bluuebunny/crossref_metadata_2025 huggingface dataset:
Wetting of Nano-Confined Electrodes By Lithium-Ion Battery Electrolytes Using Multiple Beam Interferometry
Authors: Moeremans Boaz , Cheng Hsiu-Wei , Garces Hector , Padture Nitin , Hardy An , Renner Frank Uwe , Valtiner Markus
Published: February 2020

The interface with the electrolyte is a decisive feature in the design of composite battery electrodes, which typically contain active material particles, conductive material, and polymer binder. A detailed understanding of the electrolyte layering and wetting of materials such as graphene, graphites, metals such as aluminum or even gold, silicon, and metal oxides are ultimately important for improving crucial lithium-ion battery mechanisms. In particular the solid electrolyte interphase (SEI) and lithium-ion mobility at electrode interfaces are still not well understood.

Here we use the (Electrochemical) Surface Forces Apparatus (SFA) (1) to address the wetting behavior of nano-scale-confined lithium-ion battery electrodes by battery electrolytes. After its introduction in the 1970s by Israelachvili and Adams (2), the SFA has been used to investigate interfacial phenomena in fields varying from geoscience to microbiology (3). Figure 1 shows a detail of the SFA-setup that was used for the experiments. White light is thereby guided through a flat contact area of two semi-transparent SFA disks, causing interference patterns which are analyzed using a spectrometer. Monitoring the pattern throughout the experiments allows to follow electrolyte wetting behavior in the confined contact area.

Some of the investigated surfaces were mica, gold and graphene. For instance for graphene, a unique combination of rigid and mobile lithium-ion containing electrolyte layers was observed. Figure 2 shows a typical population mapping of a SFA-experiment which focused on the initial wetting behavior of a battery electrolyte (EC/DEC - LiPF6) on dry mica, gold and graphene surfaces. After an initial drop of about 1.8 Å in the inter-mirror distance, which is due to the excretion of a monolayer of adsorbed water from the initially dry interface, the wetting process of the electrolyte was only in the case of graphene able to overcome the contact force.

Similar observations were made when nano-confined gaps were wetted with ionic liquids. Molecular beam interferometry is a versatile and powerful tool for studying such nanoscaled wetting processes using battery electrodes including ionic liquids or organic solvents.

REFERENCES

1. M. Valtiner et al., Langmuir, 28, 13080 (2012)

2. J. N. Israelachvili and G. E. Adams, Nature, 262, 774 (1976)

3. S. Raman, M. Valtiner, et al., Nature Communications, 5, 5539 (2014)

Figure 1
Engineered Ionic Diffusion Layers to Increase Rate Capability of NCA Cathode with Larger Particle Sizes in Lithium-Ion Cells
Authors: Dahlberg Kevin , Mohanty Debasish , Mahajan Vishal , Lee Myongjai , Stevenson Lisa , Stanley Joel , King David M , Wood David L , Albano Fabio
Published: February 2020

Low cost, high energy and long cycle life Lithium-ion batteries are the technology of choice widespread implementation of high-performance electric vehicles (EVs). In spite of the strides technology has made, current high energy density solutions suffer from well understood and catastrophic degradation mechanisms that have prevented the full fruition of NCA cathode materials. There is growing evidence that the cathode surface is the initiation site of all the above mechanisms, motivating the use of larger particle sizes to minimize surface area and mitigate degradation. However, larger particle sizes decrease the overall rate of diffusion of lithium ions, causing a loss of activation of Li-rich phases and an increased loss of capacity at higher rates. Here we show that Al2O3 and TiO2 ALD coatings applied to NCA powder, completely covering active material particle surfaces, create a cathode artificial SEI layer which facilitates an improved Li-ion diffusion pathway, increasing the rate capability of NCA cathodes even with larger particle sizes. Electrochemical analyses showed increased rate capability in 95x64 mm pouch cells (~2.5Ah) with coated NCA compared to uncoated, and XRD and TEM were used to characterize the underlying favorable interactions of coatings with the cathode surface. XALT Energy’s integrated cell design and manufacturing makes 95x64 mm cell performance representative of large format (216x216 mm) production EV cells, demonstrating the validity and scalability of this approach.
High Energy X-Ray Used to Investigate the Synthesis of Full Concentration Gradient Cathode
Authors: Li Yan , Xu Rui , Ren Yang , Lu Jun , Wu Huiming , Wang Lifen , Miller Dean , Sun Yang-Kook , Amine Khalil , Chen Zonghai
Published: February 2020

Nickel-rich lithium transition metal oxides can deliver a high specific capacity during cycling, but there is a concern about the highly reaction between the cathode and the non-aqueous electrolytes. To maintain high specific capacity and improve cycling performance , we have employed solid state reaction to synthesize a full concentration gradient (FCG) cathode, which has a nominal composition of LiNi0.6Mn0.2Co0.2. It is  designed to provide a nickel-rich core to deliver high capacity and a manganese-rich outer layer to provide enhanced stability and cycle life. The solid-state reaction to form a high performance nickel-rich cathode material is a complicated multiple-step reaction.  Therefore, in situ high-energy X-ray diffraction was utilized to study the structural evolution during the solid-state synthesis of FCG cathode. We found that both the pre-heating step and the sintering temperature were critical in controlling phase separation of the transition metal oxides and minimizing the content of Li2CO3 and NiO, both of which deteriorate the electrochemical performance of the final material. The insights revealed in this talk can also be utilized for the design of other nickel-rich high energy-density cathode materials.
Probing Electrochemically-Induced Structural Changes and Defects Affecting Li-Ion Intercalation and De-Intercalation in High Capacity Orthosilicate Cathodes
Authors: Lu Xia , Chiu Hsien-Chieh , Arthur Zachary , Zhou Jigang , Wei Huijing , Chen Ning , Gauvin Raynald , Jiang De-Tong , Zaghib Karim , Demopoulos George P.
Published: February 2020

Li-ion batteries (LIBs) have already made tremendous progress supplying power for multiple devices used in our daily life. Now LIBs are gradually entering the plug-hybrid and fully electric vehicles. Safety and high specific capacity enabling long range driving between charges are among industry’s priorities in this domain. One cathode material group that potentially can provide solutions to these priorities is lithium metal silicates. Orthosilicates, Li2

M
SiO4, where
M

= Fe, Mn, Co, Ni, are characterized by a theoretical specific capacity that is twice that of LiFePO4, namely 340 vs. 170 mAh/g1
,2. In this presentation, we report on the synthesis and electrochemical/structural evaluation of different phase (monoclinic and orthorhombic) Li2(Fe,Mn)SiO4 materials using a combination of organic-assisted hydrothermal and reducing annealing treatment steps. During the electrochemical process, we find that the Li2FeSiO4 cathode demonstrates rate- and phase- dependent capacity changes upon lithiation/delithiation3. We have probed these changes by conducting both in-situ/postmortem synchrotron XRD/XANES and first-principle calculations of the structure/phase stabilities and Li ion diffusion properties of monoclinic Li2FeSiO4 orthosilicate. It is revealed that formation of Li-Fe antisite defects play a key role in destabilizing the orthosilicate structure and “catalyzing” the monoclinic-to-orthorhombic transition. Furthermore the charge compensation mechanism that is essential in achieving more than one Li extraction is discussed accordingly as well as the Li-ion diffusion properties are analyzed. The rich insight obtained from these Li2FeSiO4 studies is invaluable as we move towards the design and testing of stable orthosilicate structures with fully reversible 2-Li intercalation capacity for high-energy next generation LIB cathodes.

References

1. A., Nyten; A., Abouimrane; M., Armand; T., Gustafsson & J. O., Thomas, Electrochemical performance of Li2FeSiO4 as a new Li-battery cathode material. Electrochem. Commun.
7, 156-160, (2005).

2. M. Saiful Islam et al., Silicate cathodes for lithium batteries: alternatives to phosphates?  J. Mater. Chem., 2011, 21, 9811.

3. Xia Lu; Huijing Wei; Hsien-Chieh Chiu; Raynald Gauvin; Pierre Hovington; Abdelbast Guerfi; Karim Zaghib and George P. Demopoulos, Rate-dependent phase transitions in Li2FeSiO4 cathode nanocrystals, Sci. Rep. 5 (2015) 8599.
Flexible, Foldable and Multi-Functional Paper-Based Electronics
Authors: He Jr-Hau , Yang Po-Kang , Lien Der-Hsien , Lin Chun-Ho
Published: February 2020

Great advances have been made in developing cheap, simple, multi-functional and energy-saving fabrication processes for flexible electronics.1 Paper, as a flexible, foldable, cost-efficient and mass productive substrate, has shown diverse applications for flexible electronics to meet such demand. Recently, we have successfully demonstrated the first nonvolatile resistive memory using paper as substrates by means of all-printing techniques.2 Moreover, we also implemented the algorithm of Origami art into the device design for the flexible optoelectronics, such as photodetector and nanogenerator, taking advantage of the foldability and adaptability of paper substrate. In particular, paper origami triboelectric nanogenerators (TENGs) using paper as the starting material, with high degree of ﬂexibility, light weight, low cost, and recyclability is presented.3 We believe that these findings will pave a way for future energy harvesting and sensor design, especially for the development of green flexible electronics.

Figure 1
Pyro Synthesis of Functional Nanocrystals for Energy Storage Devices
Authors: Gim Jihyeon , Song Jinju , Kim Sungjin , Mathew Vinod , Kim Seokhun , Oh Younpyo , Alfaruqi Muhammad Hilmy , Kim Jaekook
Published: February 2020

Despite nanomaterials with unique properties playing a vital role in scientific and technological advancements of various fields including chemical and electrochemical applications, the scope for exploration of nano-scale applications is still wide open. The intimate correlation between material properties and synthesis in combination with the urgency to enhance the empirical understanding of nanomaterials demand the evolution of new strategies to promising materials. Herein we introduce a rapid pyro-synthesis (Fig.1.) that produces highly crystalline functional nanomaterials under reaction times of a few seconds in open-air conditions. The versatile technique may facilitate the development of a variety of nanomaterials and, in particular, carbon-coated metal phosphates with appreciable physico-chemical properties benefiting energy storage applications. The present strategy may present opportunities to develop ‘‘design rules’’ not only to produce nanomaterials for various applications but also to realize cost-effective and simple nanomaterial production beyond lab-scale limitations.

Figure 1
Elastoplastic Properties of (Pr, Ce)O2-δ
Thin Films
Authors: Swallow Jessica G. , Kim Jae Jin , Bishop Sean R. , Smith James F. , Tuller Harry L. , Van Vliet Krystyn J.
Published: February 2020

Solid oxide fuel cells (SOFCs) rely on long term, consistent operation of non-stoichiometric oxide components under elevated temperatures and oxygen partial pressure gradients.  Materials that exhibit the desired ion transport and reactivity properties generally also exhibit electro-chemo-mechanical coupling that can affect mechanical stability in operando.  The importance of chemomechanical coupling such as chemical expansion of SOFC electrodes is increasingly relevant to the goal of reduced operating temperatures enabled by thin film electrodes. Here, we explore this coupling experimentally and computationally, for the model SOFC cathode material, (Pr, Ce)O2-δ. We quantified the Young’s elastic modulus E of (Pr, Ce)O2-δ thin films at temperatures up to 600ºC and oxygen partial pressures pO2 below 10-3 atm via environmentally controlled nanoindentation. The observed decrease in E with increased temperature or decreased pO2 correlated with the changes in oxygen vacancy concentration and lattice parameter expected due to chemical expansion. We compared these results with those we calculated for several compositions of bulk (Pr, Ce)O2-δ via density functional theory, and found that the experimentally observed reduction in mechanical stiffness of reduced (Pr, Ce)O2-δ thin films exceeded that predicted computationally for bulk counterparts. These results demonstrate that the in operando mechanical properties of non-stoichiometric oxides used in thin film SOFCs can differ significantly from those expected from characterization of bulk forms or at standard temperature and pressure. Thus, this chemomechanical coupling must be considered when designing mechanically robust SOFCs with thin film electrode components.
Performance and Degradation of Solid Oxide Electrolysis Cells in Stack
Authors: Fang Qingping , Blum Ludger , Menzler Norbert H.
Published: February 2020

A Solid Oxide Electrolyser (SOE) short stack consisting of two anode-supported cells (ASCs) was assembled in Jülich’s F10-Design. The ASCs are based on Ni/8YSZ (8 mol% yttria-stabilized zirconia) with an LSCF positive electrode (La0.58Sr0.4Co0.2Fe0.8O3-δ) and 8YSZ electrolyte. A CGO (Ce0.8Gd0.2O1.9) barrier layer was deposited between 8YSZ and LSCF by physical vapour deposition (PVD).

The stack was characterized in furnace environment in both fuel cell and electrolyser mode with 50% humidified H2 from 700 °C to 800 °C. At 800 °C, the area specific resistances (ASRs) were calculated to be 130 mΩcm² and 150 mΩcm² under fuel cell and electrolyser mode, respectively. Long-term electrolysis operation (endothermically) at 800 °C under constant current mode is being carried out with a current density of 0.5 Acm-2 and a steam conversion rate of 50% with 50% humidified H2. After 1500 h operation (status 09.12.2014), the stack showed an average voltage degradation rate of 0.7%/1000h. Electrical impedance spectroscopy (EIS) and analysis of distribution of relaxation time (DRT) showed that the degradation was mainly due to the increase of Ohmic resistance, and the electrode polarizations did not change with the chosen testing conditions. The stack is planned to be further operated at 700 °C after a 2000 h electrolysis period at 800 °C. The performance and degradation behavior of the stack at 700 °C and 800 °C will be analysed with the support of EIS and DRT.
Electrochemical MEA Characterization: Area Specific Resistance Corrected to Fuel Utilization as Universal Characteristic for Cell Performance
Authors: Kusnezoff Mihails , Beckert Wieland , Trofimenko Nikolai , Jacobs B , Dosch C , Megel Stefan , Rachau Mathias , Wieprecht Christian , Gipp Daniel
Published: February 2020

Membrane-electrode-assembly (MEA) is a heart component of SOFC and defines the limits for power density, efficiency and durability available for exploitation in stacks and systems. MEA performance is often given as measure for possibilities of fuel cell technology. Most widespread way to communicate the MEA performance is to present the I-U-characteristic at a constant temperature and to estimate the area specific resistance from the slope of this curve. Other methods for characterization of performance like current density, impedance and local resistance measurement under defined operating conditions also have been used for this purpose. The fuel composition worldwide used for MEA tests (from dry hydrogen to H2:H2O=50:50) is connected with open circuit voltage which has great impact on measured performance. Moreover the realized fuel utilization strongly depends on operating conditions and varies in broad range. For these reasons it is difficult to compare results achieved by different researchers. It is beneficial to define unified value which would characterise electrochemical MEA performance. To resolve this challenge the voltage drop during the cell performance have been mathematically separated in two parts: (i) voltage drop due to change of Nernst voltage as a result of fuel utilization (and humidification) by current flow and (ii) voltage drop due to ohmic and polarization losses in the cell. This approach allows to separate the influence of non-linearity of Nernst voltage dependence from current on estimated cell resistance. It was found that at temperatures above 750°C the area specific resistance of the cell corrected to the Nernst voltage drop (fuel utilization) is a constant value, which only weakly depend on fuel composition. Favourable operating conditions as well as influence of operating conditions for estimation of cell resistance will be presented.
A Packaged and Efficient SOEC System Demonstrator
Authors: Chatroux André , Reytier Magali , Di Iorio Stéphane , Bernard Charlotte , Roux Guilhem , Petitjean Marie , Mougin Julie
Published: February 2020

High Temperature Steam Electrolysis, based on solid oxide electrolysis cells (SOEC) is a promising way to produce hydrogen with high efficiencies. The use of steam instead of liquid water requires less energy for the water molecule splitting, and the high temperature operation (between 700 and 900°C) allows the replacement of a part of the electrical energy by heat, which allows in theory a significant increase of the electrical efficiency compared to alkaline and PEM water electrolysis. Most of works in the field of SOEC around the world are carried out at the cell or stack level. Only few results at the system level, that is to say including the stack and all BoP (balance of plant) components, are reported in literature, although it is a key point because the heat management of the system has to be optimized to effectively reach the high electrical efficiency expected.

For that purpose, the CEA-LITEN has designed and tested a packaged SOEC system demonstrator. It allows producing between 1 and 2.5 Nm3/h of H2 depending on the selected operating point, based on a single stack and the required auxiliaries, including a steam generator at 150°C and high temperature exchangers to preheat the inlet flows from heat recovered in the exhaust gases. A 25-cell-stack already validated in terms of performance [1] is the "heart" of the system. The stack as well as the other components of the system will be described in details, as well as the test results. The first test is presented in Figure 2. At 700°C, the system produces 1.2 Nm3/h of H2 with a total electrical consumption of 3.9 kWh/Nm3, achieving 92% of efficiency, this efficiency corresponding to the higher heating value (HHV) of the produced hydrogen vs the electrical consumption of the system.

Indeed, Fig. 2 shows that during the first 3 hours of operation corresponding to the standby mode and endothermic operation, an external heating (through furnace resistances) is required. But after 3 hours, the operation mode switches from endothermic to slightly exothermic mode, leading to an increase of the hydrogen production up to the targeted flow rate of 1.2 Nm3/h after 5 hours, which is associated to a decrease of the furnace power and an increase of the efficiency. It can be seen that after 5 hours, the furnace power is decreased to zero, without any decrease of the stack temperature. It demonstrates that a 150°C heat source temperature is sufficient for the steam generation, and that a slightly exothermic operating mode of the stack is sufficient to preheat the inlet gas up to 700°C and compensate the heat losses of the system.

[1]     M. Reytier et al, 20th World Hydrogen Energy Conference, 15-20th June 2014, Gwangiu, Korea; submitted to International Journal of Hydrogen Energy.

Figure 1
Metallic/Ceramic (Fe-22Cr mesh/ LaNi0.6Fe0.4O3-δ) Composite as Contact Material for SOFCs
Authors: Morán-Ruiz Aroa , Vidal Karmele , Larrañaga Aitor , Slater Peter Raymond , Arriortua María Isabel
Published: February 2020

Abstract

A Fe-22Cr mesh/LaNi0.6Fe0.4O3-δ composite, obtained via dip coating technique, was machined using a femtosecond laser as a possible gas permeable contact layer for solid oxide fuel cells (SOFCs). Both electrical performance and processing reproducibility of {Crofer22APU channelled interconnect/contact layer/La0.6Sr0.4FeO3 cathode} structure were studied through ASR testing on four replicas. In addition, the long-term behaviour of this system at 800 ºC was determined using energy dispersive X-ray spectroscopy (EDX). The metallic and ceramic parts were quantitatively analysed using EDX, focusing on different positions of the sample. A chromium content reduction in both the interconnect and mesh was observed, accompanied by a Cr enrichment in LaNi0.6Fe0.4O3-
d (LNF). Considering the obtained results, the developed setup showed an adequate reproducibility and only a short-range damage caused by the laser irradiation.

Keywords: SOFC; contact layer, metallic interconnect, contact resistance; chromium poisoning; femtosecond laser.

Acknowledgements

This research has been funded by Ministerio de Economía y Competitividad (MAT2013-42092-R) and the Dpto. Educación, Política Lingüística y Cultura of the Basque Goverment (Research Group of the Basque University System IT-630-13). The authors wish to thank SGIker-UPV/EHU technical and human support. Dr. Sergio Fernandez Armas is acknowledged for useful scientific help in discussion of EDX measurements. The authors would also like to express their gratitude to Dr. Raúl Montero Santos for helping with femtosecond laser measurements. A. Morán-Ruiz thanks UPV/EHU for funding her PhD work.
Aluminum Activation in Ionic Liquids
Authors: Shvartsev Boris , Gelman Danny , Lasman Itay , Krossing Ingo , Scholz Franziska , Ein-Eli Yair
Published: February 2020

Aluminum (Al) is the third most abundant element (after oxygen and silicon) and the most abundant metal in Earth's crust. Al is quite remarkable as it holds a low density and it has the ability to resist corrosion due to surface passivation. This passivation layer protects Al from corrosion in a relatively wide range of pH and potentials. Nevertheless, in aqueous media, the layer is vulnerable in both highly acidic and basic environments, leading to rapid corrosion reactions. As an anodic material, Al has a theoretical gravimetric capacity of 2.98 Ah/gr and its volumetric capacity is as high as 8.1 Ah/cm3. For the sake of comparison, Li metal holds capacities of 3.86 Ah/g and 2.06 Ah/cm3, respectively. 

In non-aqueous media electrochemical dissolution of Al is partly hampered due to inefficient and thus insufficient passivation layer removal prior to any current application. Similar issues pertain when the non- aqueous solutions employed are Room Temperature Ionic Liquids (RTIL).  In the present work an activation of Al was studied in EMIm(HF)2.3F RTIL. For this specific electrolyte it was already established that electrochemical dissolution of Al occurs, in considerable rates, sufficient for application in Al-Air batteries [1]. The alteration of the surface, as detected by FTIR, XPS and STEM, suggests on the formation of passivating Al-O-F compounds on the surface, instead of native oxide passivation. The source of this specific activation is established in this work, and the surface of Al prior to and following activation was identified. The applied methodology was also used for identification and study of Al activation in other family of RTILs. The preliminary results of this specific electrochemical system will be also presented.

[1] D. Gelman, B. Shvartsev, Y. Ein-Eli, J. Mater. Chem. A. 2.47 (2014) 20237-20242.
The Development of Organic Ionic Plastic Crystals As Solid State Electrolytes for Energy Storage
Authors: Pringle Jennifer M , Howlett Patrick C , Jin Liyu , Chen Fangfang , MacFarlane Douglas R , Forsyth Maria
Published: February 2020

Organic ionic plastic crystals (OIPCs) are a class of solid-state electrolyte material quite unique in their mechanical and transport properties; they combine the advantages of fast ion conduction with good stability and non-volatility even above their melting point. Significant progress has been made recently in the development of OIPCs for electrochemical devices such as lithium batteries and dye-sensitised solar cells.[1] The negligible volatility of OIPCs renders them more suitable than molecular plastic crystals for long-term device use, while the high thermal and electrochemical stability of many OIPCs fulfils an essential requirement for solid state electrolytes for many device applications.

Understanding the ion transport behaviour of OIPCs, both in their pure and doped state (i.e. in the presence of a small amount of a lithium salt, to enable their use in lithium batteries), is crucial for their development as solid electrolytes.

Here we present our investigations into the ion transport mechanism in these materials using both experimental data (single crystal XRD, multinuclear solid-state NMR, DSC, ionic conductivity and SEM) and theoretical techniques (molecular dynamics and second moment-based solid static NMR line width simulations).[2][3]

We also discuss the physical properties and application of the OIPC triisobutyl(methyl)phosphonium bis(fluorosulfonyl)imide (P1444FSI) doped with 4 mol% LiFSI. The good conductivity of this material (0.26 mS cm-1 at 22 °C) enables cycling of lithium cells (Li|LiFePO4) at room temperature, achieving about 160 mA h g-1 discharge capacity at 20 oC, which is the highest for OIPC based cells to date.[4]

References

[1] J. M. Pringle, Phys. Chem. Chem. Phys., 2013, 15, 1339

[2] L. Jin, K. M. Nairn, C. M. Forsyth, A. J. Seeber, D. R. MacFarlane, P. C. Howlett, M. Forsyth and J. M. Pringle, J. Am. Chem. Soc., 2012, 134, 9688-9697.

[3] L. Jin, S. de Leeuw, M. V. Koudriachova, J. M. Pringle, P. C. Howlett, F. Chen, M. Forsyth, Phys. Chem. Chem. Phys., 2013, 15, 19570-19574.

[4] L. Jin, P. C. Howlett, J. M. Pringle, J. Janikowski, M. Armand, D. R. MacFarlane and M. Forsyth, Energy and Environ. Sci., 2014, 7, 3352-3361.
Montmorillonite Composite Polymer Electrolytes Displayed Exceedingly High Ion Conductivity Oriented By Electric Field
Authors: Wang Robin Chih-Hsing , Chu Peter Po-jen
Published: February 2020

Solid polymer electrolytes are nonvolatile with strong film forming strength.  It is considered as critical components for next generation lithium battery to meet the many demnds of growing mobile electronic power industry.  Improving ionic conductivity of polymer electrolyte suitable for LIB, is the most urgent technical challenge.  We report in this study a novel polymer electrolyte system by incorporating surface functionalized clay into the PVDF-HFP/Ionic liquid/Li salt system under applied an electric field.  Mineral clays bear large surface areas, high aspect ratio, numerous  dissociable cations in the interlayer and low-dimensional nano structure. The application of electric field has effectively oriented clay layers uniformly and dispersed it homogeneously to form an ordered and alignment nanostructure which is confirmed by SEM. This super ionic feature is extremely favorable for delivering high ion conductivity in the solvent free electrolytes where the long range ordered inorganic moiety served to corporate rapid ion transport. X-ray diffraction and DSC measurements indicated that the α-phase PVDF crystalline form was  decreased by the electric field. The variety of crystalline degree of the polymer matrix was determined. The ionic conductivity of the composite electrolyte were measured to over 10-3 S cm-1. AC impedance spectroscopy revealed that the ionic conductivity of the electrolyte membrane containing 3 wt% MMT attains an order of 10−3 S cm−1 at room temperature. Coin cells assembled with the LFP cathode reversible discharge capacities of 140 mAh g−1 at 0.1C, accompanied with  high coulombic efficiency over 40 cycles.

Figure 1
Design of Solid Electrolytes for High Temperature Batteries
Authors: Cho Jang Hyeon , Im Chae Nam , Park Byeong June , Kang Seung Ho , Cheong Hae Won
Published: February 2020

Thermal batteries have been used for many military applications such as missiles and ordnance devices. As the thermal battery is composed of anode, cathode, MgO based-molten salt electrolyte and additional heat source, its specific energy density is lower than those of commercial batteries.

   By means of substituting MgO based-electrolyte to increase energy density of thermal batteries, we have indentified various ionic solid electrolytes such as LLT(La0.5Li0.5TiO3), LSTZ(Li3/8Sr7/16Ta3/4Zr1/4O3) and LLZ(Li7La3Zr2O12). 

   As a ruslt, we found out that the LLZ with additivies, Ca and Nb, presents not only excellent ionic conductivity but also stable discharge characteristics at high temperature(≈ 300oC). Additionally, we have verified that the LLZ solid electrolyte is suitable for the full scale of thermal batteries with high energy density.
α-MnO2 Nanoparticles with High Surface Area for Electrochemical Supercapacitor Application
Authors: Muhammed Shafi P , Chandra Bose A
Published: February 2020

The large scale energy production and developments in renewable energy sources requires efficient energy storage systems. The physical and chemical charge storage techniques along with high power and energy density brought electrochemical supercapacitors (ECs) as a versatile power source. The high rates of charging and discharging with long cycle life as well as the economical and eco-friendly nature support ECs to various energy applications.  Since the last couple of decades, Supercapacitors with various metal oxides as electrode materials got a great interest among researchers. Here we synthesised α-MnO2 nanoparticles by simple chemical precipitation method and are subjected to heat treatment at 300 ˚C, 500 ˚C and 700 ˚C. The structural formation of as- prepared and annealed MnO2 are confirmed by XRD analysis. The functional group and optical absorption studies are done by Fourier transform infrared spectroscopy (FTIR) and UV visible spectroscopy. The surface area of the samples is measured using Brunauer-Emmett-Teller (BET) method. Finally electrochemical properties are evaluated using cyclic voltammetry (CV) and galvanostatic charge-discharge techniques. The cyclic voltammogram and charge-discharge curve recorded indicates MnO2 nanoparticles annealed at 300 ˚C for 5 h shows better electrochemical behaviour.
The Effect of Membrane Fixed Charge on Ion Transport in All-Vanadium Redox Flow Batteries
Authors: Lei Yuan , Zhang Baowen , Bai Bofeng , Zhao Tianshou
Published: February 2020

In a typical all-vanadium redox flow battery (VRFB), species crossover through membranes not only deteriorates cell performance, but also reduces battery’s lifetime. To address this issue of species crossover, a better understanding of the ion transport behaviors through an ion exchange membrane is essential. The fixed charge, a very important and typical membrane property, has a deep correlation with ion transport behaviors: Firstly, the fixed charge affects ion distributions in the membrane as a result of the membrane selective adsorption. Hence, the ion transport rate is affected by all the three of transport modes including diffusion, migration and convection. Moreover, the ion selective adsorption is crucial to obtain the accurate ion diffusivity. Secondly, counter ions in the membrane may also transport via the swing of the charged functional groups. The characteristic of ion transport behavior in this way depends on the relative amount of the fixed charges and movable ions, and reflects in the ion diffusivity. However, both numerical and experimental investigations rarely concern about the intrinsic influence of the fixed charge on ion transport as the membrane parameters cannot be precisely controlled separately and an integrated impact of membrane is reflected in measured ion diffusivity. Therefore, it is urgent to explore how the fixed charge affects the ion transport behaviors.

In this work, we conceive, design and fabricate an experimental setup to study the characteristics of ion selective adsorption and ion diffusivities in an ion exchange membrane for VRFBs. As these two properties related to the relative amount of the fixed charges and movable ions, we take the amount of movable ions to be variables while the fixed charges constant to avoid the difficulty of precise production of membrane. We first perform an adsorption equilibrium test to explore the interactions between the fixed charge and movable ions. Two groups of vanadyl sulfate solution are prepared with a large difference in H+ concentration so that the amounts of total movable ions differ greatly. Each group contains three cases of vanadyl sulfate solution with the concentrations of the vanadium ion different. We then study the permeability to explore the transport mechanism. The membrane is placed between vanadyl sulfate solution and a blank one. The diffusivity can be acquired after a simple derivation. With an analysis of the same cases in the first step, the mechanism of the fixed charge affecting the ion diffusivity comes out.
All-Solid State Lithium-Sulfur Batteries
Authors: Cassel Alice , Viallet Virginie , Morcrette Mathieu
Published: February 2020

Currently, lithium-ion batteries incorporated in electric vehicles do not allow to store enough energy to ensure sufficient autonomy. Therefore, it’s necessary to develop new generations of batteries with higher energy density. Among battery technologies, the lithium-sulfur system (Li-S) is considered to be one of the most promising solutions due to a theoretical energy density of 2500 Wh/kg. However, its lifetime remains limited due to the polysulfide shuttle effect, induced by the use of liquid electrolyte. Indeed, many polysulfides (noted Li2Sx 1 ≤ x ≤ 8), formed during the sulfur reduction to Li2S, dissolve in liquid electrolyte and diffuse between both electrodes, leading to a rapid decrease of electrochemical performances. All-solid-state Li-S batteries were studied in order to bypass the limitations of liquid electrolyte. The electrode is a composite material with sulfur (S8) as active material, argyrodite (Li6PS5Cl) as solid electrolyte for ionic conduction and Ketjen Black (KB) as additive conductor for electronic percolation. The liquid electrolyte between both electrodes is replaced by the solid electrolyte used in the composite electrode and metallic lithium is used as negative electrode. /sub>Sx 1 ≤ x ≤ 8), formed during the sulfur reduction to Li2S, dissolve in liquid electrolyte and diffuse between both electrodes, leading to a rapid decrease of electrochemical performances. The positive electrode was prepared by mixing and ball-milling at 370 rpm for 5h using a high-energy planetary ball mill, S8, Li6PS5Cl and KB with a weight ratio of 25:50:25. The battery displays a reversible capacity of 1565 mAh/g after 10 cycles at a current density of 134 µA/cm² (corresponding to a rate of C/10) with an initial discharge capacity of 1230 mAh/g and an extra capacity of around 335 mAh/g, observed for the first time and currently under studies. 8), formed during the sulfur reduction to Li2S, dissolve in liquid electrolyte and diffuse between both electrodes, leading to a rapid decrease of electrochemical performances. At high current density, with lithium negative electrode, we observed strange potential decreases that can be related to short circuit phenomena. One explanation for short circuit phenomena can be the formation of lithium dendrites, although they are not supposed to grow in solid electrolyte. The presence of dendrites will be evidenced by solid state NMR. Using alternative Li-In electrode, this phenomenon was totally suppressed.  In this presentation, we will then show our best optimized solid state batteries using a Li-Indium electrode with a good capacity (1660 mAh/g after 10 cycles at C/10), a good coulombic efficiency and a reasonable polarization for a solid-state battery and at room temperature. Perspectives in term of energy density and industrialization (upscale of the lithium ion conductors) will be presented.
(Invited) Synthesis and Structures of Free-Base [14]Tribenzotriphyrin(2.1.1) and Their Metal Complexes
Authors: Xue Zhaoli , Wang Yemei , Ou Zhongping
Published: February 2020

Subporphyrins are analogues of porphyrinoids that contain only three pyrrole or isoindole rings linked by meso-sp2 carbon atoms. The first synthesis of tribenzosubporphyrins was reported by Osuka’s group in 2006 with very harsh conditions. From then on, lots of subporphyrin analogues have been reported. However, almost all of these reported subporphyrins existed only as bowl-shaped boron complexes and the yields are typically very low. In 2008, we reported a facile synthesis of meso-aryl-substituted [14]benzotriphyrin(2.1.1) compounds based on a modified Lindsey condensation method in moderate yields up to 35%. These compounds represent the first example of near planar core-free contracted porphyrinoids with 14-π-electron aromatic systems containing only the standard pyrrole and isoindoline moieties. X-ray diffraction analysis revealed that the triphyrin core is near planar. Till now, different kinds of [14]Tribenzoriphyrin(2.1.1)-metal complexes have been synthesized and characterized including Ag(I), Mn(I), Fe(II), Re(I), Ru(II), Pd(II), Rh(III), Pt(II) and Pt(IV).
(Invited) Oxidation Chemistry of Manganese Porphyrins in Interaction with DNA
Authors: Pratviel Genevieve
Published: February 2020

Metalloporphyrins associated with oxygen atom donors are biomimetic models of heme, enzymes such as cytochrome P450 and peroxidases. Some cationic porphyrins recognize DNA (double-stranded DNA and G-quadruplex DNA) with high specificity and selectivity. In aqueous buffer manganese porphyrins are activated by oxone. Two examples of oxidation reactions mediated by cationic manganese porphyrins in complex with DNA will be presented. Oxidation can be directed toward DNA and results in highly selective DNA damage (i) or may be directed toward oxidation of small molecules in a heme DNAzyme context (ii). DNA damage mediated by manganese porphyrins allowed a better understanding of the reactivity of high-valent metal-oxo species. The reaction pathway (electron abstraction versus oxygen atom transfer) depends on the protonation state of the water molecule present as axial ligand trans to the metal-oxo. The analysis of the reaction products of a manganese porphyrin in complex with G-quadruplex DNA gives insights on the mode of interaction of the porphyrin with DNA.  

- Interaction of cationic manganese porphyrin with G-quadruplex nucleic acids probed by differential labeling of the two faces of the porphyrin V. Pradines, G. Pratviel Angew. Chem. Int. Ed. 52, 2185-2188 (2013)

- Protonation state of trans axial water molecule switches the reactivity of high-valent manganese-oxo porphyrin J. Trzcionka, J. Irvoas, G. Pratviel New J. Chem. 37, 3581-3590 (2013)

- Porphyrins in complex with DNA: modes of interaction and oxidation reactions G. Pratviel Coord. Chem. Rev. http://dx.doi.org/10.1016/j.ccr.2015.07.003
Investigation of Galvanic Corrosion Behavior of Dual Phase Steel
Authors: Si Yongchao
Published: February 2020

Dual phase steel has been widely used in the automotive industry to produce lighter weight vehicles to meet stringent safety and fuel economy regulations. One potential concern with dual phase steel is galvanic corrosion when it is exposed to a corrosive environment. In dual phase steel, the dissimilarity in chemical composition and lattice structure could induce different corrosion potentials between the ferrite and martensite phases. As a result, microscopic galvanic couplings could be formed between ferrite grains and their neighboring martensite grains. In this study, the corrosion behaviors of three commercial steel grades: carbon steel, martensitic steel and dual phase steel, are investigated with a variety of electrochemical and surface analytical techniques to understand the mechanism of galvanic corrosion of dual phase steel. The corrosion potential of each steel grade is determined with potentiodynamic technique when the steel is exposed to sodium chloride (NaCl) solution. The study shows that the corrosion potential of dual phase steel is an intermediate between martensitic and carbon steels. In a galvanic coupling of carbon steel/ martensitic steel, carbon steel is found to corrode to protect martensitic steel when exposed to NaCl solution. Examination of dual phase steel after immersion in NaCL solution for an extended period of time indicates the occurrence of galvanic corrosion in the dual phase steel. The corrosion is found to occur primarily in the ferrite phase of dual phase steel.
Environmental Aspects of Using Metallic Organic Frameworks As Adsorbents in Natural Gas Storage Systems
Authors: Abd Elhamid Mahmoud Hassan , Dailly Anne , Cai Mei
Published: February 2020

The use of natural gas (NG) for automotive industry has gained renewed interest due to its growing supplies in the United States, relatively low cost compared to gasoline and diesel fuels and reduced emissions of carbon and particulate per equivalent. Because of its relatively low energy density NG must be stored at high pressure, 3,600 psi service pressure in the United States, in order to achieve an energy density suitable for vehicular use. Compressed NG cylinders are available in four types. Type 1, all metal (steel or aluminum) are the most widely used CNG cylinders in the world. Type 2 cylinders are metal liner reinforced by composite wrap (glass or carbon fiber) around the middle. Metal liner reinforced by composite wrap around the entire tank constitutes Type 3.  While Type 4 cylinders are made of plastic gas-tight liner reinforced by composite wrap around the entire tank. Utilization of CNG storage systems in light duty vehicles has limited market penetration because of the cost of the pressure vessel and its occupancy of cargo space.

Adsorbents materials are becoming an attractive option to develop low pressure and conformable NG storage system. Adsorbed NG storage relies on physisorption, i.e. weak gas-solid interactions between the fuel and the adsorbent surface. While research into adsorbents has focused on assessing their storage capabilities there is, to our knowledge, no reported data on their compatibility with the storage vessel and components in NG environment. High surface area porous materials such as Activated Carbons and Metal Organic Frameworks (MOF) are considered as the most promising adsorbents. The Cu3(btc)2 MOF, copper benzene-1,3,5-tricarboxylate also known as HKUST-1, has been extensively studied for gas storage. Herein we report its compatibility in NG environment with the pressure vessel, more particularly with the metal liner. We show that not only the stability of the adsorbent but also the integrity of the metallic liner can be drastically affected.
Evaluation of Candidate Materials for Use in Supercritical CO2 Environment
Authors: Rodriguez David , Karmiol Zachary , Summers Kodi , Chidambaram Dev
Published: February 2020

Introduction

Supercritical CO2 is capable of being used in a variety of applications. These applications include; solvent for extraction, oil recovery, carbon capture and power generation (1-4). The areas of interest for this study will focus on conditions for advanced oil recovery and carbon capture and storage. The conditions of interest are above the critical point for CO2, which is 31.1°C and 7.39MPa (5).

Experimental

The autoclave contained CO2 at a pressure of 10 MPa and temperatures ranging from 40°C up to 150°C. Materials studied include; austenitic steels (stainless steel 304 and 316), and nickel based alloys (Inconel 625 and 718). Gamry software was used to control the potentiostat and analyze the data. Surface chemistry of the oxide layer was studied using X-ray diffraction, X-ray photoelectron and Raman spectroscopies.

Results

This study will discuss the corrosion current obtained and correlate it to the surface chemistry. Corrosion current was generally very low (e.g. 34.8nA for inconel 625 at 40°C).

Acknowledgements: This study was supported by the Department of Energy (DOE) under contract DE-NE0008236 and Nuclear Regulatory Commission (NRC) under awards NRC-38-10-949 and NRC-HQ-11-G-38-0039. D.R. is supported under a Fellowship program funded by NRC. Mr. Kenny Osborne and Ms. Nancy Hebron-Isreal serve as the program managers for the DOE and NRC awards, respectively.

 

 

References:

1.     O. Babova, A. Occhipinti, A. Capuzzo and M. E. Maffei, The Journal of Supercritical Fluids, 107, 358 (2016).

2.     L. Hu, D. Chen, Y. Huang, L. Li, Y. Cao, D. Yuan, J. Wang and L. Pan, Energy, 89, 874 (2015).

3.     K. Li, X. Zhou, R. Tu, Q. Xie, J. Yi and X. Jiang, The Journal of Supercritical Fluids, 107, 298 (2016).

4.     J. Beck, M. Fedkina, S. N. Lvov, M. E. Ziomek-Moroz, G. Holcomb, J. Tylczak and D. Alman, ECS Transactions, 45, 39 (2013).

5.     S. W. Løvseth, G. Skaugen, H. G. J. Stang, J. P. Jakobsen, Ø. Wilhelmsen, R. Span and R. Wegge, Energy Procedia, 37, 7841 (2013).
Corrosion Suppression with Redox Control in KCl-MgCl2 Under Flow
Authors: Olson Luke Christopher , Gray Joshua R. , Martinez-Rodriguez Michael Joe , Fuentes Roderick Eliel , Garcia-Diaz Brenda Lee
Published: February 2020

Solar power systems must be competitive with conventional energy sources in in terms of cost to make up a significant portion of the electric power grid.  Solar power can likely more rapidly grow and make-up a larger portion of the US power grid if systems have energy storage capability that could continue to provide power for extended periods without sunlight and vary the power as needed (i.e. – be dispatchable).  Concentrated solar power tower systems with thermal energy storage using advanced high operating temperature heat transfer fluids and advanced thermodynamic cycles can potentially meet the twin goals of low cost and high reliability while being dispatchable.  Molten salts are a promising candidate for a high operating temperature heat transfer fluids.  Due to the decomposition of molten nitrates at temperatures above about 550 °C, molten fluorides or chlorides are expected to be needed for higher temperature operation.  KCl-MgCl2 is a promising  heat transfer fluid due to its low cost and good thermal transport properties.  Corrosion in molten chloride salts can be severe if salt chemistry is not well controlled.  Research has shown that the main corrosion mechanism in Fe-Ni-Cr alloys exposed to molten salts is selective oxidation of Cr and that the corrosion mechanism is mass transfer limited. In the research to be presented, thermosiphons were operated at three different temperature ranges to add flow to corrosion tests and evaluate changed  corrosion rates.  Four alloys were tested in the thermosiphons with varying temperature and with and without Mg redox control.  The most extreme case tested had the hot region at ~930 °C and cold region at ~880C.  The research found that naturally convective flow could increase up to 5 times the corrosion compared to static tests for Haynes-230 without corrosion inhibition.  Corrosion inhibition using Mg worked well to decrease corrosion and mass transfer reactions for Fe, Co, and Ni based superalloys.