bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology and Phase Changes in Fe Anodes for Rechargeable Alkaline Batteries
Authors: Lee Dong-Chan , Yushin Gleb 
Published: February 2020

Rechargeable alkaline batteries may become promising non-flammable alternatives to Li-ion batteries for the applications where achieving the highest energy density is less critical than safety, environmental friendliness and low cost of energy storage systems. A renewed interest on Ni-Fe aqueous batteries awakes due to the aforementioned advantages as well as long life and robustness against harsh conditions. The challenges for improved Ni-Fe batteries, however, remain limiting their utilization for large-scale energy storage systems: electrolyte decomposition, high self-discharge and poor cell efficiency. Such drawbacks can be overcome by sound understanding on the cell reactions happening at the electrodes.
By conducting systematic studies on Fe anodes using cyclic voltammetry and a broad range of characterization tools, four distinct stages of Fe anode evolution were revealed: development, retention, fading and failure, where each stage is associated with very specific changes in the morphology and phase of Fe anodes. The particle fragmentation with the consequent gain in the surface area resulted in the increase in the Fe anode capacity during the initial cycles of deep charge/discharge. Most importantly, it was discovered that the irreversible formation of monocrystalline maghemites (γ-Fe2O3) with low reactivity is responsible for the eventual Fe anode capacity fading. We confirmed that the microstructure change takes over during early charge-discharge cycles of Fe anodes while their phase change is dominant at later stage which is the key for the rationale explaining the failure mechanism of Fe anodes in Ni-Fe batteries. Ultimately, our study correlates the changes in the electrochemical behavior of micro-scale Fe upon deep cycling in alkaline conditions with the changes in its morphology and phase.
* DOI: 10.1021/acsenergylett.8b00063
(Invited) 2D MXenes As Building Blocks for Assembly of High-Performance Electrodes for Electrochemical Energy Storage
Authors: Beidaghi Majid 
Published: February 2020

Two-dimensional (2D) transition metal carbides/nitrides (MXenes) have shown promise for a range of applications due to their unique physical and chemical properties. The high electrical conductivity, 2D and layered structure, and rich surface chemistry of MXenes have sparked great interest in their properties as electrode materials for energy storage devices. MXenes are particularly of high interest because they can store charge in the bulk of the electrode through ultrafast intercalation of ions and fast and reversible redox reactions. To date, about 30 different MXenes with a general formula of Mn+1XnTx (M is a transition metal, X is carbon and/or nitrogen, n=1,2, and 3, and Tx represents different functional groups present at their surface) are synthesized by selective etching of the A layer atoms (i.e. Al) from MAX phases (e. g. Ti2AlC), a large group of layered ternary carbides and nitrides.1 However, similar to other 2D materials, the applications of MXenes in batteries and supercapacitors is dependent on their assembly into electrode structures with high electrical and ionic conductivities. The main focus of this talk is our group’s recent research on the assembly of MXene flakes into electrode structures with high energy and power densities. We have found that the electrochemical properties of MXene electrodes are highly dependent on the size of MXene flakes used in their fabrications.2,3 Controlling the flake size in the electrode structures leads to significant improvements in their specific capacitance and rate capability. Furthermore, our recent studies on the assembly of multilayer MXenes films and particles using electrostatic assembly methods will be discussed. The electrodes fabricated by these methods show superior chemical and electrochemical stabilities as well as energy storage capability.4 Finally, our work on 3D assembly of MXenes through a versatile 3D printing process will be presented.

References

(1) Anasori, B.; Lukatskaya, M. R.; Gogotsi, Y. 2D Metal Carbides and Nitrides (MXenes) for Energy Storage. Nat. Rev. Mater.
2017, 2 (2), 16098. https://doi.org/10.1038/natrevmats.2016.98.
(2) Kayali, E.; VahidMohammadi, A.; Orangi, J.; Beidaghi, M. Controlling the Dimensions of 2D MXenes for Ultrahigh-Rate Pseudocapacitive Energy Storage. ACS Appl. Mater. Interfaces
2018, 10 (31), 25949–25954. https://doi.org/10.1021/acsami.8b07397.
(3) VahidMohammadi, A.; Moncada, J.; Chen, H.; Kayali, E.; Orangi, J.; A. Carrero, C.; Beidaghi, M. Thick and Freestanding MXene/PANI Pseudocapacitive Electrodes with Ultrahigh Specific Capacitance. J. Mater. Chem. A
2018, 6 (44), 22123–22133. https://doi.org/10.1039/C8TA05807E.
(4) VahidMohammadi, A.; Mojtabavi, M.; Caffrey, N. M.; Wanunu, M.; Beidaghi, M. Assembling 2D MXenes into Highly Stable Pseudocapacitive Electrodes with High Power and Energy Densities. Adv. Mater.
2019, 31 (8), 1806931. https://doi.org/10.1002/adma.201806931.
Computational Insights into the Lithium Intercalation Dynamics in Manganese Oxide Cathodes
Authors: Kempaiah Ravindra , Narayanan Badri , Sankaranarayanan Subramanian K. R. S. , Subramanian Arunkumar 
Published: February 2020

Research solutions that improve the performance of Li-ion batteries are essential to meet the future needs of the electric grid and transportation industries. Increasing costs associated with sourcing Cobalt has spurred demand for new cathode materials that are inexpensive and environmentally-friendly. Manganese oxides (MnO2) are an important class of electrochemically active transition metal oxides, which have been extensively studied as a potential candidate for replacing cobalt.[1] Alpha-MnO2 is an MnO2 polymorph, which contains structurally stable and porous 2x2 tunnels with tunnel widths in the range of ~5Â. These tunnels, which are formed by edge and corner sharing MnO6 octahedra, provide low-energy sites for ionic insertion and offer suitable diffusion pathways for intercalating ions.[2] Cationic species such as Na+, K+, and Li2O reduce the lithiation-induced structural distortion in these tunnels and offer a pathway for stabilizing the tunnels during electrochemical cycling.[3,4] This poster presents results from ab-initio Density Functional Theory (DFT) based computational studies to reveal new insights into the impact of cationic stabilization on the intercalation dynamics of these materials, which are otherwise difficult to obtain directly from spectroscopic or electron microscopy techniques. Using alpha-MnO2 as a model material, we present the correlation between the concentration of cationic species and its resulting impact on lithium diffusion in the following aspects: (i) energetic barriers for Li diffusion, and (ii) structural distortions induced within the tunnels.
References:

Thackeray, Michael M., et al. Journal of Materials Chemistry23 (2005): 2257-2267.

Yuan, Yifei, et al. Nano letters5 (2015): 2998-3007.

Tompsett, David A., et al. Chemistry of Materials12 (2013): 2515-2526.

Ling, Chen, et al. Chemistry of Materials20 (2012): 3943-3951.
Corrosion Behavior of Cocrfemnni High Entropy Alloy in Acidic Solutions
Authors: Aiso Takumi , Muto Izumi , Sugawara Yu 
Published: February 2020

High entropy alloys (HEAs) are new concept in alloy design. HEAs contain five or more metallic elements in equimolar or near-equimolar ratios. Although HEAs are multi-component alloys, they form single-phase solid solutions. HEAs have outstanding properties that were not found in conventional alloys such as Fe-base alloys. CoCrFeMnNi alloy, one of the most remarkable HEA, is expected to exhibit high corrosion resistance. The mechanism of corrosion resistance of CoCrFeMnNi alloy could be applied to improve the corrosion resistance of conventional Fe-Cr-Ni stainless steels. Therefore, it is important to clarify the corrosion mechanism of CoCrFeMnNi alloy.
In this study, the equiatomic CoCrFeMnNi alloy was prepared as the specimens. CoCrFeMnNi alloy was made by arc melting. The samples were heated to 1523 K and hot-rolled to thickness of 2 mm. After solution treatment at 1473 K (2h, W.Q.), the surfaces of the specimens were successively polished with a diamond paste down to 1 µm.
Potentiodynamic anodic polarization curves were measured in deaerated 1 M H2SO4 at 298 K to elucidate the corrosion behavior of CoCrFeMnNi alloy. As a reference, polarization curves for pure Co, Cr, Fe, Mn, and Ni were measured. The surfaces of the specimen, with the exception of the electrode area (10mm×10 mm), were covered with epoxy resin and paraffin. The measurements were performed in a conventional three electrode cell. The reference electrode was Ag/AgCl (3.33 M KCl) and the counter electrode was a Pt plate.
The results of potentiodynamic anodic polarization curves are shown in Fig. 1. In the case of CoCrFeMnNi alloy, active state, passive, trans-passive, secondary passive, and O2 evolution regions appeared. Comparing with CoCrFeMnNi alloy and each pure metal, corrosion reactions of CoCrFeMnNi alloy were discussed.

Figure 1
(Invited) Saft Gen 6 Electrochemistry for GEO/LEO Application
Authors: Ma Chengsong , Borthomieu Yannick 
Published: February 2020

Satellite battery industry is facing a serious material obsolete issue. The MCMB anode and NCA cathode active materials were no longer available. Saft developed a Generation 6 space cell –VL51ES which addressed material obsolescence in the space industry and provided high specific energy to meet the demands of today’s space missions.
The selected electrodes electrochemistry provides excellent storage and cycle life. VL51ES is an iteration of proven technology and a legacy of failure-free batteries with up to 18 years in space. Manufactured in both France and the US, the redundant manufacturing capability ensures effective product delivery to customers across the globe. Saft incorporated advanced technology and enhanced manufacturing processes. Compared with the previous generations of space cells, the Gen 6 space cell is more industrialized, efficient and cost effective. Change from tabbed design to tabless design significantly reduces cell impedance, it makes VL51ES capable for higher rate discharge and cold temperature charge than previous Saft space cells. It represents a 20% height reduction along with a 10% improvement in energy. This cell has excellent GEO mission life, 45 accelerated GEO seasons were demonstrated with only 6% total energy loss. VL51ES passed voltage reversal tests without safety event, it enables a by-pass less battery design to reduce cost and complexity at battery level and maintain the same reliability. The qualification of VL51ES covers a full range of space requirements including safety, electrical, mechanical, abuse, life test and reliability. A data package has been compiled for customers with records of all test results. The qualification data is incorporated into Saft’s Li ion model (SLIM) which help customers to predict battery life performance at different scenarios and help customer with proper battery sizing.
Electrophoretically Deposited Graphene-Based Coatings for Spacecraft Charging Mitigation
Authors: Wang Dan , Liu Danny X. , Hall Timothy D. , Inman Maria , Taylor E. J. , Skinn Brian , Snyder Stephen 
Published: February 2020

Spacecraft charging has been recognized as an important consideration for spacecraft design, and occurs due to interaction between hazardous space plasmas and spacecraft surface. Spacecraft can experience charging throughout operation due to high flux of incident electrons (ex. during geomagnetic sub-storm). As a result, different materials/components may experience a range of potentials which may lead to plasma-induced arcs, damaging spacecraft components. Graphene are emerging two-dimensional (2D) carbon materials with excellent physical and chemical properties, such as high conductivity, high tensile strength, high transparency, and high carrier mobility. These excellent properties make graphene potentially useful for applications in energy storage, aerospace, coatings and polymer markets and thermal protection. Substrates constituted by graphene harness the thermal and mechanical properties to create novel coatings with superior performance, hence broadening the graphene application spectrum. Of particular interest is the potential capability of graphene-based materials to provide increased protection against spacecraft charging in the space plasma environments. The work function of graphene can be tuned by either metal doping or functionalization, thereby increasing the electron yields and enhancing the possibility of emission through negative electron affinity.
Within this context, Faraday Technology is working on developing an electrophoretic bath formulation and manipulate the pulsed electric field parameters to deposit graphene-based coatings onto test substrates, which may maintain integrity of spacecraft by autonomous electron emission in relevant environments. As shown in the Figure, uniform graphene-based coatings have been formed on an aluminum substrate. The coatings are characterized and evaluated by optical microscopy, scanning electron microscopy, and field-emission scanning electron microscopy. Faraday will also investigate the incorporation of metal particles into graphene film to tailor the emission properties, allowing for obtaining the low work function. The demonstrated technology not only addresses the desire to introduce novel manufacturing techniques for spacecraft charging mitigation, but also provides a scalable thin film and low-cost manufacturing process that has the potential of producing low reflective coatings.

Acknowledgements: The financial support of DOD Air Force Contract No.: FA9453-19-P-0573 is acknowledged.

Figure 1
In Situ Characterization of the Lithium Metal Interface
Authors: Lopez Jeffrey , Shao-Horn Yang 
Published: February 2020

Lithium ion batteries have become the dominant form of energy storage used in consumer electronics and, recently, electric vehicles. However, high costs have prevented widespread deployment of lithium ion batteries for applications other than portable electronics, and the safety issues associated with liquid organic electrolytes remain to be addressed. In order to enable the greater utilization of electric vehicles, allow for grid scale energy storage, and meet the demands of new electronic applications, new materials for high energy density batteries must be developed. High capacity electrode materials like lithium metal have the potential to facilitate these technologies, but lithium metal electrodes are presently limited by significant side reactions, poor quality deposition, and the potential to form hazardous dendrites. Therefore, it is important to develop a clear understanding of the surface reactivity and growth behavior of the lithium metal at the interface with the electrolyte in order to enable stable long-term cycling.
The products that form as a result of electrolyte decomposition reactions at the electrode interface are known to be extremely important in determining the final cell performance. Specifically, fluorinated salts and solvent additives have been shown to enable stable cycling of Li metal anodes. This improvement is ascribed to the formation of LiF in the solid electrolyte interphase (SEI), yet the understanding of how LiF and other SEI compounds are formed and how they affect battery cycling is not complete. In this presentation, in situ spectroelectrochemical techniques including infrared spectroscopy (FTIR), differential electrochemical mass spectrometry (DEMS), and electrochemical quartz crystal microbalance (EQCM), are used to clearly identify components of the Li metal SEI. An understanding of SEI formation with respect to electrochemical potential and time will be discussed. With this understanding we provide new insights into the formation and chemical nature of SEI components that promote stable cycling of lithium metal electrodes.
A Study of Practical Obstacles in Primary and Rechargeable Alkaline Zinc-Air Batteries
Authors: Sun Wei , Zhang Mengyi , Bieker Peter , Winter Martin 
Published: February 2020

As one of the proposed post lithium-ion battery technologies, metal-air batteries have received revived interest recently. Among the different types of metal-air batteries, rechargeable zinc-air battery (RZAB) is a promising electrochemical energy storage device with the advantages of high theoretical energy density of 1086 Wh kg-1, high abundance, low toxicity and intrinsic safety.1 However, current RZAB still suffer from poor energy efficiency and cycle life, owing mainly to the zinc-anodes, electrolytes, and air-cathodes. To improve the low energy efficiency, many efforts have been made to promote both of the sluggish oxygen reduction/evolution reactions in the air-cathodes by engineering bifunctional catalyst materials with high reactivity. Although significant progress has been made in developing suitable catalyst materials for the air-cathode, many technical challenges still remain in electrolyte to achieve the long cycle life while maintaining high performance.
Aqueous electrolytes, predominantly alkaline electrolytes, have been adopted by the RZAB system since its birth. Potassium hydrogen (KOH) is the most commonly used alkaline electrolyte because of its high ionic conductivity, high activity for both the zinc and air electrodes as well as good low temperature performance.2 Despite its desirable properties, the usage of KOH in RZAB raises several technical problems: i) zinc dendrite formation, shape change, surface passivation from complicated reaction between zinc and OH- as well as the dissolution and migration of Zn(OH)4
2-; ii) corrosion of the carbon-based air cathode in concentrated alkaline electrolyte; iii) formation of insoluble K2CO3 arising from the reaction of aerial CO2 with KOH; iv) reduced cell shelf due to the high corrosive ability of concentrated alkaline electrolyte to the stainless steel used in the experimental cell component.
In this work, specific attention is given to the obstacles caused by the alkaline electrolytes with the focus on the fundamental understanding of zinc-anode reaction mechanisms, carbonization of electrolyte as well as the precipitation of carbonates on the air cathode. Furthermore, the effects of the practical operating conditions on battery performance and durability are discussed, including the experimental cell configuration for RZAB as well as the contaminants commonly encountered in ambient air (e.g. carbon dioxide). The approaches to overcome the challenges are also presented and analyzed for facilitating further research and development of the electrolyte for RZAB.

Reference

Li, Y.; Dai, H., Recent advances in zinc-air batteries. Chemical Society reviews
2014,
43 (15), 5257-75.

R. Mainar, A.; Leonet, O.; Bengoechea, M.; Boyano, I.; de Meatza, I.; Kvasha, A.; Guerfi, A.; Alberto Blázquez, J., Alkaline aqueous electrolytes for secondary zinc-air batteries: an overview. International Journal of Energy Research
2016,
40 (8), 1032-1049.
High-Energy Lithium/SeS2 Batteries with Hierarchical Nanocomposite Cathode and Ionic Liquid-Based Electrolytes
Authors: Dong Panpan , Lee Jung-In , Cha Younghwan , Zhang Xiahui , Song Min-Kyu 
Published: February 2020

Selenium disulfide (SeS2)-based composites have received much attention as a promising cathode material for high-energy lithium metal batteries due to their higher theoretical capacity (1342 mAh g−1) than that (675 mAh g−1) of selenium and a less significant shuttle effect than that of sulfur.[1] However, the biggest challenges faced by Li/SeS2 batteries are (1) the development of high-performance cathodes that can maintain the functional interface during cycling and (2) the identification of suitable electrolytes that can allow good cyclability without the degradation of lithium metal anodes. It has been reported that an ionic liquid, N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, i.e. Py14TFSI, can be used as co-solvent in ether-based electrolytes to form high-quality protection layer on lithium metal.[2] In this study, an effective strategy for developing high-performance Li/SeS2 batteries is introduced via a synergistic enhancement comprising the effective cathode design and the lithium anode protection in Py14TFSI containing electrolytes. We found that the hierarchical SeS2@carbon nanocomposites, confirmed by X-ray nano-computed tomography, facilitated Li-ion transportation and enhanced the electrochemical utilization of SeS2, enabling the improved rate capability of Li/SeS2 battery. Furthermore, the systematic studies on the morphological change as well as the electrochemical stability of lithium anode indicate that Py14TFSI-LiNO3­-containing electrolytes could effectively suppress the shuttle effect and protect lithium metal by forming a stable and LiF-dominated solid-electrolyte-interphase layer, leading to much improved Coulombic efficiency and cyclability of Li/SeS2 batteries. These results underscore a synergistic approach toward the development of high-energy Li/SeS2 batteries with long cycle life.
[1] a) A. Abouimrane, D. Dambournet, K. W. Chapman, P. J. Chupas, W. Weng, K. Amine, J. Am. Chem. Soc.
2012, 134, 4505-4508; b) Y. Cui, A. Abouimrane, J. Lu, T. Bolin, Y. Ren, W. Weng, C. Sun, V. A. Maroni, S. M. Heald, K. Amine, J. Am. Chem. Soc.
2013, 135, 8047-8056.
[2] J. Zheng, M. Gu, H. Chen, P. Meduri, M. H. Engelhard, J.-G. Zhang, J. Liu, J. Xiao, Journal of Materials Chemistry A
2013, 1, 8464.

Figure 1
Diagnostics for Failure Modes in Non-Aqueous Flow Batteries
Authors: Pratt Harry D. , Small Leo J. , Anderson Travis M. 
Published: February 2020

Expansion of promising, non-aqueous flow battery chemistries may increase energy densities, lower costs, and ultimately increase penetration of energy storage technologies into electric grids throughout the world. However, significant research efforts are required to understand their potential relative to the well-studied aqueous vanadium and organic systems. Among the most promising non-aqueous chemistries are those based on the bipyridine metal coordination complexes. Like their aqueous counterparts, they are very susceptible to crossover. Having a key mechanistic understanding of the role that the electrolytes, solvents, and membranes play in crossover is critical to designing longer lasting batteries. Recently, we examined the role of the membrane in crossover using the aqueous organic methylviologen and TEMPO molecules and five commercially available anion exchange membranes. Capacities between the batteries were found to differ by >50% after 100 cycles with the different membranes. The capacity loss was attributed to crossover across the membrane and was dominated by mechanisms including diffusion, migration, and electroosmotic drag.
For this study, we have investigated the role of not just the membrane on crossover, but the effects that both the electrolyte and solvents have on battery performance as well. Conditions were chosen to prevent crossover through both physical and chemical variabilities. This included using bulkier cations and anions in the electrolyte as well varying the dielectric constant of the solvents. Membranes were chosen based on chemical compatibility, tortuosity, and physical robustness. Collectively, the results have informed us on how to effectively design membranes within the parameters of electrolyte and solvent selection.
Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.