bluuebunny/crossref_metadata_2025 huggingface dataset:
Galvanic Corrosion of AA5052 Aluminum-Magnesium Alloy and Carbon Steel in NaCl Solutions
Authors: Urase Gaku , Tada Eiji , Nishikata Atsushi
Published: February 2020

Aluminum alloys (AAs) such as 5000 and 6000 series, which show relatively good corrosion resistance and plastic workability, have been utilized to automobile body parts for reducing the weight of the body and for the improvement of fuel consumption. However, since the body parts made of Al alloys should be joined with steel parts by welding or other methods and the joined parts can be exposed to atmospheric corrosion environments, there has been a concern about degradation of the parts due to galvanic corrosion between Al alloy and steel. In this study, galvanic corrosion behavior of AA5052 aluminum-magnesium alloy and SS400 carbon steel is investigated in NaCl solutions.

A galvanic couple used in this study consisted of AA5052 Al-Mg alloy (Mg: 2.65, Si: 0. 08, Fe: 0.27, Cu: 0.01, Cr: 0.17, Zn:0.01, Al: bal. (mass%)) and carbon steel (JIS SS400). Both materials were 15-mm-square plates of 3 mm in thickness. After lead wire was connected on the surface of the plates, they were embedded in an epoxy resin. At this time, both materials were separated with a 500-um gap. The surface of the galvanic couple was polished with SiC papers down to JIS 2000 grit and rinsed in EtOH. Galvanic corrosion experiments were done in aqueous NaCl solutions of various concentrations ranging from 5 mM to 500 mM. Galvanic current and corrosion potential of the couple were measured during the immersion in the solutions.

When a galvanic couple was immersed in a NaCl solution, galvanic current decreased gradually with immersion time and reached almost a constant value. On the other hand, corrosion potential for the galvanic couple showed complex behavior with immersion time. Just after immersion, the corrosion potential decreased in the less noble direction, which may be due to the initiation of corrosion of AA5052, and then after reaching the minimum value, the corrosion potential started to increase to a noble potential. Although the corrosion potential and the magnitude of the galvanic current were different depending on the concentration of the NaCl solutions, they did not change in a regular manner as a function of the NaCl concentrations. The changes in the corrosion potential and the galvanic current may be related to the transition of anodic dissolution behavior of AA5052 in the NaCl solutions of different concentrations.
Evaluation of Ant-Nest Corrosion Rate of Copper in Formic Acid Vapor
Authors: Kumakura Sayoko , Hayashi Michitaka , Tada Eiji , Nishikata Atsushi
Published: February 2020

Copper is used for electric wires, pipes, heat exchanger, etc. because of good workability, electrical conductivity, thermal conductivity and corrosion resistance. However, copper suffers from a kind of pitting corrosion, so-called ant-nest corrosion, in the present of organic acids such as formic or acetic. The pit has a characteristic form, that is, there are many branches within the pit like ant-nest. The morphology is very complicated. The growth rate of the pit and the detailed mechanism are not yet clarified. In this study, pure copper foils of different thickness were exposed to formic acid vapor in order to evaluate the rate at which the ant-nest corrosion proceeds.

Pure copper foils (99.96 %) were used as a sample. The thickness was varied from 2 μm to 500 μm. The copper foils were cut into a small piece of 20 mm x 20 mm. The samples were degreased with acetone. Exposure test was done in a transparent capped glass container. The sample was fixed with adhesive agent on the inside wall of the cap of the container. Formic acid solution of 30 mL was set in the bottom of the container. In this way, only one surface (downside) of the copper foil was exposed to formic acid vapor. The concentrations of the formic acid were varied from 500 ppm to 10000 ppm.

In this study, progress rate of ant-nest corrosion was evaluated as follows. The copper foils of different thicknesses were set in the container, as mentioned above, where only one side surface of the sample was exposed to formic acid vapor. The time it took for a pit to first penetrate to the back side of the sample was measured by observing the back side (upside) with a microscope.

Fig.1 shows the result of the exposure test of copper foils to 10000 ppm formic acid vapor at 25 °C. The vertical axis indicates time to pit penetration to the backside t
pit and the horizontal axis shows the thickness of the copper foil. In other words, Fig.1 indicates the relationship between the maximum depth of pitting corrosion (horizontal axis) and the exposure time (vertical axis). It seems that pit growth in depth direction will occur linearly with time at initial stage, although the data over 100 h were scattered. The pit can progress to maximum 500 μm depth at 120 days in 10000 ppm formic acid vapor. Influences of temperature and formic acid concentration on the pit growth will be discussed.

Figure 1
Numerical Models of Cathodic Protection for Buried Steel Pipes Under Insulator Coating Layer
Authors: Odahara Masashi , Tsuchiya Hiroaki , Fujimoto Shinji
Published: February 2020

Buried steel pipes are protected by insulator coatings such as polyethylene and rubber from corrosion under practical use. Furthermore, cathodic protection is often applied to prevent corrosion at locations where the insulator coatings are damaged and removed. However, when the coatings are peeled off, a large crevice is formed above the buried steel surfaces. This leads to the undesirable situation that the locations away from the open mouth of a crevice are not protected by the process as the cathodic current does not reach the locations. In the present work, in order to get insight on reactions and chemistries occurred in the large crevice generated above buried steel pipes with insulator coatings, numerical simulations on the corrosion behavior of buried steel pipes in two different types of crevice in ground water were performed.

Two-dimensional crevices were considered for the simulation; for one model, the open mouth was created on one side of crevice (defined as one open mouth model hereafter) while for the other, the open mouths were created on both sides of crevice (defined as two open mouths model). Boundary conditions for the simulations were provided at the open mouths and chemicals considered in the simulations were H+, OH-, Na+, Cl-, Fe2+ and Fe(OH)2. The simulations were carried out based on Tafel’s equation and Fick’s first law of diffusion assuming iron oxidation, oxygen reduction and hydrogen reduction are occurred at the interface between ground water and steel surface. The effects of the cathodic protection, the crevice thickness and the flow in crevice were evaluated.

In the one open mouth model, as the inflow of oxygen to the crevice is limited and as the result, dissolved oxygen in the crevice was rapidly consumed as cathodic reaction after the simulation commenced, the anodic current attributed to the iron oxidation was relatively small when cathodic protection was not applied. On the other hand, when cathodic protection was applied, the decrease in the anodic current was recognized near the open mouth, but no changes in the anodic current were confirmed at locations relatively away from the open mouth, indicating that cathodic current does not reach the locations. In the two open mouths model where flux of ground water is generated from one end to the other within the crevice, as the supply of oxygen was increased near the entry side by the flux of ground water, the anodic current increased near the entry side. The increase in the crevice width led to the further increase in the anodic current. Therefore, it was revealed that the formation of the crevice where the flux can be generated and/or the crevice with large width should be prevented.
Operando Analyses of Reactions using Synchrotron Radiation and the Design of High Rate Capability Cathode
Authors: Uchimoto Yoshiharu
Published: February 2020

To improve the performance of lithium ion batteries, it is essential to understand reaction hierarchies over wide temporal and spatial ranges. To this end, operando measurement techniques have been developed that enable analysis of the electrode/electrolyte interface of the reaction site, phase transitions of active materials, and macro reactions within real electrodes over various spatial and temporal scales. These analytic techniques pioneer a new way of performing kinetic analysis by introducing axes of space and time into reaction analyses, and are applicable to various types of electrochemical devices.
Electrolytes without Ethylene Carbonate for High Voltage NMC/Graphite Li-Ion Cells
Authors: Dahn Jeff R , Xia Jian , Petibon Remi , Glazier Stephen , Nelson Kathlyne , Abarbanel Dan , Xiong Deijun , Ellis Leah , Louli Alex
Published: February 2020

Ethylene carbonate is used in virtually every lithium-ion cell.  In efforts to produce high voltage NMC/graphite cells, electrolytes without ethylene carbonate are being explored.  The use of electrolytes based on fluoroethylene carbonate (FEC), difluoroethylene carbonate (di-FEC), bis(2,2,2-trifluoroethyl) carbonate (TFEC) and other solvents are explored in this presentation.  Studies using ultra high precision coulometry, impedance spectroscopy, isothermal battery microcalorimetry, in-situ gas evolution, storage testing, XPS and long-term charge-discharge testing show the benefits and drawbacks of such electrolytes.  Although progress is being made, there remains substantial work to do to produce high energy denisty NMC/graphite cells which can operate for years to 4.5 V.   This work was done by Jian Xia, Remi Petibon, Steven Glazier, Kathlyne Nelson, Dan Abarbanel, Deijun Xiong, Leah Ellis and Alex Louli. The authors thank Xiaodong Cao of HSC Corporation for kindly providing many of the solvents used in the work.
Concentrated Liquid Electrolytes
Authors: Yamada Atsuo , Yamada Yuki
Published: February 2020

Ever-increasing demand for better batteries has set extraordinarily high standards for electrolyte materials, which are far beyond the realm of a conventional electrolyte design. Superconcentrated (or highly concentrated) solutions are emerging as a new “realistic” class of electrolytes with various unusual functionalities beneficial for advanced battery applications. In this invited contribution, we will introduce our original technical achievements towards (i) versatile salt/solution combination, (ii) ultra high-rate reaction, (iii) high voltage operation over 5 V, iv) corrosion/dissolution prevention, (v) extreme safety, and (vi) advanced high-voltage aqueous energy storage systems, none of which were realized by the conventional electrolytes. Several unique inherent features, as well as the fundamental physicochemical properties, underneath the surprisingly superior battery performance realized by concentrated liquid electrolytes, will be analyzed from the viewpoint of their peculiar solution structure, providing the firm design considerations toward better batteries.
Developments of Lithium Solid Electrolytes and their Application to All Solid-State Batteries
Authors: Kanno Ryoji
Published: February 2020

Lithium solid electrolytes promise the potential to replace organic liquid electrolytes and thereby improve safety of the next-generation batteries. Among the electrolytes proposed, the sulphide system is a candidate for practical batteries because of their high ionic conductivity; the Li10GeP2S12 (LGPS) phase exhibits high ionic conductivity of over 10-2 S cm-1 at room temperature and is promising for applications requiring batteries with high powers and energy densities. The present study focuses on several topics of the all solid-state system using the inorganic electrolytes. (i) Material varieties of the LGPS system may provide suitable combinations of the electrodes and the electrolyte. To improve the materials variety, the substitution systems with the LGPS type structure were examined, and their phase diagram, structure and ionic conduction were studied. (ii) The combination with high-voltage electrode or high-capacity electrode may provide high capacity systems. The all solid-state batteries using various electrode materials were examined. (iii) The reaction at the electrolyte/electrode interface is the important issue to improve the stability and rate capabilities. High resistance at the interface of the solid-state system might prevent their usage for high current battery systems. Reactions at the interface were also examined. Based on these experimental results, the battery characteristics of the all solid-state system using LGPS electrolytes will be discussed.
Battery Safety Performance and Modeling
Authors: Miller Ted J.
Published: February 2020

Advanced lithium ion batteries are a critical enabler to vehicle electrification.  However, there are technology challenges which must be understood in order to ensure battery safety.  Battery behavior in the event crush due to a crash, and other safety issues such as overcharge, short circuit, and overheating, must be understood and addressed in the vehicle system design.  This talk will focus on the development of a battery safety performance simulation tool which can provide insight into battery safety behavior under a range of mechanical, electrical, and thermal extremes.  When complete, the modeling tool will allow vehicle and battery system designers to simulate a wide spectrum of abuse conditions.  Dedicated work in this important area has been undertaken by the Ford Energy Storage and Materials Research Team for the past several years, including a multi-year contract with the DOT/NHTSA on the Safety Performance of Rechargeable Energy Storage Systems.  Ford’s present effort on the development and validation of a battery safety performance simulation tool is also supported the U.S. Department of Energy.
What is the Best Anode Material to Achieve High Energy Li-ion Batteries in Next 5 Years?
Authors: Cho Jaephil
Published: February 2020

In spite of some technical advances in mitigatingthe volume-change problem toward the practical application of Si anodes, several challenges are still remained and should be resolved. First, the development of noble surface-coating methods and stable electrolytes for reducing the side reactions should be considered to stabilize the SEI of the Si anode. Although reducing methods of the HF derived from fluoroethylene carbonate (FEC), which is widely used in Si anodes to stabilize the SEI layer, is required because substantial capacity fading occurs as the HF attacks both the cathodes and Si. Second, in order to apply the Si anode to commercial LIBs and to achieve a high energy density, the change in the electrode thickness after tens of cycles should be examined in calendared Si anodes having an electrode density greater than 1.6 g   cc-1, as an industrial standard. Based upon these requirements, I presents the best anode material, along with the real full cell test results.
Closing the Battery Loop for Rechargeable Batteries
Authors: Quix Maarten
Published: February 2020

Umicore’s mission is to transform metals into “materials for a better life”. Umicore Rechargeable Battery Materials provides its customers with the best cathode active material, which leads to greater mobility and a reliable source of energy. Umicore Battery Recycling takes this to the next level by also providing a solution for these materials at the end of life. By transforming end-of-life Li-ion and NiMH batteries into metals that can be used again in cathode powders for new rechargeable batteries, the battery loop is closed.
Combined Experimental-Computational Investigation of Electrolytes for Sodium Based Rechargeable Battery Technology
Authors: Kuroda Daniel G , Schneider Gerald J , Kumar Revati , Jorn Ryan
Published: February 2020

A joint experimental-computational approach is being used to investigate the role of ion solvation environment on electrolyte properties, both in the electrolyte as well as the electrolyte-electrode interface for a glyme based electrolyte (sodium triflate in diglyme) relevant to sodium-air as well as sodium ion battery technologies. Despite the recent advances in computational chemistry, ab initio/quantum mechanics of the relevant length and time scales appropriate for realistic simulations of the glyme based electrolytes is intractable from a computational standpoint. However, ab initio MD simulations of the sub-systems of interest are indeed feasible. Classical empirical force-fields have been developed by parameterization to the data from these types of ab initio MD simulations. The solvation structure and dynamics of the sodium ion obtained from these simulations as a function of salt concentration as well as the presence of an electrode interface are being used to interpret the results on the structure from FTIR and neutron scattering experiments, conductivities from dielectric spectroscopy, as well as the dynamics from ultrafast 2DIR spectroscopy. The results of this synergistic investigation as well as the methodology will be presented.
Design and Investigation on Soft-Packed Sodium-Ion Batteries Based on Layered Sodium Transition Metal Oxide Cathodes
Authors: Wang Hong , Liao Xiao-Zhen , He Yu-Shi , Ma Zi-Feng
Published: February 2020

Sodium ion battery (SIB) technology is considered as an attractive alternative to lithium ion batteries for the large scale energy storage systems due to vast availability of sodium resource. Up to now, much research effort has been devoted to the exploration of advanced electrode materials for SIBs. In order to promote the industrialization of sodium ion batteries, we scale up the synthesis of layered oxides NaxMO2 (M: Fe, Mn, Ni, Cu, Ti) using facile hydroxide co-precipitation combined with following calcination method. The obtained cathode materials showed good rate performance and excellent cycling stability even at low temperature. The Nax(Fe0.5Mn0.5)O2 cathode showed excellent reversibility between 2.0 V and 4.0 V with reversible capacity of 100 mAh g-1 (0.1 C). After Ni doping, the Nax(Fe0.5Ni0.3Mn0.2)O2
cathode showed good rate performance and excellent cycling stability with an initial capacity of 130 mAh g-1 at 1C. When hard carbon was used as anode, we designed soft-packed batteries with capacities ranging from 0.5Ah to 5Ah. Electrochemical behaviors of the batteries at different temperatures were studied and thermal stability of these batteries was also evaluated.

     A 0.1KWh sodium ion battery pack was fabricated and evaluated as shown in Fig.1. The sodium ion packs can be assembled and used in portable energy storage device, household electrical energy storage, smart grid and low-speed electric vehicle, etc.

     The authors are grateful for the financial support of this work by the Natural Science Foundation of China (21573147, 21506123, 21336003) and the 973 Program of China (2014CB239700).

Figure 1
Polypyrrole Films Derived from Vapor Phase Polymerization As Free-Standing Anodes for Li-Ion and Na-Ion Batteries
Authors: Yuan Tao , Zheng Shiyou
Published: February 2020

Recently, lightweight, bendable and wearable electronic devices have been prevailing in the markets, there is a strong demand for high performance flexible electrode-active materials without binder and conductive agent that possess a high flexibility and energy capacity [1-3]. Li-ion batteries have received great attention as power sources for portable electronic devices, hybrid electric vehicles and energy storage system. However, considering the limited and uneven distribution of lithium minerals, room temperature Na-ion batteries have received growing attention because of their low cost and abundant supply. Na-ion batteries and Li-ion batteries share the same architecture of battery design. One of the major challenges for Na-ion batteries is to discover suitable electrode materials with high and stable sodium storage capabilities.

We propose here a polypyrrole (PPy) thin film synthesized by an easy, inexpensive and scalable vapor phase polymerization (VPP) technique (Figure 1) [3]. As shown in Figure 1, the obtained PPy film shows smooth surface and continuously cross-linked structure. From the XRD and HR-TEM results (Figure 1), the obtained PPy film possesses well-ordered crystallized structure, which is helpful for Li+ and Na+charges transfer and storage. The as-derived free-standing PPy film anodes exhibit high rate performance and stable cycling life for both Li-ion batteries and Na-ion batteries.

Detailed electrochemical properties and the structural transformation during charge-discharge processes of PPy film as anodes for Li-ion batteries and Na-ion batteries will be presented at the meeting.

Acknowledgements:

The authors gratefully acknowledge the support of the National Science Foundation of China (21403139, 51472161, 51472160), the Shanghai Pujiang Program (No. 14PJ1407100), the Key Program for the Fundamental Research of the Science and Technology Commission of Shanghai Municipality (15JC1490800, 12JC1406900) and the International Cooperation Program of the Science and Technology Commission of Shanghai Municipality (14520721700). We acknowledge the support of the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning (TP2014048) and the Hujiang Foundation of China (B14006).

References:

[1] S. Zheng, Y. Chen, Y. Xu, F. Yi, Y. Zhu, Y. Liu, J. Yang, C. Wang, ACS nano, 10995-11003, 7 (2013).

[2] T. Yuan, B. Zhao, R. Cai, Y. Zhou, Z. Shao, J. Mater. Chem.,
15041-15048, 21 (2011).

[3] T. Yuan, Y-S. He, W. Zhang, Z-F. Ma, Chem. Commun., 112-115, 52 (2016).

Figure 1
Dual-Type Si Nanocrystals Embedded Si/SiOx Nanocomposites Using a Sol-Gel Reaction As High Capacity Lithium Storage Anode Materials
Authors: Park Eunjun , Yoo Hyundong , Kim Dae Sik , Park Min-Sik , Kim Young-Jun , Kim Hansu
Published: February 2020

SiOx-based materials have gained much attention as high capacity materials for lithium-ion battery because of their good cycle performance. However, the commercial use is still limited by their low initial coulombic efficiency as well as complex synthetic method. In this work, we propose a dual-type Si nanocrystal-embedded SiOx nanocomposites using a cost-effective sol-gel reaction of SiOx precursor with commercial crystalline Si particles. This core shell structured high-capacity Li+ storage materials showed a reversible capacity of 1914 mAh g-1 with excellent cycle performance. The SiOx matrix would be helpful in accommodating the volume changes of Si nanoparticles core during cycling. To further improve electrochemical performance, we employed additional carbon coating on the surface of the dual-type silicon nanocrystal-embedded SiOx nanocomposites for sufficient electrical conductivity of active materials. The resulting carbon coated anode materials showed improved cycle performance with capacity retention of 80.3% after 100 cycles. The microstructure and electrochemical properties of the dual-type silicon nanocrystal-embedded SiOx nanocomposites will be discussed in more detail.
Thin Film Cathodes for Lithium and Beyond Lithium-Ion Batteries
Authors: Feng Zhenxing , Burrell Anthony K. , Fenter Paul
Published: February 2020

The development of advanced batteries that have a higher energy density for current lithium-ion and beyond lithium-ion battery relies not only on the identification of new chemistries (e.g., a compatible combination of cathode, anode and non-aqueous electrolyte), but also mechanistic understanding of cathode performance during charge-discharge processes. For these reasons we focus on model thin film systems, which provide controllable geometry, orientation and surface roughness. Using pulsed laser deposition, we have grown lithium-based (e.g., LiMn2O4) and magnesium based (MgMn2O4) oxide thin films. Using these model systems, we have explored the electrochemical performance of these materials as new battery cathodes, as well as the intercalation mechanism of cations, namely Mg2+ and Li+, at the electrode/electrolyte interfaces. For example, the cubic phase of MgMn2O4 (MMOC) can only be found in powder form at high temperature (> 950 °C) or high pressure (> 15.6 GPa), but is stabilized as thin films, which exhibited reversible Mg2+ insertion and extraction in non-aqueous electrolyte such as Mg(TFSI)2 in diglyme with associated changes in bulk film structure and Mn-oxidation states. Using in situ X-ray reflectivity we have observed the film structural changes during charge-discharge processes. Our thin film model system studies provide a platform for material design and mechanistic understanding for lithium and beyond lithium-ion batteries.

This work was supported by the Joint Center for Energy Storage Research (JCESR) through the Office of Basic Energy Sciences (BES), U.S. Department of Energy (DOE).
Advanced Electrolyte for Rechargeable Magnesium Batteries
Authors: Ha Jung-Hoon , Cho Byung-Won , Nazar Linda F , OH SI Hyoung
Published: February 2020

Recently, rechargeable magnesium batteries gains more and more attention as a commercially-viable future energy storage system for mid-/large-scale applications such as ESS and electric vehicles (EV).[1-4] Magnesium is attractive as an anode material, since it is not only naturally abundant, but delivers a high gravimetric and volumetric capacity of 2,205 mAh/g and 3,833 mAh/cm3 at relatively low reduction potential of -2.372 V vs. standard hydrogen electrode. Therefore, batteries based on magnesium metal negative electrode can be potentially manufactured at very low cost and possess a market competitiveness in their energy density. However, the most intriguing problems of these systems are slow development of electrolyte systems having a reversible Mg plating/stripping character on the anode without a dendrite formation and at the same time exhibiting a wide electrochemical window, which would hire a cathode material having a high electrode potential for the high energy density of the system. It is well-known that the conventional Grignard solution (RMgX, R = alkyl or aryl, X = Cl, Br) which has a good reversibility on Mg plating/stripping reaction, functions as strong nucleophile and its anodic stability is poor so that it cannot be applied to common cathode materials. In this work, we will present a new electrolyte system which can be prepared by a simple process and can be directly applied to magnesium electrode with a high coulombic efficiency more than 99.9 % and stability up to 4.0 V vs. magnesium electrode. We will characterize this electrolyte system through many analysis tools including NMR, single-crystal XRD and other spectroscopic methods. We will also show that full cells employing Mo6S8 Chevrel phase cathode and this new electrolyte can be run for hundreds of cycles without a noticeable capacity fading.

References

[1] D. Aurbach et al., Nature, 407(2000) 724

[2] D. Aurbach et al., Energy Environ. Sci., 6 (2013) 2265.

[3] R. Mohtadi et al., Beilstein J. Nanotechnol., 5(2014) 1291.

[4] J. Muldoon et al., Energy Environ. Sci.,
5 (2012) 5941.
To Break or Not to Break: Solution and Surface Mechanisms of DMSO Decomposition in Aprotic Li-O2 Battery Electrolytes
Authors: Scheers Johan , Sodeyama Keitaro , Tateyama Yoshitaka
Published: February 2020

The aprotic Li-O2 battery offers an appealing opportunity to make use of atmospheric oxygen (together with metallic lithium) to achieve batteries with truly remarkable energy densities. However, oxygen is reduced to superoxides and peroxides, which react irreversibly with most materials; non-aqueous electrolytes, binders, and cathodes – hindering stable and rechargeable battery operation. Therefore, preventing parasitic reactions, in particular developing stable electrolytes, is critical for progress.

Dimethyl sulfoxide (DMSO) is a promising solvent for Li-O2 battery electrolytes. It has been scrutinized both experimentally and computationally, but there are conflicting opinions on the stability of DMSO. Experimental work by Kwabi et al. [1] and computational results by Laino et al. [2] suggest that DMSO is readily oxidized to dimethyl sulfone (DMSO2) at Li2O2 surfaces, also forming LiOH. These results have, however, been challenged by Schroeder et al. [3], claiming that DMSO is sufficiently stable in the presence of Li2O2 – as long as there are no other sources of acidic protons present that can initiate decomposition by forming more reactive hydroperoxy species.

More fundamental research on the reaction mechanisms of DMSO with reduced oxygen species is needed to resolve this contradiction. In this work we have used DFT-MD to model DMSO decomposition by LiO2 in solution and by Li2O2 surfaces. We present reaction energies and barriers to reactions for alternative decomposition mechanisms; proton abstraction (DMSO-H), methyl abstraction (DMSO-CH3), and addition reactions (DMSO2) with the aim of better understanding the relative importance of surface and solution reactions, the reacting oxygen species, and the mechanisms of reaction.

References

[1] D.G. Kwabi et al., J. Phys. Chem. Lett.
5 (2014) 2850.

[2] T. Laino et al., New J. Phys. 15 (2013) 095009.

[3] M.A. Schroeder et al., ACS Appl. Mater. Interfaces. 7 (2015) 11402.

Figure
Free energy of methyl abstraction reaction between DMSO and LiO2 in solution phase (left). Highlight of transition state geometry (right). DFT-MD, PBE functional, T=353K.

Figure 1
Vanadium-Based Nanomaterials As Cathodes for Mg-Ion Batteries
Authors: Christensen Christian Kolle , Mathiesen Jette , Ravnsbaek Dorthe Bomholdt
Published: February 2020

Exchanging the active specie, Li+ in Li-ion batteries by multivalent, abundant and cheap cations, such as Mg2+, are projected to boost the energy density and lower the cost per kilo-watt-hour significantly, making the Mg-ion battery technology a promising candidate for one of the battery technologies of the future.1,2

The increase in energy density is i.a. a result of the divalent Mg2+ carrying twice as much charge as the monovalent Li+.1,2 However, the higher charge also poses a problem as it significantly increases the charge density of the ion, which results in stronger interactions with the host lattice of the electrodes and hampers facile ion transport. Therefore, development of novel electrode materials for effective Mg-ion storage is a vital step for the realization of this battery technology.3

In this study, we have synthesized series of vanadium oxides with varying chemical composition and varying nanotopologies, e.g. nanosheets, xerogels and nanotubes. The mechanism for Mg-intercalation and deintercalation is studied by electroanalysis, impedance spectroscopy and through operando synchrotron powder X-ray diffraction measured during battery operation. These results show e.g. that Mg-intercalation in multivalled V7O16-nanotubes occurs within the space between the individual vanadium oxide layers building the walls of the nanotubes while the underlying V7O16 frameworks constructing the walls are affected only to a minor degree by the intercalation. Our investigation provides new insights into the size requirements of the channels/layers in the host frameworks that will allow for efficient Mg-ion storage.

Reference:   

R. van Noorden, Nature 2014, 507, 26

Pellion Technologies, “Moving Beyond Lithium with Low-Cost, High-Energy, Rechargeable Magnesium Batteries”, Pellion White Paper, September 2011

P. Saha, M. K. Datta, O. I. Velikokhatnyi, A. Manivannan, D. Alman, P. N. Kumta, Progress in Materials Science 2014, 66, 1.
Sb-Based Transition Metal Oxohalides As Negative Electrode Materials for Lithium Ion Batteries
Authors: Renman Viktor , Hu Shichao , Zimmermann Iwan , Maibach Julia , Eriksson Rickard , Pay Gómez Cesar , Johnsson Mats , Edström Kristina
Published: February 2020

An electrochemical and structural investigation of two transition metal oxohalides has been undertaken. As negative electrodes for Li-ion batteries, these materials exhibit a combination of both conversion and alloying reactions within the same cell, giving rise to interesting electrochemical performances. Alloying-type reactions, typically involving Si, Sn or - as in this case - Sb, generally occur at low potentials vs. Li+/Li and show relatively good reaction kinetics. The main concern regarding alloying reactions, however, is the expansion/contraction exerted by repeated insertion of Li+, which leads to poor cycleability over time. Storage of Li in the family of conversion materials is based on the conversion of metal oxides into metallic nano-clusters and Li2O.1 This generally occurs at higher potentials and with larger voltage polarization between the charge and discharge processes. Here, these two types of reactions are exemplified using Ni3Sb4O6F6
2 and Mn2Sb3O6Cl3 with the intent of finding a compromise between the alloying and conversion mechanisms. The inclusion of a halide allows for a more careful tuning of the crystal structure. In this respect, the relatively open structures are believed to at least partly affect the insertion of Li, and thereby the efficiency of the conversion process in the early stages of lithiation. The choice of the transition metal (i.e. Mn or Ni) and its specific redox potential vs. Li+/Li effectively determines the order in which the (transition metal oxide-conversion) ↔ (antimony conversion-alloying) reaction sequence occurs, with possibly crucial consequences.

Both compounds are shown to react reversibly with Li, with a good cycleability, in complex systems where multiple reactions occur sequentially and/or simultaneously via the in-situ formation of a nano-composite material. Operando XRD complemented with ex-situ XRD, XANES, TEM and an extensive electrochemical analysis have been used to illuminate the mechanisms involved.

1. Poizot, P.; Laruelle, S.; Grugeon, S.; Dupont, L.; Tarascon, J. M., Nano-sized transition-metal oxides as negative-electrode materials for lithium-ion batteries. Nature
2000,
407, 496-499.

2. Hu, S.; Johnsson, M.; Lemmens, P.; Schmid, D.; Menzel, D.; Tapp, J.; Möller, A., Acentric Pseudo-Kagome Structures: The Solid Solution (Co1–xNix)3Sb4O6F6. Chemistry of Materials
2014,
26 (12), 3631-3636.

3. Zimmermann, I.; Johnsson, M., A Synthetic Route toward Layered Materials: Introducing Stereochemically Active Lone-Pairs into Transition Metal Oxohalides. Crystal Growth & Design
2014,
14 (10), 5252-5259.
Modeling the Positive Electrode Side Reaction for a High Voltage Lithium-Ion Battery
Authors: Vadivel Nicole Raley , Gallagher Kevin G. , Dees Dennis W.
Published: February 2020

Side reactions in battery electrodes lead to a decrease in battery performance and lifespan. In this work, the side reaction in the positive electrode is examined both computationally and experimentally. Computationally, a transport model was created using the finite element method to track the lithium concentration, potential, and current in each part of the battery. The transport model employs concentrated solution theory and Butler-Volmer kinetics. The side reaction was accounted for with an extra current in the positive electrode. Different functions based on physical conditions were fitted to this current and correlated to our experimental results to determine an expression for the side reaction rate.

Experimentally, a lithium-ion half-cell, coin-cell was charged to 4.6 V at 45°C. The coin cell was held at this potential and temperature for 60 hours. The resulting current at this potentiostatic hold correlates to the relaxation of concentration gradients and the side reaction current. Additionally, the concentration of carbon-conductive additive in the positive electrode, the temperature, and the potential were varied to determine how each factor affects the side reaction rate. By performing both a computational and experimental study, we are able to incorporate an expression for the side reaction into our model with physical significance.
Understanding Failure Mechanisms of Solid Electrolyte Interphase on Silicon Anodes: An in-Situ AFM Approach
Authors: Kumar Ravi , Tokranov Anton , Sheldon Brian W. , Huang Zhuangqun , Mueller Thomas , Li Chunzeng , Xiao Xingcheng
Published: February 2020

The formation and evolution of solid electrolyte interphase (SEI) directly governs the lifetime and performance of rechargeable Lithium-ion batteries. There are lots of studies dealing with chemistry of the SEI layer but very little information is available in terms of its mechanical behavior for example fracture behavior, strength etc. To enable utilization of high capacity anode materials such as Silicon which goes through large volume changes (~300%) during cycling, a mechanistic understanding of SEI layer is of critical importance. In this study we have used in-situ atomic force microscopy (AFM) to monitor the formation, evolution and failure of the SEI layer on patterned Si island electrodes. The unique PeakForce tapping mode was used to image the extremely fragile SEI layer, which is very challenging for conventional AFM modes in organic solvent. Our in situ studies show for the first time the in operando cracking of SEI layer and its evolution during cycling. Based on a succession of AFM images showing failure of SEI layer, we were able to calculate the critical strain at which this failure starts. A classical energy release rate approach was used to get a bound of fracture energy values of SEI layer for a range of elastic moduli of SEI layer. This study not only provides an in-depth understanding of failure modes of SEI layer but also offer guidance towards tailoring passivation layers for optimal battery performance.
Surface Functionalization of LiNi1/3Mn1/3Co1/3O2 Cathodes for the Enhancement of Rate Properties and the Electrochemical Stabilization at 4.6V
Authors: Yamada Tetsuya , Uchida Shuhei , Zettsu Nobuyuki , Teshima Katsuya
Published: February 2020

LiNi1/3Co1/3Mn1/3O2 (NCM) and related materials have been focused as alternative cathode materials of Li-ion rechargeable batteries (LIBs) to LiCoO2due to its higher specific capacity and lower Co usage. For the view point of practical use, the increase of working voltage from 3.6 V to 4.6 V will be responsible to further enhancement of the energy density of the LIBs. However, the oxidative reaction at the interface between liquid electrolytes and electrodes at higher voltage of 4.3 V causes drastic capacity fade through the impedance growth and degradation of the NCM electrodes during the charge-discharge operation.

The surface functionalization of cathode with thin oxide layer of electrochemically-inactive materials has been proposed to suppress these unfavorable reactions. Indirect contact between the cathode and electrolytes plays a key role for the electrochemical stabilization, however these oxide layer possibly works as an insulating layer, leading to impedance growth. On the basis of these backgrounds, we propose herein the surface modification of NCM cathode with self-assembled monolayer of NbO
x
nanosheet as well as fluorocarbon-containing organosilane molecule for stabilizing the electrode at high voltage. Through systematic studies, we found the coatings suppress effectively the oxidative decomposition of the electrolyte and disorder in the layered structures on the NCM surface, which result in impedance growth. After 100 cycles at voltage ranges 4.6 V–2.8 V more than 70% of the initial discharge capacity was retained in the coated electrodes. In comparison, the discharge capacity completely faded in the bare NCM cathode. Furthermore, according to Raman spectroscopy, the nanosheets stabilize the delithiated NCM lattice with rock-salt structure and inhibit transformation to the spinel structure.
A Research Tool to Evaluate Safety Response of Lithium Batteries to Internal Short Ciurcuit
Authors: Pesaran Ahmad , Keyser Matthew
Published: February 2020

Safety of Li batteries is a major concern for many applications. One of major safety concerns is thermal runaway due internal short circuits created because of dormant internal defects. New processes, designs, and materials are being investigated to improve safety of batteries, particularly to prevent thermal runaway due to internal short circuits (ISC). The challenge is how to evaluate these improvements as existing methods using external triggers, such as nail or blunt rod penetration, crush, and heating, are widely known to be deficient. 

In response to this challenge, we have developed a very thin and small “thermal switch” to be implanted in a Li-ion cell for triggering ISC on demand to see if the cell goes to thermal runaway. This “thermal switch” or “ISC emulator device” consists of very thin layers of copper, wax, aluminum, and separator that are all compatible with the Li-Ion chemistries. The ISC device is inactive when is placed anywhere in a cell during its fabrication; the cell could be cycles many times without any performance issues.  ISC device is activated by applying heat to raise the temperature of the thermal switch to tunable 45°C-60°C to melt the thin layer of wax and create a current path between positive and negative electrode and or current collectors.  The ISC device can create any of 4 types of internal short circuit: +ve current collector to –ve current collector, anode active to +ve current collector, cathode active to –ve current collector, and anode active to cathode active.  The ISC device can work in any li-ion cell format (cylindrical can and prismatic pouch/can).

With support from DOE’s Vehicle Technologies Office, we have demonstrated that more than ISC devices are triggered in a cell creating ISC. In laboratory testing, the activated device can handle currents in excess of 300 A to simulate hard shorts (< 2 mohms).  Phase change melting has been 100% successful during trigger tests to go from non-conducting to conducting. Experiments have shown that the creating ISC in cells can lead to thermal runaway depending on the type of internal short circuit is created, the safety measures in the cell, and the chemistry.  We have provided more than 300 ISC devices to several cylindrical and pouch cell manufacture to implant them into their cell for evaluation of their safety supplying them to their clients for evaluation.  The ISC device has been able to initiate thermal runaway in portion of the cells tested.  In this paper, we provide details of the ISC device and the results of triggering the device.  We believe that the ISC device a useful research tool for evaluating the safety of lithium ion batteries in response to inherent internal defects.

Figure 1
Phosphoranimine Electrolytes for Alkali-Ion Batteries
Authors: Dufek Eric J. , Klaehn John R. , McNally Joshua S. , Rollins Harry W.
Published: February 2020

Organic carbonates currently compromise the bulk solvent components in electrolytes for Li-ion and Na-ion batteries.  With interest in improving the safety and stability of electrolytes under more aggressive use conditions (i.e. higher temperature, higher voltage etc.) there is the need to investigate alternatives for the traditional carbonate mixtures. One key class of electrolyte compounds which has received significant interest is phosphorus-containing electrolytes. As a class of compounds improvements in both electrolyte stability and safety have been observed. Included in the class of phosphorus-containing compounds are phosphazenes. The presentation will describe early work using a sub-class of phosphazenes, phosphoranimines (PAs), as a partial replacement of carbonates in alkali-ion batteries. 

            Early investigations suggest that the PAs may improve both the stability and safety of alkali-ion batteries due to their wide thermal stability and due to the ability to achieve loading levels which surpass those seen for larger phosphazene compounds. As an example, open-cup flashpoint analysis of high PA content electrolytes shows that the flashpoint can be increased by up to 20˚C and at loading levels of 35% by volume the viscosity of the solution is maintained below 8 cP. As a component in an electrolyte system the use of PAs show the ability to retain capacity on par with traditional carbonate blends. The presentation will discuss cycling performance of a host of electrolyte combinations which contain PAs including the interaction seen with additives such as vinylene carbonate and fluoroethylene carbonate. Also included will be a discussion of synthetic preparation and characterization of this sub-class of phosphazenes.
An Advanced Symmetric Sodium Ion Cell Based on O3-Type NaNi0.33Li0.11Ti0.56O2
Authors: Zhang Shuming , Shang Mengshi , Yang Jianhua , Zhang Na , He Shiyang , Liu Yu
Published: February 2020

P2-type layer Na0.66Ni0.33Ti0.67O2
is a promising active host for symmetric sodium ion cell as both anode and cathode material due to the high-voltage redox couple Ni2+/Ni4+ (about 3.6V) and the low-voltage redox couple Ti4+/Ti3+ (about 0.6V) [1]. In this work, a new compound of O3-type NaNi0.33Li0.11Ti0.56O2
was proposed and synthesized by introducing Li atom into Ti sites in P2-type Na0.66Ni0.33Ti0.67O2. A symmetric sodium-ion cell based on the O3-type NaNi0.33Li0.11Ti0.56O2
was further assembled. The cell exhibits a high voltage of 3.0 V and a reversible charge/discharge capacity of 80 mAh g-1. The electrochemical performance of the as proposed cell is superior to that of the symmetric cell based on P2-type Na0.66Ni0.33Ti0.67O2. As shown in Fig. 1, the crystal structure and phase purity of the compounds are confirmed from powder XRD patterns. The particle size of the NaNi0.33Li0.11Ti0.56O2 material varies in the range from 2 to 5 μm. Fig. 2a shows the schematic of the symmetric sodium-ion cell. Fig. 2b and 2c represent the CV and typical charge-discharge profiles of the NaNi0.33Li0.11Ti0.56O2 material as anode, cathode and full cell, respectively. In contrary to P2-type Na0.66Ni0.33Ti0.67O2, Li-substituted NaNi0.33Li0.11Ti0.56O2 shows an improved cycling stability, especially as cathode (Fig. 3b). It is obvious that the NaNi0.33Li0.11Ti0.56O2-based symmetric full cell has a good cycle life and excellent charge/discharge capacity (Fig. 3c).

[1] R. Shanmugam, W. Lai, ECS Electrochemistry Letters, 3(4), A23-A25 (2014).

Figure 1
Carbon Based Electrodes for Sodium Storage in Quasi-Solid-State System
Authors: Fu Lijun , Wang Faxing , Zhu Yusong , Wu Yuping
Published: February 2020

Rechargeable sodium storage gained increasing research attention because of the abundant reserves and relatively even geological distribution of sodium element [1]. Carbon attract great interest as electrode material due to the existing versatile preparation methods [2]. In this contribution, we present carbon based materials for sodium storage in a quasi-solid-state system.

Nitrogen-doped porous carbon prepared via pyrolysis of polypyrrole and activation with KOH presents excellent rate performance as anode material for Na ion battery [2]. When it combines with macroporous graphene prepared by microwave-assisted electrochemical exfoliation method as positive material, and a gel polymer as electrolyte, a quasi-solid-state sodium storage system can be assembled, it could operate at a cell voltage of 4.2 V with an energy density of 168 Wh/kg, and excellent cycle performance [3].

Acknowledgment:

Financial support from Natural Distinguished Youth Scientists Project of China (No. 51425301), NSFC (No. 51502137) and Basic Research Programs of Science and Technology Commission Foundation of Jiangsu Province (BK20151534) are greatly appreciated.

References:

[1] N. Yabuuchi, K. Kubota, M. Dahbi, S. Komaba, Chem. Rev., 2014, 114: 11636-11682

[2] L. J. Fu, K. Tang, K. Song, Y. Yu, J. Maier et al., Nanoscale, 2014, 6: 1384-1389

[3] F. Wang, X. Wang, L. J. Fu*, Y. P. Wu* et al., Adv. Mater., 2015, 27:6962-6968