bluuebunny/crossref_metadata_2025 huggingface dataset:
Charge-Discharge Characteristics on Low Viscosity Phosphonium Ionic Liquid Electrolytes for Lithium Ion Battery
Authors: Sakguchi Yuki , Yamada Hirohisa , Higashi Toshikazu , Nomizu Daiki , Tsunashima Katsuhiko , Sakai Chikako , Katakura Katsumi
Published: February 2020

We evaluated low viscosity Ionic Liquids (ILs) based on quaternary phosphonium cations as electrolytes for Lithium Ion secondary Battery (LIB) in this work. The secondary batteries are required more safety and higher energy density per volume and/or mass for electric vehicles (EVs) to equipped to convenient driving technology, i.e. IOT, electric sensing technology and devices. LIB is one of the promising batteries for EVs, and is mainly used for cellular phones and portable devices for its large capacity and light weight. Carbonate solvents are commercially used as an electrolyte in LIBs, but they are highly inflammable for a short circuit and/or thermal runaway. Hence we focused on ILs as an electrolyte for LIB because of their properties (e.g. incombustibility, hard volatility, wide potential window and high ion conductivity, etc.). Since the discovery of water stable 1-ethyl-3-methylimidazolium tetrafluoroborate 1), ILs have attracted attention. The ILs which are based on mainly imidazolium cations, pyridinium cations and quaternary ammonium cations, etc., have been studied in various fields including electrolytes for LIB 2, 3). On the other hand, ILs based on quaternary phosphonium cations have more unique properties, especially, i.e. lower viscosity than quaternary ammonium cations system 4), while a few electrochemical properties as electrolyte for LIB are reported 5, 6). Moreover, they have higher thermal stability and wider potential window than ammonium cation systems, so their properties are advantageous for safety.

High discharge capacities of near the theoretical capacity of LiCoO2 and coulomb efficiencies of ca. 100% were obtained during Charge-discharge cycle tests on P111X-FSA system which consist of trimethylphoshine (TMP) based phosphonium cations (P111X
+
; X = 1O1(methoxymethyl group), Al(allyl group) etc.) and bis(fluorosulfonyl)amide anion (FSA-). Moreover, the discharge rate capability of P111(1O1)-FSA was quite higher than another functionalized ILs, while the ion conductivity was not so higher. This is indicated that some physical parameters, e.g. transport numbers of Li+ in ILs or electrode-electrolyte interfacial phenomenon would affect to the rate characteristics.

[References]

1) S. Wilkes, and M.J. Zaworotko, J. Chem. Soc. Chem. Commun., 0, 965-967 (1992).

2) N. Papageourgiou, Y. Athanassov, M. Armand, P. Bonhote, H. Pettersson, A. Azam, and M. Gratzel, J. Electrochem. Soc., 143(10), 3099-3108 (1996).

3) H. Sakaibe, H. Matsumoto, and K. Tatsumi, J. Power Sources, 146, 693-697 (2005).

4) K. Tsunashima, F. Yonekawa, and M. Sugiya, Electrochem. Solid-State Lett., 12(3), A54-57 (2009).

5) K. Tsunashima, Y. Sakai, and M Matsumiya, Electrochem. Commun., 39, 30-33 (2014).

6) X. Lin, R. Kavian, Y. Lu, Q. Hu, Y. Shao-Horn, and M. W. Grinstaff, Chem. Sci., 6, 6601-6606 (2015).
The Effect of Heat-Treatments on Corrosion Resistance of Martensitic Stainless Steel
Authors: Kanda Reiya , Muto Izumi , Sugawara Yu
Published: February 2020

Martensitic stainless steels are widely used in industries because of their high strength and corrosion resistance. However, pitting corrosion sometimes occurs in chloride environments. It is known that pitting corrosion is usually initiated at MnS inclusions. The pit initiation at the MnS inclusions in Type 304 stainless steels was found to be inhibited by interstitial carbon. However, the effect of interstitial carbon on pit initiation of martensitic stainless steels is still unknown. In this research, in order to change the amount of interstitial carbon, the specimens were heart-treated by different tempering conditions, and potentiodynamic polarization curves were measured.

A commercial Type 420J2 (13Cr-0.3C) martensitic stainless steel (low S) and re-sulfurized Type 420J2 martensitic stainless steel (high S) were used. After solution treatment at 1273 K (5 h, air-cooling), the specimens were tempered at various temperature (from 473 to 1023 K, 2h, air-cooling). After these heat-treatments, the surfaces of the specimens were successively polished with a diamond paste down to 1 µm. With the exception of the electrode area, the surfaces of the specimens were covered with a resin.

Figure 1 shows the macroscopic anodic polarization curves of low-sulfur and re-sulfurized Type 420J2 stainless steels in boric-borate buffer solution with 10 mM NaCl (pH 8.0). The electrode area was 1.0 cm2. In the case of low sulfur steels, pitting potentials decreased with increasing tempering-temperature (473-773 K), but the pitting potential of the specimen tempered at 1023 K was higher than that of non-tempered specimen. It is supposed that tempering at 1023 K improves pitting corrosion resistance. For high sulfur steels, pitting potential decreased with tempering-temperature. Because the amount of interstitial carbon decreased with tempering-temperature, these results suggests that interstitial carbon inhibits pit initiation.

Figure 1
Processes for the Electrowinning of Metals and Oxygen from Lunar Regolith
Authors: Dietz Andreas , Moustafa Essam
Published: February 2020

One of the great goals of manned space flight is the colonization of the moon. It can serve as a rocket launch pad for deep space missions, or for the development of new processes under reduced gravity. Tourism can also be a worthwhile goal.

For the scientific and economic development of the moon, large quantities of different materials are necessary, which cannot be transported from the earth for cost reasons. This concerns materials for the construction of accommodation for astronauts and other infrastructures. Regolith, the easily available upper powdery layer of the Moon, can be used to build houses, roads, etc. For this purpose, processes such as additive manufacturing are under investigation.

In addition, pure metals like iron or aluminium for the construction of tools and machines as well as oxygen as breathing air and fuel are needed. These can also be obtained from regolith. Regolith consists of the oxides of silicon, iron, titanium, aluminium, magnesium and other materials. By means of a combined process, the components of regolith are chemically dissolved and electrochemically extracted as metal (cathodic process) and oxygen (anodic process). The aim is to develop an almost closed process for the electrowinning of metal and oxygen, which only requires the regolith without any additional consumables.

The process is based on the use of so-called Ionic Liquids (IL), which are transported once from the earth. IL serve as solvents for the chemical dissolution of the oxides. In addition, they are also the electrolyte for the electrochemical production of metal and oxygen. Ionic liquids are salts that are present in liquid form at room temperature or slightly higher temperatures and are very stable electrochemically. In addition, they have a very low vapour pressure. Since Ionic Liquids do not participate directly in the electrochemical reaction, they are not consumed. This is a great advantage compared to the known aqueous electrochemical processes, in which hydrogen is often produced as a by-product at the cathode. This consumes the water as electrolyte. In addition, the electrochemical production of aluminum, an important raw material in the regolith, from aqueous electrolytes is not possible.

The oxygen obtained, can be used as breathing air. In addition, in combination with water it can also be further processed electrochemically to hydrogen peroxide, H2O2. H2O2 can be used as fuel for mobility on the moon, but also as fuel for other rockets, e.g. for deep space missions.

The lecture presents the principle and discusses first results.

Figure 1
Modeling Electrolytic Conversion of Metabolic CO2 and Optimizing a Microfluidic Electrochemical Reactor for Advanced Closed Loop Life Support Systems
Authors: Dominguez Jesus A , Brown Brittany R , Dennis Brian , Chanmanee Wilaiwan , Curreri Peter
Published: February 2020

Water electrolysis is required in any life support system intended to be operated in a closed loop system, as metabolic CO2 contains 87% of the O2 consumed by the crew members requiring the generation of the 13% O2 balance (assuming 100% efficiency of O2 recovery from CO2) via water electrolysis. Metabolism of food produces 0.34 kg/day/crewmember more water than consumed leading to having sufficient water to generate the 13% O2 balance via electrolysis. The current state of the art for oxygen recovery onboard the International Space Station (ISS) is the Environmental Control and Life Support System (ECLSS) Atmosphere Revitalization (AR) System. The AR includes four integrated units, which provide critical functions for life support including trace contaminant control (Trace Contaminant Control (TCC) system), CO2 removal (CO2 Removal Assembly (CDRA)), oxygen generation (Oxygen Generation Assembly (OGA)), and oxygen recovery (Carbon Dioxide Reduction System (CDRS)).

CDRS is a Sabatier reactor that reduces CO2 to CH4 and water using H2 from OGA (an electrolysis unit that generates O2 as main product and H2 as byproduct) as reactant. The CDRS limits the feasibility of having a closed loop system, as it requires more water than the water metabolically generated ultimately resulting in a recovery rate of approximately 50%. NASA Marshall Space and Flight Center (MSFC) and University of Texas, Arlington (UTA) are currently developing an Engineering Development Unit (EDU) of a Microfluidic Electro Chemical Reactor (MFECR) to convert a continuous stream of CO2 and water into O2 and C2H4 at standard conditions. The novel design combines CO2 conversion and water electrolysis (currently conducted in OGA and CDRS units respectively) into one compact unit that runs at standard conditions and is theoretically capable of generating metabolic O2 with a maximum metabolic CO2 conversion of 77% while consuming less than metabolic water.

This paper presents a multi-physic 3D model developed at MSFC on CO2 conversion to O2 and C2H4 at standard conditions via MFECR. In the model the electrochemical physics is coupled with all the other physics phenomena involved in the process, such as micro fluid flow, mass and heat transfer, and generation as well as conduction of DC electrical current. This work aims to use this 3D model to build a comprehensive, rigorous, and experimentally validated simulator that will be used as a valuable tool to not only assist the authors on the EDU design but also to optimize its operation.
(Invited) Capillary Electrophoresis Instrumentation and Methods for Spaceflight Missions of Exploration
Authors: Mora Maria Fernanda , Kehl Florian , Tavares da Costa Eric , Bramall Nathan , Creamer Jessica , Noell Aaron C , Willis Peter
Published: February 2020

The search for evidence of life beyond Earth is among the highest level goals in planetary exploration. However, despite multiple orbiter and landed missions to extraterrestrial bodies in the solar system, we still haven’t found evidence of life. A powerful approach in this search involves seeking biochemical signatures of life at the molecular level, as distributions of organic molecules. The separation techniques capillary electrophoresis (CE) and its miniaturized version, microchip electrophoresis (ME) overcome the limitations of gas-phase techniques and hold unique promise in the search for signatures of life on other worlds. These techniques offers high resolution separations of molecules dissolved in water and are the simplest of all liquid separation methods to implement for flight. Here we describe CE and ME instrumentation developed at JPL and the steps we are taking to someday enable the its implementation on other worlds.

Although multiple detection methods can be coupled to CE and ME, we focus on three detection modes: laser-induced fluorescence (LIF) for state-of-the-art measurements of amino acids, mass spectrometry (MS) for broad detection of ionizable organics, and contactless conductivity detection (C4D) for measurements of inorganic and organic ions. These techniques are complementary of each other and would allow full characterization of the chemical composition of a sample in situ. We are not only developing instrumentation but also analytical methods that could be implemented on a mission scenario.

Here we also describe a system we dub The Chemical Laptop, which would provide the sample processing capabilities required for in situ analysis on extraterrestrial destinations with ultra-high sensitivity in a compact, low-mass, and low-power package. The Chemical Laptop is a truly portable, battery-powered, automated, and reprogrammable microchip electrophoresis instrument coupled to laser-induced fluorescence detection.

This instrument concept could be adapted to the environmental requirements of a variety of astrobiologically interesting targets like Europa, Enceladus, or Titan. This system also serves as a general prototype that could be reprogrammed for terrestrial-based analyses as well.
The Thermodynamic and Kinetic Influence of Solvent, Counter Anion and Salt Concentration on ORR in Li-O2 Batteries
Authors: Leverick Graham , Tatara Ryoichi , Feng Shuting , Crabb Emily , France-Lanord Arthur , Tulodziecki Michal , Stephens Ryan M. , Grossman Jeffrey C. , Shao-Horn Yang
Published: February 2020

Aprotic Li-O2 batteries have been extensively studied due to their very high theoretical gravimetric energy density; potentially 2-3 times that of commercial Li-ion batteries1. Despite this significant research effort, practical rechargeable Li-O2 batteries remain elusive due to significant issues relating to high overpotential and parasitic side reactions that limit the cycling performance of the battery chemistry. In order to address these issues, a stronger fundamental understanding of the underlying oxygen redox reactions is needed. In this work, the complex influence of the solvent2, counter anion3 and salt concentration4 during the oxygen reduction reaction are unified within a single framework. Ionic coupling between Li+ ions and the superoxide (O2
-) anion formed following the first electron transfer is highlighted as the critical parameter for determining the selectivity between the two competitive discharges pathways. By weakening the Li+-O2
- coupling through interactions with solvent/counter anions with high donor number, or by lowering the Li+ activity, we observe a significant enhancement in the proportion of observed soluble discharge products. Additionally, electrolyte design strategies for suppressing the direct two electron transfer reaction to form an insulating film of Li2O2 will be discussed in their relation to enabling redox mediators during the reduction process, such as DBBQ5 and EV.

References

D. Aurbach, B. D. McCloskey, L. F. Nazar, and P. G. Bruce, Nature Energy, 1, 16128 (2016).

D. G. Kwabi et al., Angewandte Chemie International Edition, 55, 3129–3134 (2016).

C. M. Burke, V. Pande, A. Khetan, V. Viswanathan, and B. D. McCloskey, Proceedings of the National Academy of Sciences, 112, 9293–9298 (2015).

R. Tatara et al., The Journal of Physical Chemistry C, 121, 9162–9172 (2017).

X. Gao, Y. Chen, L. Johnson, and P. G. Bruce, Nature Materials, 15, 882–888 (2016).
Low-Temperature Behavior of Lithium Metal Anodes in Carbonate and Ether Electrolytes
Authors: Thenuwara Akila C , Sandoval Stephanie , Klein Emily J , McDowell Matthew T
Published: February 2020

The development of energy storage devices that can efficiently operate at temperatures below 0 °C is necessary for both terrestrial and space-based applications. NASA has previously carried out pioneering work that has enabled Li-ion batteries to operate at temperatures down to -30 °C through the development of new carbonate electrolyte formulations. [1-2] However, secondary batteries that utilize lithium metal anodes instead of conventional graphite anodes could significantly boost energy density and specific energy, but the behavior of lithium electrodes at low temperatures are largely unknown. In this work, we investigate the effect of sub-zero temperatures on electrochemical behavior, morphological evolution, and solid-electrolyte interphase (SEI) formation of Li metal anodes in carbonate and ether solvents. Electrolytes made with solvents such as ethylene carbonate and ethyl methyl carbonate with ester co-solvents (e.g., ethyl propionate) exhibit sufficient conductivity and show effective Li deposition/stripping down to -30 °C, but with relatively low average Coulombic efficiencies (CEs) of ~70 % (similar to the room-temperature CE of ~73 %). The introduction of SEI-stabilizing additives such as fluoroethylene carbonate (FEC) boosts the average Coulombic efficiency across a range of temperatures (CE = ~94 %). Ether-based electrolytes, on the other hand, enable Li deposition/stripping down to -70 °C with high CEs (~95 %). Interestingly, investigation of the Li morphology after cycling revealed that distinct Li morphologies form at different temperatures, which may be related to differences in SEI chemistry and structure. These results provide important new information for engineering Li metal anodes for efficient operation under a variety of conditions.

References

[1] Smart, M. C., B. V. Ratnakumar, L. D. Whitcanack, K. B. Chin, S. Surampudi, H. Croft, D. Tice, and R. Staniewicz. "Improved low-temperature performance of lithium-ion cells with quaternary carbonate-based electrolytes." Journal of power sources 119 (2003): 349-358.

[2] Smart, M. C., B. V. Ratnakumar, Larry D. Whitcanack, Kiah A. Smith, Stuart Santee, Robert Gitzendanner, and Vince Yevoli. "Li-Ion Electrolytes Containing Ester Co-Solvents for Wide Operating Temperature Range." ECS Transactions 11 (2008): 99-108.
Development of High-Performance Ion Selective Membranes for Lithium Polysulfide Redox Flow Batteries (Li-PS RFBs)
Authors: Kim Sangil , Wang Tongshuai , Gao Yuechen , Amiri Azadeh , Bae Chulsung
Published: February 2020

There has been a surge of research interest in the lithium polysulfide (Li-PS) redox flow batteries (RFBs) for large scale energy storage applications because of their high theoretical energy density (~2600 Wh/kg and 2199 Wh/L for elemental Li and S) and low material cost. They also can bring additional advantages, such as design flexibility, easy scalability, and safe operation condition. However, the Li-PS battery systems suffer from polysulfide crossover (polysulfide shuttling) between their two working electrodes which decreases the batteries’ columbic efficiency and shortens their cycle lives. This shuttling effect is more detrimental in Li-PS RFBs which doesn’t have carbon matrix to immobilize the solid-state sulfur. In conventional redox flow batteries (e.g. vanadium redox flow battery), the membrane separators has an important role by suppressing the active species crossover between catholyte and anolyte. However, commercial porous battery separators (e.g. Celgard) cannot be adopted due to their low rejection for polysulfide (PSn-) active species and fast capacity decay. Recent few research works revealed the feasibility of using ion exchange membranes (IEMs) as a barrier layer to selectively transport Li+ ions and block PSn- ions. Unfortunately, most commercial IEMs are unstable in the organic polysulfide electrolyte because of its high swelling ratio which can cause the electrolytes crossover. Hence, there is a critical need to develop high performance membrane materials for the Li-PS RFB applications.

In this work, we will present our recent progress on developing novel ion exchange membrane materials for the Li-PS RFBs which can greatly suppress the polysulfide shuttling while maintaining high Li+ conductivity and mechanical stability. Our biphenyl polymer membrane (BP-SA) presents excellent stability the DOL/DME organic electrolyte solution, exhibiting potential for Li-PS RFBs application. We studied its selective ion transport properties through diffusion and electrochemical measurement. Diffusion test shows that there is close to 100 % rejection of Li-PS ions by the BP-SA membrane, while considerable amount of Li-PS crossover was found for Celgard and Nafion. Moreover, the BP-SA membrane possess comparable Li conductivity (0.13 mS/cm2) to Nafion (0.29 mS/cm2) in organic solvent. As a result, the Li-PS single cell with the IEM/Celgard composite membrane shows better efficiencies in comparison to the cell with Celgard 2325. Our results unambiguously demonstrate that the BP-SA membrane has greater Li+/PS anion selectivity than Nafion and can be a promising base material to make separators for Li-PS RFBs.
Low Cost Zinc-Iron Rechargeable Flow Battery with High Energy Density
Authors: Accogli Alessandra , Panzeri Gabriele , Gibertini Eugenio , Magagnin Luca
Published: February 2020

In current research, electrochemical energy storage systems have gaining interest because they constitute an essential element in the development of sustainable energy technologies [1,2]. Among them, rechargeable flow batteries (RFBs) are one of the most promising technology for the integration in grid-connected electricity, especially if combined with unpredictable and intermittent renewable energy sources, due to their high efficiency, power/energy independent sizing and room temperature operation [3]. At the moment, among all RFBs systems, the most investigated and advanced technology is the vanadium based RFB, characterized by an energy efficiency equal to 80% and energy density ranging 15-45 Wh/l [4]. However, nowadays the main bulk of research is focused on finding an economically convenient and technically competitive flow battery chemistry, able to ensure long lifetime and high energy efficiency [5,6]. In this study, a zinc-iron RFB with low cost and high energy density will be presented. In particular, inorganic electrolytes based on high soluble salts have been developed, achieving a charge density of 30-70 Wh/l. Moreover, in order to enhance the capacity of Zn-Fe flow battery, the use of slurry electrodes to decuple capacity from the power rating have been studied. The combination of high energy efficiency of the Zn-Fe RFB with its ability to withstand a large number of charge/discharge cycles and the low cost, makes this battery system suitable for energy storage applications.

References

P. Alotto, M. Guarnieri, and F. Moro. Renewable and Sustainable Energy Reviews 29 (2014): 325-335.

A. Z. Weber, M.M. Mench,, J.P. Meyers, P.N. Ross, J.T. Gostick and Q. Liu. Journal of Applied Electrochemistry (2011), 41(10), 1137.

G. Kear, A.A Shah, and F.C. Walsh. International journal of energy research, (2012), 36(11), 1105-1120.

C. Ding, H. Zhang, X. Li, T. Liu, and F. Xing. The Journal of Physical Chemistry Letters, (2013), 4(8), 1281-1294.

C- Xie, Y. Duan, W. Xu, H. Zhang, and X Li. Angewandte Chemie International Edition, (2017) 56(47), 14953-14957.

S. Selverston, R. F. Savinell, and J. S. Wainright. Journal of The Electrochemical Society 164.6 (2017): A1069-A1075.
High-Rate and Long Cycle-Life of Bulk Na2/3[Ni1/3Mn2/3]O2 Sodium-Ion Battery Cathode Enabled through Structural Inclusion
Authors: Detsi Eric , Fu Jintao , Corsi John S , Li Manni
Published: February 2020

Recently, sodium-ion batteries (SIB) have been considered a promising alternative to lithium-ion batteries due to the abundance of sodium resources (sodium is the Earth’s 6th most abundant element, while lithium is 33rd) and its low extraction costs. Among various cathode candidates, the layered oxides NaTMO2 (TM=3d transition metal elements and their mixture) can accommodate sodium ions through intercalation mechanism, but suffer from major limitations including poor rate capability and short cycle-life. We have developed a novel bulk Na2/3[Ni1/3Mn2/3]O2 structure containing inclusions, which exhibits an unprecedented rate capability with roughly 50 % capacity retention at 50 C, and a remarkable long-term cycling stability with 95% capacity retention after 1000 cycles at 5 C. During this talk, I will present our new results and elucidate the mechanism through which the cycling performance of the novel materials system is enhanced.

References

Ruiz, M. Cochrane, M. Li, Y. Yan, K. Ma, J. Fu, Z. Wang, SH. Tolbert, VB. Shenoy, E. Detsi, Adv. Energy. Mater., 8 (2018) 1801781.

Li, Z. Wang, J. Fu, K. Ma, E. Detsi, Scripta Materialia, 164 (2019) 52-56.
Oxygen Barrier Composite Membrane for Li-Air Battery Using Cuboid LiAlTiPO4 in Orthogonal Array
Authors: Choi Kyoung Hwan , Choi Wonsung , Im Dongmin
Published: February 2020

The Li-Air batteries which convert the electrochemical reactions of lithium and O2 into electrical energy have high theoretical gravimetric capacity (3861 mAh/gLi) that is ten times higher than that of lithium ion batteries (372 mAh/gc). Its potential to generate high energy density makes it a promising candidate to replace the lithium ion in the electric vehicle applications. To meet the requirements of the electric vehicle applications, the technical barriers that limit the cycle life such as oxygen permeation, electrolyte and cathode instability and low rate capability need to be overcome. Especially the consumption/de-activation of Li metal is accelerated when oxygen in cathode side moves into Li metal side through the electrolyte, which is one of the most significant factors preventing long-term operation of the system.

Ceramic solid state electrolyte (SSE) separator has a remarkable gas blocking capability, but it should be thick and heavy (~0.3 mm) to be used as a gas barrier of Li-Air battery due to fragile property. This leads to a sharp decrease in energy density. We fabricated composite membrane consisting of micron-sized SSE particles arrayed in matrix shape and polymer grid. Here SSE particles and polymer have functions of lithium ion conduction and gas blocking, respectively. Cuboid particles were synthesized using silicon wafer template with cuboid pattern on it in size of 50 ~ 200um.

Interface energy between particle and polymer was controlled by bimodal surface modification for better mechanical strength of membrane. Compared to amorphous particles, composite membrane using cuboid LATP particle has many benefits in high ionic conductivity, uniform thickness, light weight and flexibility. In this presentation, how to fabricate cuboid SSE particles in matrix shape array and characterization of composite membrane using it will be discussed.
New Nitrile Type Bi-Functional Additive for High-Performance Li-Metal Batteries
Authors: Lee Seon-Hwa , Sun Yang-Kook
Published: February 2020

Despite the lithium metal has been considered as an ideal anode for boosting the energy density of Li-ion batteries, thermodynamic dendritic lithium growth and aggressive degradation of Ni-rich cathode during charge process hinder the practical application of Li metal/Ni-rich Li[NixCoyMn1-x-y]O2 battery. Herein, we propose an effective multifunctional nitrile type additive. This additive-induced lithium metal anode SEI layer is robust and compact, and thus beneficial to obtain mound-like Li platting morphologies during charge. This uniform and dendrite-free morphology significantly enhanced the safety issues and improved the coulombic efficiency. At the same time, this additive also enhanced the stability of electrolyte/cathode interface by strong coordination between nitrile group (additive) and transition metal (cathode active material) during charge. This coordination effectively hinders decomposition of carbonate solvent on the cathode/electrolyte interface. As a result, Li metal/Ni-rich Li[Ni0.73Co0.10Al0.02Mn0.15]O2 battery is able to achieve an excellent cycle retention even when applying the high current density (1.8 mA cm-2).

[1] S.-J. Park, J.-Y. Hwang, C. S. Yoon, H.-G. Jung, Y.-K. Sun, ACS Appl. Mater. Interfaces
2018, 10, 17985-17993

[2] Zheng, M. H. Engelhard, D. Mei, S. Jiao, B. J. Polzin, J.-G. Zhang, W. Xu, Nat. Energy
2017, 2, 17012.

[3] J.H. Kim, S. J. Kim, T. Yuk, J. Kim, C. S. Yoon, Y. K. Sun, Acs Energy Lett 2018, 3, 3002-3007

[4] S. Kim, T. H. Kim, H. Lee, H. K. Song, Energy Environ. Sci.
2011, 4, 4038-4045.
Von-Alpen Type Nasicon for Seawater Battery Application
Authors: Go Wooseok , Kim Youngsik
Published: February 2020

For utilization of renewable energy, energy storage systems (ESS) are becoming more important. Seawater battery have attracted attention for large scale ESS system due to high capacity, good cyclability and environment friendly. The seawater battery consists of seawater, cathode current collector, solid electrolyte, organic electrolyte and anode. Among the components, solid electrolyte does critical role for selective transfer of sodium ion. The requirements for the solid electrolyte are high sodium ion conductivity at room temperature, high chemical stability against seawater, wide electrochemical window (0~5V), thermostability (4oC~25oC) and strong mechanical strength. The possible candidates were sodium beta alumina and Hong type NASICON (Na3Zr2Si2PO12). In the previous research, Hong type NASICON has superior seawater stability than sodium beta alumina. So the conventional seawater battery utilizes Hong-type NASICON as solid electrolyte due to applicable properties. Among the NASICON solid electrolytes composition, Na3.1Zr1.55Si2.3P0.7O11 composition was proposed by V. von Alpen et al in 1981. As far as we know, there has no research about Na3.1Zr1.55Si2.3P0.7O11 composition on electrochemical device. In this study, Na3.1Zr1.55Si2.3P0.7O11 composition was used as solid electrolyte for seawater battery application. We investigated on the required properties and compared with Hong-type NASICON. The resulting Na3.1Zr1.55Si2.3P0.7O11 exhibited higher sodium ion conductivity due to bigger grain size and strong mechanical strength. When it applied into the seawater battery, it showed smaller overpotential and higher power with over 1 thousand hours cycling. Thus, Na3.1Zr1.55Si2.3P0.7O11 composition solid electrolyte satisfied the above requirements and exhibited superior properties than previously researched solid electrolytes for seawater battery.

References

Y. Kim, H. Kim, S. Park, I. Seo, and Y. Kim,
Electrochimica Acta
, 191, 1–7 (2016)

V. Von Alpen, M.F. Bell and H.H. Hofer,
Solid State Ionics,
3-4,215-218 (1981).

S.M. Hwang, J. Park, Y.Kim, W.Go, J.Han, Y.Kim and Y.Kim,
Advanced Materials
, 1804936 (2018)
Highly Active Transition Metal Dichalcogenides As Bifunctional Electrocatalysts for Li-Oxygen Batteries
Authors: Majidi Leily , Salehi-Khojin Amin , Curtiss Larry A
Published: February 2020

Lithium-air (Li-O2) batteries -comprising of an air (O2) cathode and a lithium anode- are able to deliver significantly higher amounts of theoretical energy densities compared to conventional Li-ion batteries. Therefore, these batteries have been extensively investigated lately to become the practical substitution for Li-ion batteries especially in transportation and electric vehicles.

Performance of a Li-O2 battery is fundamentally governed by two main reactions occurring at the cathode: oxygen reduction reaction (ORR) during discharge and oxygen evolution reaction (OER) during charge. In order to improve the performance of Li-O2 batteries, seeking a bifunctional catalyst which operates favorably in both ORR and OER reactions, is a challenging issue. The role of various materials has been investigated in OER-ORR reduction in both aprotic and non-aprotic media, including: noble metals, metal oxides, transition metals, transition metal carbides, and etc. Among these catalysts, transition metal dichalcogenides (TMDCs) such as MoS2 indicated a superior performance towards a bifunctional catalytic activity for ORR and OER in aprotic electrolytes.

Herein we report for the first time the catalytic activity of a number of novel two dimensional TMDCs with transition metals of groups V-IX and the three heavier chalcogens (S, Se, Te) in ORR-OER in an aprotic medium with Li salt. We have synthesized these materials via chemical vapor transport (CVT) and the nanoflakes accompanied by different characterization techniques such as: Raman, XPS, UPS, DLS, AFM and etc. We performed cyclic voltammetry experiements to comparatively study the TMDCs catalytic activity in ORR-OER reactions, their turnover frequency and so on. These catalysts outperformed all of the reported catalysts in aprotic media with Li salts during ORR and OER. A number of them exhibited an excellent bifunctional behavior such as: NbS2, VS2 and VSe2. Density functional theory (DFT) calculations were also performed on a number of these catalysts in order to understand their catalytic activity during ORR and OER in ionic liquid electrolyte. We believe these materials possess great potential to enhance the catalytic activity in core electrochemical reactions especially in Li-O2 battery applications.
Finite Element Simulation of Electrochemical Impedance Spectra in Li-S Batteries
Authors: Shen Chao , Andrei Petru , Zheng Jim P.
Published: February 2020

It is well-known that electrochemical impedance spectra (EIS) can provide important information about the diffusion and reaction processes in Li-S systems. While there is a large amount of experimental characterization of Li-S batteries using EIS, the theoretical modeling is mostly limited to simplified models based equivalent circuits. While these simplified models provide important information about the resistance of the electrolyte, the charge transfer resistance, and double layer capacitance, they fail to provide a more detailed physical understanding of the electrochemical processes inside the battery. Such an understanding can be provided by physics-based models, in particular by finite element models.

In this work we present for the first time a numerical method for the computation of electrochemical spectra in Li-S batteries based on finite element simulations. The model has the advantage that it is entirely framed in terms of measurable quantities, such as ion mobilities and diffusivities, reaction rate parameters, and double layer capacitance. The model is formulated in the form of a nonlinear system of partial differential equations derived from our previous work1 and which can be easily implemented numerically in standard battery simulators. In addition, the model can accurately describe the depressed semicircles of the EIS. More details about the numerical implementation of the method and a comparison with experimental results will be presented at the conference.

References

P. Andrei, C. Shen, and J. P. Zheng, Electrochim. Acta, 284, 469–484 (2018)
(Invited) Predicting the Performance of Lithium Metal Electrodes Stabilized By Polymer Electrolytes
Authors: Balsara Nitash P. , Pesko Danielle Marie , Maslyn Jacqueline A.
Published: February 2020

It is now commonplace to report the data obtained during cycling of symmetric lithium-electrolyte-lithium cells with solid polymer electrolytes. The parameter that is usually the focus is the number of cycles prior to cell failure. Quantitative prediction of cell failure is a daunting task. As a step toward that aim, we seek to predict the potential needed to cycle such cells at a function of the applied current density. We show that such predictions cannot be made on the basis of conductivity alone. The importance of complete characterization of polymer electrolytes will be discussed. This includes determination of the thermodynamic factor, salt diffusion coefficient and transference number using Newman’s concentrated solution theory. The connection between these parameters and dendrite growth is being explored. If new results are obtained, I will present them at the meeting.
Experimental Measurement of the Local Current Density in the Vicinity of a Lithium Protrusion: Plating and Stripping
Authors: Maslyn Jacqueline A. , McEntush Kyle D. , Harry Katherine J. , Balsara Nitash P.
Published: February 2020

Successful prevention of lithium dendrite growth would enable the use of lithium metal as an anode material in next-generation secondary batteries. Mechanically stiff solid polymer electrolytes have been shown to prolong the life of lithium metal cells by partially suppressing lithium dendrite growth. However, we lack fundamental knowledge about the nature of lithium electrodeposition and stripping as a function of time, as direct observation of this phenomenon is non-trivial.

Synchrotron X-ray microtomography was used observe lithium metal plating and stripping through these solid polystyrene-block-poly(ethylene oxide)-LiTFSI electrolyte membranes in the vicinity of lithium protrusions. Local current density was calculated from these experimental measurements and mapped on the top and bottom electrode under conditions of lithium metal plating and stripping. Local current density at one electrode was correlated to local current density at the other electrode and to electrode thickness. We show quantitatively how lithium protrusions are stripped at a faster rate than planar lithium and gain insight into the lithium ion transport governing protruding lithium growth in a cycled lithium metal electrode.
Toward Garnet-Based Electrolyte Li-Metal Batteries: A Highly Effective Solid-State Electrolyte- Li Metal Interface
Authors: Sharafi Asma
Published: February 2020

The widespread adoption of electric-powered vehicles (electric vehicles, plug-in hybrids, etc.) stimulated the desire to pursue solid-state batteries (SSBs) with energy densities beyond those of lithium-ion batteries as well as long cycle life and safety. Many technological elements are involved in successful development and commercialization of SSBs, including solid-state electrolyte (SSE) materials, ionic conductivity enhancement, electrolyte/electrode interface stability, enabling Li metal anode, cell and pack manufacturing methods, battery management system, and battery pack design. The principle focus of this talk will be a discussion centered on charge transfer at the Li metal-SSE interface and its effect on electrolyte/electrode interface stability during Li plating/striping to enable Li metal anode. Further discussion will focus on the impact of lithiated interfacial coating layers on the interfacial impedance, which has enabled the uniform plating of Li at the Li-SSE interfaces. In this study, garnet-type oxide with nominal composition of Li7La3Zr2O12 (LLZO) has been used as model system due to its simultaneous fast-ion conductivity and stability against metallic Li.
Highly Conductive Li7La3Zr2O12/PVDF Composite Polymer Electrolyte for Rechargeable Lithium Ion Batteries
Authors: Li Junhao , Wang Ruigang
Published: February 2020

Commercialized LIBs have disadvantages such as overheating and catching on fire due to the utilization of liquid organic electrolytes. To expand the applications of LIBs, the development of solid-state lithium-ion conductive electrolyte materials, which are nonflammable, more durable for high temperature, more resistive to lithium dendrite and have wider electrochemical operating voltage window, is urgently needed.

Among the various types of solid-state lithium-ion conductive electrolyte candidates, the garnet-type Li7La3Zr2O12 (LLZO) has attracted significant attention due to its high ionic conductivity and superior electrochemical stability corresponding to a wide electrochemical window. By combine the sol-gel synthesis and high energy ball milling, we investigated the phase transition from tetragonal Li7La3Zr2O12 to cubic Li7La3Zr2O12 without subsequent high-temperature calcination. For the sample calcined at 900 °C for 6 h, X-ray diffraction measurement revealed that the ball milling treatment induces a direct phase transition from tetragonal Li7La3Zr2O12 to cubic Li7La3Zr2O12 without high-temperature heat treatment. However, in a comparative study, cubic Li7La3Zr2O12 can only be obtained after high-temperature calcination above 1180 °C. We hypothesize that the high energy ball milling promotes the accumulation of Li+ vacancy leading to this easy phase transition. This study establishes an efficient way to transform tetragonal Li7La3Zr2O12 to cubic Li7La3Zr2O12 at lower calcination temperature via high energy ball milling treatments.

In addition, dispersing cubic Li7La3Zr2O12 powders as active inorganic electrolyte fillers in polymer matrix to synthesize flexible and easy-to-process Li7La3Zr2O12/PVDF composite polymer electrolytes (CPEs) is also being investigated in order to enhance not only ionic conductivity but also mechanical properties and thermal stability of polymer electrolytes.
Approaches and Needs for the Validation of Lithium Metal Plating Stability Models with a Solid Electrolyte
Authors: Albertus Paul
Published: February 2020

Numerous models have been proposed that treat the stability of lithium metal plating in cells that use a solid electrolyte, and the conditions under which dendrite initiation and propagation can be suppressed. These models treat a variety of systems (e.g., liquid electrolytes, solid polymer electrolytes, and inorganic electrolytes both with and without grain boundaries) and types of physical processes (e.g., current and potential distributions, elastic and plastic mechanics) . However, one underlying challenge for all lithium plating stability models is the lack of validation for the predictions they make about stability. This talk will provide an overview of previously developed stability models, highlight the gaps in the physical processes and practical operating conditions they address, and describe experimental methods being pursued and that may be pursued to provide the critical experimental feedback required for the validity of stability models to ultimately be assessed. A number of practical issues and perspectives gained from the time the author served as a Program Director at ARPA-E working in the area of lithium metal batteries will also be included.
Properties of Li7La3Zr2O12 Solid Electrolytes Synthesized from Highly Basic Molten Salts Fluxes
Authors: Weller Jon Mark , Chan Candace K.
Published: February 2020

Molten salt synthesis (MSS) is an alternative synthetic route to solid state reaction to obtain dopant stabilized, garnet-type Li7La3Zr2O12 (LLZO) with both fine particle size and high ionic conductivity. Molten salt fluxes are high temperature solvents with properties that can be tuned based on the salt composition, use of additives, and Lux-Flood basicity of the media. Compared to solid state reaction, molten salt synthesis can produce highly crystalline powders with smaller particle sizes at lower temperature and with shorter reaction times. Herein, our work investigating the effect of basicity on the reaction kinetics, formation temperature, phase purity, dopant distribution, and particle size distribution for the formation of doped LLZO garnets will be presented. We find that a variety of halide, hydroxide, and nitrate salt fluxes are effective for preparation of LLZO garnets with a range of particle sizes and crystal morphologies. Furthermore, highly basic salt fluxes can enable Ta-doped LLZO with cubic crystal structure to be obtained at 400 oC, an unprecedented low temperature synthesis for LLZO. The distribution of Ta5+ dopant in individual LLZO particles is assessed using high resolution transmission/scanning electron microscopy and reveals that the composition is inhomogeneous. The origin of this inhomogeneity is attributed to differences in solubility of the Ta and Zr oxides in the molten salt melt, but is mitigated by using a novel quasi-single source precursor that enables better delivery of the reagents in the salt flux. Finally, the Li ionic conductivity of LLZO pellets prepared using molten salt synthesis using various sintering conditions is compared to LLZO made by conventional solid state reaction.
Graphene Mesosponges for the Conductive Additive of Cathode Composites in Lithium−Sulfur All-Solid-State Batteries
Authors: Yamamoto Masanori , Nishihara Hirotomo , Goto Shunsuke , Yoshioka Youichi , Ito Masashi , Mitsuyama Tomohiro , Morooka Masahiro , Kyotani Takashi
Published: February 2020

All-solid-state lithium−sulfur batteries are a class of promising energy storage technologies because of the low cost of sulfur as the active material, high safety due to no use of volatile organic solvents, high theoretical energy density (2600 Wh kg−1), and being operative at high temperature. However, they suffer from the limited utilization of sulfur when the rate of charge/discharge processes is fast, partly because the active material is highly insulating with s of 10−30 S cm−1. Moreover, it is highly desired to use as much sulfur in the cathode composite as possible while maintaining the electrochemical performance for the practical application, but the literatures reported thus far utilized lower surface loading of sulfur ranging from 9 to 50wt%. The choice of conductive additive such as activated carbons in the cathode composites will be crucial in improving and controlling the electrochemical processes. In this regard, graphene mesosponges (GMS) are a class of unprecedentedly functional carbon materials having the high electrochemical stability, electric conductivity, structural flexibility, and mesostructured nanopores (Nishihara, H. et al. Adv. Funct. Mater.
2016, 26, 6418–6427; Energy Environ. Sci.
2019 DOI: 10.1039/C8EE03184C), and therefore, are promising as the conductive supports in cathode composites of lithium−sulfur all-solid-state batteries.

The utilization of GMS as the conductive additive indeed showed a good electrochemical performance with a gravimetric capacity of 690 mA h g−1 at 80 ºC at a rate of 0.2C even with 50wt% of sulfur loaded in the cathode composites. The elastic nature with the bulk modulus of ca. 0.8 GPa and large pore volume (~5 mL g−1) of the 3D graphene materials will be suitable for the charging/discharging processes that require a large volumetric change of the cathode composites (ca. 80%) as going from sulfur (~2 g cm−3) to lithium sulfide (1.66 g cm−3) with the following equation 2Li++S+2e− ⇄ Li2S. Moreover, the phase segregation in micrometer scale occurred with high loading of the active material (50−60wt%) was suppressed by the confinement of insulating sulfur into the mesopore of the elastic 3D graphene, achieving the durable three-phase contact between a solid-electrolyte, insulating sulfur, and the electric conductive carbon. As a result, both the rate characteristic and durability of the all-solid-state batteries were higher than those with a typical activated carbon, and the electrochemical operation was feasible under the harsh operation conditions up to 80 ºC with the specific charge/discharge capacities of 3.4 mA h cm−2 (2 C) even with the unprecedentedly high sulfur-loading (60wt%).