bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potential Tuning in the Benzenedicarboxylate System for Improved Organic Negative Electrodes
Authors: Lakraychi Alae Eddine , Dolhem Franck , Becuwe Matthieu 
Published: February 2020

Lithium-ion batteries (LIBs) represent one of the most successful battery chemistry with a range of applications starting from small portable electronic devices to advanced electric vehicles. The increasing demands concerning these large-scale applications have generated intense requirements of improved safety, low costs and of course high energy densities. Anode materials generally used in commercial LIBs, i.e. carbonaceous materials, have a very low operating potential (~ 0.1 V vs. Li+/Li) which cause some safety and cost issues.
As an alternative, several anode materials have been proposed, such as spinel lithium titanate (Li4Ti5O12) which can operate at potentials of 1.0-1.6 V vs. Li+/Li, this fact leading to a decrease of the cell voltage, or such as Si and SnO2, which are confronted to huge volume variation and structural reorganization during charge-discharge process.
In order to achieve the required improvements, anode materials must operate at an intermediate operating potential (0.5-1.0 V vs. Li+/Li). In addition there is a growing interest in designing greener LIBs. In this context, organic carboxylate-based derivatives have been considered as promising materials for the next generation of such greener LIBs due to their structure based on relatively naturally abundant atoms like C, H, O or N, their possible flexible molecular design, ease of recyclability and especially their operating potential allowing to substitute copper-based current collector by aluminum, thus inducing a drastic cost and weight reduction.
We will present an electron-donating substitution approach with the aim to decrease the operating redox potential in benzenedicarboxylate systems. More precisely, dilithium DiMethylTerepthalate compound (Li2-DMT) was synthesized, fully characterized and evaluated electrochemically as an anode material for Li-ion storage system. This new carboxylate-based material shows promising electrochemical performance, noticeably a stable cycling performance, high thermal stability and an operating potential of 0.65 V vs. Li+/Li, (i.e., -110 mV in comparison with Li terephthalate).

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The Performance of Lithium Bis(trifluoromethanesulfonyl)Amide in Propylene Carbonate on Binder Free Graphite Electrode
Authors: Pan Yue , Lucht Brett L 
Published: February 2020

An investigation of the performance of different concentrations of bis(trifluoromethanesulfonyl)amide (LiTFSA) in propylene carbonate (PC) on binder Free(BF) graphite electrode is studied. The changing of electrolyte concentrations results in a change in the reduction at the electrode interface and the reversible cycling of the cell. For a further study, the electrochemical behavior of LiTFSA in PC as electrolyte for lithium-ion rechargeable batteries is investigated by galvanostatic discharge/charge measurements and cyclic voltammetry, and the structure of the solid electrolyte interface (SEI) at the surface of binder free graphite electrode is characterized by fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). With the increasing concentrations of LiTFSA/PC electrolytes, BF graphite electrodes reveal reversible lithiation/delithiation of graphite instead of continuous electrolyte reduction.
Li-Sulfur Chemistry: Challenges and Opportunities
Authors: Moganty Surya 
Published: February 2020

Despite the excellent specific capacity (1672 mAh/g) and energy density (2567 Wh/kg), sulfur has several challenges that prevent the material from achieving commercial status. The primary setback with sulfur is its insulating property. The second detrimental problem is the dissolution of intermediate charge/discharge lithium polysulfide (Li2Sx) products in the electrolyte that leads to decreased utilization of sulfur, triggering parasitic side reactions with Li metal anode, poor cycle life. Hence, the design of electrolytes with lower solubilizing power for Li2Sx is perhaps the most straightforward and valid approach to suppress Li2Sx deduced redox shuttle. A liquid electrolyte designed for this purpose should act as a poor solvent for all of the Li2Sx species of the sulfur cathode, while enabling good Li-ion conduction by the originally doped Li salts. Given that the active species exhibit a wide range of hydrophilic−hydrophobic character: sulfur (hydrophobic, soluble in nonpolar solvents), lithium sulfide (soluble in highly polar solvents) and polysulfide species (intermediate solubility depending on the chain length). At NOHMs Technologies Inc, we have been developing functional ionic liquids as electrolyte additives in conjunction with novel cathode architectures to improve the Li-S battery performance. NOHMs has already demonstrated Li-S pouch cells that has exhibited full-cell specific energy density above 300 Wh/kg and excellent abuse tolerance during standard nail penetration tests. Figure 1 depicts the NOHMs Li-S cell level performance. This presentation will focus on the ongoing R&D work at NOHMs in maturing the Li-S battery chemistry.

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Effects of Polymeric Layers on Li Depletion and Electrochemical Performance of Li-O2 Rechargeable Batteries
Authors: Jang Il-Chan , Ishihara Tatsumi 
Published: February 2020

Li‒O2 batteries have received enormous attention as alternatives to current state-of-the-art rechargeable Li-ion batteries because of their high theoretical specific energy density. However, there are still substantial technical obstacles to developing a practical battery. One of the most significant challenges arise from reactivity of Li metal anode resulting in Li depletion such as solid electrolyte interphase (SEI) and Li dendrite formation. Most approaches to reduce Li depletion focus on adjusting electrolyte components, additives and mechanical barrier. On the other hand, extremely high capacity from a cathode in Li-O2 batteries needs much higher Li utilization of an anode. High Li utilization accelerates Li depletion seriously and consequently results in poor electrochemical performance including cycle stability. Therefore, it is recommended to study on Li depletion and its prevention in more detail for rechargeable Li-O2 batteries.
In this study, effects of polymer coating layers on the cycle stability were investigated. Li metal adopting poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) highly and effectively increased the cycle stability of a Li-O2 battery. The introduction of this polymeric layer, which exhibited sufficient mechanical strength, suppressed the needle-like dendrite formation. This indicates that the coating may prevent shape changes of the metal during discharge and charge cycles. It was found that improved reversibility of Li redox was achieved by coating with PVdF-HFP polymer.
Spheroidization of Graphite As Anode Material for Li-Ion Batteries: Spheroidization Process and Material Texture and Morphology
Authors: Rapp Manfred , Mundszinger Manuel , Farsi Sarvenaz , Golla-Schindler Ute , Kaiser Ute , Wachtler Mario 
Published: February 2020

Natural graphite (NG) is the dominant anode material for lithium ion batteries (LIBs) today, with a market share of approx. ~55%. With the continuous growth of portable, automotive, and other applications the total LIB market is expected to double within in the next decade. In view of this growth scenario, some prognoses predict supply bottlenecks of NG. Furthermore, the NG sources are geographically strongly concentrated today, which poses an immanent risk to supply security. In principle, the increasing demand for graphite as LIB anode material can be met by synthetic graphite, for which an upscaling of the production capacity is possible with economically justifiable effort within short time. Nonetheless, there are strong activities to develop new sources of NG. To benchmark the quality of these new materials, convenient and cost-effective characterization methods and facilities are required.
Pristine flat flakes of NG are usually mechanically turned into spherical shapes (“spheroidization”) and coated with a thin film of amorphous carbon, in order to alleviate problems with exfoliation due to electrolyte solvent co-intercalation during lithium intercalation, to decrease the surface area and thus the irreversible capacity in the first charge/discharge cycle, as well as to increase density and thus the volumetric capacity. Recently, spheroidization is also more and more applied to synthetic graphite materials. Characteristic of the spheroidization procedure is that the yields are usually around 50% only. Any process improvement will therefore have a strong economic impact.
The present work focuses on the lab-scale reconstruction of the industrial spheroidization and fractionation processes, using a rotor impact mill, an air jet sieve, and an air classifier. The aim is:

to obtain a better understanding of the spheroidization process, by identifying critical process parameters and their influence on the resulting products (spherical graphite particles as well as by-products),

to identify potentials for improving the process (especially in terms of yield), and

to offer the opportunity to benchmark graphitic materials in lab-scale in comparison to industrially manufactured references.

The obtained materials are analysed with regard to their electrochemical performance, as well as to their particle morphology (particle size distribution, particle shape, tap density and texture). The microstructure and texture is studied by SEM and FIB/SEM tomography, which provide information on the outer appearance in the nm scale and the open and closed porosity of the materials (Fig. 1).
Acknowledgement:
The authors are indebted to the German Federal Ministry of Education and Research (BMBF) for financial support (Project: Li-EcoSafe, contract no. 03X4636).

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Doped Si Nanoparticles As a High Performance Anode for Li Ion Batteries
Authors: Li Yan , Xiao Lisong , Ren Yang , Schulz Christof , Wiggers Hartmut , Amine Khalil , Chen Zonghai 
Published: February 2020

Graphite, with a theoretical storage capacity of Li ions with an equivalent of 372 mAh/g, has been used as anode in commercial lithium ion battery for decades. Due to the advancement of electronic portable devices and the development of electrical vehicles, higher capacity and energy density anode materials are needed. Silicon, which has a theoretical capacity 3579 mAh/g, has been explored as the next generation anode material. Being different from graphite, Li has an alloying reaction with Si instead of intercalation, which leads to severe volume expansion (as much as 370%) during charging. The repeated volume change during cycling can destroy Si particles and the surrounding solid electrolyte interphase and leads to capacity fade. Reducing the size of Si particles has been proven as an effective way to alleviate decomposition. Therefore, Si has been synthesized as thin film, nanowires, and nanoparticles to improve its cycling stability. For nanosized Si, the capacity retention is satisfying even with high amounts of Si contained in the electrode. In this work, nitrogen doping of silicon is used to further improve the cycling performance of the Si nanoparticles. It is found that N-doping modifies the crystallization of Si nanoparticles leading to amorphous Si nanoparticles with high nitrogen concentration. At the same time, with increasing N doping concentrations, the specific capacity decreases. However, better capacity retention, rate performance, and reduced side reactions can be achieved. It is demonstrated that high-performance Si-based anode material can be obtained by carefully controlling doping nitrogen in Si nanoparticles.
Safe Lithium-Ion Batteries? Predicting Performance over a Range of Operating Conditions
Authors: Francis Candice , Best Adam Samuel , Lammas Andrew , Sammut Karl 
Published: February 2020

Electrochemical-thermal coupled modelling of lithium-ion batteries is used to simulate battery performance. Modelling can be used to investigate the effects of different materials and design parameters on battery performance and safety. Numerous models exist for lithium-ion batteries1 from microscopic through to module scale simulations. Majority of these models simulate cell performance under normal charge and discharge operation. Generally these models do not accurately predict cell behaviour outside of normal conditions, such as at high temperatures. Operating lithium-ion cells at high temperatures can lead to an internal thermal event and ultimately cell failure. A number of models have been developed to simulate cell behaviour outside normal conditions however these models do not include the performance of cells during normal operation. A model that simulates cell performance over a range of conditions is necessary to make an informed decision regarding material and design changes. This work aims to combine two existing models to create a new model for simulation of cell performance under normal and high temperature conditions.
Two existing models were chosen to create the new model. The models were selected to meet the following criteria: 1) single cell model 2) stacked plate configuration 3) individual component layers modelled (no homogeneous core assumption) 4) includes temperature dependent material properties (or able to be included). The first is a 1D electrochemical-thermal reduced order model developed by Gambhire et al.2 for simulation under normal charge and discharge operation. The second is a 1D electrochemical-thermal coupled model developed by Wang et al.3 for simulating internal thermal events including decomposition reactions for each cell component. Key aspects of both models have been used to create a new model implemented in COMSOL Multiphysics®. The new model is expected to more accurately describe cell behaviour over a range of conditions. The results of this study will be presented at the conference.
Acknowledgments: The authors acknowledge the funding support provided by the ARC Research Training Centre for Naval Design and Manufacturing, PMB Defence Engineering, and the CSIRO Manufacturing High Performance Metal Industries Program.
References:

D. Miranda, C.M. Costa, S. Lanceros-Mendez, J. Electroanal. Chem, 739, 97 (2015).

P. Gambhire, N. Ganesan, S. Basu, K.S. Hariharan, S.M. Kolake, T. Song, D. Oh, T. Yeo and S. Doo, J. Power Sources, 290, 87 (2015).

S. Wang, L. Lu and X. Liu, J. Power Sources, 244, 101 (2013).
Improving Stability of High Voltage Cathodic Materials Using Polyfluorinated Additives and Electrolyte Solutions
Authors: Sun Haoran , Li Yizhi 
Published: February 2020

High capacity and high voltage cathodic materials are key to increase the power and energy densities of rechargeable batteries. The cause of instability of the high voltage cathodic materials is that these cathodic materials irreversibly react with the electrolyte solutions during charging/discharging and/or storage processes. As a result of such reactions, the cathodic materials decompose to non-electrochemical active materials, and the same time electrolyte solution decomposes to gaseous molecules, leading to the batteries dry out condition, a deadly condition for rechargeable batteries. Fundamentally, there are approaches to solve this problem as demonstrated in the literature: 1) preparation of new electrolytes and solvents that are thermodynamically stable, i.e. their first oxidation and first reduction potential are outside the potential of anodic redox couple (e.g. Li+/Li) and the potential of the cathodic redox couple (e.g. Li(1-x)CoPO4/LiCoPO4); 2) discover new electrolytes and solvents systems that are kinetically stable, i.e. the electron transfer rates between electrolyte solution and both cathodic and anodic materials are slow, providing large overpotentials for those unwanted electrochemical reactions; 3) addition of new reagents (e.g. additives) into the electrolyte solutions to form an interfacial layer (e.g. SEI layer) on both cathodic and anodic materials, resulting slow electron transfer rate between electrolyte solution and both cathodic and anodic materials, providing, again, large overpotentials for those unwanted electrochemical reactions.
Many works have done over the past decade or so to improve the stability of the cathodic materials. Due to synthetic challenges possessed in preparation of thermodynamically stable electrolyte solutions, discovering new additives that can slow down the ET processes becomes another popular approach. Here we report the use of new polyfluorinated additives that can improve the stability of high voltage cathodic materials (e.g. LiCoPO4) by slowing down the ET process between electrolyte solution and the cathodic materials during the charging/discharging processes by forming a fluorinated protective SEI layer. The high electronegativity of fluorine results in exceptionally strong bonds to carbon (bond dissociation energy (BDE) C-F = 110-126 kcal/mol). Furthermore, fluorine substitution results in an increase in the C-C bond energy in fluorocarbons compared to the corresponding hydrocarbons. The preformed fluorinated protective SEI layer on cathodic material surface either prevents or slows down the ET process between commonly used electrolyte solutions (i.e. PC with 1.0 M LiPF6). We find that such protective SEI layer can be pre-formed when treating the cathodic materials with polyfluorinated additives. This result indicates that pre-modification of cathodic materials is possible to increase the stability and compatibility with the electrolyte solution.
The Effect of Al2O3 on the Sintering of Garnet-Type Li Ion Conductors Li6.5La3Zr1.5Ta0.5O12
Authors: Wang Yuxing , Yan Pengfei , Xiao Jie , Deng Daniel , Lu Xiaochuan , Sprenkle Vincent 
Published: February 2020

It is widely recognized that Al plays a dual role in the fabrication of garnet-type Li ion conductors, i.e., a dopant that stabilizes the cubic structure and a sintering aid that facilitates the densification. However, so far, the sintering effect of Al2O3 has not been well-understood due to the common practice of ‘unintentionally’ introducing Al from crucibles during the sintering process. In this study, the sintering effect of Al on the phase composition, microstructure and ionic conductivity of Li6.5La3Zr1.5Ta0.5O12 was investigated by using an Al-free crucible and intentionally addition of various amounts of γ-Al2O3.
XRD analysis showed that all sample have pure cubic phase regardless of the quantity of γ-Al2O3 addition up to 0.3 mol per formula unit of LLZT0.5. While the sample with no sintering aid cannot be successfully densified at 1100 °C, 0.05 mol of Al sintering aid can effectively enhance the densification. The morphology is characterized by small densely-packed polygonal grains. Further addition of Al sintering aids leads to rapid grain growth and increased secondary phases which are detrimental to the densification process. The drastically different morphology of samples with different Al contents are explained by the liquid phase sintering mechanism based on the Li2O-Al2O3 eutectic system. Our EDS analysis showed that Al prefers to stay at the grain boundary rather than enter the garnet lattice. Uneven Al distribution in high Al-content samples is observed as Al predominately exists in small, concentrated area as secondary phases. Transport properties characterized by impedance spectroscopy are largely consistent with the morphology results that the sample with 0.05 mol of Al showed the best densification and a maximum total ionic conductivity of 0.5 mS/cm was achieved. Therefore, a 0.05 mol of Al in the form of γ-Al2O3 is the optimal quantity of sintering aids for this system. This study clarifies the role of Al as sintering aids and will be useful for harnessing the sintering power of Al in a controllable manner.

Acknowledgment

This work was supported by the U.S. Department of Energy’s (DOE’s) Office of Electricity Delivery & Energy Reliability (OE), U.S. Department of Energy Wind and Water Power Technologies Office and the U.S. Army Corps of Engineers, Portland District. We appreciate the useful discussions with Dr. I. Gyuk of the DOE-OE Grid Storage Program.

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Electrolyte Composition Influence on Oxygen Reduction and Evolution in Li-Air Cells
Authors: Gittleson Forrest S , Jones Reese E , Ward Donald K , Foster Michael E. , Anstey Mitchell R 
Published: February 2020

The lithium-air battery is a promising next generation energy storage technology, yet the current combinations of electrolytes and electrodes have been unable to demonstrate long-term efficient cell cycling. Major issues include the decomposition of electrode and electrolyte materials and high overpotentials for the oxidation reaction. While there is significant work exploring the possibility of catalyzed electrodes to reduce cell overpotentials and encourage reversibility, there is a lack of understanding about how to select appropriate complementary electrolyte systems. In this study we employ data from hundreds of Li-air cells to reveal meaningful relationships between electrolyte composition (solvent, salt, oxygen solubility and concentration), oxygen reduction kinetics and mass transport properties. Data from practical coin-type cells are compared to fundamental studies using flat disc electrodes to prove the validity of the method. Findings are supported by molecular dynamics simulations to elucidate the interaction of various electrolyte components. The relationships derived in this work form necessary criteria for downselecting electrolyte systems with the most desired properties.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.
Cathode Materials for Rechargeable Mg and Ca Batteries
Authors: Lipson Albert L. , Kim Soojeong , Proffit Danielle L. , Han Sang-Don , Pan Baofei , Lapidus Saul , Sa Niya , Liao Chen , Burrell Anthony K. , Vaughey John T. , Ingram Brian J. 
Published: February 2020

Batteries based on magnesium or calcium metal anodes have the potential to achieve energy densities exceeding current Li-ion batteries. However, there are major challenges to overcome to make such a battery a reality. One challenge is that currently no cathode materials have been identified that have sufficient energy density for a practical magnesium or calcium based battery. Towards the end of finding higher energy density cathode materials, this poster presents two different materials approaches for the successful incorporation of Mg and Ca. In particular, materials based on a Prussian blue type structure and with a polyanionic layered structure will be discussed. Results presented include cycling performance, X-ray diffraction and X-ray based spectroscopies that prove intercalation of both Mg and Ca. Comparing these classes of materials to others that have been shown to successfully intercalate Mg, yields insights into what makes a material a good candidate for future multivalent cathode research. With these design principles guiding the search, a material that can achieve high energy densities for Mg or Ca chemistry can hopefully be found.