bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of High-Energy Li-S Batteries Based on Commercial Materials and Water-Soluble Functional Binders
Authors: Lacey Matthew , Österlund Viking , Jeschull Fabian , Edström Kristina , Brandell Daniel
Published: February 2020

The lithium-sulfur (Li-S) battery has seen a resurgence of interest in recent years, with hundreds of journal articles now published every year. Significant advances have been made towards tackling the long-standing issues of poor efficiency and cycle life, most of which derive from the well-known polysulfide redox shuttle. Optimisation of the structure of the positive electrode, to improve contact to insulating solid particles and control the diffusion of soluble intermediates, has been one of the most intensely explored areas within this field. However, much of the published research involves increasingly exotic materials synthesis techniques which may not prove suitable when scaled up to the order of tons, which would be required if the system is to break into consumer applications.

Our group has previously investigated the use of functional polymers for use as binders in this system, particularly polyethers, such as PEO, and amide/lactam-containing polymers such as PVP. These water-soluble commodity polymers can actively improve active material utilisation, efficiency, and rate capability, depending on the materials chosen. Recently, we have investigated the compatibility of these materials with commercially available carbon materials suited towards electrodes with higher energy densities (e.g., highly porous carbon blacks). In this way, electrodes have been prepared from water-based processes with sulfur loadings of 65% and higher and areal capacities up to 4 mAh/cm2, with reversible sulfur utilisations in excess of 1000 mAh/g. Such figures are among the highest reported for this system.

This presentation will summarise our work in optimising positive electrodes based on porous carbon blacks and functional binders. New results on previously unreported materials will also be presented, as well as the results of electrochemical characterisation of cells employing these electrodes where other cell components have been further optimised towards high-energy: particularly the electrolyte volume and the excess of the lithium-metal anode.
X-Ray Absorption Spectroscopy of Solid-State Lithium Sulfur Batteries
Authors: Wujcik Kevin , Pascal Tod , Prendergast David , Balsara Nitash P
Published: February 2020

Lithium sulfur (Li-S) batteries have become a popular focus of energy storage research due to their high theoretical energy density and the economic viability.  The primary issues that Li-S batteries face stem from the high solubility of lithium polysulfide reaction intermediates (e.g. Li2Sx, 2 ≤ x ≤ 8) formed during the charge and discharge processes.  Dissolution of these species out of the cathode causes battery capacity to fade and leads to detrimental reactions that occur at the lithium anode, ultimately causing the battery to fail.  The reaction pathways through which lithium polysulfides are formed have been studies for over four decades, but are still unclear. 

Complicating spectro-electrochemical approaches to study Li-S redox chemistry is the challenge of obtaining spectral standards for individual polysulfide species.  Lithium polysulfide molecules cannot be isolated as individual components, and instead exist in solution as a distribution of molecules formed via disproportionation reactions (e.g. 2 Li2S6 ↔ Li2S4 + Li2S8).

In this work, X-ray absorption spectroscopy (XAS) at the sulfur K-edge was used to probe solid-state Li-S battery redox pathways.  Solid-state Li-S cells consisted of a lithium metal anode, a block copolymer electrolyte separator of polystyrene-poly(ethylene oxide) (SEO) containing LiClO4, and a cathode containing carbon black, elemental sulfur, and SEO/LiClO4.  Cells were charged/discharged while X-ray photons probed the battery cathode in situ to provide spectroscopic information regarding the sulfur-containing species formed during the charge and discharge processes.

If properly interpreted, sulfur K-edge XAS can provide power insight into the species formed during charge/discharge.  To overcome the issues typically associated with spectroscopic studies of Li-S chemistry, ab initio molecular dynamics simulations were performed to probe lithium polysulfide species dissolved in an oligomer of the polymer electrolyte used in the battery, tetraethylene glycol dimethyl ether (TEGDME).  Based on these simulations, theoretical X-ray absorption spectra for each lithium polysulfide were obtained using the eXcited Core Hold (XCH) approach.  Theoretical spectra were used to interpret experimentally obtained spectra to reveal the distribution of species formed throughout the charge and discharge processes.
First-Principles Study of Orthorhombic and Xerogel-V2O5 As Mg (and Multi-valent) Battery Cathode Materials
Authors: Gautam Gopalakrishnan Sai , Canepa Pieremanuele , Ceder Gerbrand
Published: February 2020

Multi-valent (MV) ion intercalation batteries that replace the Li+ with a MV cation such as Mg2+ provide a promising approach to meet the high energy density demanded by the next generation of electrical devices. One of the challenges in achieving high energy density MV-ion systems is to develop a suitable cathode with a high enough voltage and diffusivity of the MV cation. Mg intercalation into Orthorhombic and Xerogel-V2O5 is one of the very few that has been shown to function reversibly at reasonable efficiency. In this study, we gain insight into the thermodynamics of Mg insertion into various Orthorhombic V2O5-polymorphs (including α and δ) and the Xerogel, from first-principles calculations. While we have calculated the 0 K phase diagram and the equilibrium voltage curves for all polymorphs, we have computed the migration barriers for Mg diffusion in the α and δ-V2O5 polymorphs and find significant influence on the Mg mobilities by the coordination environment in the respective polymorphs. We have also evaluated the performance of α and δ-V2O5 for other MV ions including Ca2+, Zn2+ and Al3+. Furthermore, we evaluated the role of H2O in the intercalation of Mg in the hydrated Xerogel-V2O5 structure and found that H2O+Mg co-intercalation can happen based on electrolytic conditions with consequent impact on the voltage and phase behavior of the Mg-Xerogel system. We believe that this study can be further used to improve the performance of V2O5 as a cathode material for Mg (and MV)-batteries. This work has been done as part of the Joint Center for Energy Storage Research (JCESR).
Electrochemical Non-Destructive Analysis of Commercial 18650 Cells
Authors: Wei Li , Song Jinhua , Feng Zhenhe , Liu Xiang , Xie Jingying
Published: February 2020

Lithium-ion batteries have attracted much interest since widely used in consumer electronics and large scale system such as electric vehicles and smart grids [1]. Safety and duration are the most important performance for electrochemical system, to understand the aging mechanism, electrochemical non-destruction analysis differential voltage (DV) and incremental capacity (IC) analysis (dV/dQ and dQ/dV),provided insight into degradation phenomena [2].

Commercial 18650s (NCA/Graphite) were chosen to study the aging mechanism. The measured cells capacity was 3018.5mAh at 0.2C at 2.75V to 4.2V at the beginning of life, and 3152.0mAh at 0.01C. After 500 cycles, the 0.2C capacity was 2533.3mAh, and 2939.7mAh at 0.01C. The reversible lithium loss was 212.3mAh, and the resistance increased at the end of life. The fig.2 indicated that the active material was decreased on cycle.

References

[1] M. Armand and J. M. Tarascon, Nature, 451, 652 (2008)

[2] Ira Bloom and Andrew N. Jansen, Journal of Power Sources, 295, 139 (2005)

Figure 1
Performance Effect of Fast Charging Lithium-Ion Cells
Authors: Prezas Panos D. , Basco John K. , Duong Tien Q. , Bloom Ira
Published: February 2020

As electrically propelled vehicles become more commonplace, consumers who have grown accustom with internal-combustion driven vehicles, would expect to have similar experiences. This is especially true when considering “refueling.” Refueling an internal combustion vehicle can take up to 10-15 min. However, fully charging a lithium-ion battery system can take over 1 hour. To meet the expectation set by internal-combustion engines and liquid fuels, the battery system would have to be charged at the 4-to-6-C rate. If a motorist runs low on liquid fuel during a long trip, additional fuel can be added quickly, partially refilling the tank, and enabling the motorist to reach the destination without much delay. We investigated the performance effects of fast-charging commercially-available lithium-ion cells at various rates which would coincide with similarly minimal “refueling” delays. The effects on performance and life of the cells in both scenarios, full and partial fast-charging, will be presented.

The work at Argonne National Laboratory was performed under the auspices of the U.S. Department of Energy (DOE), Office of Vehicle Technologies, under Contract No. DE AC02 06CH11357. The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory ("Argonne"). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government
High Capacity Li2FeSiO4/Carbon Composite Cathode Powder Prepared By Spray-Frozen/Freeze-Drying Method
Authors: Fujita Yukiko , Shida Kenji , Sugimura Seiji , Fukui Takehisa , Matsuda Motohide
Published: February 2020

Much attention has been payed to lithium metal silicate (Li2MSiO4, M=Fe and Mn) as a promising cathode of large-scale lithium ion battery which can be used in electric vehicles and renewable energy generation systems. The Li2MSiO4, however, has a disadvantage in electronic conduction: their electrical conductivities are below 10-14 S/cm, which are much lower than those of LiCoO2. In addition, the diffusivity of lithium ion in the Li2MSiO4 is low compared with that in LiCoO2. Two approaches have been proposed for improvement in the conduction properties of Li2MSiO4: one is addition of conductive carbon, and the other reduction of particle size. Although various processes including use of expensive graphene and carbon nano-tube have been reported to obtain high capacity Li2MSiO4/carbon composite fine powders, it is important to develop cost-effective processes for broad commercial applications of the lithium ion batteries.

The authors have applied spray-frozen/freeze-drying (SF/FD) process to preparation of Li2MSiO4/carbon composite fine powders. The SF/FD is a practical process based on combination of spray-drying and freeze-drying processes, leading to ceramic fine powders with large specific surface area in high purity. In this study, Li2FeSiO4/carbon composite powder was prepared by SF/FD of solutions containing carbon sources followed by heat-treatment in flowing argon. Indian ink and glucose was added as the carbon sources. High capacity of 255 mAh/g was obtained at an initial discharge for the as-prepared Li2FeSiO4/carbon composite cathode powders even though any conductive additives were not added to the composite powders thus prepared. The Li2FeSiO4 showed high value of 173 mAh/g even after ten cycles of charge/discharge. This result indicates that most of Li2FeSiO4 particles are connected with carbon network from the starting carbon sources. The capacity at an initial discharge was increased to 323 mAh/g by adding an amount of Ketjenblack to the composite powder. The value became 238 mAh/g after ten cycles. TEM observations revealed that most of Li2FeSiO4 particles had size of 30-50 nm and the nano-Li2FeSiO4 particles were homogeneously complexed with colloidal carbons from Indian ink. In addition, it was observed that the nano-Li2FeSiO4 particles were coated with carbon layer with about 2 nm in thickness. Thus, homogeneous composites of Li2FeSiO4 and carbon nano-particles were successfully prepared by SF/FD of the solutions containing two kinds of carbon sources, leading to high cathode performance. These results clearly indicate that the practical SF/FD process can be applied for preparation of high capacity Li2FeSiO4/carbon composite cathode powder.
High Voltage Commercial Layer-Struacture Cathodes (NMC & LiCoO2) Surface and Bulk Degradation in Full Cell Systems
Authors: Tao Liang
Published: February 2020

As the commercial market is perpetually asking for smaller and lighter batteries, energy density (both gravimetric and volumetric) had become a very important criterion to select a cathode material for both automotive and mobile application. Nowadays, one of the most effective ways to elevate energy density is to raise the cutting off voltages of NMC or LiCoO2 cathodes. On the other hand, the capacity decay rate is much faster when the cutting voltage is higher than 4.5V vs. graphite, as illustrated in Fig. 1. In order to fully understand the mechanism, we’ve conduct multiple characterizations including TEM/SAED, XRD, hard/soft XAS, XPS Spectroscopy, combining with simulation work (first principle calculation), to reveal the degradation procedure of NMC and LiCoO2 during high voltage cycling. It turns out both surface (majorly) and bulk degradation contributes to the capacity fast decay. We hope the results might be helpful to tackle the problem of short cycling life of cells using high voltage NMC and LiCoO2 cathodes.

Figure 1
Determination of Irreversible Lithium Loss and Pre-Lithiation Studies for High-Capacity Anode Materials
Authors: Holtstiege Florian , Brunklaus Gunther , Placke Tobias , Winter Martin
Published: February 2020

A major disadvantage of anode materials, in particular high-capacity materials like silicon, is the high irreversible lithium loss attributed to solid electrolyte interphase (SEI) formation triggered by electrolyte decomposition. For this reason, pre-lithiation of anode materials is getting more attention. However, therefore the exact amount of irreversible lithium loss is needed.  Even if the SEI formation presents the major part of lithium loss, there are some other parasitic reactions which can lead to irreversible lithium loss, e.g., positive electrode degradation or the reaction of lithium ions with water. In addition, there are also some parasitic reactions which do not change the active lithium content of the cell but still possess an impact on the capacity or are able to transfer lithium ions out of the electrolyte into the electrodes.

Typically, the irreversible lithium loss is set equal with the accumulated irreversible capacity (sum of the differences between charge and discharge capacity in each cycle). It can be shown that this approach possesses a relatively low accuracy and one can only get an acceptable estimation of the first cycles. With increasing cycle number, the determination of the irreversible lithium loss with help of the accumulated irreversible capacity becomes more inaccurate because the impact of SEI formation and regeneration becomes smaller in comparison to other parasitic reactions.

In this work, a novel approach is investigated in order to determine the irreversible lithium loss with high accuracy. Therefore, “pseudo full cells” are built, while the term “pseudo full cell” refers to a cell with an oversized cathode (in terms of capacity). These cells are cycled like “real” full cells and afterwards the positive electrode is de-lithiated with help of the reference electrode in order to determine the remaining active lithium content of the cell. Finally, the exact amount of irreversible lithium loss can be determined as difference between initial and remaining active lithium content.
3D MoS2/MoSe2 Nanosheets Entanglement for Lithium-Ion Battery Anode
Authors: Zhang Sanpei , Wen Zhaoyin
Published: February 2020

Rechargeable lithium-ion batteries (LIBs) have attracted great attention in many fundamental applications due to their high energy and powder density, environmental benignity and long cycle life.1In order to further increase the energy density and power capability of current LIBs, enormous efforts have been made to develop high-performance electrode materials.

In a typical reaction, 1 mmol (NH4)6Mo7O24·4H2O, 15 mmol CH4N2S and 15 mmol CH4N2Se were dissolved in deionized water (35 mL) under vigorous stirring to form a homogeneous solution. Then, the solution was transferred into a 45 mL Teflon-lined stainless steel autoclave and maintained at 220 °C for 18 h. After being cooled to room temperature. The final precipitates were centrifuged and washed with water for several times and dried at 80°C under vacuum for 12 h.

Fig 1a shows the XRD pattern of 3D MoS2/MoSe2 nanosheets entanglement. The different diffraction peaks to the standard pattern of MoS2 and MoSe2 indicates the special entanglement structure. TEM and the corresponding high-magnification TEM images (Fig. 1b and c) reveal the uniform nanosheets entanglement of the 3D MoS2/MoSe2. More importantly, the corresponding liner element mapping indicates the uniform distribution of Mo, S and Se elements in the nanosheets entanglement, confirming the obtained uniform 3D entanglement architecture.

Fig 2a shows the typical discharge-charge profiles for the initial three cycles at 100 mA/g in the voltage window of 0.01 to 3 V. The initial discharge specific capacity is 1367.8 mAh/g. The discharge-charge cycling performance was evaluated at the current density of 100 mA/g and is shown in Figure 2b. For the 3D MoS2/MoSe2nanosheets entanglement, a high discharge specific capacity of ∼1234.3 mAh/g has been retained after 20 cycles.

Fig 1. (a) XRD pattern and (b) TEM image of the 3D MoS2/MoSe2nanosheets entanglement, (c) High-magnification TEM image corresponding to area 1 in (b), (d) Corresponding liner element mapping of (c).

Fig. 2. (a) Dischargeª¢charge voltage profiles of 3D MoS2/MoSe2 nanosheets entanglement. (b) Cycling performance of MoS2/MoSe2nanosheets entanglement.

In summary, the 3D MoS2/MoSe2nanosheets entanglement are successfully synthesized by a simple hydrothermal method. Moreover, this 3D interesting architecture shows greatly enhanced capacity and cycling performance when used as an anode material for LIBs

 

References:

[1] Kang B, Ceder G. Battery materials for ultrafast charging and discharging [J]. Nature, 2009, 458(7235): 190-193.

Figure 1
Electrodeposition Behavior of Lithium in Ionic Liquid at Various Temperatures
Authors: Sano Hikaru , Kitta Mitsunori , Matsumoto Hajime
Published: February 2020

Lithium dendrite formation is one of the largest obstacles against commercialization of secondary lithium metal battery1.  Our group has been focused on the morphology determination factors of lithium deposition from the view point of electrochemistry2-5.  Ionic liquids with high stability at the very cathodic potential as metallic lithium potential can be used to avoid the SEI formation and its effect on electrodeposition behavior.  In this study the lithium electrodeposition behavior in ionic liquid was examined changing holding temperature in order to control the electrochemical properties such as charge-transfer resistance of lithium redox and the ion diffusion coefficient in the electrolyte.

   An ionic liquid, [C4mpyr][Tf2N] (N-methyl-N-butyl-pyrrolidinium bis(trifluoromethanesulfonyl)amide), was selected as a model electrolyte-base, which has high stability at the very cathodic potential such as lithium redox potential2.  The electrolyte was prepared by adding 10 wt.% of Li[Tf2N] to [C4mpyr][Tf2N] in dried air.  The cell was fabricated using Ni foil as working electrode and Li foil as counter electrode, in an Air-filled glove box.  Lithium electrodeposition was conducted with current density of 200 μA cm-2 for charge amount of 0.1 C cm-2 at the temperature ranged from 25 to 55 °C.  The Ni working electrode was observed by SEM after dismantling the cell and washing the electrode with dimethylether. 

   The number of the deposits on the working electrode tends to decrease with increase in holding temperature6.  The number of the deposits per unit area, in other words, nuclear density is thought to be affected by overpotential of working electrode.  The overpotential is thought to be proportional to charge-transfer resistance.  To confirm this hypothesis the charge-transfer resistance was obtained though impedance spectroscopy measurement at each temperature and the result imply the hypothesis is to be the case.  At the meeting site, the growth behavior of electrodeposited lithium and lithium ion diffusion coefficient at each temperature will be also presented, and the ideal electrochemical properties for dendrite suppression will be discussed.

References:

1.   D. Aurbach et al., Solid State Ionics, 148, 405 (2002).

2.   H. Sano et al., J. Power Sources, 196, 6663 (2011).

3.   H. Sano et al., Electrochemistry, 80, 777 (2012).

4.   H. Sano et al., Chem. Lett., 42, 77 (2013).

5.   H. Sano et al., J. Electrochem. Soc., 161, A1236 (2014).

6.   H. Sano et al., 82th Annual Meeting of the Electrochemical Society of Japan, Abstr., 1J34 (2015).
Asynchronous Stress and Strain Measurements of LiMn2O4 Composite Electrodes
Authors: Lundberg Kimberly E. , Capraz Omer Ozgur , Sottos Nancy R. , Gewirth Andrew A
Published: February 2020

LiMn2O4 (LMO) is a promising cathode material for Li ion batteries due to its high voltage, environmental benignity, and natural abundance.1,2 Currently, LMO suffers from capacity fade due to Mn ion dissolution and a Jahn-Teller distortion which reduces the stability of the cathode structure.3,4 Mechanical thin film measurements can provide information on the mechanical deformations of LMO during cycling and how these deformations affect the stability and longevity of LMO.

The surface stress and bulk strain associated with the mechanical deformation of LiMn2O4 as a result of lithiation and delithiation is measured using an in situ bending cantilever technique and an in situ digital image correlation technique, respectively. The combination of these techniques allows for a comparison between bulk and surface changes in the cathode material in a slurry cast electrode. The composite electrodes consist of ball-milled LMO active material, carboxymethylcellulose sodium salt binder, and conductive Super P carbon black and were tested in 1 M LiPF6 electrolyte in 1:1 ethylene carbonate/dimethyl carbonate.

Strain measurements show volume contraction upon delithiation and volume expansion upon lithiation of the LMO electrode. The derivative of strain with respect to potential exhibits four distinct features, two upon delithiation (see figure) and two upon lithiation. The main features are aligned with the peaks in the cyclic voltammogram (CV) and correlate to changes in the LMO spinel lattice parameters.5

Tensile stress (surface contraction) is observed upon LMO delithiation, and compressive stress (surface expansion) is observed upon lithiation. The derivative of stress with respect to potential also exhibits four distinct features. The stress derivative feature at lower potentials during delithiation precedes the current peak and therefore indicates that a significant surface contraction occurs before delithiation (see figure).

Stress and strain occur asynchronously during delithiation of LMO suggesting that different processes control bulk versus surface expansion and contraction. Strain is governed by changes in the bulk lattice parameters, and stress is controlled by numerous processes such as surface film growth and lattice distortions at the electrode/electrolyte interface.

 References

Thackeray, M. M.; Johnson, P. J.; Depicciotto, L. A.; Bruce, P. G.; Goodenough, J. B. Mater. Res. Bull. 1984, 19, 179.

Yi, T. F.; Zhu, Y. R.; Zhu, X. D.; Shu, J.; Yue, C. B.; Zhou, A. N. Ionics
2009, 15, 779.

Thackeray, M. M.; David, W. I. F.; Bruce, P. G.; Goodenough, J. B. Mater. Res. Bull. 1983, 18, 461.

Amatucci, G. G.; Schmutz, C .N.; Blyr, A.; Sigala, C.; Gozdz, A. S.; Larcher, D.; Tarascon, J. M. J. Power Sources
1997, 69, 11.

Sun, X.; Yang, X. Q.; Balasubramanian, M.; McBreen, J.; Xia, Y.; Sakai, T. J. Electrochem. Soc. 2002, 149, A842. 

Figure 1
Development of New Polyanionic Positive Electrode Materials within the European Project Spicy
Authors: Trad Khiem , Mulder Grietus , Mantels Bart
Published: February 2020

SPICY is a collaborative research project associating 5 industrial partners (4 large groups and 1 SME) with 8 academic and research centers to the multidisciplinary development of a new generation of Li-ion batteries meeting the expectations of electrical vehicle end-users, including performances, safety, cost, recyclability and lifetime. For this purpose, SPICY will consider the development of new chemistry materials, cell architectures and packaging with the support of understanding and modelling activities. SPICY will address the whole value chain until the implementation of manufacturing. SPICY will focus on polyanionic phosphates for the cathode material. LiFePO4is well known as a safer and more durable cathode material. Unfortunately, its energy density is low due to the electrochemical potential of Fe. One objective of SPICY will be to bind metals having a higher potential than Fe, allowing an increase of the material potential, and thus a higher energy. Regarding the anode material, SPICY will study two chemistries. Graphite is used in current Li-ion cells and remains one of the major anode materials for the next generation of Li-ion cells. Silicon is appropriate for high energy cell applications but has lower cyclability. Silicon will be investigated through new synthesis process methods providing nanoparticles and core-shell structures to improve particle stability. Active and passive components will be harmonized for a higher energy density i.e.: polyanionic phosphate /graphite up to 200 Wh/kg, and polyanionic/Si up to 230 Wh/kg. In addition, cell architecture and packaging will be investigated. The thermal behaviour of these cells will be studied in ageing tests in order to model Li-ion cells. Finally, the industrial environment will be considered and SPICY solution will be assessed so as to optimise cost and to integrate eco-design, thereby supporting the future development of a strong industrial base in this field.

The SPICY project is funded by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 653373. The Spicy partners are CEA, Tekna, KIT, TUM, FZJ, BeLife, EMPA, IK4-Cidetec, Prollion, PEP, Hahn Schickard, Recupyl and Vito.
Operando Core-Shell Spectroscopy of Battery Materials
Authors: Balasubramanian Mahalingam
Published: February 2020

Battery based energy storage is expected to play a vital enabling role in future energy supply and demand. In particular, it is likely that storage of electricity generated from major renewable energy sources (such as solar, wind, or wave power) will be an important component of future energy portfolios worldwide.  In the realm of transportation, rechargeable batteries are already being used for hybrid and all-electric applications. However, for mass adaptation of battery technology, either for grid-storage or transportation applications, transformative changes in battery technology are required. Critical to the advancement of batteries (Li-ion or other beyond Li-ion solutions) is a fundamental and in depth understanding of the electronic and structural changes of the electrode materials during battery operation.

Research at the APS using hard x-ray spectroscopy (energy in the range 2.5-55 KeV) focuses on x-ray absorption fine structure spectroscopy (XAFS), x-ray emission spectroscopy, x-ray Raman scattering and micro beam( mapping, micro-XAFS and micro-diffraction) applications of hard x-rays. Spectroscopy beamlines are designed primarily for energy variable applications. Using in situ core-shell spectroscopic methods we seek to capture the intricate details of the redox behavior (electronic structure) as well as the element specific local structure of these materials. Such studies provide unique insight to develop structure-property correlations that are important to predict long-term battery performance as well as help tailor new novel materials with high capacities, high power, and stable crystal structures.

Work on Li-rich materials and Li-S systems, performed collaboratively with Argonne’s battery group and Prof. Nazar’s group (University of Waterloo, Canada) respectively, will be presented in this poster.

The submitted abstract has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government.
Influence of the Graphite Morphology on Anion Intercalation
Authors: Heckmann Andreas , Winter Martin , Placke Tobias
Published: February 2020

The redox-amphoteric character of graphitic carbon makes it possible to intercalate a broad range of anions and cations. These graphite intercalation compounds (GICs) are divided into two types: donor-type GICs, which host cations and acceptor-type GICs, which are formed by anions. A well-known application for a donor-type GIC is lithium-intercalated graphite (LiC6) as anode material in lithium-ion batteries. Besides this example, also acceptor-type GICs are known as active material in batteries. In this context, Placke et al.1 presented the “dual-ion cell”, that also deals with anion intercalation into the graphite structure. During charge anions and cations are inserted into the respective electrode and are released back into the electrolyte during discharge. In the charged state the cathode reaches a potential of 5 V (vs. Li/Li+). In order to avoid electrolyte degradation, an ionic liquid mixture is chosen as electrolyte. It is composed of N-butyl-N-methyl-pyrrolidinium bis(trifluoromethanesulfonyl) imide (Pyr14TFSI) and lithium bis(trifluoromethanesulfonyl) imide (LiTFSI).

The focus of this work is to investigate the influence of different graphite characteristics on the intercalation of the bis(trifluoromethanesulfonyl) imide anion into the graphite structure. For that purpose, nitrogen adsorption measurements were performed in order to determine the porosity of the graphite samples and X-ray diffraction was carried out to identify the crystallite size. Both structural parameters are correlated to the electrochemical performances.

1.            Placke, T.; Bieker, P.; Lux, S. F.; Fromm, O.; Meyer, H. W.; Passerini, S.; Winter, M., Dual-ion cells based on anion intercalation into graphite from ionic liquid-based electrolytes. Zeitschrift für Physikalische Chemie
2012,
226, 391-407.
Lithium Manganese Oxide By Atomic Layer Deposition As a Cathode for Lithium-Ion Batteries
Authors: Chen Lin , Meng Xiangbo , Libera Joseph A. , Stalzer Madelyn , Delferro Massimiliano , Marks Tobin , Elam Jeffrey W
Published: February 2020

Increasing energy needs demand radical improvement in energy storage technology. A robust molecular-level understanding of interfacial electrochemical processes will enable discoveries of fundamentally new concepts and advanced energy systems, such as the state-of-the-art lithium ion batteries. Lithium manganese oxide (LMO) with spinel structure is an excellent platform for studying fundamental electrochemical processes at the cathode surface. Atomic layer deposition (ALD) is a thin film technique with the capability of molecular-thickness control and conformality to substrate shape.  Thus, ALD of LMO and subsequent ALD of ultrathin protective coatings on the LMO will facilitate detailed interfacial studies, offering great insight into the molecular-level understanding. LMO has already been successfully deposited by ALD and the ratio of lithium content in LMO can be precisely controlled by adjusting the Li2O:MnO2 ALD cycle ratio.
A Chemical, Mechanical and System-Level Approach to Lithium-Ion Cell and Battery Safety
Authors: Gitzendanner Rob , Puglia Frank , Moore Greg , Trebukhova Svetlana
Published: February 2020

Lithium-ion cell and battery safety, or limitations thereof, have been hot-button topics for everyone in the energy storage industry for many years. Safety concerns have limited Lithium-ion adaptation in many large-format applications, most naval and undersea applications and several applications where the high energy density, long life characteristics, and many other advantages of the technology would have been mission-enabling. Safety is not a single-point problem, and addressing safety of electrical, chemical and mechanical systems such as batteries requires a semi-holistic approach to provide a meaningful advancement of system-level safety. In many applications, it is not a question of IF an abuse condition will occur, or IF a safety issue will arise, but WHEN; and thus, the need to know how to detect, manage and mitigate the effects of an uncontrolled release of energy in a highly energy dense system.

The Yardney Division of EaglePicher Technologies has looked at safety from multiple sides to address Lithium-ion safety. Recent work on improvements in the chemical safety, utilizing reduced flammability electrolytes, ionic liquid based electrolytes, and stable active materials will be presented; as well as test data in small and large format cells to demonstrate the effectivity of these enhancements in real-world applications. Mechanical and Thermal design aspects of both cells and batteries have been evaluated to develop designs that can manage the thermal load from a single cell thermal runaway event and prevent propagation to nearest neighbors in a battery pack. Similarly, system-level safety designs and approaches have been developed to mitigate the effects of an abuse event within the battery and control impact to exterior systems and personnel. All of these design enhancements have been tested in large-format cells and batteries, and results of these tests will be discussed.
Development of Novel Electrolyte Additives to Reduce Impedance of Lithium Ion Batteries
Authors: Milien Mickdy S , Lucht Brett L
Published: February 2020

The reaction of non-aqueous electrolytes on the surface of the anode during the first few charging cycles results in the generation of a solid electrolyte interphase (SEI) which is critical to the performance of LIB’s, however lithium ion intercalation through the SEI and into the anode is one of the largest limitations for high rate performance.  Electrolyte additives, which result in the generation of phosphate or sulfur rich SEI’s (as opposed to the carbonate rich SEI which results from the decomposition of electrolyte solvents such as EC), have been reported to reduce cell impedance and improve high rate performance.  The novel organophosphorous additive, α, has been investigated as an anode-film forming additive, which decreases impedance.  A comparative study of LiNi1/3Mn1/3Co1/3O2/Graphite cells with the standard electrolyte and the standard electrolyte with 0.1% (wt.) of added α was conducted in order to assay the effect of the additive on cycling behavior.  Although incorporation of α does not significantly alter the cycling behavior at standard rates, cells containing α demonstrate improved capacity retention at elevated rates.  Electrochemical impedance spectroscopy reveals that the improved rate performance of cells containing electrolyte with added α is the result of a significant decrease in charge transfer resistance on the anode.  X-ray photoelectron spectroscopy reveals changes to the composition of the anode SEI upon incorporation of α, which is likely the source of improved first cycle efficiency and reduced impedance.  Incorporation of α into a standard electrolyte formulation results in improved first cycle efficiency, improved rate performance, and decreased cell impedance on the graphitic anode.
Na1+XFexTi2-X(PO4)3/C (x = 0-1) Electrode Materials for Na-Ion Batteries
Authors: Lippens Pierre-Emmanuel , Sougrati Moulay Tahar , Difi Siham , Saadoune Ismael , Hakkou Rachid , Edstrom Kristina
Published: February 2020

Lithium resources are unevenly distributed worldwide and might not meet the increasing global demand for energy. Rechargeable Na-ion batteries can be considered as a serious alternative due to the natural abundance and the low cost of sodium especially for electrical energy storage associated with the deployment of sustainable and renewable energy sources. In addition, aqueous electrolytes improves the safety of the batteries and are environmentally benign. Thus, there is an increasing interest in the research of new electrode materials that can be used in such systems. Transition metal phosphates with NASICON structure are good candidates due to their high ionic conductivity and the possibility of tuning the potential by selecting the transition metal. However, they present low electronic conductivity that require doping, nanostructuration or coating to improve electrochemical performances.  

Na1+xFexTi2-x(PO4)3/C composites, with x=0-1, could be used as anode or cathode materials for Na-ion batteries since they exhibit three different potential plateaus at 4 V, 2.2 V and 0.4 V vs. Na+/Na0 depending on the amount of inserted Na+. These composite materials were obtained by solid state reaction with sucrose as carbon source for conductive coating and were characterized by different experimental and theoretical methods (Figure 1). The electrochemical mechanisms were identified from operando techniques, especially for the intermediate potential plateau at 2.2 V vs. Na+/Na0 that is related to changes in the oxidation states of both Ti and Fe. For example, the reduction of Fe3+ into Fe2+ was observed at the beginning of the discharge from 57Fe Mössbauer spectroscopy. High electrochemical performances were obtained at this potential including long cycle lifetime, high specific capacity and high power rate that are explained by the morphology of the particles, the carbon coating and the substitution of Fe for Ti (Figure 2).

Acknowledgments

Financial supports by Campus France (PHC Toubkal 008/SM/13), the Centre National de la Recherche Scientifique (CNRS, France), the Centre National de la Recherche Scientifique et Technique (CNRST, Maroc), the Institut de Recherche en Energie Solaire et en Energies Nouvelles (IRESEN, Maroc), the Swedish Research Council (contract 2012-3392) and StandUp for Energy (Sweden) are gratefully acknowledged.

Figure 1
A Layered Delta-MnO2 Nanoflake Cathode with High Zinc-Storage Capacities for Eco-Friendly Battery Applications
Authors: Pham Duong Tung , Vu Thi Trang , Song Jinju , Kim Sungjin , Alfaruqi Muhammad Hilmy , Jo Jeonggeun , Kim Seokhun , Islam Saiful , Kim Jaekook
Published: February 2020

This study reports the use of a layered-type birnessite δ-MnO2 nano-flake cathode for eco-friendly zinc-ion battery (ZIB) applications. The present δ-MnO2 was prepared via the simple low temperature thermal decomposition of KMnO4. The X-ray diffraction (XRD) pattern of the samples was well indexed to the δ-MnO2 phase. Field emission SEM and TEM images of the δ-MnO2 revealed flake-like morphologies with an average diameter of 200 nm. The electrochemical properties, investigated by cyclic voltammetry and constant current charge-discharge measurements, revealed that the nano-flake cathode exhibited first discharge capacity of 122 mAh g-1 under a high current density of 83 mA g-1 versus zinc. The discharge capacity thereafter increased until it reached 252 mAh g-1 in the fourth cycle. On the hundredth cycle, the electrode registered a discharge capacity of 112 mAh g-1. Coulombic efficiencies of nearly 100% were maintained on prolonged cycling and thereby indicate the long cycle stability of the δ-MnO2. Besides, the realization of specific capacities of 92 and 30 mAh/g at high current densities of 666 and 1333 mA/g, respectively, clearly demonstrates the decent rate capabilities of δ -MnO2 nano-flake cathode. These results may facilitate the utilization of layered-type birnessite δ-MnO2 in ZIB applications.
Implementation of Monitoring Algorithms for the Battery Pack Optimal Design and Control in an Electric Vehicle
Authors: Makinejad Kamyar
Published: February 2020

Battery monitoring algorithms and exclusively state of charge (SOC) estimation is the key function for successful operation of the battery management system (BMS). Enabling high storage utilization, safe operation environment for the battery pack and individual cells, cost reduction by avoiding over engineering, fault detection and lifetime enhancement are among all other benefits provided by monitoring algorithms. In this work, up-scaled dynamic voltage simulation and SOC estimator are described for the high power lithium ion cell (63Ah) used in parallel-series connection (2X108) to form the battery pack used in concept electric vehicle (EV) taxi ‘‘EVA‘‘ developed at TUM CREATE Singapore. Models are developed in offline platform with matlab/Simulink based on the aging experiments. Models are evaluated in realtime hardware in the loop (HIL) system and the interaction between HIL and experimental set up are described. Verified models are implemented on target microcontroller for small scale evaluation and BMS of the EV for large scale implementation in the final stage.

Each individual cell affects the overall performance of the pack, to deal with this, single cell SOC estimation within the battery pack is considered critical feature of the BMS. Battery pack is the most expensive component of the EV and conducting aging experiments on the pack is very expensive and requires specific laboratory equipment, hence extensive experimental tests are performed on the cells level at various controlled ambient temperature to simulate different conditions for the cells which they will go through in real application. These experimental tests are also used to create reliable reference data under controlled laboratory conditions, cell parameterization, diagnostics and aging studies on the cells among all.

Not all the cells in the battery pack are identical; external/internal influences lead to cell to cell discrepancies. These influences can be from slight manufacturing process differences, hot spots due to cell locations inside the pack, sudden failures among other influences causes different behavior between cells.

Weakest cell in the pack dictates the charging and discharging limits and safety level of the battery pack. This is due to the fact that the weak cell charges faster among other cells and reaches it critical voltage/temperature values before other cells being charged and discharges faster due to less capacity compared to other cell. This work demonstrates the simulation method to estimate the SOC for individual cell among the battery pack and the overall battery pack SOC considering the cell to cell variations, surface temperature differences and aging influences of the cell. This method leads to battery utilization of the high storage system and safe and reliable operation of the cells and is beneficial as well in cell balancing applications as it will be shown that these variations can be as high as 5-10% capacity difference between two cells in the battery pack.

Figure 1
A Fast, Efficient Discrete-Time Realization Algorithm for Reduced-Order Battery Models
Authors: Gopalakrishnan Krishnakumar , Zhang Teng , Offer Gregory James
Published: February 2020

Research into reduced-order models (ROM) for lithium-ion batteries is motivated by need for a real-time embedded model with the accuracy of physics-based models but having computational simplicity comparable to that of equivalent-circuit models. An attractive approach to this problem was recently proposed by Lee et al [1] with a model order reduction method known as Discrete-time-Realization Algorithm (DRA). The ROM obtained in standard state-space representation could then be used to obtain the time-evolution of all the internal electrochemical quantities of the standard porous-electrode model. An unresolved issue of this reduced-order modelling approach is the high computation requirement associated with the DRA, which has to be performed multiple times to identify cell parameters at various SOC and temperatures.

In this presentation, we analyse the computational bottleneck in the existing DRA and propose a significant improvement to the overall modelling procedure. Our analysis indicates the Singular Value Decomposition of a large Block-Hankel matrix of the system’s Markov parameters is a key inefficient step for the overall high computational requirement of DRA. A fast computational approach is presented that significantly reduces both the memory and the floating-point operation count by bypassing the redundant step of forming the large Block-Hankel matrix. Comparisons with the existing DRA method highlight the significant reduction in computation time and memory usage (Figure 1), as well as the accuracy improvement in key electrochemical quantities, afforded by our new method. With the aid of the improved modelling procedure, the transfer functions forming the porous electrode model is reformulated and suitably combined to arrive at a physics-informed equivalent circuit model of the Panasonic NCA 18650 BD cells used in automotive applications.

Figure 1
Copper Doped Cobalt Oxide As Efficient Catalyst for Li-O2 Battery
Authors: He Lewei , Zhang Wenqing , Wen Zhaoyin
Published: February 2020

Rechargeable aprotic lithium-oxygen (Li-O2) batteries, owning a high theoretical energy density of , have received extraordinary attention for their potential applications in electric vehicles and energy storage.1 However, several challenges of the lithium-oxygen batteries are still perplexing the researchers and hindering the practical applications of Li-O2 batteries, which involve high overpotential, poor cyclic stability, weak power capability, low round-trip efficiency and so on. Hence, it is important and imperative to develop efficient cathode catalysts if a better Li-O2battery is required

Here, we show that copper doped cobalt oxide(CuxCo3-xO4) nanoneedles as efficient catalysts in Li-O2 batteries. This catalyst showed good catalytic activities in both ORR and OER that could reduce the recharge plateau to 3.9V versus Li/Li+. The synergistic effect of high electrocatalytical activity and large specific surface area ensures the improved cycle stability and enhanced capacity of Li-O2 batteries. Furthermore, we found that the catalytical activity of this catalyst was strengthened with more proportion of doped copper, which indicated that the mingle of copper promoted the performance of cobalt oxide as cathode catalyst. This study suggests that CuxCo3-xO4 nanoneedles could be used as a competent cathode catalyst in Li-O2 batteries, while we can control its catalytical activity by changing the amount of dopant. We expect that CuxCo3-xO4 nanoneedles are the promising candidate as the cathode catalyst to be used in practical Li-O2batteries.

Fig. 1. (a)Discharge and charge profiles of a Li-O2 battery containing 30% CuxCo3-xO4 in carbon matrix using TEGDME electrolyte with limited capacity of 1000 mAh/g at a constant current density of 100 mA/g; (b) Cyclability of the same cell shown in (a).

References

[1] Luntz, A. C., Bryan D. M. Chemical reviews. 2014, 114, 11721-11750.

[2] Shao Y, Park S, Xiao J, Zhang JG, Wang Y, Liu J. Acs Catalysis. 2012,2, 844-857

Figure 1