bluuebunny/crossref_metadata_2025_split huggingface dataset:
On-Demand Internal Short Circuit Device Reveals Li-Ion Cell Design Vulnerabilities and Enables Verification of Safer, Higher Performing Battery Designs
Authors: Darcy Eric 
Published: February 2020

In partnership with the National Renewable Energy Laboratory (NREL), we have invented (U.S. Patent #9,142,829) an on-demand internal short circuit (ISC) device that is activated by raising the cell temperature > 57 degC, rather than > 130 degC required without the device. We have achieved > 90% success rate in driving a 2.4Ah (180 Wh/kg) cell design into thermal runaway with a device designed for an anode active material to cathode current collector short and usign a non-shutdown separator (M. Keyser, ECS Phoenix mtg, Oct 2015). Building on this success, we are now implanting the device in cell designs exceeding 250 Wh/kg to learn their design vulnerabilities and effectiveness of safety features like shutdown separators, cathode coatings, current interrupt devices, positive thermal coefficient switches, center mandrels, cell vents, and crimped headers. We are providing our cells to researchers conducting in-operando tomography on cells during thermal runaway (Finegan et. al, Nature Communications, 7924, 2015) for first time video insight into the response of an 18650 cell to a thermal runaway that is internally induced by an internal short circuit instead of external driven by thermal, mechanical, or electrical abuse. This enables the study of conditions that replicate latent defect induced field failures with the most fidelity.
As the specific energy of commercially available 18650 cell designs exceed 250 Wh/kg, we are presented with additional challenges for integrating them into safe, high performing (> 200 Wh/kg) battery designs for manned spacecraft applications. Specifically, these cell designs are susceptible to side wall rupturing and/or eletrode jellyroll ejection during thermal runaway. Such packs require cell interstitial materials that provide high thermal conductivity and structural structural strength. This leaves very little cell surface area for heating unmodified cells into thermal runaway for battery safety testing. In fact, the only way to acheive single cell thermal runaway in these battery designs is by triggerring cells implanted with the ISC device. These tests give us insight into the impact of battery design parameters life cell-cell spacing, cell electrical isolating wraps, and features that protect the adjacent cells from propagating into thermal runaway. Finally, battery flame arresting materials and vents are crucial to prevent flames and sparks for exiting battery enclosures. Our IMLB submission will be our first public forum disclosure of these results.
Implications of Material Reponse for Battery Safety
Authors: Santhanagopalan Shriram , Cao Lei , Zhang Chao , Pesaran Ahmad 
Published: February 2020

There has been a significant amount of effort to make lithium ion batteries safer, resulting in improvements across the board from safer cathode chemistries, alternate candidates for anode materials, electrolytes with wider operating windows, separators with better mechanical and thermal properties, to binders that are less reactive under abuse conditions. At the cell level, safety improvements include tabs that limit electrical conductivity at high temperatures, alternate pathways to dissipate heat and/or abuse reaction currents and preferential channeling of vent gases. Test methodologies have improved a great deal over the last few years: we are able to selectively investigate the effect of SEI additives on abuse response of the cell in situ and obtain tomographic images during thermal runaway. All these capabilities have enabled our understanding of the interactions among the different cell components during cell abuse scenario considerably.
As reported previously, improvements to individual components are not always adequate to address cell safety. Given the extent of advancements in characterization techniques and material properties, the next logical step is to understand the influence of material-scale-improvements on the cell level response during short-circuit. However, this step is not straightforward. There are several chemical/ electrochemical reactions involving multiple components that take place simultaneously. Material properties such as thermal diffusivity and electrical conductivity change during both nominal operation as well as during the abuse reactions. In this study, we present a rigorous characterization of the reactivity, as well as material properties with aging of the cell. We then proceed to use these properties to better explain the temperature distribution within the cell during short-circuit. Implications of changes in material properties for propagation of thermal runaway at the cell level are described based on experimental observations. The results are used in mathematical models to assess effectiveness of different design options in improving cell-level safety.
Electrospun Gel Electrolytes for Li-Ion Batteries
Authors: Croce Fausto 
Published: February 2020

The quest for more efficient and low environmentally impacting energy conversion and storage technologies has become a priority for modern society. In particular, rechargeable, high capacity and high power electric energy storage systems, if developed, would play a central role in accelerating the transition toward an electric transportation economy, which, in turn, would dramatically reduce the risks associated with the burning of fossil fuels. To this purpose, ‘ad hoc’ engineered functional materials that join improved electrochemical properties with scalable preparation process for electrodes and electrolytes are needed. The most promising of such materials are those with nanometric-scale dimensions, including nanoparticles and nanofibers. These materials, having very high surface to volume ratio, show enhanced bulk charge transport and faster electrodic reaction rates. Nowadays, new methods have emerged for manipulation, assembly and characterization of nanostructured materials, particularly regarding functional electrodes and electrolytes based on nanofibers. Among the methods for generating nanofibrous structures, electrospinning is a top-down approach proved to be simple, cost effective and versatile, which allows the fabrication of polymeric and inorganic nanofibers in a scalable process. Electrospinning is based on the application of an electric field to a drop of a viscous solution on the tip of a spinneret. The electric field elongates the drop to form a conical shape known as the Taylor cone. For an electric field critical value, the repulsive electrical forces between the charges in the fluid overcome the surface tension of the drop and a charged jet of the solution is ejected from the tip of the Taylor cone. The jet becomes unstable and rapidly whipping leading to the evaporation of the solvent and the formation of dry, continuous, ultra-thin fibers on the collector [Fig. 1]. The collected electrospun mats present peculiar properties, such as very high surface to volume ratio, low density, high pore volume and remarkable mechanical strength.
In this presentation, the electrospinning technique will be illustrated particularly regarding the optimization of the system and process parameters, which mostly influence the electrospun nanofibers. The characteristics of some gel electrolytes formed by electrospun polymeric separators based on PVdF and PEO will be discussed.

Figure 1
Carbon Disulfide As a Novel Additive for High-Performance Lithium Sulfur Batteries
Authors: Gu Sui , Jin Jun , Wen Zhaoyin , Qian Rong , Zhuo Shangjun 
Published: February 2020

Rechargeable lithium batteries with long cycle life and high energy density have great market demand for energy storage systems. The lithium sulfur battery is attracting intense interest because of its theoretical capacity and energy density, which is much higher than that of Lithium ion battery based on intercalation reactions. Moreover, the cathode, sulfur, is highly abundant, low cost and nontoxic. Lithium sulfur battery has been considered as a next-generation energy storage system, especially for large scale applications.[1] The main obstacle to realize the practical use of lithium sulfur battery lies in the rapid capacity fading, which is primarily attributed to the solubility and shuttle of polysulfides generated during charge and discharge.[2] The shuttle of polysulfides between electrodes not only decreases utilization of sulfur, but also greatly corrodes lithium and reduces coulombic efficiency of the cell.
Here, we introduced carbon disulfide (CS2) as an additive for DOL/DME-based electrolytes. We found that CS2 is able to form complexes with polysulfides. These complexes are soluble in DOL/DME and can suppress shuttle reactions. In addition, the employ of CS2 can also passivate the surface of both cathodes and anodes. Improved coulombic efficiency and cycling performance were exhibited in Fig 1.a combined with LiNO3[3] as binary additives. Fig 1.b presents the morphology of anode after 50 cycles. It's observed that the surface is quite dense and smooth. XPS (Fig 1.c) shows the existence of LiF. This result indicates the ability of CS2 to passivate the Li metal because of the halides, which can improve Li cycling.[4]

Fig 1. a. Electrochemical performance of lithium sulfur batteries. b. Morphology of Li anode after 50 cycles with CS2 and LiNO3 additives. c. The F 1s XPS spectra of Li anode after 50 cycles with CS2 and LiNO3 additives.

References

[1] X.L. Ji, L.F. Nazar, Journal of Materials Chemistry, 20 (2010) 9821-9826.
[2] Y.V. Mikhaylik, J.R. Akridge, J. Electrochem. Soc., 151 (2004) A1969.
[3] D. Aurbach, E. Pollak, R. Elazari, G. Salitra, C.S. Kelley, J. Affinito, J. Electrochem. Soc., 156 (2009) A694.
[4] Y.Y. Lu, Z.Y. Tu, L.A. Archer, Nature Materials, 13 (2014) 961-969.

Figure 1
Lithium Complex Hydride Solid-State Electrolytes with Conventional Liquid Electrolyte-like Conductivity
Authors: Kühnel Ruben-Simon , Yan Yigang , Remhof Arndt , Rentsch Daniel , Lodziana Zbigniew , Battaglia Corsin 
Published: February 2020

Solid-state electrolytes have the potential to improve the safety properties of lithium-ion batteries. Many different materials have been proposed over the years. However, especially at lower temperatures (at or near room temperature), most solid-state electrolytes display lithium ion conductivities lower than the one of conventional organic liquid electrolytes (about 3-5 mS cm-1 at room temperature). Several sulfides are among the only compounds reported so far displaying lithium ion conductivities in or above this range. However, issues regarding costs and/or electrochemical stability of sulfide electrolytes still remain.
Here we report on several complex hydrides that display, for the first time, lithium ion conductivities near room temperature comparable to liquid organic electrolytes, adding a second class of materials to the group of highly conductive solid-state electrolytes and paving the way for high-power lithium solid-state batteries. An in depth study was carried out to understand the lithium transport mechanism of these materials. Density functional theory calculations combined with molecular dynamics simulations support a new anion assisted lithium hopping mechanism. We also show excellent stability of our solid-state electrolytes via long-term cycling in half-cell battery configuration.

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Electrolyte Studies for High Voltage Lithium Ion Batteries
Authors: Delp Samuel A. , Allen Joshua L. , Jow T. Richard 
Published: February 2020

Extensive research on next generation lithium ion batteries, specifically batteries operating at high voltage (>4.4V), is currently underway. There are several issues that need to be addressed in order to produce a viable product. For example, graphite anodes are used in current state of the art batteries but silicon-based anodes offer higher energy density. Also, cathode materials that are electrochemically active at high voltages are available, e.g. LiNi0.5Mn1.5O4 (LNMO) @ 4.7V and LiCoPO4 (LCP) @ 4.8V. Unfortunately, batteries composed of these materials with the state of the art electrolyte suffer from poor cycle life. New electrolytes are essential for the operation of next generation high voltage lithium ion batteries.
This research focused on the electrolyte for LNMO-graphite based batteries. The importance of not only the high voltage stability of the electrolyte but also the low voltage stability will be discussed. Cyclic voltammetry (CV) on glassy carbon electrodes allow for the investigation of both the oxidative and reductive stability of the electrolytes. Cycle life data, Coulombic efficiency, and fade rate data was collected from LNMO-graphite coin cells. Differential capacity (dQ/dV) vs. V plots were also constructed from the coin cell data to show how the electrochemical behavior changed over time. The dQ/dV vs V data for the state of the art electrolyte show a buildup of impedance over time which was also evidenced via electrochemical impedance spectroscopy (EIS). Several different lithium salts and additives were investigated in this study. The results suggest that while the oxidative stability of the electrolyte is important, the reductive stability must not be ignored.
Reaction Mechanism of Alluaudite Sodium Iron Sulphate As High Energy Density Cathode Material for Na-Ion Battery
Authors: Nishimura Shinichi , Oyama Gosuke , Yamada Atsuo 
Published: February 2020

The sodium-ion battery system is now growing as a potential alternative to the lithium-ion battery for large energy storage systems. The ubiquitous element Na allows us to realize stable production of large scale storages for broader applications. Electrode materials for the Na system is under intensive development by many battery researchers to make properties of the Na-ion battery comparable to those of Li-ion battery. In such pursuit we developed an ideal cathode material with abundant constituents sodium, iron and sulfate ions.1 Alluaidite-type sodium iron sulfate Na2+2x
Fe2–x
(SO4)3 exhibits high energy density due to high working potential of 3.8 V vs. Na/Na+. Large tunnel structure in the alluaudite framework derives high Na-ion conductivity. Thus Na2+2x
Fe2–x
(SO4)3 electrode allows high-rate battery operation.In this poster, we present detailed reaction mechanisms of Na2+2x
Fe2–x
(SO4)3 for Na batteries by means of crystal structural characterizations.
As mentioned in our first report of this system, Na2+2x
Fe2–x
(SO4)3 (NFS) electrode undergoes irreversible change during first charing of NFS/Na half cells. Subsequent discharging and charging cycles are reversible. We carried out ex situ structural analysis to understand about the irreversible and reversible changes during electrochemical reaction.
Crystal structure of NFS powder (x ~ 0.28) was successfully analyzed by the alluaudite structure model with C2/c symmetry.2 Ex situ structural analysis of NFS electrodes were carried out by powder X-ray diffraction using synchrotron radiation at Photon Factory in KEK, Japan. Electrochemically reacted samples were also successfully analyzed by using a monoclinic lattice with C2/c symmetry, which is isomorphic with the pristine lattice. Volume change is less than 5% in whole reaction range. The refined structure shows that the desodiation/resodiation reactions are essentially topochemical, while partially irreversible cation rearrangement is observed. One of the Na sites, Na3, is preferentially extracted due to higher site-potential than the other two sites. This model is consistent with computational evaluation of relative defect formation energy at the Na sites.1 Subsequent extraction sequence shows complex behaviors involving Fe migrations.
[1] P. Barpanda, G. Oyama, S. Nishimura, S.-C. Chung, and A. Yamada, Nat. Commun., 5:4358, 2014.
[2] G. Oyama, S. Nishimura, Y. Suzuki, M. Okubo, and A. Yamada. ChemElectroChem, 2(7):1019–1023, 2015.
[3] G. Oyama, O. Pecher, K. J. Griffith, S. Nishimura, R. Pigliapochi, C. P. Grey and A. Yamada, in preparation.

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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)

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