free chemistries with the potential to significantly enhance performance in multivalent energy storage systems.
Electrodeposition of Free Standing Copper Structures with Organic Additives
Authors: Huang Qiang , Gyorgak Raymond , Pak Ryan , Collins Jacob
Published: February 2020

Organic additives have been often used in electrodeposition to modulate the deposition kinetics, film morphology and material property. One particular example is the well-known super conformal deposition of copper in trenches and other fine structures used in interconnects1-3. Additives that suppress and accelerate copper deposition are used together to achieve a high deposition rate at the bottom of trenches while maintaining little deposition at the top4. Electrochemical 3D printing has recently gained more and more interest in research as an approach to make free standing arbitrary shaped structures for micro-devices. 3D growth of microstructures with local counter electrode in a vicinity of deposition substrate5-7, meniscus droplet depositio8, 9 and local injection of metal cation electrolyte10 have all been demonstrated. This paper presents a new method of fabricating 3D structures with a local injection of organic additives that controls the growth rate of metals.

Figure 1 shows the diagram of the deposition system including an additive injection pump, an electrochemistry workstation, an electrochemical cell fixed on a 3D moving stage, and an optical monitoring system. Figure 2 shows the optical images of the evolution of a copper pillar structure. In this particular case, the background electrolyte contains both polyethylene glycol as a suppressor and chloride ion as the suppression promoter, whilst the injected electrolyte does not have the suppression promoter. Therefore, the growth rate of copper in the injected electrolyte is faster than in the background electrolyte. On the other hand, the fast diffusion of chloride results in a confined region where the chloride is absent and therefore a confined growth region. Both experimental observations and numerical simulation results will be discussed in the talk.

REFERENCES

J. Kelly and A. West, Journal of The Electrochemical Society, 145, 3472 (1998).

J. Kelly and A. West, Journal of The Electrochemical Society, 145, 3477 (1998).

T. P. Moffat, J. E. Bonevich, W. H. Huber, A. Stanishevsky, D. R. Kelly, G. R. Stafford and D. Josell, Journal of The Electrochemical Society, 147, 4524 (2000).

R. Akolkar and U. Landau, Journal of The Electrochemical Society, 151, C702 (2004).

J. D. Madden and I. W. Hunter, Journal of microelectromechanical systems, 5, 24-32 (1996).

S. K. Seol, A. R. Pyun, Y. Hwu, G. Margaritondo and J. H. Je, Adv Funct Mater, 15, 934-937 (2005).

J. Sun, D. Liu, F. Wang and T. Chen, Proceedings of Electronic Packaging Technology (ICEPT), 2016 17th International Conference on, pp. 322-326, 2016.

J. Hu and M. F. Yu, Science, 329, 313-316 (2010).

S. K. Seol, D. Kim, S. Lee, J. H. Kim, W. S. Chang and J. T. Kim, Small, 11, 3896-3902 (2015).

L. Hirt, S. Ihle, Z. Pan, L. Dorwling-Carter, A. Reiser, J. M. Wheeler, R. Spolenak, J. Voros and T. Zambelli, Advanced Materials, 28, 2311-2315 (2016).

Figure 1
Hierarchically Porous Structures Prepared By Electrodeposition Onto 3D-Printed Substrates
Authors: Robinson David B. , Salloum Maher , Jones Christopher G. , Kaehr Bryan J. , Gallegos Michael A. , Buffleben George M. , Mills Bernice E. , Higginbotham Aidan W. , Garcia Gail F. , Lebegue Victoria , Atwal Roopjote K. , Nishimoto Ryan K.
Published: February 2020

Electrochemical energy storage devices such as batteries and supercapacitors, and chemical separation technologies such as chromatography and distillation, involve multiphase transport of chemical species, where the phases may be mobile or stationary. In these cases, a high contact area between the phases is desirable, which can be achieved through nanoscale porosity. However, transport through nanoscale pores can be slow, so a hierarchy of larger-scale pores can allow faster operation, such as more rapid charging of an energy storage device.

We have combined photopolymer 3D printing, which allows creation of ordered pores on a micrometer to millimeter scale, with electroless deposition and electrodeposition of a nanoporous layer, to create millimeter-scale hierarchically porous structures. We have demonstrated that the pore network confers advantages in storage capacity and transport rates versus non-hierarchical porous structures. Our methods allow fabrication of dense structures, where the volume fractions of pore and solid are of the same order of magnitude, with spatial resolution exceeding that of 3D printing methods based on laser heating of powders or thermal extrusion of polymers.

This work was supported by the Laboratory-Directed Research and Development program at Sandia National Laboratories, a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. SAND2018-2643 A
(Invited) Atomic Layer Deposition for the Synthesis and Integration of 2D Materials for Nanoelectronics
Authors: Bol Ageeth A.
Published: February 2020

Graphene and other layered 2D materials have been the focus of intense research in the last decade due to their unique physical and chemical properties. This presentation will highlight our recent progress on the synthesis and integration of 2D materials for nanoelectronics applications using atomic layer deposition (ALD). ALD is a chemical process that is based on self-limiting surface reactions and results in ultrathin films, with sub-nm control over the thickness and wafer-scale uniformity. In the first part of this presentation I will focus on the fabrication of low resistance contacts and ultrathin dielectrics to graphene using atomic layer deposition. In the second part I will show how we use plasma enhanced-ALD to synthesize large-area 2D transistion metal dichalcogenides for nanoelectronics applications.
The Effect of Dual-Chelator on Cu Electroless Deposition Employing Cu Nanoparticles As the Catalyst
Authors: Lo Hui-Hung , Dow Wei-Ping
Published: February 2020

Chelator plays an important role in Cu electroless deposition (ELD) solution. It has the function to maintain the stability and to regulate the deposition rate of the ELD solution. Industry uses Cu ELD process to deposit Cu layer on non-conductive substrate, such as a printed circuit board (PCB). This process relies on the traditional Sn/Pd colloid as the catalyst to initiate the Cu ELD. However, Sn/Pd colloid has disadvantages, such as Pd is very expensive and the residual Pd has to be removed after the photolithography process for preventing the short between two copper lines in the semi-additive process (SAP). As a result, we employ copper nanoparticle (CuNP) as catalyst to overcome these issues. In this work, we select two chelators to study their effect on the Cu ELD by using CuNP and formaldehyde as the catalyst and the reducing agent, respectively. The surface roughness of deposited copper layer was measured by atomic force microscopy (AFM). The amount of ELD Cu was measured by atomic absorption spectrometry (AA). The morphology of the ELD Cu deposited layer on the sidewall a of through hole of a PCB was imaged by scanning electron microscope (SEM) and optical microscope (OM) to evaluate the influence of the two chelators on the Cu ELD, whose catalyst is CuNP rather than Pd.

Keywords:

Chelator, Cu electroless deposition, Copper nanoparticle, Printed circuit board

Reference:

M. Lin, S.C. Yen, Applied Surface Science,116-126, 178 (2001)
Elucidating the Key Factors in Ni-Rich Layered Materials: Structural Behavior, Redox Chemistry, and Electrochemical Performance
Authors: Lee Wontae , Kim Jaeyoung , Kwon Kyeongkeun , Yoon Won-Sub
Published: February 2020

An increase in the amount of nickel in LiMO2 (M = Ni, Co, Mn) layered system is actively pursued in lithium ion batteries (LIBs) to achieve higher capacity. Nevertheless, fundamental effects of Ni element in the three-component layered system have not been systematically studied. Therefore, to unravel the role of Ni as a major contributor to the structural and electrochemical properties of Ni-rich materials, Co-fixed LiNi0.5+xCo0.2Mn0.3-xO2 (x = 0, 0.1, and 0.2) layered materials were investigated. The results, on the basis of synchrotron-based characterization techniques, present a decreasing trend of Ni2+ content in Li layer with increasing total Ni contents. Moreover, it is discovered that the chex.-lattice parameter of layered system is not in close connection with the inter-slab thickness related to actual Li ion pathway. The inter-slab thickness increases with increasing Ni concentration even though the chex.-lattice parameter decreases. Furthermore, the lithium ion pathway is preserved in spite of the fact that the c-axis is collapsed at highly de-intercalated states. Also, a higher Ni content material shows better structural properties such as larger inter-slab thickness, lower cation disorder, and smoother phase transition, resulting in better electrochemical properties including higher Li diffusivity and lower overpotential when comparing materials with lower Ni content. In addition, some other topics will be discussed in the meeting such as the relationship between the anionic redox chemistry and the structural behavior, and the effect of the particle size on the layered cathode materials.

Figure 1
Electrochemical and Thermal Model of a 21700 Cylindrical Lithium Ion Battery with Integrated Solid Electrolyte Interphase
Authors: Hari Bostjan , Odio Maria Ximena , Somerville Limhi , McGordon Andrew , Widanage Widanalage Dhammika
Published: February 2020

An exact prediction of temperature inside cylindrical lithium ion (Li-ion) batteries is important for their safe operation, extended life expectancy and development of next generation battery management systems. Research attempts have been made to place temperature sensors inside cylindrical Li-ion batteries [1, 2], but such arrangements are not yet commercially available. Alternatively, a computational fluid dynamics (CFD) approach can be used to accurately predict internal temperature profiles. This computational technique couples the multiphysics phenomena occurring inside cylindrical Li-ion batteries [3, 4].

In this work we present a coupled one dimensional electrochemical and three dimensional thermal CFD model, to predict internal and surface temperature profiles of a commercially available 21700 cylindrical Li-ion battery. Since the operating temperature has an important effect on Li-ion battery ageing, the CFD model is coupled with the solid electrolyte interphase (SEI) formation on the negative electrode. The SEI formation and growth is one of the main reasons that shortens the life expectancy of Li-ion batteries with liquid electrolytes and needs to be addressed in computational models [5]. The developed CFD model will be used to predict temperature profiles and SEI growth response to charge, discharge and rest duty-cycle periods of the 21700 cylindrical Li-ion battery. Surface temperature and voltage profiles acquired from the CFD model will be compared against experimental results to confirm the validity of the computational model. Such an extended model will represent a computational framework to potentially decrease the cost and number of 21700 cylindrical Li-ion battery experiments with different duty-cycle scenarios. It will also support the design of more advanced battery management systems and optimise the cooling and heating system of battery modules and packs.

References:

[1] Horizon 2020 Projects: Portal – Issue 13, Smarter battery management, 93, 2017.

[2] G. Zhang, L. Cao, S. Ge, C.-Y. Wang, C. E. Shaffer, C. D. Rahn, Reaction temperature sensing (RTS)-based control for Li-ion battery safety. Scientific Reports, 5, 18237, 1-6, 2015.

[3] D. H. Jeon, Numerical modeling of lithium ion battery for predicting thermal behavior in a cylindrical cell. Current Applied Physics, 14 (2), 196-205, 2014.

[4] L. H. Saw, Y. Ye, A. A. O. Tay, Electrochemical-thermal analysis of 18650 lithium iron phosphate cell. Energy Conversion and Management, 75, 162-174, 2013.

[5] M. B. Pinson, M. Z. Bazant, Theory of SEI formation in rechargeable batteries: capacity fade, accelerated aging and lifetime prediction. Journal of The Electrochemical Society, 160 (2), A243-A250, 2013.
Mechanical Measurements of Aging in Lithium-Ion Pouch Cells Under Various Cycling Ranges
Authors: Liu Xinyi M , Arnold Craig B.
Published: February 2020

Lithium-ion batteries are widely used in many applications and it is important to monitor battery aging over time. However, it remains challenging to quickly and accurately measure aging. The correlation between battery mechanics and capacity fade can be a useful tool in battery diagnosis [1]. In this work, we present a method which uses the coupling between mechanics and electrochemistry to measure aging of a pouch cell. To quantify aging, state of health (SOH) measurements are often used. By measuring the initial peak stress and peak stress at later times, with the known stress-SOH relationship, the amount of aging can be determined [2]. We investigate the relationship between stress and SOH in different types of commercial batteries under various cycling ranges.

A lithium ion pouch cell was constrained inside a fixture along with a sensor that monitors stresses. Pouch cells were cycled at two different rates, C/2 and C/4, under Constant Current Constant Voltage charging scheme. Every 50 cycles, capacity was accurately measured through a slow discharge. In this presentation, we present the stress evolutions of pouch cells cycled at various ranges, shown in Figure 1 [3]. Using a model, we show that the observed stress-SOH relationship is composed of a long term linear film growth and a short term non-linear stress relaxation, as indicated in Figure 2 [3]. The various cycling ranges cause the average stress level inside the batteries to vary, which leads to different levels of softening. Such stress relaxation mechanism first dominates the overall stress behavior, but is gradually overtaken by the linear stress-increasing mechanism due to film growth. Commercial batteries with different compositions exhibit qualitatively similar results on stress-SOH, but vary quantitatively due to differences in their mechanical properties. We characterize the mechanical responses of individual components and compare their softening behaviors under low stress ranges.

Reference:

Cannarella, John, and Craig B. Arnold. "Stress evolution and capacity fade in constrained lithium-ion pouch cells." Journal of Power Sources 245 (2014): 745-751.

Cannarella, John, and Craig B. Arnold. "State of health and charge measurements in lithium-ion batteries using mechanical stress." Journal of Power Sources 269 (2014): 7-14.

Liu, Xinyi M., and Craig B. Arnold. "Effects of Cycling Ranges on Stress and Capacity Fade in Lithium-Ion Pouch Cells." Journal of The Electrochemical Society 163.13 (2016): A2501-A2507.

Figure Captions:

Figure 1. a) Representative stress evolution profiles plotted using maximum and minimum stresses during each cycle for batteries cycled between 1) 75-100% SOC 2) 50-100% SOC 3) 25-100% SOC 4) 0-100% SOC. For every 50 cycles, capacity is measured at a C/10 rate through a full discharge. b) A comparison between stress evolution profiles of batteries cycled from 0% to 100% SOC and from 75% to 100% SOC.

Figure 2. A comparison between experimental results and the fitted stress-SOH model.

Figure 1
The Real Impact of LiPF6/Organic Carbonate-Based Electrolyte Oxidation on Specific Capacity Losses and Cycle Life at High Positive Electrode Potentials
Authors: Kasnatscheew Johannes , Winter Martin
Published: February 2020

The progress of renewable energy sources and electro-mobility is accompanied with a successful implementation of effective electrochemical energy storage devices, among which the Li ion batteries (LIB) constituting the state-of-the-art (SOTA) technology, occupy a highly positioned place. For reasons of competitiveness to fossil fuels, a significant boost in specific energy is necessary, affording intense research and development (R&D) efforts. For SOTA negative and positive electrodes based on graphite and layered oxide (LiTMO2) active materials, respectively, the increase in the cell operation voltage represents a widely pursued and promising strategy in this regard.

However, the intended gain in specific energy is accompanied with the rise in specific capacity losses and thus, with the limitations comprising battery life time (cycle life), which is associated with the elevated potential of the positive electrode. The oxidative instability of the aprotic SOTA electrolyte (based on LiPF6/organic carbonates), as an inactive but essential multicomponent material in electrochemical energy storage devices, is assumed to be the main cause. As a consequence, many R&D efforts in terms of LIB high voltage operation are focused on the improvement and development of advanced electrolyte formulations.

In analogy to negative electrodes in literature, for positive electrodes as well, the specific capacity losses in the initial charge/discharge cycle commonly act as indicators for electrochemical electrolyte decompositions. However, in contrast to negative electrodes, the specific capacity losses for positive electrodes reveal ambiguous results upon variation of active materials and charge cut-off potentials. Moreover, data obtained from potentiodynamic based electrochemical stability measurements point to even sufficient oxidative stabilities of the nonaqueous aprotic electrolytes, thus conflicting with the conventional interpretation of specific capacity losses.

In this work, the apparently contradicting interpretations of the data obtained from galvanostatic and potentiodynamic measurements are systematically unraveled to finally understand the real role and the significance of the oxidation of liquid SOTA electrolytes during high voltage applications in LIBs.

[1] J. Kasnatscheew, B. Streipert, S. Röser, R. Wagner, I. Cekic Laskovic and M. Winter, ‘
Determining oxidative stability of battery electrolytes: Validity of common electrochemical stability window (ESW) data and alternative strategies
.’Physical Chemistry Chemical Physics, 2017, 19, 16078-16086.

[2] J. Kasnatscheew, M. Evertz, B. Streipert, R. Wagner, R. Klöpsch, B. Vortmann, H. Hahn, S. Nowak, M. Amereller, A. C. Gentschev, P. Lamp and M. Winter, ‘
The truth about 1st cycle Coulombic Efficiency of LiNi1/3Co1/3Mn1/3O2 (NCM) Cathodes
.’
Physical Chemistry Chemical Physics, 2016, 18, 3956-3965.
Dual Coatings, Triple the Benefit: A Study in ALD Surface-Modifications to Nickel-Rich Architectures
Authors: Hughes Barbara K. , Herbert-Walters Meghan N. , Valceschini Annette M. , Trevey James E
Published: February 2020

NMC 811 has elicited great attention as a high energy cathode material for next generation lithium ion batteries. With 80% Ni content, NMC 811 has surpassed energy densities of previous generations of NMC cathodes. However, there exist inherent drawbacks to increasing nickel content, which limit the long-term cell performance. As compared to structurally similar NMCs, 811 suffers from poor cycle life and decreased stability due to the surface reactivity of now heightened nickel in the fully oxidized state. A number of surface-modification methods have been adopted to address these significant degradation issues including atomic layer deposition (ALD). ALD is a platform technology that has been widely demonstrated throughout the literature to impart significant processing and performance gains on lithium ion battery technologies, having notable impacts on surface stabilization of the positive electrode. In this work we will explore ALD as a means of controlling surface phenomena in cell architectures containing NMC 811, and present evidence for improved performance under high voltage conditions. In addition, we will demonstrate the synergistic effects of dually coated cells with significant enhancement resulting upon pairing ALD-enhanced 811 with surface-modified natural graphite. Alongside observations of high voltage stability, ALD-modified cells exhibit upwards of 30% increased cycle life and superior rate capabilities, increasing the attractiveness of this material for next generation LIBs.
(Invited) Developing P Based Anode Materials for Na Ion Batteries
Authors: Lan Danni , Li Quan
Published: February 2020

The Na abundance and its low cost make Na ion batteries (NIBs) promising alternatives for Lithium ion batteries (LIBs) in large scale energy storage application. However, the size of Na ions is larger than that of Li ion, making graphite no longer suitable as anode material. In addition, the higher redox potential of Na+/Na (vs. that of Li+/Li) indicates a smaller voltage window achievable (when similar cathode is employed). These factors urge the search for anode material of high capacity for NIBs. Among various material choices, P based material caught much research attention in recent years. Phosphorus is a most promising candidates for anode applications in sodium ion batteries due to its highest theoretical capacity （2596 mA h/g）and reasonably low redox voltage (~0.6 V vs. Na/Na+), implying achievable high energy density. Nevertheless, experimentally pure phosphorous anode suffers from fast capacity decay during cycling and low initial coulomb efficiency. These are caused by intrinsic characteristics of the phosphorous, including (1) low electrical conductivity (~10-14 S/cm); (2) instability of the Na-P phases; and (3) electrode pulverization due to sodiation induced volume expansion (390% to its original volume). In the present work, we will discuss two different approaches (forming metal phosphides or dispersing phosphorus in conducting matrix) that can improve the electrochemical properties of the anode. We show that although phosphide formation can largely stabilize the electrode for longer cycle life, the stable chemical bonds of metal-phosphorous make the sodiation difficult, and thus significantly reduce the capacity of the electrode. Manipulation of material chemistry may lead to an optimized balance between the stabilization of P and their active sodiation, resulting in high capacity, high rate performance and long cycle life. The authors are grateful to the financial support from GRF of RGC under project No. 14316716
Influence of the Structure of Parent Materials in Blended Li2CuO2-Limx Cathodes, Limx = LiFePO4, LiCoO2 and LiMn2O4
Authors: Juarez-Yescas Carlos , Guzmán Gregorio , Santiago-Ruiz Leslie Fernanda , Osorio-Santiago Fransisco Javier , López-Vicente Carlos Iván , Ramos-Sánchez Guadalupe , González I
Published: February 2020

In recent years, it has been demonstrated that the use of blended cathodes is a convenient method for improving the performance of Lithium ion batteries by exploiting the advantageous properties of the parent materials. Blended cathodes allow the tailoring of cathodes with specific characteristics, often beyond the capabilities of any of the parent materials. While there are many high specific capacity lithium ion cathode materials, most of them lack long term stability for commercial use, for instance, Li2CuO2 is a promising material with a theoretical capacity of 490 mAh g-1; however, it exhibits a large capacity fade [1]. High capacities are only obtained during the first cycle, subsequent cycles presenting large capacity fade mainly due to structural transformations of the orthorhombic Li2CuO2 to densely packed layered structure during charging [1]. The present work aims to utilize commercial active materials to stabilize the Li2CuO2 phase and inhibit its degradation via blending. The materials chosen for this study are LiFePO4, LiCoO2 and LiMn2O4 considering their high stability, different structure and different average operation voltages (olivine/3.4 V, layered/3.8 V, spinel/4.1 V respectively) [2]. The blending process carried out in this study is via ball mill, because preliminary results have shown that physical mixing via stirring does not yield important synergic effects between the blended materials. Cycling Li2CuO2 at 0.1 C yields an initial capacity of 165 mAh g-1, with a capacity fade of 55 mAh g-1 after only ten cycles, while Li2CuO2/LiFePO4 cathode blends exhibit only a 22 mAh g-1 capacity fade, despite an initial capacity of 120 mAh g-1. Furthermore Li2CuO2/LiCoO2 cathode blends only present a capacity fade of 6 mAh g-1 after ten cycles, with an initial capacity of 112 mAh g-1. Lastly, preliminary results of the Li2CuO2/LiMn2O4 blends have also shown a slight improvement with respect to cyclability. It is evident that the different structure and average voltage of the secondary active material has a large impact on the capacity fade of the blended cathode, it is of great interest to identify the key parameters which optimize the performance of the blended cathode through further analysis by spectroscopic methods. The authors thank CONACyT project No. 1456 and SECITI project seciti/080/2017 for the financial support.

References:

1 G. Ramos-Sanchez, I. C. Romero-Ibarra, J. Vazquez-Arenas, C. Tapia, N. Aguilar-Eseiza and I. Gonzalez, Solid State Ionics, 2017, 303, 89–96.

2 N. Nitta, F. Wu, J. T. Lee and G. Yushin, Mater.
Today, 2015, 18, 252–264.
Estimating and Identifying Parameters from Discharge Curves of Lithium-Ion Batteries
Authors: Mashioka Hiroki , Inoue Gen , Tsuge Yoshifumi
Published: February 2020

In order to improve the performance of Lithium ion secondary batteries (LiBs) for electric vehicles and hybrid electric vehicles, it is very important to understanding the internal transport phenomena and resistance under high rate condition to increase power density. In our previous studies, we focused on the actual porous electrode structure, and the Li ion and electron conductivity was evaluated by the effective conductive path with the actual reconstruction electrode structure [1]. In addition, the charge-discharge performance was simulated with the model of reaction and mass transfer in heterogeneous porous electrode structure [2]. In this simulation, as assumptions, Li concentration and potential distribution in active material (AM) and electrolyte (EL) were calculated with mass transport simulation and Butler-Volmer equation as the boundary condition of the interface between AM and EL. From these calculation results, the effect of heterogeneous porous structure, which consist of active material, conductive material and binder, on the cell performance could be evaluated. Then, the values of parameters in this model are essential to accuracy of it. However, some parameters cannot be measured precisely in the experiment, especially, reaction rate constant, tortuosity of separator, Li+ diffusion coefficient, and transport number in electrolyte are treated as literature value or ex-situ results.

In this paper, we established the method of identifying these parameters by using experimental data in various condition and complex method [3]. We conducted fitting on experimental data of some SOC and some discharge rate condition. We adopted RMSE (Root Mean Square Error) to judge this fitting. Figure1 shows the overview of complex method. it is non-linear optimization method. Figure2 indicate transition of RMSE. From this, we can understand RMSE decreasing, and then, the value finally settle at 0.021. Thus the parameters can be identified. In addition, we will present the results of electrode structure optimization with complex method for high output power density cell.

References

[1] G. Inoue et al., J. Power Sources,
342, 476-488 (2017).

[2] G. Inoue, et al., ECS 228th meeting, A2 #164 (2015).

[3] M. J. Box.The Computer Journal, 8, 42-52 (1956).

Figure 1
A Novel Material Design for Li-Rich Cathode Material’s Long-Term Cycling and High Volumetric Energy Density
Authors: Oh Pilgun , Ko Min-Sung , Jung Jae-il
Published: February 2020

Fast development of portable electronic devices (such as a smart phone, iPad, and Galaxy Note) and electrified vehicles (such as EVs and HEVs) require better and smaller lithium ion batteries as their energy storages. What is needed for the cathode of the lithium ion battery is a material capable of higher energy density. However, not only the development of cathode material but also the commercialization of high energy density anode material has been limited due to the cathode material’s much lower energy density compared to anode material. In this regard, Li-rich material (Li2MnO3-LiMO2, M=Ni, Mn and Co) that has 150 % higher energy density than commercialized LiCoO­2 is the unique next generation cathode material to solve the problem. In the past decade, many researches have focused on the surface stabilization method of this material to improve its intrinsic problems of poor cycle/ rate capability and such surface treatment methods have been demonstrated in a few examples, including AlF3 coating and spinel heterostructures, yielding noticeable improvements in rate and cycle ability. Although such surface treatments showed improved rate and cycle performances, the realization of the Li-rich material’s high volumetric energy density and long-term cycle life which are more critical factors for the commercialization of Li-rich material still remained unsatisfied. For instance, AlF3 coated Li-rich LNCMO has abrupt capacity fade after 100 cycles, while it showed good rate and cycle capability within 100 cycles. Hence, new active material design, instead of simple surface modification methods such as coating or doping, is required to solve above previous limits.

Here we demonstrate a novel approach for lithium storage, which is a material design of a secondary structure which consists of large primary particle with a novel activation method using simple chemical treatment, to achieve superior long-term cycle life with high volumetric energy density. In this design, the large primary particle effectively reduced its surface area producing markedly decreased surface instability reaction as well as high tap density. Interestingly, the chemical approach activates only surface Li2MnO3 phase of large primary particle and the very surface activation effectively overcome the activation problem, which is limit of large primary particle have. This novel concept is very meaningful in that it is the first and unique method to achieve cathode material’s high volumetric energy density with long-term cycle life. As a result, this novel designed material affords remarkable battery performance with high volumetric energy density of ~1980 Wh L-1 and extremely high cycle retention of 90% during 300 cycles.
Study on Capacity Fading from Bulk and Surface Degradation in Ni-Rich Li[Ni
x
Co
y
Mn1-X-Y
]O2 (0.6 ≤ x ≤ 0.95) Cathodes for Lithium-Ion Batteries
Authors: Ryu Hoon-Hee , Sun Yang-Kook
Published: February 2020

Lithium-ion batteries (LIBs) have become a high-density energy source for portable electronic devices and small home appliances. However, LIBs are beset with significant challenges for replacing gasoline-powered automobiles with fully electric vehicles (EVs), which are becoming increasingly necessary to achieve a sustainable mode of personal transportation. One of the most difficult technological hurdles for EV batteries is increasing the specific energy density, which dictates the drive range of EVs per charge.1 LIBs based on layered transition-metal oxides, Li[Ni
x
Co
y
Mn1−x−y
]O2 (NCM), have long been considered as an alternative cathode for EVs and the main strategy for increasing the discharge capacity of NCM cathodes has been a progressive increase of the Ni fraction.1,2 However, it causes a proportional deterioration of the cathode’s ability to retain its original capacity during cycling.3 The observed capacity fading of NCM cathodes is typically attributed to the parasitic surface reactions arising from accumulation of a NiO-like phase on the surface of the cathode material and oxygen release that destabilizes the crystal structure.2,4 Anisotropic lattice contraction during cycling, which is the main capacity fading mechanism for LiNiO2, can also contribute to structural degradation of NCM cathodes.5 A comprehensive study of the capacity fading mechanisms of NCM cathodes for a wide range of Ni-rich compositions (i.e., Li[Ni0.6Co0.2Mn0.2]O2, Li[Ni0.8Co0.1Mn0.1]O2, Li[Ni0.9Co0.05Mn0.05]O2, and Li[Ni0.95Co0.025Mn0.025]O2) was investigated by examinging the relative effects of the bulk structural degradation (anisotropic volume change) and the surface degradation (formation of an inactive and resistance-increasing surface layer) during cycling. The electrochemical data for the NCM cathode series are correlated to the bulk and surface structural changes determined by X-ray diffraction and transmission electron microscopy.

References

S.-T. Myung, F. Maglia, K.-J. Park, C. S. Yoon, P. Lamp, S.-J. Kim, Y.-K. Sun, ACS Energy Lett.
2017, 2, 196.

D.-W. Jun, C. S. Yoon, U.-H. Kim, Y.-K. Sun, Chem. Mater.
2017, 29, 5048-5052.

H.-J. Noh, S. Youn, C. S. Yoon, Y.-K. Sun, J. Power Sources
2013, 233, 121-130.

S. Watanabe, M. Kinoshita, T. Hosokawa, K. Morigaki, K. Nakura, J. Power Sources
2014, 260, 50-56.

J.-M. Lim, T. Hwang, D. Kim, M.-S. Park, K. Cho, M. Cho, Sci. Rep.
2017, 7, 39669.
Development of Three-Dimensional Ni-Sn Anodes for Lithium-Ion Batteries
Authors: Nurpeissova Arailym , Adi Akylbek , Bakenov Zhumabay
Published: February 2020

Advances in energy storage devices in the next 10-15 years are expected to come from lithium-ion batteries1. However, the current architecture used in Li-ion electrodes appears to pose a limit on energy and power densities in electrodes. New architectures are needed to design Li-ion batteries with the improved performance desired in advanced high-power applications.

Novel 3D Li-S battery architecture combines power density and energy density in a single battery in a way that a high surface area cathode and anode are interdigitated. Interdigitation allows multi-directional flow of Li ions compared to the one-directional movement in conventional 2D Li-ion batteries making the path length for Li ions short at all points between the electrodes.

The battery is fabricated using anode tin-nickel alloy (Ni3Sn4) deposited on high surface area nickel foam used as the negative electrode current collector. The anode is then conformally coated with a solid polymer electrolyte using layer-by-layer method. Remaining void spaces in the foam are filled with lithium sulfide (Li2S) cathode using a slurry coating process. To complete the cell, nickel mesh current collector is applied to the slurry.

References

1. V. Sapru, September 2012. Frost & Sullivan Battery Power Conference, Slide 5.

Acknowledgments

The work has been supported by the targeted program No. 0115РК03029 “NU-Berkeley strategic initiative in warm-dense matter, advanced materials, and energy sources for 2014-2018” from the Ministry of Education and Science of the Republic of Kazakhstan.
High-Power and Safe Lithium Metal Battery in 3D Substrate
Authors: Petrovic Slobodan , D'Couto Chris , Diaz Christian , McGee Michael
Published: February 2020

The use of 3D structures has been shown to have the high potential for solving several problems that are currently preventing the performance improvements in lithium batteries. The high-surface area structures can provide elimination of dendrites and elimination of safety concerns, improved energy density and specific energy, high power density, low cost per kWh and improvement in cycle life. Compared with traditionally designed battery electrodes three-dimensional structures also enable short diffusion path in the active mass, better current collection and lower impedance.

A perfectly engineered three-dimensional structure is demonstrated using porous silicon. Both anode and cathode can be fabricated on the porous substrate, leading to numerous improvements in performance. A lithium metal anode in porous silicon is shown to be dendrite-free for over 200 cycles as a result geometrical effects in suppressing dendrite growth and low current density. The suppression of dendrites enables the use of lithium metal anodes and eliminating the safety concerns. Both anode and cathode also show improved specific capacity as a result of lower overall impedance and better utilization of the active material; as well as higher power density due to larger three-phase boundary and perfectly arranged active material inside uniformly spaced pores.

A complete cell based on the porous silicon structure can use any anode and cathode material; and can therefore be optimized for a particular application or requirements. It is also amenable to use of both liquid and solid electrolytes. A design is demonstrated that enables lithium metal air battery using a solid electrolyte. Another design shows a monolithic full cell within a single porous silicon wafer, eliminating the need for a separator or additional packaging.

Results of a half-cell, full cell and symmetrical cell testing are presented. The half-cell testing demonstrates the basic behavior of the porous structure and shows current densities in the excess of 5 mA/cm2 (geometrical or projected surface area), but with a low current density per true surface area. The symmetrical cell testing shows stable anode cycling and absence of dendrites for over 200 cycles, while the full cell testing proves the feasibility of pairing the porous silicon metal lithium anode with several conventional cathode materials.
Rational Design of 2D Sn/MXene Hybrid As Anode Battery with Long Cycling and High Rate Performance
Authors: Niu Junjie
Published: February 2020

Current lithium ion batteries (LIBs) can’t provide sufficient energy density due to a limiting capacity of 372 mAh/g from graphite anode and a low capacity from cathode. Therefore, searching novel electrode materials for large energy storage that can deliver much higher energy density becomes critical. Li-M (M = Si, Al, Sn) alloy batteries are in particular attracting more attention due to the conspicuous advantages on industrial availability, specific capacity and rate capability. Sn has a 3 times greater capacity of ~1000 mAh/g that allows it as one of primary candidates for the next-generation LIBs. Scientists have made numerous attempts to stabilize the Sn alloy geometry by constructing various structures. However, most of these nano-structured particles can’t long survive because of the severe agglomeration and pulverization, nevertheless some types of carbon may limit the particle growth. Here we report a rational design of 2D Sn/MXene hybrid as anode battery with long cycling (over 1000 cycles) and high rate performance (over 5C), which is based on our previous work on Sn (Kang et al Nano Letter 2018; Liu et al Nano Letter 2016; Liu et al Chem Commun 2017) and MXene (Nagui et al Adv Mater 2011). The excellent Li+/e- conductivity and strong chemical/physical bonding of the interface between MXene and Sn lead to the improved half-cell (VS Li) and full-cell (VS NMC) battery performance at both coin and pouch cell scales. The structure evolution of the hybrid composite, the SEI forming and disappearing, and the interface between electrode and electrolyte upon cycling will be investigated via electrochemical measurements and in-situ TEM technique. Our strategy based on the benefits of MXene and the major capacity contribution of loaded metal active material can elevate the development and utilization of this new type of 2D hybrid materials with a high rate capability, high storage capacity, and low voltage, making it a promising candidate for next-generation batteries.
Development of Sn@Pt Core-Shell Nanostructures Supported on Vulcan and N-Doped Graphene As Nanocatalysts for the Ethylene Glycol Oxidation Reaction
Authors: Hernández-Vázquez G. , Dessources S. , Alonso-Lemus Ivonne Liliana , Escobar Beatriz , Reguera Edilso , Rodriguez-Varela F.J.
Published: February 2020

Direct Ethylene Glycol Fuel Cells (DEGFCs) are an attractive alternative to methanol cells, since ethylene glycol fuel (C2H6O2) is less toxic, generates more electrons during its electro-oxidation reaction and has a higher boiling point, which allows an easier handling and storage. Pt/C nanocatalysts are widely used for the Ethylene Glycol Oxidation Reaction (EGOR). However, Pt is negatively affected by the presence of reaction intermediates produced from the reaction, which are strongly bonded to Pt active sites, poisoning the nanomaterial. In view of this issue, one efficient strategy to enhance the catalytic activity and tolerance of Pt-based anodes is the design of catalysts with the addition of a co-catalyst, either as an alloy or as a core-shell nanostructure. Among the co-catalysts with appropriate physicochemical properties, Sn has been widely used to enhance the performance of Pt. In a core-shell configuration, Sn is typically the core and Pt the shell. When used as core material, Sn atoms modify the electronic and structural properties of Pt. This synergetic effect changes the binding energy of EG and intermediate species on the active sites of Pt, increasing its catalytic activity. In this work, core-shell nanocatalysts based on Sn and Pt supported on Vulcan (Sn@Pt/C) and N-doped graphene (Sn@Pt/NG) have been synthesized by the polyol method. The core-shell nanocatalysts have been tested as anode materials for the EGOR and compared with monometallic Pt/C and Pt/NG in 0.5 mol L-1 H2SO4. Electrochemical characterization by cyclic voltammetry (CV) shows that Sn@Pt/C has a higher catalytic activity than Sn@Pt/NG, Pt/C and Pt/NG for the EGOR. For example, Sn@Pt/C generates mass and specific current densities 1.3 and 3.4 times higher than Pt/C. Sn@Pt/NG also shows higher mass and specific activity than Pt/C at low overpotentials. Moreover, Sn@Pt/C and Sn@Pt/NG oxidize COads at more negative potential than the monometallic nanocatalysts. Meanwhile, the NG support shows a positive metal-support effect, since Pt/NG is more tolerant to COads than Pt/C. In conclusion, Sn@Pt core-shell nanocatalysts are an attractive alternative for the EGOR, due to their higher catalytic activity and tolerance to COads than monometallic Pt.
Polyaromatic Ionomers for High Performance Alkaline Membrane Fuel Cells
Authors: Maurya Sandip , Matanovic Ivana , Chung Hoon T , Park Eun Joo , Narvaez Villarrubia Claudia Wuillma , Noh Sangtaik , Han Junyoung , Bae Chulsung , Fujimoto Cy , Hibbs Michael , Kim Yu Seung
Published: February 2020

Quaternized polyaromatics are one of the promising polymer electrolytes for alkaline membrane fuel cells (AMFCs) as these materials have good hydroxide conductivity, mechanical properties, and processibility.1 In this presentation, we present how the molecular design of quaternized polyaromatic ionomers has been evolved from quaternized poly(arylene ether sulfone)s to quaternized poly(phenylene oxide)s to quaternized aryl-ether free poly(phenylene)s to quaternized poly(fluorene)s. The major driving force to design quaternized polyaromatics includes polymer backbone stability,2 tethered cationic group stability,3 and minimum ionomer interaction with hydrogen oxidation catalysts4,5. Improved quaternized polyaromatic based AMFCs from < 200 mW cm-2 peak power density to 1500 mW cm-2 peak power density will be demonstrated. Remaining challenges of polyaromatic based AMFCs including AMFC durability, implementing low-PGM or non-PGM catalysts will be briefly discussed.

References

Dongwon Shin, Chulsung Bae, Yu Seung Kim, Chapter 8. Anion Exchange Membranes: Stability and Synthetic Approach, in The Chemistry of Membranes Used in Fuel Cells: Degradation and Stabilization, Ed. Shulamith Schlick, John Wiley & Sons, Inc. (2018).

Cy Fujimoto, Dae-Sik Kim, Michael Hibbs, Debra Wrobleski, Yu Seung Kim, Memb. Sci. 423-424, 438-449 (2012).

Yoong-Kee, Choe, Cy Fujimoto, Kwan-Soo Lee, Luke T. Dalton, Kathy Ayers, Neil J. Henson, Yu Seung Kim, Mater. 26, 5675-5682 (2014).

Hoon Taek, Chung, Ulises Martinez, Ivana Matanovic, Yu Seung Kim, Phys. Chem. Lett. 7, 4464-4469 (2016).

Ivana Matanovic, Hoon Taek Chung, Yu Seung Kim, Phys. Chem. Lett. 8, 4918-4924 (2017).
Differential Electrochemical Mass Spectrometry Coupled with Linear and Non-Linear Electrochemical Impedance Spectroscopy of Gadolinia-Doped Ceria: CO2 and H2o Co-Electrolysis
Authors: Witt Jonathan Michael , Adler Stuart B. , Stuve Eric M.
Published: February 2020

Recent advances in carbon capture create new opportunities for recycling CO2 into liquid fuels to store intermittent electrical energy1. One option is to co-electrolyze CO2 and H2O at high temperature using solid oxide electrolysis cells (SOECs). Although promising, the factors controlling rates of CO2 and H2O reduction in SOECs are not well understood, hampering development2,3. Traditional electrochemical techniques have difficulty resolving the mechanisms and kinetic parameters of the individual steps governing CO2 and H2O reduction. This limitation can potentially be overcome using linear and non-linear electrochemical impedance spectroscopy (EIS and NLEIS) in conjunction with dynamic measurement of gas-phase species using differential electrochemical mass spectrometry (DEMS).

Regarding co-electrolysis, mixed ionic electronic conductors (MIEC) have gained interest as alternatives to nickel-yttria stabilized zirconia (Ni-YSZ) because the active region is not limited to the triple phase boundary and they are more stable in reducing environments3. The MIEC studied here, gadolinia-doped ceria (GDC), has been well characterized as an electrolyte3 and is a promising cathode in SOECs. Unlike Ni-YSZ, it does not coke in carbon environments or oxidize completely in a feed of water and CO2.

We have performed NLEIS and EIS measurements of co-electrolysis on button cells composed of GDC as the working electrode with electrolyte YSZ under various temperatures and gas compositions. Gas atmospheres surrounding the cells contain mixtures of water, CO2, CO, H2, and carrier gas such as Ar or N2, used to manipulate the oxygen partial pressure of the system and thus the oxygen vacancy concentration of the surface and bulk electrode. The data we have collected on co-electrolysis of CO2 and water on GDC have been compared with model NLEIS spectra developed to include CO­2 reduction, water reduction, and reverse water gas shift reaction mechanisms and rate determining steps. A rough vacuum and low volume reactor was developed to cross-check the proposed mechanisms through measuring a gas phase response in DEMS and a micro-kinetic model was developed to predict product distributions corresponding to the mechanism that most closely matched the results.