bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure Control of Thin Films Via Advanced Electrostatic Spray Coating Technique and Its Application of Fuel Cells
Authors: Shin Dongwook , Lee Sewook , Lee Taejun , Lee Hunhyeong , Park Sangho 
Published: February 2020

To enhance overall properties of solid oxide fuel cells (SOFC), fabrication of each components is one of significant part in this field. Among the various coating techniques for fabrication of single cells, the coating method using pre-synthesized powder slurry has been widely used due to the fact that the powder technique is cost effective and easily controllable the process parameters than the other techniques using vacuum system such as RF sputtering, PLD and CVD. However, previous powder processes including tape casting, screen printing and dip coating have a difficulty in formation of 1~5 μm thin films for micro-fuel cells. Also, the microstructures of deposited films are very sensitive to process parameters, therefore, not easy to fabricate appropriate films to each layer in SOFC. So, our suggested deposition method in this work is an electrostatic slurry spray deposition (ESSD) technique which uses electrical energy to atomize and spray solutions same as in electrostatic spray deposition (ESD). The ESSD technique is a method of spraying prepared slurry containing powders with pre-developed crystalline phase, while the conventional ESD is a technique of spraying metal salts dissolved solution and the crystalline phases are developed after deposition by post-heat treatment. Dense and porous films without any cracks and delamination can be easily fabricated by the ESSD. Also, it is very powerful tool to fabricate a layer with composite materials and to control film thickness. In overall, the ESSD is a more advanced deposition technique than the conventional ESD in terms of the controllability of the deposition process and the microstructure of the deposited film, the flexibility in process application, the performance of the obtained film, the diversity of film material, so on.
In this study, the objective is to develop advanced electrostatic slurry spray deposition (ESSD) and its application to SOFC. The key parameters in process includes an applied voltage, a flow-rate and a distance to substrate. Through the optimization of deposition conditions, microstructures are easily fabricated as intended. Firstly, our group has optimized the deposition conditions to form thin films ( < 3 μm) for electrolytes. Also, the several trials such as composition and porosity controlled microstructures for electrodes have been investigated. Furthermore, the effective microstructures such as honeycomb, snowball and nano-fibers have been studied and employed to electrodes in single cells. The overall micro-graphical and electrochemical analysis for fore-mentioned microstructures were carried out to verify the effectiveness of each films formed by ESSD technique.

Figure 1
Li7La3Zr2O12 Interface Modification for Li Dendrite Prevention
Authors: Finsterbusch Martin , Tsai Chih Long , Roddatis Vladimir , Nair Vinod Chandra , Ma Qianli , Uhlenbruck Sven , Heitjans Paul , Guillon Olivier 
Published: February 2020

Li metal is the ideal anode for rechargeable batteries due to the lowest native electrochemical potential ( -3.4 V vs. H2), extremely high specific capacity (3860 mA h/g) and low density (0.59 g/cm3). However, the use of metallic Li in a rechargeable battery was not successful until now, due to the difficulty of suppressing the growth of Li dendrites. Theoretical calculations suggest that if the shear modulus of the used electrolyte is more than twice that of metallic Li, ~109 Pa, or the Li-ion transference number tLi+ approaches 1, then the dendrite growth can be suppressed. Therefore, the garnet-structured Li7La3Zr2O12(LLZ) solid-state Li-ion conductor is an ideal material as electrolyte in rechargable batteries because of its unity ionic transference number, high mechanical strength and chemical stability to metallic Li.
However, Li dendrite formation was reported by Ishiguro et al [1,2] for their Nb- and Ta-substituted LLZ with unclear reason. In the presented research, Ta-substituted LLZ samples which are Al-contaminated and Al-free were fabricated by hot pressing as well as a regular sintering process. Samples fabricated by hot pressing have relative densities >99% and total conductivities of ~1 mS/cm at room temperature. During this study, impedance measurements show rapid decrease in total resistances within a couple of hundred seconds, which indicates that the dendrites can be formed even in such a highly dense ceramic in a short time (just like in regularly sintered samples with ~93% relative density). Solid-state NMR demonstrates the presence of metallic Li inside the dense pellets, which is also supported by TEM-EELS result [3]. From these dendrite test results, reasons for the formation of the Li dendrite and options to prevent the formation of Li dendrites by interface modification were derived and will be discussed in this presentation.
[1] Ishiguro et al., J. Electrochem. Soc. 2013, 160, A1690−A1693.
[2] Ishiguro et al., J. Electrochem. Soc. 2014, 161, A668−A674.
[3] Tsai et al., ACS Appl. Mater. Interfaces, 2016, DOI: 10.1021/acsami.6b00831
Effect of Lithium Nitrate (LiNO3) on Lithium Metal Secondary Batteries As a Lithium Metal Stabilizing Electrolyte Additive
Authors: Jin Dahee , Lee Hoogil , Han Taeyeong , Kim Seokwoo , Ryou Myung-Hyun , Lee YongMin 
Published: February 2020

To realize the successful implementation of the electric vehicles (EVs), the development of advanced lithium secondary batteries having excellent cycle life, high energy density and high power density with low price is prerequisite. To achieve this goal, the conventional active materials such as LiCoO2 and graphite based on the intercalation chemistry, which are used in the commercialized lithium-ion batteries, should be replaced.
Although lithium metal has been a promising anode material over four decades, it could not fully used in commercialized secondary battery system due to poor cycle life ascribed to the dendrite formation during repeated operation. To solve this problem, we introduced a novel lithium metal stabilizing electrolyte additive, lithium nitrate (LiNiO3).
The effect of LiNiO3 was characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). The cycle performance of coin cells containing 0.3wt% of LiNiO3 revealed an improved cycle performance even at high voltage (3.0~4.5V vs. Li/Li+, C/2) and the rate capability at high current density. We believe this is attributable to the formation of stable solid electrolyte interphase (SEI) layer on the surface of lithium metal during precycling, resulting smaller resistance.

Acknowledgements

This work was supported by the international Collaborative Energy Technology R&D Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea. (No. 20158510050020).

References

H. S. Kim. et al. Ionics (2013) 19:1795 – 1802

Jing Guo et al. Electrochemistry Communications 51 (2015) 59–63
High Ionic Conductivity and Moduli Iongels Made with Tetraglyme/Litfsi /Methyl Cellulose for Lithium Batteries
Authors: Chinnam Parameswara Rao , Chereddy Sumanth , Wunder Stephanie 
Published: February 2020

The motivation for the development of solid polymer electrolytes (SPEs) arises from their safety advantages over liquid electrolytes. In particular SPEs are non-flammable and avoid the problem of electrolyte leakage, both of which can result in fires/explosions. However, SPEs have lower conductivities at room temperature (RT) compared to those of liquid electrolytes, so there is a need to develop SPE with improved RT conductivities.
Recently, glymes, (CH3−O-(CH2−CH2−O)n−CH3) n=3 or 4, have been studied as solvents for non-aqueous electrolytes because of unique properties such as their solvation power (Lewis basicity), relatively long-lived (stable) solvates, and complex formation in certain molar ratios, [M(glyme)x]+, with alkali metal ions. Li(G3 or G4)][TFSI] is molten at room temperature and can be considered as a representative ionic liquid. It has very low volatility, is nonflammable, and has good oxidative stability.
Here we report the preparation, ionic conductivity (s), mechanical and thermal properties of iongels made from Li(G4)TFSI and methyl cellulose (MC), in ratios of 90/10, 80/20 and 70/30 Li(G4)TFSI/MC. The ionic conductivity decreases with increase in MC content over the temperature range measured, 10 oC to 90 oC (Figure 1A), while the storage moduli increase with increase in MC content. For 90/10 Li(G4)TFSI/MC at 30 oC , s = 3.78×10-4 S/cm and the storage modulus = 50 MPa(Figure 1B). Thermogravimetric analysis of G4, Li(G4)TFSI, Li(G4)TFSI/MC and MC indicates that iongels are stable until the vaporization of the G4(Figure 2A). DSC data for G4, G4 with TFSI, and G4 with TFSI/MC (Figure 2B ) show that: (i) complexation of Li+ with G4 results in an increase in Tg and a suppression of the melt temperature Tm, and (ii) MC content increases Tg and decreases conductivity (Figure 1A).

Figure 1A. Log (conductivity) versus 1000/T for Li(G4)TFSI and Li(G4)TFSI/MC gels. Figure 1B. Storage modulus for 90/10 Li(G4)TFSI/MC as a function of temperature

Figure 2A.TGA of G4,Li(G4)TFSI, Li(G4)TFSI/MC and MC Figure 2B. DSC scans (second heating cycle) of Li(G4)TFSI and Li(G4)TFSI/MC

References

(1) Zhou, S.; Kim, D. Polymers for Advanced Technologies
2010, 21, 797.
(2) Henderson, W. A. The Journal of Physical Chemistry B
2006, 110, 13177.
(3) Pappenfus, T. M.; Henderson, W. A.; Owens, B. B.; Mann, K. R.; Smyrl, W. H. Journal of The Electrochemical Society
2004, 151, A209.

Figure 1
Improved Low-Temperature Performance of Li-Ion Battery of LiCoO2//Graphite By Electrolyte Control
Authors: Pham Hieu Quang , Kim Jae-Hee , Kwon Young-Gil , Hwang Eui-Hyung , Lee Jung-Gyu , Song Seung-Wan 
Published: February 2020

For the universal use of electric vehicle and energy storage system applications, Li-ion batteries are required to operate at low temperatures below –10 ○C. Battery performance at low temperatures is however often limited by electrolyte, mainly due to a lowered Li-ion conductivity and a phase change of high melting point component from liquid to solid. In an effort to overcome those drawbacks, researchers have made attempts on electrolyte development mostly by blending several solvents to ternary and quaternary electrolytes,1 and by using functional electrolyte additives.2 Although some improvements were made, challenges for finding new electrolyte component remains and the new electrolyte component has to be practically tested in the Li-ion batteries operated at low temperature. In this presentation, we report a development of new lithium salt as an additive to use in the conventional Li-ion cells of LiCoO2//graphite operated at –20 ○C. Improved low temperature performance by the effects of salt additive and its correlation to surface chemistry would be discussed in the meeting.

Acknowledgements

This research was supported by the Korean Ministry of Trade, Industry & Energy (A0022-00725 & R0004645).

References

1. M. C. Smart, B. V. Ratnakumar, L. D. Whitcanack, K. B. Chin, S. Surampudi, H. Croft, D. Tice, R. Staniewicz, J. Power Sources, 119–121, 349 (2003).
2. L. Liao, X. Chenga, Y. Ma, P. Zuo, W. Fang, G. Yin, Y. Gao, Electrochim. Acta, 87, 466, (2013).
Composite Polymer-Ceramic Electrolyte for High-Energy Lithium Secondary Batteries
Authors: Samuthira Pandian Amaresh , Delnick Frank , Dudney Nancy J 
Published: February 2020

The demand for high-energy batteries is driving development of high voltage lithium batteries, where the electrolyte must be electrochemically stable and resistant to formation of metallic Li dendrites. Replacing the current liquid electrolytes with a robust solid electrolyte that has high ionic conductivity and good mechanical stability is one path to improve the performance and safety. Polymer electrolyte formed with a dissolved Li ion salt are preferred for their low cost, mechanical flexibility and easy processability, however the low room-temperature conductivity restricts the use of most polymer electrolytes. Composite polymer electrolytes, consisting of a polymer electrolyte containing a dispersed inorganic powder, such as alumina, tend to have high conductivity because the filler impedes crystallization of the polymer.1 Another approach is to disperse powders of a highly conductive ceramic electrolyte, rather than insulating filler, such that both phases in the composite conduct the lithium ions. This permit a high ceramic loading such that the mechanical, transport, and chemical stability can be optimized.2

In the present study, we chose a traditional polymer electrolyte composed of polyethylene oxide (PEO) as the polymer host and Lithium triflate is the mobile ion conducting salt. The solid electrolyte powder from Ohara® Corporation LIC–GC® was selected for the ceramic component because of its inherent high ionic conductivity and stability against water and heat. With these materials, thin composite membranes were fabricated with reasonable conductivity and stability. A solid-state battery consisting of a thin film cathode, the composite electrolyte membrane and vapor deposited metallic Lithium was evaluated. The results to be presented include ionic conductivity of the membrane, stability against Lithium and preliminary cyclic voltammetry of the battery.
Acknowledgement: This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U. S. Department of Energy under Contract No. DE-AC02-05CH11231, under the Advanced Battery Materials Research (BMR) Program.
References:

E. Quartarone, P. Mustarelli, and Aldo Magistris, Solid State Ionics, 110, 1 (1998).

Wyatt E. Tenhaeff and Sergiy Kalnaus, Handbook of Solid State Batteries, 2nd Edition, Nancy Dudney, William West, and Jagjit Nanda, World Scientific, Ch. 7 (2015).

*Corresponding author email: dudneynj@ornl.gov
Electrochemical Behavior of Li4Ti5O12 in Ionic Liquid/Water Bilayer Electrolyte
Authors: Miwa Hiroshi , Fukutsuka Tomokazu , Miyazaki Kohei , Abe Takeshi 
Published: February 2020

Introduction

Lithium-ion batteries (LIBs) have been used in portable electronic devices, and recently expected to be used in large-scale energy facilities for electric vehicle or large energy storage systems. Flammable organic solvents were used in LIBs and it threaten the safety of LIBs. Therefore, nonflammable aqueous electrolytes have been investigated[1]. However, its narrow potential windows restrict the use of negative electrodes, which makes it difficult to obtain high voltage. In this study, we utilized stable liquid-liquid interface between water and hydrophobic ionic liquids in order to enhance the negative potential window. The electrochemical behavior of Li4Ti5O12(LTO) thin-film electrode, which cannot be used in aqueous solution, was investigated.

Experimental

LTO thin-film electrodes were prepared on a Pt substrate by a sol-gel method. LTO thin-film electrode was used as a working electrode. The bilayer electrolyte was formed on the working electrode: the upper layer was 1.0 mol dm −3 LiNO3 aqueous solution, and the lower layer was butyltrimethylammonium bis(trifluoromethylsulfonyl)amide (BTMATFSA) containing 1.0 mol kg −1 of lithium bis(trifluoromethylsulfonyl)amide (LiTFSA). The counter electrode was platinum wire and the reference electrode was Ag/AgCl electrode (sat. KCl), and these electrodes were placed in the aqueous solution layer. Cyclic voltammetry was performed. Hereafter, all potentials are referred to as Ag/AgCl.

Results

Figure 1(a) shows the cyclic voltammograms of LTO thin-film electrode in bilayer electrolyte. At volume ratio of ionic liquid:aqueous solution = 3:4, clear redox peaks around ca. −1.33 V were observed. This reaction can be assigned to lithium-ion insertion/extraction into/from LTO. In contrast, Figure 1(b) shows that only large reduction current was observed and the redox peaks of LTO were not detected at volume ratio = 1:29. At this ratio, ionic liquid was miscible with aqueous solution. Thus, the reduction current below 0.9 V can be assigned to the hydrogen evolution reaction from water. These results reveal that bilayer electrolyte with clear interface prevent the hydrogen evolution reaction and enable lithium-ion to insert/extract into/from LTO.

Reference

[1] W. Li, J. R. Dahn, and D. S. Wainwright, Science, 264, 1115 (1994).

Acknowledgment

This work was partially supported by CREST, JST.

Figure 1
(Invited) CO2 Electrolysis for Syngas Production
Authors: Masel Richard I , Liu Zengcai , Kutz Robert , Sajjad Syed , Yang Hongzhou 
Published: February 2020

Economic production of syngas from CO2 and H2O could produce new routes to synthetic fuels. In this paper we will describe recent work on the electrolysis of CO2 in a 5 cm² alkaline electrolyzer using standard Fuel Cell Technologies fuel cell hardware. Previous work had demonstrated CO2 conversion with steady state currents of 50 mA/cm² or less at 3 V. In this paper we find that by optimizing the composition of the membrane and ionomer we can raise the current to 280 mA/cm² at 3V and 600 mA/cm² at 3.25-3.35 V.
Table 1 shows how the performance of the electrolyzer varies with membrane composition for several different membranes using bare silver cathode catalysts, ruthenium anode catalysts and a variety of membranes. In all cases the measurements were done by sandwiching the membrane between two pieces of carbon cloth that were coated with membrane, mounting the resultant MEA in 5 cm² fuel cell hardware, supplying humidified CO2 to the cathode, applying 3 V, waiting 20 minutes to 1 hr for the current to stabilize and recording the current.
Notice that the faradaic efficiency for the conversion of CO2 to CO varies from 0 to 95%. While the current varies from 5 to 80 mA/cm². Sustainion™ membranes give higher currents and faradaic efficiency than the others. These results demonstrate that the membrane composition makes a significant difference to the electrolyzer performance.
Figure 1 shows how the polarization curve of the cell varies as we add different amounts of Sustainion™-X5 to the cathode layer in a cell with a Sustainion™-X4 membrane. Notice that one can obtain currents of 1.4 amps (280 mA/cm²) at 3 volts with a Sustainion™-X4 membrane and and Sustainion™-X5 ionomer.
Figure 2 shows a steady state run at 600 mA/cm² using an optimal amount of Sustainion™-X6 in the catalyst layer. Notice that we can maintain 600 mA/cm² at between 3.25 and 3.35 V. By comparison, the closest competitor needed almost 7 V to obtain the same current.
Figure 3 shows a steady state run at 200 mA/cm² using a Sustainion™-X1 membrane and an optimal amount of Sustainion™-X5 in the catalyst layer. Notice that we were able to maintain constant current for over 600 hours. Unfortunately, these runs ended abruptly when the power went off and then surged as it went on. But in runs without Sustainion™-X5 in the catalyst layer and no power surges, stable performance was observed for over 4000 hours.
These results show that the ionomer and membrane can make a substantial difference to the performance of a CO2 electrolyzer.

Acknowledgement

Parts of this work were supported by ARPA-E under contract DE-AR0000345 and by 3M. The opinion are those of the authors and may not reflect the opinions of ARPA-E or 3M.

Figure 1
Fouling Behavior of Negatively Charged Natural Organic Matters to Anion Exchange Membranes in Reverse Electrodialysis
Authors: Kim Da-Eun , Oh Yoontaek , Choi Jang-Uk , Song Chan-Ho , Chae Soryong , Kim Chan-Soo , Jeong Nam-Jo , Kang Moon-Sung , Park Jin-Soo 
Published: February 2020

Reverse electrodialysis (RED) represents an energy conversion technology from the salinity difference of concentrated salt solutions (e.g., sea water) and diluted salt solutions (e.g., river water). The RED stack is comprised of an alternating arrangement of cation- and anion-exchange membranes between two electrodes that selectively transfer anions and cations. However, the river water used for the RED may contain natural organic matters (i.e., humic acid and fulvic acid). Thus, electrostatic characteristics of organic matter may lead to membrane surface fouling. The membrane fouling cause increase electrical resistance and the increase of maintenance cost, and a significant decrease in operating performance. In this study, the influence of membrane fouling in RED by commercially available humic acid was investigated experimentally, and adsorption tests, open circuit voltage, stack resistance, and power density were measured at different operation conditions. As a result, it was confirmed that the adsorption of humic acid onto the surface of anion-exchange membranes occurred even though the direction of the electromigration of negatively charged humic acid was toward cation-exchange membranes. The fouling of anion exchange membranes by humic acid was highly influenced by the roughness of the surface of anion-exchange membranes. It was confirmed by isothermal curves (i.e., Frendlich isotherm).
Acknowledgements
This work was supported by the New and Renewable Energy of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, and Republic of Korea (No. 20143030071240).
The Role of Temperature on Salt Removal Using Capacitive Deionization
Authors: Zhang Jiankai , Nazemi Mohammadreza , Leksana Caitlin , Hatzell Marta C. 
Published: February 2020

Current technologies utilized for seawater desalination, reverse osmosis (RO) and Membrane distillation (MD), are energy intensive because they operated by separating the main component water (H2O) from the salt (NaCl). Capacitive deionization (CDI), an emerging separations based technology, operates by extracting the minority component (NaCl). CDI is similar to a supercapacitors[1], where ions adsorb to the high surface area activated carbon once an electric potential is applied across the electrochemical cell (ion separation process)[2-5]. However, in place of traditional non-aqueous based electrolytes is a electrolyte comprised of sea, brackish or wastewater.
More recent theoretical based studies have emphasized the role heat transfer has on ion adsorption dynamics within CDI cells[6].Traditional CDI cells operate in a cyclic process where the capacitive electrodes are brought in contact with a concentrated salt solution (e.g. brackish water) and charged. Once the charged electrodes are fully saturated with salt ions, the electrodes are regenerated through discharging the electrodes in a brine solution. Analogous to a P-V diagram for traditional heat engines, the enclosed area of the charge versus voltage represents the energy consumed during this charging-discharging process. Here we explore the effect of temperature on salt removal in a CDI cycle. Experimentally, we use traditional electrochemical characterization methods, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), to evaluate the capacitance and resistance changes with temperature. Specifically the salt adsorption capacity is shown to decrease from 13.82±1.13, to 6.58±1.01 milligram NaCl/mg carbon as the cell temperature is increased from 25oC to 45oC.
1. Hatzell, K.B., M. Boota, and Y. Gogotsi. Chemical Society Reviews, 2015. 44(23): p. 8664-8687.
2. Porada, S., R. Zhao, A. Van Der Wal, V. Presser, and P. Biesheuvel.Progress in Materials Science, 2013.
3. Hatzell, K.B., M.C. Hatzell, K.M. Cook, M. Boota, G.M. Housel, A. McBride, E.C. Kumbur, and Y. Gogotsi. Environmental science & technology, 2015. 49(5): p. 3040-3047.
4. Ren, C.E., K.B. Hatzell, M. Alhabeb, Z. Ling, K.A. Mahmoud, and Y. Gogotsi. The journal of physical chemistry letters, 2015. 6(20): p. 4026-4031.
5. Hatzell, K.B., E. Iwama, A. Ferris, B. Daffos, K. Urita, T. Tzedakis, F. Chauvet, P.-L. Taberna, Y. Gogotsi, and P. Simon. Electrochemistry Communications, 2014. 43: p. 18-21.
6. Janssen, M., A. Härtel, and R. Van Roij. Physical review letters, 2014. 113(26): p. 268501.