bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanochemical Synthesis of High Purity Anhydrous Binary Alkali and Alkaline Earth Chloride Mixtures
Authors: Halstenberg Philip , Maltsev Dmitry , Kim Ellie , Nguyen Dianna , Ivanov Alex , Mahurin Shannon , Dai Sheng
Published: December 2020

A direct synthesis route for high purity anhydrous binary and ternary salt mixtures has been developed. This atom efficient, solvent free process is easily scalable with potential to produce salt eutectics with purity standards required to meet the needs of industrial heat transfer and nuclear applications. The methodology involves mechanochemical mixing of alkali and alkaline earth chloride salts followed by subsequent drying under dry air laminar flow. Each salt mixture was then analyzed for waters of hydration, purity, and oxide content through subsequent thermogravimetric analysis, X-ray diffraction, and strong acid titration. This process is proposed to provide a cost effective, single pot synthesis for both fuel and coolant chloride salt compositions for use in generation IV molten salt reactor systems. This work was supported as part of the Molten Salts in Extreme Environments Energy Frontier Research Center, funded by the U.S. Department of Energy Office of Science.
A Comparative Study of Imidazolium-Based Ionic Liquid-Single-Walled Carbon Nanotube Composites with Enhanced Conductivity Properties for Supercapacitor Applications
Authors: Hemraj-Benny Tirandai , Lall-Ramnarine Sharon I. , Suarez Sophia , Paterno Domenec , Ramdihal Jasodra D. , Sumner Rawlric , Urena Katelyn , Wishart James F.
Published: December 2020

Mixtures of ionic liquids (ILs) containing single-walled carbon nanotubes (SWCNTs) were prepared and characterized to obtain electrolytes with optimized transport properties for the use in energy storage devices such as supercapacitors. Imidazolium ILs bearing cations with side chains of different functionality coupled with bis(trifluoromethylsulfonyl)amide (NTf2
-) or bis(fluorosulfonyl)amide (FSA-) anions were used in mixtures containing up to 5 wt % SWCNTs. It was determined that the ionic conductivities of all ILs studied can be significantly increased with the addition of single-walled carbon nanotubes when the loading of the nanotubes is above 2 wt %. Moreover, higher conductivities were observed for the ILs containing the NTf2
- anion and 5 wt % SWCNTs. These results can significantly contribute to the development of improved energy storage devices. The work at Brookhaven National Laboratory was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences under contract DE-SC0012704. The work at Brooklyn College was supported by the National Science Foundation, Solid State and Materials Chemistry Program, Division of Materials Research, EAGER award #1841398.
Developing Polyionic Biocomposite Materials through Natural Fiber Welding
Authors: Durkin David P. , Hoffman Christian E. , Cosby Tyler , Aiello Ashlee , Mcfarland Julia A. , De Long Hugh C. , Woodcock Jeremiah W. , Trulove Paul C.
Published: December 2020

Biomaterials such as cotton and silk are abundant natural resources that have demonstrated material properties equal or superior to many synthetic polymers. Using ionic liquids (ILs) and the Natural Fiber Welding (NFW) process, these biomaterials can be chemically and physically enhanced. Here we present our progress on using imidazolium-based polymerizable ionic liquids (Poly-ILs) in the NFW process to prepare polyionic biocomposites. A variety of Poly-ILs with different cation and anion structures were synthesized and subsequently characterized using 1H and 13C NMR. Each Poly-IL was evaluated for its ability to (i) polymerize and (ii) solubilize a biopolymer (cellulose) matrix, revealing anion structural motifs that either limit or enhance a Poly-IL’s ability to polymerize and weld. Optimized parameters yielded polyionic biocomposite materials whose physicochemical properties were evaluated using ATR, SEM and EIS.

Figure 1
Influence of Physicochemical Properties on Gas Transport Properties of Silver-Containing Ionic Liquid Mixtures for Olefin/Paraffin Membrane Separation
Authors: Park Sejoon , Freeman Benny D. , Brennecke Joan F.
Published: December 2020

Olefin/paraffin separation by cryogenic distillation is one of the most energy-consuming processes not only among the entire chemical processes but also among all the energy-consuming activities by human beings. The purification of propylene and ethylene accounts for 0.3% of global energy use (1). Membrane separation is an attractive alternative, owing to its high energy-efficiency compared to conventional distillation processes. Liquid membranes that utilize gas transport through the liquid phase confined in the pore structures have shown promising performance due to the faster transport compared to solid membrane materials (2).

Since the liquid phase is where the transport of olefin/paraffin molecules occurs, the liquid membrane performance in terms of permeability, selectivity, and stability mainly relies on the properties of the liquid component. Ionic liquids are a suitable material since the liquid component in the membranes provide stable separation performance owing to their extremely low vapor pressure and good thermal/chemical stability. Moreover, the limitless turnability of ionic liquids can be manipulated to enhance the molecular interaction with certain gas molecules to result in better gas solubility. For olefin/paraffin separation, in addition to physical solubility of the olefin in the ionic liquid, silver ions are commonly added to further improve olefin solubility. The silver ions can complex with olefin molecules via interaction between the double bonds of olefins and the orbitals of silver ions.

Here we have investigated the effect of the anion, concentrations of the silver salt, and temperatures on the physicochemical properties of the silver-containing ionic liquid mixtures. The macroscopic physicochemical properties, such as viscosity and density, affect the filling of the membrane pores and stability to transmembrane pressure. However, we show that they are also indicators of ion aggregation in the mixtures, which can be correlated with relevant membrane properties, including solubility, diffusivity and silver ion reactivity with contaminant gases. The physiochemical viewpoint on the silver-containing ionic liquid mixture will provide appropriate insight for understanding the olefin/paraffin gas transport in the ionic liquid mixture, which leads to a design idea for better separation performance.

(1) D. S. Sholl, R. P. Lively, Seven chemical separations: to change the world: purifying mixtures without using heat would lower global energy use, emissions and pollution--and open up new routes to resources. Nature
532, 435 (2016).

(2) C. M. Sanchez, T. Song, J. F. Brennecke, B. D. Freeman, Hydrogen Stable Supported Ionic Liquid Membranes with Silver Carriers: Propylene and Propane Permeability and Solubility. Industrial & Engineering Chemistry Research
59, 5362-5370 (2020).
Melt Spinning of Polyacrylonitrile (PAN) Fibers Based on Ionic Liquids
Authors: Luo Huimin , Martin Halie , Chen Hao , Dai Sheng
Published: December 2020

The production of high strength carbon fibers is an energy intensive process where a significant cost involves the wet or dry spinning of polyacrylonitrile (PAN) fiber precursors. Melt spinning PAN fibers would allow for significant reduction in production cost and production hazards. Ionic liquids (ILs) are an attractive fiber processing medium due to their negligible vapor pressure and low toxicity. In addition, they are carbon forming precursors; upon carbonization residual ILs can enhance carbon yield although primarily useful for plasticized melt spinning of PAN precursor fibers. In this presentation, the influence of the molecular structure of the ILs and the control of the plasticizing interactions with PAN during melt spinning will be discussed. The structure, thermal and mechanical properties of the melt spun PAN fibers are investigated by a combination of various characterization methods, such as differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-Ray Diffraction (XRD) and mechanical testing. Our results demonstrate that ionic liquid structure and counter-anions influence the PAN fiber formation. More specifically, ILs containing bromide counter-anions produced PAN precursor fibers with increased mechanical properties compared to ILs containing chloride anions. We believe that our research can provide foundation to understand the influence of ILs on melt spinning of PAN fibers and gives the guidelines for the more cost/energy efficient production of PAN-based carbon fibers.
Nucleation Study on Deposition of Aluminum from 1-Butyl-3-Methylimidazolium Chloride and Aluminum Chloride Ionic Liquid Electrolyte
Authors: Peng Yuxiang , Shinde Pravin , Reddy Ramana G.
Published: December 2020

In this study, aluminum is electrodeposited from ionic liquids comprising a melt of 1-butyl-3-methylimidazolium chloride (BMIC) and aluminum chloride (AlCl3) at the AlCl3 mole fraction of 0.667 (molar ratio of 1:2). The electrochemical behavior of chloroaluminate species in the ionic liquid is investigated by the chronoamperometry (CA) technique at different temperatures. The diffusion coefficients (D) of Al2Cl7
- species in such ionic liquid are calculated at various temperatures. The SEM was used to measure the grain size of the deposits. The calculated average radius of the Al deposit was 6.3 × 10-6, 5.2 × 10-6, and 4.3 × 10-6 m at 363 K, with an applied potential of 1.7, 1.75, and 1.8 V respectively. The calculated grain radius is comparable to the experimental data of electrodeposits. In addition, the rate of nucleation during the electrodeposition is also investigated.
Charge Transport and Dynamics in Imidazolium Chloroaluminate Ionic Liquids
Authors: Cosby Tyler , Durkin David P. , Mantz Robert A , Trulove Paul C.
Published: December 2020

Imidazolium based chloroaluminates were the first widely studied room-temperature ionic liquids. However, work in these systems has waned over the past 25 years in favor of ionic liquids with less reactive anions. Researchers are beginning to rediscover chloroaluminates because they possess some very advantageous properties that hold significant promise for applications such as energy storage, electrodeposition, and chemical synthesis. Chloroaluminates are not simple mixtures of a single cation with a single anion. It is more appropriate to think of these systems as binary mixtures of two ionic liquids which share the same cation. The binary nature of the chloroaluimates leads to highly tunable physical and chemical properties including liquidus range, electrochemical stability window, dc ionic conductivity, zero-shear viscosity, and static dielectric permittivity. However, the binary nature also leads to significant experimental challenges with respect to characterization of the structure and anion speciation in the chloroaluminates. The majority of work characterizing the imidazolium based chloroaluminate was conducted more than 25 years ago and focused on physical property measurements across limited compositions and/or narrow temperature/frequency ranges. The data from these early studies revealed important aspects of chloroaluminate physical properties; however, due to their limited scope they failed to make significant progress in understanding underlying structure-property relationships which are critical to realizing the full potential of chloroaluminate ionic liquids as electrolyte systems. Our current work seeks to reexamine imidazolium chloroaluminate ionic liquids leveraging the improved experimental tools and capabilities available today. In this presentation we will discuss our initial studies of imidazolium chloroaluminate ionic liquids using broadband dielectric spectroscopy, oscillatory shear rheology, and Raman spectroscopy. We will present preliminary work on the impact of changes in cation structure and ionic liquid composition on anion speciation, transport properties, and dynamics.
Mesoporous All-Cellulose Composites
Authors: Aiello Ashlee , Mcfarland Julia A. , Cosby Tyler , De Long Hugh C. , Durkin David P. , Trulove Paul C.
Published: December 2020

Natural cellulosic biopolymer matrices are readily dissolved using ionic liquid (IL) solvents. The dissolved biopolymer can be reconstituted from the ionic liquid using a solvent exchange. Variations in the solvent exchange process have been shown to strongly influence the final morphology in reconstituted cellulose from IL-cellulose solutions, including mesopore formation. We will report on the use of variable solvent exchange to form mesoporous all-cellulose composites. We have characterized these materials using AFM (height and nanomechanical mapping), SEM, XRD, and gas physisorption techniques. We will discuss these results, including the effects of variable IL treatment and solvent exchange parameters on the BET surface area, pore size, and material properties (e.g. modulus and adhesion).
Ion Conductivity of Li0.5+XLa0.5TiO3 Materials for Li-Ion Solid Electrolyte
Authors: Tsai Chia Sheng , Yen Chih Ping , Lee Yi Hsuan , Wu Maw Kuen
Published: December 2020

The practical application of Li0.5+xLa0.5TiO3(LLTO) perovskite structural materials is limited by its low total conductivity. In order to improve the ionic conductivity, different ratios of Li-doping material were investigated in this study. LLTO materials were synthesized by the solid-state reaction method. From XRD pattern results, with increasing the ratio of Li/La to 1.6, the structure of the Li0.8La0.5TiO3 material was starting to change from complete perovskite structure to partial Ruddlesden–Popper perovskite structure. Also, the ohmic resistance of the LLTO materials decreased with the ratios of Li/La from 1 to 1.5. As the ratios of Li/La were larger than 1.6, the ohmic resistance would increase because of the structure change.
Synthesis of Li7La3Zr2O12 Li-Ion Conducting Electrolytes By a Rapid Solution-Combustion Method
Authors: Badami Pavan P , Arif M Z , Rettenwander Daniel , Chan Candace K. , Kannan Arunachala Mada
Published: December 2020

Garnet structured Li-ion conductors (Li7La3Zr2O12, LLZO) have attracted great attention as promising solid electrolytes for all-solid-state batteries, owing to their wide electrochemical window, better thermal stability and high Li-ion conductivity at room temperature [1,2]. Synthesis of cubic phase LLZO using solid state reaction routes requires high reaction temperatures and long reaction time producing unfavorable micron sized particles [3]. In the present study, a rapid and facile synthesis of LLZO in sub-micron size by combustion method using CH6N4O fuel is demonstrated. The effect of fuel to oxidizer ratio, calcination temperature on phase purity, particle size towards formation of LLZO was systematically was examined and the synthesis conditions were optimized to attain high relative densities and conductivities of the pellets. In particular, Al and Ga stabilized LLZO were synthesized as low as 600 °C for duration of 4 h and the pellets showed high Li +conductivity (up to 0.5 mS.cm-1) with relative densities (~ 95 %). Furthermore, studies on critical current densities (CCD) measurements of these pellets would be presented compared to conventional solid-state reaction-based pellets. The presented work is expected to provide insight on producing sub-micron sized LLZO particles at lower synthesis temperatures allowing to explore improved performance of composite-polymer electrolytes and producing thin films.

Keywords
: garnets, solution combustion synthesis, sintering and critical current densities.

References

[1] R. Murugan, V. Thangadurai, and W. Weppner, Angew. Chemie - Int. Ed., 46, 7778–7781 (2007).

[2] R. Pfenninger, M. Struzik, I. Garbayo, E. Stilp, and J. L. M. Rupp, Nat. Energy, 4, 475–483 (2019).

[3] P. Badami, J.M. Weller, A. Wahab, G.J. Redhammer, L. Ladenstein, D. Rettenwander, M. Wilkening, C.K. Chan and A.M. Kannan, ACS Appl. Mater. Interfaces (Under review).

Figure 1
Solid-State Battery Designed for Electric Aviation
Authors: Dornbusch Donald , Viggiano Rocco P. , Kowalski Benjamin A , Lin Yi , Dynys Frederick W. , Connell John W. , Wu James J.
Published: December 2020

The demand for higher energy density batteries increases as the demand for portable electronic devices and electric automotive increases, as well as a variety of other applications requiring substantially higher power and energy than attainable with current lithium-ion capabilities which includes the areas of high performance vehicles, military applications, and electric aviation. However, the improvement of energy density is insufficient alone for enabling electric aviation when considering the high flammability and risk of thermal runaway inherent in current state-of-the-art liquid electrolytes. The development of high energy, high power, and safe batteries are required to enable hybrid and fully electric aircraft.

Next generation chemistries such as lithium-sulfur provide high theoretical specific energy density suitable for electric aviation without as strict of volumetric requirements observed in the automotive industry. However, due to the phase transition during discharge where sulfur generates a series of soluble intermediate polysulfides, which are lost to the liquid electrolyte, cause detrimental side effects, and severely limit cycle life battery performance is severely reduced. Additionally, the low electrical conductivity of sulfur requires a large amount of inactive carbon dramatically increasing parasitic mass.

The dissolution issue make sulfur a desirable candidate to pair with a solid-state electrolyte in order to avoid polysulfide dissolution and shuttling. In addition, inorganic solid-electrolytes have low flammability providing the improved safety required. Combining this chemistry with a solid-state electrolyte provides a path for achieving the energy and safety required for electric aviation.

The development of scalable thin solid-state electrolytes paired with lithium-sulfur chemistry will be discussed and how their development will aid in enabling a unique application.
(Invited) Temperature-Flexible High Performance Quasi Solid-State Batteries
Authors: Gritton Jack , Fu Zhezhen , McOwen Dennis W. , Wachsman Eric
Published: December 2020

Lithium-rich garnet solid electrolytes are one of the most promising avenues for high temperature lithium metal batteries due to the non-flammability, high ionic conductivity, and exceptional thermal stability compared to liquid electrolytes. One of the main issues remaining is the interface of garnet with cathode materials. Simply layering the garnet and cathode results in high interfacial impedance
[1]
, whereas co-sintering studies attempting to improve contact have shown detrimental reactions
[2],[3]
. Organic or ionic liquid electrolytes have been applied to wet the interface with traditionally cast cathodes and have shown improvement in room temperature performance
[1]

,[4]
. In this study, the ionic liquid electrolyte (IL) 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide with LiTFSI was utilized as catholyte due to its inherent high thermal stability >100°C and nonvolatility to produce cells capable of both room temperature and high temperature cycling. The catholyte was applied in garnet-based batteries with a lithium metal anode and either LiFePO4 or TiS2 cathodes. The cell performance and solid-liquid electrolyte interface were studied from room temperature into the high (> 90°C) temperature regime. High utilization of cathodes, high rate capability, and impressive cycling stability were observed during high temperature cycling. Using tools such as electrochemical impedance spectroscopy, distribution of relaxation times analysis, and electron microscopy, the role of interfacial layers was elucidated to understand and optimize the system. This dual electrolyte approach shows thermal flexibility from room temperature to beyond the boiling point of many common liquid electrolytes.

[1] Frederic Aguesse and others, ‘Investigating the Dendritic Growth during Full Cell Cycling of Garnet Electrolyte in Direct Contact with Li Metal’, 2017 .

[2] V Thangadurai and W Weppner, ‘Investigations on Electrical Conductivity and Chemical Compatibility between Fast Lithium Ion Conducting Garnet-like Li 6 BaLa 2 Ta 2 O 12 and Lithium Battery Cathodes’, 142 (2005), 339–44 .

[3] Lincoln J Miara and others, ‘First-Principles Studies on Cation Dopants and Electrolyte | Cathode Interphases for Lithium Garnets’, 2015 .

[4] Manuel Weiss and others, ‘From Liquid - to Solid - State Batteries : Ion Transfer Kinetics of Heteroionic Interfaces’, Electrochemical Energy Reviews, 2020 .
Lowering the Interfacial Resistance in LLZTO:PEO Electrolytes By Covalent Surface Modifications
Authors: Kuhnert Eveline , Slugovc Christian , Trimmel Gregor , Wilkening Martin , Rettenwander Daniel
Published: December 2020

Reducing the high interfacial resistance across the cubic Li7La3Zr2O12 (LLZO) | poly(ethylene oxide) (PEO) interface in LLZO:PEO membranes is one of the key challenges to realize future solid-state lithium batteries.1,2

Recently, several groups presented various approaches to enhance the ionic charge transport across the interface.3,4 As an example, Gupta and Sakamoto showed that heat treatment to remove surface impurities and that an increase in the Li-salt concentration in PEO to match the chemical potential between LLZO and PEO lead to significantly lower interfacial resistance.3

Herein, we present an alternative but complimentary approach to improve the interfacial kinetics by an advance surface modification strategy. For this purpose, we activated the surface terminated oxygen of Li6.4La3Zr1.4Ta0.6O12 (LLZTO) particles by plasma etching and functionalized the activated oxygen by immersing the LLZTO particles in a (3-glycidyloxypropyl)trimethoxysilane solution to form covalently bonded self-assembled monolayers (SAMs). The SAMs are terminated by an epoxy group that react with the hydroxyl group of the PEO’s according to a ring-opening reaction. This reaction may lead to an ordered arrangement of covalently bonded PEO segments around the LLZO particles enabling the Li ions to easily cross the LLZTO | PEO interface. Indeed, we managed to lower the interfacial resistance by more than four orders of magnitude. Finally, with our approach we realized an area specific resistance of 500 Ω cm2 at 20 °C; to our knowledge, this value is the lowest one reported so far.

Reference
s
:

[1] J. Schwenzel, K. Kun, F. Langer in: R. Murugan, W. Weppner (Eds.), Solid Electrolytes, Springer, Swizerland, 2019, pp. 281–304.

[2] X. Judez, G.G. Eshetu, C. Li, L.M. Rodriguez-Martinez, H. Zhang, M. Armand, Joule 2 (2018) 2208–2224.

[3] A. Gupta, J. Sakamoto, Electrochem. Soc. Interface 28 (2019) 63–69.

[4] Z. Huang, W. Pang, P. Liang, Z. Jin, N. Grundish, Y. Li, C.A. Wang, C.A., J. Mater. Chem. A, 7 (2019) 16425–16436.
Room Temperature to 150 °C Lithium Metal Batteries Enabled By a “Molecular Ionic Composite” Solid Electrolyte
Authors: Yu Deyang , Pan Xiaona , Zanelotti Curt J. , Lin Feng , Madsen Louis A.
Published: December 2020

Molecular ionic composites (MICs) are a new class of solid electrolyte materials developed recently in our group. These materials are constructed from various ionic liquids and a highly charged rigid rodlike polymer, poly(2,2′-disulfonyl-4,4′-benzideneterephthalamide) (PBDT). MICs demonstrate an unprecedented combination of thermal properties (stability up to 300 °C), mechanical properties (E′ up to ~ 1 GPa), and ion transport properties (ionic conductivity up to 8 mS/cm).[1-3] Here we present preparation and characterization of a MIC membrane based on the PBDT polymer, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (Pyr14TFSI) and LiTFSI. This MIC membrane is robust and flexible, and exhibits ionic conductivity ~ 0.2 mS/cm at room temperature. Due to the electrochemical and mechanical stability of the MIC membrane at elevated temperature, Li/MIC/LiFePO4 coin cells demonstrate excellent cycling performance over a wide temperature range from 20 to 150 °C. This study demonstrates that MIC materials represent a promising electrolyte platform for safe and wide-temperature-range lithium batteries.

References:

[1] Y. Wang, Y. Chen, J. W. Gao, H. G. Yoon, L. Y. Jin, M. Forsyth, T. J. Dingemans, L. A. Madsen, Adv. Mater.
2016, 28, 2571.

[2] J. E. Bostwick, C. J. Zanelotti, C. Iacob, A. G. Korovich, L. A. Madsen, R. H. Colby, Macromolecules
2020, 53, 1405.

[3] R. J. Fox, D. Yu, M. Hegde, A. S. Kumbhar, L. A. Madsen, T. J. Dingemans, ACS Appl. Mater. Interfaces
2019, 11, 40551.

Figure 1. Cycling performance of Li/MIC/LiFePO4 coin cell at 150 °C. Inset image is a MIC membrane.

Figure 1
Highly Sodium-Ion Conductive Sulfide Electrolyte Film Prepared By Pulsed Laser Deposition
Authors: Sakuda Atsushi , Nishimura Masaki , Yubuchi So , Tatsumisago Masahiro , Hayashi Akitoshi
Published: December 2020

All-solid-state sodium secondary batteries exhibit significant potential for use in next-generation batteries that offer advantages associated with safety and cost. The key material in this battery technology is a solid electrolyte that conducts sodium ions. The most typical solid electrolyte for all-solid-state sodium batteries is Na3PS4 [1]. All-solid-state batteries using Na3PS4 and several electrode active materials operate at room temperature. At their present stage of development, the operation of all-solid-state sodium batteries under high current densities is challenging. It was recently reported that Na3SbS4 solid electrolytes showed a high ionic conductivity that exceeded 10-3 S cm-1 [2-4], which was higher than that of Na3PS4 glass-ceramic [1]. The evaluation of bulk ionic conductivity is important for determining the potential of the electrolytes. However, most previous studies have reported on the ionic conductivities of compressed powder pellets.

Numerous studies have employed pulsed layer deposition (PLD) for fabricating lithium-ion-conducting sulfide electrolyte films. However, PLD has been seldom used for developing sodium-ion-conducting solid electrolyte films thus far. Herein, a thin film of highly dense Na3SbS4 solid electrolyte was prepared by PLD to evaluate its potential sodium-ion conductivity. The as-deposited film was observed to be amorphous, whereas a cubic crystalline phase of Na3SbS4 was formed in the thin film after heat treatment at 190°C. Crystallization of the thin film after heat treatment increased ionic conductivity and decreased activation energy. The heat-treated film showed a conductivity of 1.7×10-2 S cm-1 at 25°C and an activation energy of 15 kJ mol-1 for conduction. Further, it was discovered that the Na3SbS4 solid electrolyte has a high conductivity of more than 10-2 S cm-1 at room temperature. The evaluation of the chemical composition of the film suggested that there are some vacancies in sodium site.

Acknowledgements:

This work was supported by the MEXT program "Elements Strategy Initiative to Form Core Research Center (ESICB)" and JSPS KAKENHI Grant Nos. 18H05255 and 19H05816.

References:

[1] A. Hayashi, K. Noi, A. Sakuda and M. Tatsumisago, Nat. Commun., 3, 856 (2012).

[2] H. Wang, Y. Chen, Z.D. Hood, G. Sahu, A. S. Pandian, J. K. Keum, K. An, C. Liang, Angew.Chem. Int. Ed., 55, 8551 (2016).

[3] A. Banerjee, K. H.Park, J. W. Heo, Y.J. Nam, C. K. Moon, S. M.Oh, S.-T. Hong, Y.S. Jung, Angew. Chem. Int. Ed., 55, 9634 (2016).

[4] L. Zhang, D. Zhang, K. Yang, X. Yan, L. Wang, J. Mi, B. Xu, Y. Li, Adv. Sci.
3, 1600089 (2016).
(Invited) Metal-Carbon Nanocomposite Anode for Solid-State Li Batteries
Authors: Im Dongmin , Lee Yong-Gun , Kim Jusik
Published: December 2020

Li metal has long been considered as one of the most promising anodes for rechargeable batteries as it can store larger energy than other conventional ones. However, the dendritic growth of Li metal during the plating process aggravates the cycling performance and causes the safety issues, restricting the use of it in commercial batteries. We have found that a silver-carbon nanocomposite layer, when employed in combination with solid electrolyte, prohibits the dendrite formation and allows the homogeneous Li metal plating and stripping on the surface of current collector. The high coulombic efficiency thus achieved also eliminates the need of excessive Li metal, further increasing the cell energy density and decreasing the production cost. The silver particles are dissolved in the Li metal during the charging process and appear to assist the homogeneous Li plating. On the other hand, the carbon layer keeps the solid electrolyte physically separated from Li metal, preventing the chemical degradation of solid electrolyte and the Li metal penetration through it. Consequently, the nanocomposite anode formed on a current collector can offer high energy density and long cycle life in the solid-state batteries.
Lithium Dissolution Using Garnet-Type Solid Electrolyte with a Thin Ionic Liquid Interlayer
Authors: Fuchs Till , Richter Felix H. , Janek Juergen
Published: December 2020

Currently, all-solid-state batteries enjoy widespread attention in research due to their expected high safety, power and energy density. This stems from their promise of being able to utilize lithium metal as the anode material. As of now, competitive batteries using lithium metal do not exist since most solid electrolytes are not chemically compatible in combination with a lithium anode. As garnets based on the Li7La3Zr2O12 system are stable versus lithium, this solid electrolyte can be used as a model system to study lithium metal stripping and plating.(1,2)

One of the manifold problems regarding lithium metal anodes is based on the morphological changes occurring when stripping and depositing lithium during cycling of a cell.(1) Current densities above a certain threshold lead to pore formation and subsequent contact loss of lithium from the solid electrolyte, as vacancies are not transported away at a sufficient rate. This issue also leads to dendrite formation when depositing lithium due to current constriction on the remaining contact spots. Hence, this work aims to exploit thin ionic liquid interlayers as a means to compensate or attenuate pore formation at the interface. We observed an improvement in dissolution behavior of the lithium metal anode and additionally were able to identify the transport processes when using ionic liquids in combination with Li6.25Al0.25La3Zr2O12 using electrochemical impedance spectroscopy. We underline our conclusions with microscopic morphological studies using scanning electron microscopy. This work acts as a stepping-stone for the assembly of all-solid-state batteries using lithium metal as the anode in hybrid-cell configurations.

(1) Krauskopf, T.; Hartmann, H.; Zeier, W. G.; Janek, J. Toward a Fundamental Understanding of the Lithium Metal Anode in Solid-State Batteries - An Electrochemo-Mechanical Study on the Garnet-Type Solid Electrolyte Li6.25Al0.25La3Zr2O12. ACS Appl. Mater. Interfaces
2019, 11 (15), 14463–14477.

(2) Krauskopf, T.; Dippel, R.; Hartmann, H.; Peppler, K.; Mogwitz, B.; Richter, F. H.; Zeier, W. G.; Janek, J. Lithium-Metal Growth Kinetics on LLZO Garnet-Type Solid Electrolytes. Joule
2019, 3 (8), 2030–2049.
Deformation and Stresses in Solid-State Composite Battery Cathodes
Authors: Yu Hui-Chia , Taha Doaa , Thompson Travis , Taylor Nathan J , Drews Andy , Sakamoto Jeff , Thornton Katsuyo
Published: December 2020

Differences in thermal contraction/expansion and volume changes during discharge/charge cycles lead to internal stresses that ultimately cause degradation of solid-state composite cathodes, hindering the realization of their practical applications. The mechanical equilibrium equation is solved using the smoothed boundary method for the residual stresses induced by cooling from the sintering temperature and by (de)lithiation in polycrystalline composite microstructures that are similar to realistic solid-state composite cathodes. The composite slabs' deformations under the fabrication and operation conditions are also predicted from the simulations. The effects of cathode thickness and selections of different cathode materials on the resulting residual stresses and deformations are examined. It is found that the (de)lithiation stresses during cycling are more than twice the residual thermal stresses after sintering. Furthermore, the maximum (de)lithiation and residual thermal stresses are sensitive to the cathode thickness only when the cathode-layer thickness is comparable to that of the electrolyte separator layer. We also investigate the impact of the lithium site fraction of the cathode particles prior to sintering on the cycling stresses and deformations, which may pave the path toward an approach to mitigating mechanically induced degradation.
4,4'-Bipyridine Adsorption on Sb(111) from Ionic Liquid- in Situ STM and EIS Study
Authors: Pikma Piret , Siimenson Carolin , Siinor Liis , Lust Enn
Published: December 2020

Room-temperature ionic liquids (RTIL) draw a lot of attention in modern electrochemical research due to their high stability under applied electrode potential, the wide electrochemical window and dual usability as a solvent and an electrolyte RTILs have become very attractive. Molecular self-assembly at solid surfaces, resulting in the formation of nanostructures with well-controlled properties and functionality presents multiple prospective applications in science and technology [2], e.g., the smart tailoring of the structural properties of the functionalized electrodes attracts a lot of attention due to an ability to trigger the specific electrochemical processes.

In this study, the in situ scanning tunnelling microscopy (STM) and impedance spectroscopy methods have been applied to study the structure and adsorption properties of the electrochemically polished Sb(111) single crystal electrode | EMImBF4, and EMImBF4 + X% 4,4'-bipyridine (x= 1; 2; 5), interface.

During the measurements, atomically flat areas have been observed on the in situ STM images of Sb(111) single crystal electrode surface in EMImBF4 and atomic resolution was obtained. The in situ STM data show that there is no quick surface reconstruction process. The surface structure is stable within the potential region investigated (-0.8 — -0.1 vs. Ag/AgCl|EMImBF4) as it has been shown for inactive electrolyte solutions [3].

Additionally, the influence of electrode potential on the adsorption kinetics of 4,4'-bipyridine on Sb(111) has been demonstrated. Within the region of maximal adsorption, the capacitance pits in the differential capacitance vs. electrode potential curves have been observed, depending on the 4,4'-bipyridine concentration [4]. The influence of electrode potential (E) on the adsorption kinetics of 4,4'-BiPy on Sb(111) has been demonstrated. From the in situ STM data it has been found that 4,4’-BP adsorbs in a form of a stripe pattern on antimony single crystal electrodes.

Acknowledgements

This work was supported by Estonian Research Council grants PUT PSG249 and RSG676, and by the EU through the European Regional Development Fund under project TK141 (2014-2020.4.01.15-0011).

References

[1] H. Ohno (Ed.), Electrochemical Aspects of Ionic Liquids, John Wiley & Sons, Inc., New Jersey, 2005, p.1.

[2] T. Wandlowski, Phase Transitions in Two-dimensional Adlayers at Electrode Surfaces: Thermodynamics, Kinetics, and Structural Aspects, A.J. Bard, M. Stratmann (Eds.), Encyclopedia of Electrochemistry, Wiley VCH, Weinheim (2002) p. 383-471.

[3] V. Grozovski, S. Kallip. E. Lust, Surface Science, 613(2013) 108-113.

[4] P. Pikma, L. Siinor, O. Oll, and E. Lust. Electrochemistry Communications, 61 (2015): 61-65.
Controlling of Dispersion State of Particles in Slurry and Electrochemical Properties of Electrodes
Authors: Kuratani Kentaro , Ishibashi Kaoru , Komoda Yoshiyuki , Hidema Ruri , Suzuki Hiroshi , Kobayashi Hironori
Published: December 2020

The electrode materials which exhibit high capacity have attracted much attention because the capacity of the materials directly commits to the energy density of LIBs and driving miles of EVs. So that, many researchers devote their efforts to find new electrode materials with high capacity such as lithium excess layered oxide, Ni-rich materials and silicon. Electrode manufacturing process, generally consists of (1) preparing slurry, (2) coating the slurry on current collector, (3) drying, (4) pressing steps, is another important issue to achieve LIBs with high energy density.

Compared with numerous reports described with the electrode material development, however, only the limited numbers of papers related to the electrode construction process have been published [1-5]. To shed light the relationship between the electrode construction process and the battery performance is an essential research for obtaining the best performance from electrode materials and assembled LIB cells.

In the present study, we focused our attention on the slurry preparation step among above-mentioned four steps. The slurry preparation is the first step in the electrode construction process, and we recognize the dispersion state of particles achieved during slurry preparation greatly influences the battery performance.

Three different preparation processes were applied to achieve the different dispersion state of particles in slurries, and thus obtained slurries are characterized by rheological measurement. It is found that dispersion process with highly loaded slurry or under high shear flow reduces elastic moduli and that their combination achieved the most dispersed state of the particles among the slurries investigated. X-ray computed tomography unveiled that the electrodes manufactured from these slurries contain the aggregates and the size of aggregates in the electrodes was reduced with the decrease in elastic moduli of slurry. At the discharge current density of 10 mA g–1, these electrodes exhibited 140 mAh g–1 of discharge capacities. At 1000 mA g–1, the electrode prepared from highly loaded slurry maintained 80% of the capacity that obtained at the current density of 10 mA g–1. The capacity of the electrode prepared from the slurry under highly loaded and high shear flow, on the other hand, dropped below 10%, indicated that the electrode from the most dispersed slurry has the worst rate performance.

[Ref.]

1) K. M. Kim et al., J. Power Sources, 83, 108 (1999).

2) E. Ligneel et al., J. Electrochem. Soc., 154, A235 (2007).

3) G.-W. Lee et al., J. Power Sources, 195, 6049 (2010).

4) B. Bitsch et al., J. Power Sources, 265, 81 (2014).

5) S. Lim et al., J. Power Sources, 299, 221 (2015).
Enabling Aqueous Processing for Low/No-Cobalt Lithium-Ion Battery Cathode Active Materials
Authors: Hawley William Blake , Parejiya Anand , Bai Yaocai , Meyer Harry M , Wood David L. , Li Jianlin
Published: December 2020

Industrially, lithium-ion battery cathodes are manufactured through a wet slurry mixing and coating process. There is great interest in replacing the presently-used N-methyl-2-pyrrolidone (NMP) solvent with water due to the cost and toxicity associated with NMP. In this study, the modifications made to the active materials as a result of water exposure were studied and two materials, LiMn2O4 (LMO) and LiNi0.8Co0.15Al0.05O2 (NCA), were assembled in high-performing aqueous-processed cathodes for the first time.

Five cathode active materials were the subject of this study: LiCoO2 (LCO), LiFePO4 (LFP), LMO, NCA, and LiNi0.5Mn0.3Co0.2O2 (NMC532). All materials exposed to DI water exhibited rapid increases in pH over the first 10 min, with stable pH values ranging from 9.0 (LFP and LMO) to 12.5 (NCA). Given that the protective aluminum oxide layer on the current collector breaks down at a pH of 8.5, corrosion is predicted for all materials, with NCA being the most extreme case. Pristine samples of the same five materials were submerged in water for 24 h, then the moisture was dried in a vacuum oven. The crystal structures of these materials (henceforth referred to as the wetted samples) were evaluated using X-ray diffraction and compared with pristine samples. No changes were observed in the crystal structure of any material as confirmed by Rietveld refinement. X-ray photoelectron spectroscopy was used to evaluate the changes of the surface composition of each wetted and pristine material.

Based on inductively coupled plasma-mass spectrometry results, the amount of Li and transition metal leaching in water was found to be independent of time in excess of 1 h, and the amount of Li leaching in water for NCA was found to be five times that of NMC532 and more than 30 times that of the other materials. As a result, using a traditional aqueous slurry formulation (active material, carbon black, emulsion binder, carboxymethylcellulose thickener) resulted in a severely cracked and unusable NCA cathode. By including high-molecular weight polyacrylic acid (PAA), the adhesion of the cathode was restored. Half coin cells of this PAA-processed and an NMP-processed NCA cathode were constructed using punches with 1.7 mAh·cm-2 areal capacity and a charge and discharge rate of C/3 between 3.0-4.3 V. The initial capacity of the PAA-processed NCA cathode was slightly lower (176.3 mAh·g-1 to 185.2 mAh·g-1), though it did exhibit better capacity retention through 100 cycles (84.2% to 78.1%).
Hydrogen Evolution and Oxygen Reduction Reactions on Conducting Polymers
Authors: Vagin Mikhail Yu. , Gueskine Viktor , Crispin Xavier
Published: December 2020

The electrocatalytic processes for the energy conversion are the key aspects in the development of sustainable economy. Being one of the main technological stimuli of electrocatalysis research, the direct chemical-to-electrical energy interconversion is employed in a variety of applications from the electrical transportation to the balancing of the grid. Among the examples of the electrocatalytic processes, where the wide commercialization is limited by the cost of catalysts, the oxygen reduction reaction (ORR) and the hydrogen evolution reaction (HER) are the most critical for the development of technological infrastructure of fuel cells. This stipulates the intensive research on noble-metal-free electrocatalysts.

The quantification of ORR and HER on the intrinsically conducting polymers allows the rational design of catalyst, systematic investigation of mass transport phenomena and mechanistic evaluation of electrocatalysis due to the open material architecture. Firstly, the landscape of ORR phenomena happening on conjugated polymers is discussed at the mechanistic and device levels. The effects of co-catalyst and proton supply on ORR efficiency and the pathway is illustrated on the examples of poly(3,4-ethylenedioxythiophene) (PEDOT) [1-4] and other polymers as organic ORR catalyst. Secondly, the effect of proton supply is rationalized at both mechanistic and device levels for HER on PEDOT-triflate [5].

References

1. V. Gueskine, A. Singh, M. Vagin, X. Crispin, I. Zozoulenko. Molecular Oxygen Activation at a Conducting Polymer: Electrochemical Oxygen Reduction Reaction at PEDOT Revisited, a Theoretical Study. The Journal of Physical Chemistry C, 2020, accepted

2. E. Mitraka, M.J. Jafari, M. Vagin, X. Liu, M. Fahlman, T. Ederth, M. Berggren, M.P. Jonsson, X. Crispin. Oxygen-induced doping on reduced poly(3,4-ethylenedioxythiophene). Journal of Materials Chemistry A, 2017, 5(9):4404.

3. E. Mitraka, M. Gryszel, M. Vagin, M.J. Jafari, A. Singh, M. Warczak, M. Mitrakas, M. Berggren, T. Ederth, I. Zozoulenko, E.D. Głowacki, X. Crispin. Electrocatalytic production of hydrogen peroxide with poly(3,4-ethylenedioxythiophene) electrodes. Advanced Sustainable Systems, 2019, 3(2), 1800110.

4. E. Mitraka, M. Vagin, A. Sjöstedt, M. Berggren, K. Håkansson, M. Jonsson X. Crispin. PEDOT-Cellulose Gas Diffusion Electrodes for Disposable Fuel Cells. Advanced Sustainable Systems, 2019 3(12), 1900097

5. R. Valiollahi, M. Vagin, V. Gueskine, A. Singh, S. A. Grigoriev, A. S. Pushkarev, I. V. Pushkareva, M. Fahlman, X. J. Liu, Z. Khan, M. Berggren, I. Zozoulenko, X. Crispin. Electrochemical hydrogen production on a metal-free polymer. Sustainable Energy & Fuels, 2019, 3(12), 3387-3398.
Long-Range Surface Plasmon Enhanced Raman Spectroscopy at Catalytic Platinum Electrodes
Authors: Ikeda Katsuyoshi
Published: December 2020

Surface enhanced Raman scattering (SERS) is recognized as a powerful method for in-situ observation of electrode/electrolyte interfaces, due to the high chemical sensitivity and surface selectivity. However, the applicability of this technique is limited by the nature of surface plasmon resonances at the interface. Although platinum group metals (PGMs) are one of the most interesting materials for electrocatalysis, surface plasmon polaritons are largely damped at these metal surfaces by their localized d-electrons near the Fermi level. Thus, the plasmon enhanced Raman spectroscopy is normally useless for studying such catalytic surfaces. So far, the signal enhancement factors reported at PGM surfaces are in the order of 102 while those at coinage metal surfaces can reach the order of 106 to 1010. In order to gain more intensity at highly damping PGM surfaces, the intensity-borrowing method is a common method; for example, when a large number of Au nanoparticles are deposited on a PGM surface, Raman scattering signals are largely enhanced by the sphere-plane type coupled plasmon modes [1,2]. However, such a nanostructure may influence mass transport, selectivity, and reactivity of electrochemical reactions. For spectro-electrochemistry, it is necessary to reduce the plasmon damping without suffering from such a nanoscale effect. In this work, the attenuation of surface plasmons at highly damping Pt surface is reduced using a symmetric slab mode, which is a strongly coupled surface plasmons excited at both interfaces of a thin metal film [3]. The prolonged propagation of surface plasmons in this double-interface configuration leads to a substantial enhancement of local fields even at lossy Pt surface. The theoretical calculation indicates that the enhancement factor of Raman scattering intensity can reach the order of 104 at Pt/solution interfaces in this coupled plasmon mode. We experimentally demonstrate that Raman scattering signals are significantly enhanced at Pt surface under electrochemical conditions. This strategy provides us a novel surface-specific spectroscopic method for the molecular-scale investigation of electrocatalytic reactions.

[1] J. Hu, N. Hoshi, K. Uosaki, K. Ikeda, Nano Lett., 15, 7982-7986 (2015).

[2] J. Hu, M. Tanabe, J. Sato, K. Uosaki, K. Ikeda, J. Am. Chem. Soc.,136, 10299-10307 (2014).

[3] S. Ikegaya, K. Motobayashi, K. Ikeda, J. Raman Spectrosc. DOI: 10.1002/jrs.5925 (2020)