bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation Mechanism and Stability of Solid Electrolyte Interphases in Linear Carbonate-Based Electrolytes
Authors: Ebrahiminia Mahsa , Wang Cun , Bedrov Dmitry 
Published: May 2020

Broad application of lithium batteries, necessitates improvements in their safety, cycle life, durability and energy density. Clear understanding of the electrode/electrolyte interfaces is one of the important factors in designing batteries with enhanced performance. Linear organic solvents are extensively used in electrolytes of lithium batteries to reduce viscosity and melting temperature of cyclic carbonates. However, these organic compounds are not stable in contact with anode, leading to decomposition of the electrolyte and formation of Solid Electrolyte Interphase (SEI). Although SEI is proven to be one of the most important parts of batteries, its structural complexity, mechanism of formation, and properties are not completely understood yet. In this work, we consider mechanism of formation and stability of SEIs composed of redox products of linear carbonate solvents. So far, the main focus of research was on decomposition products of cyclic carbonates. In case of linear carbonates, the SEI stability consideration is limited to the systems being in DMC solvent and to the best of our knowledge, there are no theoretical investigations on linear carbonate-based SEIs formation mechanism and properties.
In this work, we study Lithium Methyl Carbonate (LMC), Lithium Ethyl Carbonate (LEC) and Lithium Propyl Carbonate (LPC), which are single-electron reduction products of carbonate solvents in contact with the electrode, in their corresponding solvents being Dilithium Methyl Carbonate (DMC), Dilithium Ethyl Carbonate (DEC) and Dilithium Propyl Carbonate (DPC), respectively (Figure 1). Our aim is to chemically, kinetically, and thermodynamically study the aggregation, formation and stability of SEI layer in these systems from experimental, Molecular Dynamics (MD) simulation and Density Functional Theory (DFT) calculation points of view. Our study indicates that in LMC/DMC mixture LMC molecules have strong tendency to self-assemble and have low barriers to undergo second-electron reduction to form stable Li2CO3. Stable SEI was also observed in LPC/DPC as well, which is believed to be a result of slow dynamics of larger molecules and therefore increased possibility of the second-electron reduction near electrode surface. In the LEC/DEC system, however, we did not observe a stable SEI formation due to low tendency of LEC molecules to self-assemble, low electronic affinity coupled with high energy barrier for possible second electron reduction reaction. Therefore, our work illustrates that the selection of the linear carbonate as a blending partner for cyclic carbonates, might have an important impact on the ability of electrolyte to form stable and compact SEI layer.

Figure 1. Carbonate solvents and components studied in this work.

Figure 1
Effect of Electrode Fabrication Process on the Crystallinity of PVDF Binder and Electrochemical Performance of Electrode
Authors: Fu Yanbao , Song Xiangyun , Liu Gao , Battaglia Vincent 
Published: May 2020

In lithium ion battery in fabrication of electrode with good mechanical performance, active materials and conductive agent have to be mixed with specific polymer as binder to binding the other components together. As an effective binder, the polymer should meet some requirements for battery performance and production, such as excellent adhesion to current collector, suitable cohesion to active material and conductive agent, good electrochemical stability over a wide voltage window, high lithium ion conductivity, and so on. Because the binder may coat on the surface of active material particles, the binder layer should have high ionic conductivity and lithium ion can pass through the binder. Poly (vinylidene fluoride) (PVDF) is the mostly common used binder in lithium ion battery production. The amorphous phase in PVdF is a good matrix for polar molecules, and lithium ions can pass through a thin layer of swollen PVdF[1]. PVDF is a semi-crystalline polymer with a repeating unit of –CH2-CF2-. The spatial arrangement of the CH2 and CF2 groups along the polymer chains can contribute to the unique properties of PVDF from its crystalline phase. But it is seldom researched that the effect of crystalline structure of PVDF on the electrochemical performance in lithium ion battery. In our recent study, we found that the impedance of electrode is dependent on the drying temperature of coated slurry[2]. In this research we investigated the relationship of process conditions with crystalline phases of PVDF binder in the electrode and the dependence of the electrochemical performance of the electrode on the process conditions.
[1]. K. Tsunemi , H. Ohno , E. Tsuchida , Electrochimica Acta , 28 (6) , 591 (1983) .
[2]. Y. Fu, X. Song, G. Liu, V. Battaglia, 236th ECS Meeting Abstract,353, Oct. 13-17, 2019, Atlanta, GA.

Figure 1
Operando Electrochemical Pressiometry Using Three-Electrode Cells Probing (Electro)Chemo-Mechanics for All-Solid-State Lithium-Ion Batteries
Authors: Jun Seunggoo , Nam Young Jin , Kwak Hiram , Song Yong Bae , Kim Kyu Tae , Park Juhyun , Jun Dayoung , Jung Yoon Seok 
Published: May 2020

Due to the nonflammability of inorganic solid electrolytes (SEs) and the wide operation temperature ranges, bulk-type all-solid-state lithium or lithium-ion batteries (ASLBs) have been emerged as a promising power source. In particular ASLBs using sulfide SEs, such as Li10GeP2S12 (LGPS, 1.2 × 10-2 S cm-1) and Li3P7S11 (1.7 × 10-2 S cm-1), are attractive because of the extremely high ionic conductivities of sulfide SE materials, which are comparable to those of conventional organic liquid electrolytes used for lithium-ion batteries.
For the success of practical ASLBs, however, a current level of understanding and development on the electrode microstructure and interfacial (electro)chemistry is insufficient. While ASLBs consist of all the solid-state components (i.e., electrode active materials, SEs, conducting additives such as carbon, binders), volumetric strains of electrode active materials upon repeated charge-discharge cycles cause a serious deterioration of the performances. Thus, (electro)chemo-mechanics have been emerging as the critical issue. However, the relevant reports are scarce to date. Moreover, complex interfacial evolutions which could also contribute to the (electro)chemo-mechanical behaviors have been overlooked.
In this work, we first report an operando pressiometry using three-electrode cells to enable deconvolution of voltages and volumetric strains of positive and negative electrodes in-situ. Figure 1 shows the result of Li[Ni,Co,Mn]O2/Li6PS5Cl/graphite all-solid-state full cells cycled at 30 °C. The pressiometry profiles reveal signatures of phase transitions of electrode active materials, providing valuable information in terms of the assessment of the electrochemical performances and/or the management of battery system. More details will be discussed in the presentation.

Figure 1
Full Cell Understanding of Solvents in Battery Systems
Authors: Usrey Monica Lee , Guillot Sarah Lucienne , Johnson Tobias , Peña Hueso Adrián , Zhou Liu , Kerber Brian , Du Peng 
Published: May 2020

Lithium ion batteries are complex systems with multiple components that can be optimized to obtain desired performance capability. These components include electrolyte salts, solvents, and additives, as well as electrode active materials and coatings. Rational optimization of battery components requires an understanding of the fundamental science driving the observed performance. Silatronix® has developed a suite of analytical tools and methods using a combination of full format batteries, lab R&D cells, and model systems to construct a complete understanding of the battery from the cell level performance to the fundamental chemistry. This process includes the recovery and analysis of all parts of a full format pouch cell, including liquid electrolyte, generated gas, and electrode surface layers (Fig. 1).
Using this process, Silatronix® has evaluated several battery components, including organosilicon solvents for Li-ion electrolytes, to acquire a comprehensive picture of how these components provide observed performance benefits. For example, OS3®, a novel organosilicon chemistry that merges a silane with a Li+ coordinating nitrile functionality, has provided multiple performance benefits in various advanced Li-ion chemistries. Key experimental results include improved high temperature cycling stability in full format graphite/NMC622 pouch cells with 1%, 2%, or 3% OS3® (Fig. 2a), and using a model system of electrolyte in NMR tubes, we show that enhanced thermal stability of the bulk electrolyte results from HF scavenging and LiPF6 salt stabilization when 2-16% OS3® is present (Fig. 2b). Reduction of gas generation during high temperature testing in pouch cells with a commercial Si-based anode is also shown with 2% OS3® (Fig. 2c), and gas product identification and quantification is determined by GC-TCD for mechanistic analyses. In addition, OS materials change the reactivity of other electrolyte components, particularly at the electrolyte/electrode interfaces that govern critical performance attributes in Li-ion cells such as gas generation and interfacial impedance. These key performance benefits serve to enable several next generation battery chemistries, including a strong synergy with Si-based anodes.

Figure 1
Effect of Pitch-Coating on the Electrochemical Chracteristics of Graphite As Anode Materials for Lithium Ion Battery
Authors: Lee Jongdae , Jo Yoon Ji 
Published: May 2020

Lithium ions batteries (LIBs) have become the most promising energy storage device in energy field due to their potential utility as high-energy-density batteries for electric vehicles and hybrid electric vehicles. Graphite, which is the most widely commercialized anode material of LIBs, exhibits structural stability and excellent cycle characteristics. However, graphite has some problems to overcome. Due to the uneven SEI (Solid Electrolyte Interface) layer generated after the initial cycle, considerable irreversible capacity loss occurs. This results in electrode collapse and cycle instability especially in high-rate charging. Therefore, many researchers have been reported to improve the stability of graphite with carbon coating.
In this study, electrochemical characteristics of artificial graphite coated with petroleum pitch were investigated as anode materials of lithium ion batteries. To improve the capacity and stability of graphite, it was coated with petroleum pitch(SP, 150, 200 and 250 ℃). The physical properties of prepared samples were analyzed by MALDI-TOF, TGA, XRD, SEM and TEM. The electrochemical performances of graphite composites as an anode were evaluated by initial charge/discharge, cycle, rate performance, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) tests. The electrolyte used in the half cell was 1.0 M LiPF6 dissolved in organic solvents (EC:DEC=1:1 vol%).
It was found that the pitch(SP 250 ℃) coated graphite as anode materials had excellent electrochemical characteristics: initial efficiency (92.9%), discharge capacity (343 mAh/g), cycle stability (97%), and rate performance (84.1% in 10 C/0.1 C) than those of pristine graphite.
Investigating Increasing Molar Conductivity in Low Permittivity Electrolytes for Multivalent Battery Applications
Authors: Self Julian , Hahn Nathan T , Fong Kara D , Zavadil Kevin R , Persson Kristin A 
Published: May 2020

Many of the liquid electrolyte candidates for multivalent batteries exhibit increasing molar conductivity with concentration. In other words, the concentration-normalized conductivity increases as a function of salt concentration. This is in contrast to conventional electrolytes, e.g. aqueous or cyclic carbonate-based electrolyte solutions, where the molar conductivity decreases with concentration due to increased viscosity and ion aggregation. Low permittivity electrolytes with increasing molar conductivity include Ca(BH4)2 in tetrahydrofuran, Mg(TFSI)2 in monoglyme and Mg(TFSI)2 in diglyme.
In order to investigate the origin of this anomalous molar conductivity trend, we study the physicochemical properties of the electrolytes using a combined computational/experimental approach. Ab initio calculations and classical molecular dynamics simulations are undertaken to study ion speciation, ion activity and changes to solution permittivity. Furthermore, we undertake conductivity, microwave and raman spectroscopy measurements.
The Effect of Crystalline Structure and Iron Doping on the Electrochemical Behavior of Germanium Oxide Anodes in Lithium-Ion Batteries
Authors: Eisenmann Tobias , Passerini Stefano , Bresser Dominic 
Published: May 2020

The need for alternative anode materials for lithium-ion batteries (LIBs) is one of the decisive steps towards the electrification of our public and private transportation, since the state-of-the-art anode material graphite intrinsically limits the energy and power density of current LIBs.1,2 As a potential alternative, alloying metal-oxides such as ZnO and SnO2 have been widely studied, mostly due to their high theoretical specific capacities of 988 mAh g-1 and 1494 mAh g-1, respectively. Nevertheless, the pure oxides reveal poor electrochemical performance as a result of the eventually irreversible formation of the Li2O matrix and the pronounced volume variation, causing active material exfoliation.3–5 When doped with transition metals, however, the Li2O formation turns very reversible and the theoretically possible capacities can be achieved.6–9 As an example, Co-doped ZnO offers substantially higher specific capacities than pure ZnO (i.e., 966 mAh g-1 vs 330 mAh g-1). Recently, the class of TM-doped alloying metal oxides has been extended to Fe-doped GeO2, offering even higher specific capacities than transition metal doped SnO2 (theoretically 2152 mAh g-1).10

Within this study we enlighten the beneficial effects of iron doping on the structural evolution and electrochemical performance of GeO2. For this purpose, we combined a series of highly complementary in situ/operando techniques, including in situ high temperature XRD, operando dilatometry, and operando XRD. The results shed light on a commonly overlooked impact factor for the electrochemical performance of such materials and, in fact, metal oxides in general.

1. D. Bresser et al., J. Power Sources, 382, 176–178 (2018).
2. Y. Yamada, Y. Iriyama, T. Abe, and Z. Ogumi, Langmuir, 25, 12766–12770 (2009).
3. I. A. Courtney and J. R. Dahn, J. Electrochem. Soc., 144, 2045–2052 (1997).
4. I. A. Courtney, W. R. Mckinnon, and J. R. Dahn, J. Electrochem. Soc., 146, 59–68 (1999).
5. F. Mueller, D. Geiger, U. Kaiser, S. Passerini, and D. Bresser, ChemElectroChem, 3, 1311–1319 (2016).
6. D. Bresser, S. Passerini, and B. Scrosati, Energy Environ. Sci., 9, 3348–3367 (2016).
7. G. Giuli et al., Inorg. Chem., 54, 9393–9400 (2015).
8. G. Giuli et al., Materials, 11, 49 (2017).
9. Y. Ma et al., Sustain. Energy Fuels, 2, 2601–2608 (2018).
10. J. Wu, N. Luo, S. Huang, W. Yang, and M. Wei, J. Mater. Chem. A, 7, 4574–4580 (2019).
Silicon-Aluminum-Alloy-Derived Porous Silicon/Carbon As Anode Materials for Lithium Ion Batteries
Authors: Liu Shih-Fu , Fang Feng-Zun , Chen Han-Yi 
Published: May 2020

Nowadays, most of countries in the world promote energy saving and carbon emission reduction. The development of electric vehicles (EVs) is one of the main solution to reduce the carbon emission. Lithium ion batteries (LIBs) have higher energy density than other secondary batteries so they serve as the most popular energy storage device for EVs. However, the capacity of commercial graphite anode material is limited to ~372 mA h g-1 which is hard to meet the high-energy demand for long-range EVs. Silicon with highest theoretical capacity of 4200 mA h g-1 has been considered as the next-generation anode material. Despite the high capacity, the severe volume change of silicon during charge and discharge processes leads to the peeling-off of the active materials from the current collector. Therefore, the capacity retention of Si is poor. Porous structure and carbon coating are two major methods applying for improving the capacity retention of Si.
In our work, we utilized Si-Al alloys as precursors to synthesize micro-size porous Si anode materials by acidic treatment. Besides, carbon was coated on the porous Si particles to increase the electronic conductivity. Si-Al alloys are commercial available so this micro-size porous Si/C anode material can be mass-produced. High capacity around 1000 mA h g-1 could be achieved with good capacity retention. It indicates that the micro-sized porous Si/C is a promising LIB anode materials for electric vehicle application.
Study of the Lithium/Polymer Interface and Conductive Deposits on Lithium Metal Used for Lithium Metal Polymer Batteries.
Authors: Storelli Alexandre , Alzate-Carvajal Natalia , Rousselot Steeve , Pelé Vincent , Dollé Mickael 
Published: May 2020

Lithium metal anode has recently regained tremendous attention in the frame of the development of higher power and energy density lithium batteries for automotive industry. Lithium metal is indeed an ideal anode for lithium batteries due to its high capacity (3860 mAh/g). However, upon high discharge currents, the growth of dendrites leads to cell short cuts and limited coulombic efficiency.
This issue had first restrained its practical application in rechargeable batteries for high power applications until the use of solid polymer electrolytes that could mechanically prevent the dendrites from crossing the electrolyte. Among the different families of polymer electrolytes, polyethylene oxide-based (PEO-based) electrolytes have been established as the reference thanks to a reasonable conductivity above 60oC and its ability to form a stable solid electrolyte interphase (SEI) with lithium. Nevertheless, due to the low transference number of POE/LiTFSI electrolytes (t+≈0.15), dendrites or uneven lithium plating are still susceptible to form. Nowadays, many efforts are dedicated to solve these problems by focusing either on the improvement of the electrolyte or on the modification of the lithium-electrolyte interface. Gold layers have been proposed as an alternative to prevent dendrite formation; these gold coatings are used mainly together with ceramic electrolytes in order to improve the interface between Li metal anode and electrolyte. However, their use with polymer electrolytes where dendrite formation is favorable due to low transference number and mechanical strength have not being widely studied. In this presentation, three different coatings will be considered; aluminum (Al), gold (Au) and lithium fluoride (LiF). The choice of Al and Au is based on their ability to form Li-rich alloys while LiF is known to act as an artificial ion conducting SEI. The morphology and physico-chemical properties of the coatings are first characterized by Atomic Force Microscopy (AFM), X-Ray Diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) before evaluation of the interface between POE-based electrolyte and coated Lithium. Eventually stability during long-term cycling in Lithium Metal Polymer batteries is performed and compared to that of cells made using bare Lithium.
(Invited) Memory-Centric Artificial Intelligence with Nanodevices
Authors: Querlioz Damien 
Published: May 2020

When performing artificial intelligence tasks, central and graphics processing units consume considerably more energy for moving data between logic and memory units than for doing actual arithmetic. Brains, by contrast, achieve vastly superior energy efficiency by fusing logic and memory entirely, performing a form of "in-memory" computing. Currently emerging memory nanodevices such as (mem)resistive, phase change and magnetic memories give us an opportunity to achieve similar tight integration between logic and memory. In this talk, we will look at neuroscience inspiration to extract lessons on the design of in-memory computing systems.
We will first study the reliance of brains on approximate memory strategies, which can be reproduced for artificial intelligence. We will give the example of a hardware binarized neural network relying on resistive memory. Binarized neural networks are a class of deep neural networks discovered in 2016, which can achieve state-of-the-art performance with a highly reduced memory and logic footprint with regards to conventional artificial intelligence approaches. Based on measurements on a hybrid CMOS and resistive hafnium oxide memory chip exploiting a differential approach, we will see that such systems can exploit the properties of emerging memories without the need of error correcting codes, and achieve extremely high energy efficiency.
Second, we will see that brains use the physics of their memory devices in a way that is much richer than only storage. This can inspire radical electronic designs, where memory devices become a core part of computing. We will illustrate this concept by our works using magnetic memories as artificial neurons. We have fabricated neural networks where magnetic memories used as nonlinear oscillators implement neurons, and their electrical couplings implement synapses. We will see that such designs can harness the rich physics and dynamics inherent to magnetic memories, without suffering from their drawbacks. This physics-rich approach nevertheless raises important challenges that we will highlight.
References
M. Bocquet, T. Hirztlin, J.-O. Klein, E. Nowak, E. Vianello, J.-M. Portal and D. Querlioz, "In-Memory and Error-Immune Differential RRAM Implementation of Binarized Deep Neural Networks", IEEE International Electron Devices Meeting (IEDM), p. 20.6.1, 2018.
M. Romera, P. Talatchian, S. Tsunegi, F. A. Araujo, V. Cros, P. Bortolotti, J. Trastoy, K. Yakushiji, A. Fukushima, H. Kubota, S. Yuasa, M. Ernoult, D. Vodenicarevic, T. Hirtzlin, N. Locatelli, D. Querlioz and J. Grollier, "Vowel recognition with four coupled spin-torque nano-oscillators", Nature, Vol. 563, p. 230, 2018.