bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-Power and Safe Lithium Metal Battery in 3D Substrate
Authors: Petrovic Slobodan , D'Couto Chris , Diaz Christian , McGee Michael 
Published: February 2020

The use of 3D structures has been shown to have the high potential for solving several problems that are currently preventing the performance improvements in lithium batteries. The high-surface area structures can provide elimination of dendrites and elimination of safety concerns, improved energy density and specific energy, high power density, low cost per kWh and improvement in cycle life. Compared with traditionally designed battery electrodes three-dimensional structures also enable short diffusion path in the active mass, better current collection and lower impedance.
A perfectly engineered three-dimensional structure is demonstrated using porous silicon. Both anode and cathode can be fabricated on the porous substrate, leading to numerous improvements in performance. A lithium metal anode in porous silicon is shown to be dendrite-free for over 200 cycles as a result geometrical effects in suppressing dendrite growth and low current density. The suppression of dendrites enables the use of lithium metal anodes and eliminating the safety concerns. Both anode and cathode also show improved specific capacity as a result of lower overall impedance and better utilization of the active material; as well as higher power density due to larger three-phase boundary and perfectly arranged active material inside uniformly spaced pores.
A complete cell based on the porous silicon structure can use any anode and cathode material; and can therefore be optimized for a particular application or requirements. It is also amenable to use of both liquid and solid electrolytes. A design is demonstrated that enables lithium metal air battery using a solid electrolyte. Another design shows a monolithic full cell within a single porous silicon wafer, eliminating the need for a separator or additional packaging.
Results of a half-cell, full cell and symmetrical cell testing are presented. The half-cell testing demonstrates the basic behavior of the porous structure and shows current densities in the excess of 5 mA/cm2 (geometrical or projected surface area), but with a low current density per true surface area. The symmetrical cell testing shows stable anode cycling and absence of dendrites for over 200 cycles, while the full cell testing proves the feasibility of pairing the porous silicon metal lithium anode with several conventional cathode materials.
Polyaromatic Ionomers for High Performance Alkaline Membrane Fuel Cells
Authors: Maurya Sandip , Matanovic Ivana , Chung Hoon T , Park Eun Joo , Narvaez Villarrubia Claudia Wuillma , Noh Sangtaik , Han Junyoung , Bae Chulsung , Fujimoto Cy , Hibbs Michael , Kim Yu Seung 
Published: February 2020

Quaternized polyaromatics are one of the promising polymer electrolytes for alkaline membrane fuel cells (AMFCs) as these materials have good hydroxide conductivity, mechanical properties, and processibility.1 In this presentation, we present how the molecular design of quaternized polyaromatic ionomers has been evolved from quaternized poly(arylene ether sulfone)s to quaternized poly(phenylene oxide)s to quaternized aryl-ether free poly(phenylene)s to quaternized poly(fluorene)s. The major driving force to design quaternized polyaromatics includes polymer backbone stability,2 tethered cationic group stability,3 and minimum ionomer interaction with hydrogen oxidation catalysts4,5. Improved quaternized polyaromatic based AMFCs from < 200 mW cm-2 peak power density to 1500 mW cm-2 peak power density will be demonstrated. Remaining challenges of polyaromatic based AMFCs including AMFC durability, implementing low-PGM or non-PGM catalysts will be briefly discussed.
References

Dongwon Shin, Chulsung Bae, Yu Seung Kim, Chapter 8. Anion Exchange Membranes: Stability and Synthetic Approach, in The Chemistry of Membranes Used in Fuel Cells: Degradation and Stabilization, Ed. Shulamith Schlick, John Wiley & Sons, Inc. (2018).

Cy Fujimoto, Dae-Sik Kim, Michael Hibbs, Debra Wrobleski, Yu Seung Kim, Memb. Sci. 423-424, 438-449 (2012).

Yoong-Kee, Choe, Cy Fujimoto, Kwan-Soo Lee, Luke T. Dalton, Kathy Ayers, Neil J. Henson, Yu Seung Kim, Mater. 26, 5675-5682 (2014).

Hoon Taek, Chung, Ulises Martinez, Ivana Matanovic, Yu Seung Kim, Phys. Chem. Lett. 7, 4464-4469 (2016).

Ivana Matanovic, Hoon Taek Chung, Yu Seung Kim, Phys. Chem. Lett. 8, 4918-4924 (2017).
Differential Electrochemical Mass Spectrometry Coupled with Linear and Non-Linear Electrochemical Impedance Spectroscopy of Gadolinia-Doped Ceria: CO2 and H2o Co-Electrolysis
Authors: Witt Jonathan Michael , Adler Stuart B. , Stuve Eric M. 
Published: February 2020

Recent advances in carbon capture create new opportunities for recycling CO2 into liquid fuels to store intermittent electrical energy1. One option is to co-electrolyze CO2 and H2O at high temperature using solid oxide electrolysis cells (SOECs). Although promising, the factors controlling rates of CO2 and H2O reduction in SOECs are not well understood, hampering development2,3. Traditional electrochemical techniques have difficulty resolving the mechanisms and kinetic parameters of the individual steps governing CO2 and H2O reduction. This limitation can potentially be overcome using linear and non-linear electrochemical impedance spectroscopy (EIS and NLEIS) in conjunction with dynamic measurement of gas-phase species using differential electrochemical mass spectrometry (DEMS).
Regarding co-electrolysis, mixed ionic electronic conductors (MIEC) have gained interest as alternatives to nickel-yttria stabilized zirconia (Ni-YSZ) because the active region is not limited to the triple phase boundary and they are more stable in reducing environments3. The MIEC studied here, gadolinia-doped ceria (GDC), has been well characterized as an electrolyte3 and is a promising cathode in SOECs. Unlike Ni-YSZ, it does not coke in carbon environments or oxidize completely in a feed of water and CO2.
We have performed NLEIS and EIS measurements of co-electrolysis on button cells composed of GDC as the working electrode with electrolyte YSZ under various temperatures and gas compositions. Gas atmospheres surrounding the cells contain mixtures of water, CO2, CO, H2, and carrier gas such as Ar or N2, used to manipulate the oxygen partial pressure of the system and thus the oxygen vacancy concentration of the surface and bulk electrode. The data we have collected on co-electrolysis of CO2 and water on GDC have been compared with model NLEIS spectra developed to include CO­2 reduction, water reduction, and reverse water gas shift reaction mechanisms and rate determining steps. A rough vacuum and low volume reactor was developed to cross-check the proposed mechanisms through measuring a gas phase response in DEMS and a micro-kinetic model was developed to predict product distributions corresponding to the mechanism that most closely matched the results.
Polycarbonate Assisted Bi-Walled Multiscale Cathode for High-Performance Solid Oxide Fuel Cells (SOFCs) at 500 °C
Authors: Shin Sung Soo , Kim Jinhyeon , Choi Jiwoo , Lee Channyung , Kim Hyoungchul , Son Ji-Won , Shin Hyunho , Choi Mansoo 
Published: February 2020

As an environmentally friendly future power source, the Solid Oxide Fuel Cells (SOFCs) have several attractive advantages such as high efficiency of direct conversion from chemical energy to electric, reduced over-potential losses and an application of non-precious metal catalyst for electrodes due to high operating temperature (> 800 °C). In contrast, this high operating temperature of SOFCs results in main issues including higher system cost and rapid cell degradation rate which limits practicality of SOFCs for commercial applications such as portable device. The most recently, the electrolyte material, Er0.4Bi1.6O3 (ESB) with exceptionally high ionic conductivity (0.027 S/cm at 500 °C) was developed to lower the operating temperature. However, their applications are limited by inter-diffusion reaction with cobalt-based perovskite catalyst such as La0.6Sr0.4CoO3-
δ (LSC), known as a conventional and highly active for materials for oxygen reduction reaction and severe weakness in reducing atmosphere.
In this study, we suggest a novel architecturing method to utilize ESB along with LSC for superior electrochemical performance. For this, we used Ce0.9Gd0.1O1.95 (CGO) and ESB as dense electrolyte and barrier electrolyte to prevent current leakage through CGO. Anode support with a thickness of 1 mm was fabricated by tape casting method. CGO and ESB were deposited on the anode support by screen printing and polymer-assisted electrospray deposition (PA-ESD) method, respectively. To achieve the compatibility of ESB with LSC, we suggested bi-walled nanotube structure cast by polycarbonate (PC) template. Ln-doped ceria (Ln: Ga or Sm) sol spread on the PC template inner surface enter into the cylindrical hole of PC due to the capillary force. After the gelation, the Ln-doped ceria sol converges to the wall surface to form a perforated cylinder. The same procedure was repeated with LSC sol, resulting in bi-walled nanotube after sintering. In this case, Ln-doped ceria not only blocks the reaction pathway between the LSC and the ESB but can lead to improved performance from extended reaction area obtained from the multiscale structure. In conclusion, our study shows that the novel architecturing method opens the possibility of expanding the range of materials selection for low-temperature SOFCs.
Electrochemical Behavior of Spinel Oxide during Magnesium Ion Insertion/Extraction Reactions at Moderate Temperature
Authors: Otani Saeko , Yamamoto Kentaro , Uchiyama Tomoki , Ichitsubo Tetsu , Uchimoto Yoshiharu 
Published: February 2020

Introduction

Magnesium rechargeable batteries are deemed the next-generation secondary battery systems because of their high theoretical capacity and the terrestrial abundance of magnesium[1]. However, the Mg rechargeable battery research is still a very challenging ﬁeld. One major problem is the slow diffusion of magnesium ions in cathode materials because coulombic interaction between the carrier ion and host material is strong [2]. In this study, we examined the electrochemical performance and reaction mechanism of MgCo2O4 spinel oxide cathode [3] under moderate temperature of 150 °C, using molten salts as the electrolyte and analyzed.

Experimental

MgCo2O4 cathode material was prepared by inverse coprecipitation. The electrochemical measurement was carried out using the three-electrodes cell. The electrolyte was mixed molten salts of 10 mol% magnesium bis(trifluolomehanesulfonyl)amide (Mg(TFSA)2) and 90 mol% CsTFSA. The composite cathode was prepared from a paste by mixing 80 wt% of as-prepared active materials, 10 wt% of acetylene black (as conductive agents) and 10 wt% of polyvinylidene difluoride (binder) in 1-methyl-2-pyrrolidone solvent and then this paste was coated on the Al foil collector. A Mg ribbon was used as the anode. The reference electrode was a Li ribbon immersed in a 0.5 M LiTFSA/N, N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium bis(triﬂuoromethanesulfonyl)amide electrolyte in a glass tube separated with a porous ceramic ﬁlter. Galvanostatic charge/discharge measurements were performed at 150 °C in the Ar-filled glove box.

Results and Discussion

The prepared MgCo2O4 was a single phase and the particle size was a few micrometers, which were confirmed by X-ray diffraction and scanning electron microscopy. The MgCo2O4 cathode exhibited about 250 mAh g-1 discharge capacity and about 120 mAh g-1 charge capacity during the 1st cycling at the C/10 rate. This material shows high capacity as the cathode for Mg rechargeable batteries at moderate temperature and the reaction mechanism will be discussed in the presentation.

References:
[1]D. Aurbach., Z. Lu, A. Schechter, Y. Gofer, H. Gizbar, R. Turgeman, Y. Cohen, M. Moshkovich and E. Levi, Nature
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[3] S. Okamoto, T. Ichitsubo, T. Kawaguchi, Y. Kumagai, F. Oba, S.Yagi, K. Shimokawa, N. Goto, T. Doi, and E. Matsubara, Adv. Sci.
2015, 2, 1500072.

Acknowledgement:
This research was financially supported by the Japan Science and Technology Agency (JST), Advanced Low Carbon Technology Research and Development Program (ALCA), Specially Promoted Research for Innovative Next Generation Batteries (SPRING) Project.
Design and Development of Advanced Air-Cathodes for Li-Air Battery
Authors: Wu James J. 
Published: February 2020

NASA’s future missions demand high energy density batteries. Current state-of-the-art lithium-ion batteries (LIBs) reach the specific energy capacity limits (<250 Wh/kg), thus new electrochemical storage technologies are needed to meet NASA’s future mission requirement of >400 Wh/kg. Battery chemistries with higher theoretical energy densities in particular, Li-metal based battery chemistries such as Li-air, are being actively pursued, but there remains a number of issues to be solved. Development of advanced and optimized air cathodes will be crucial for improving capacity retention and cycle life of Li-air battery. The microstructure of carbon substrates and the catalytic oxygen reduction of the air-cathode play critical roles in the electrochemical performance in Li-air batteries. With the development and proper design of air cathodes, the energy efficiency and energy density can be enhanced significantly.
In this presentation, the results of advanced permeable air cathodes design with different substrates such as 2D carbon paper or carbon cloth, vs. 3D graphene or metal foam, different high surface area carbon materials and incorporation with catalysts on oxygen reduction reactions, different porosity controlling of air cathode as well the additives in electrolyte will be presented. The cycling and rate capability performance of these air-cathodes in the Li-air cells will be discussed as well.
Click Reaction Assisted By Cu Electro-Oxidation
Authors: Carre-Rangel Luceldi , Oropeza-Guzman Mercedes Teresita , Rivero Ignacio Alfredo 
Published: February 2020

The click chemistry is a green, selective, qualitative, pH-sensitive and economical approach, suitable characteristics for use in the synthesis of a variety of bioconjugates including peptides, proteins, polysaccharides, etc. The purpose of the click chemistry reactions is to bind two molecular building blocks, selectively and under mild reaction conditions, obtaining high yields, generating only harmless byproducts of reaction and easy to separate by non-chromatographic methods.
In 2002, Sharpless's research group reported the 1,3-dipolar Copper catalyzed Alkyne Azide Cycloaddition (CuAAC) reaction, which is regioselective for the formation of 1,4-disubstituted triazoles, becoming the best known click reaction.The reaction is carried out at room temperature and has high conversions at shorter times, compared to the uncatalyzed (not regioselective) cycloaddition reported by Huisgen in 1963. Other strategies have been reported to perform the cycloaddition of alkynes and azides without the use of a copper catalyst, however, for these reactions the kinetics are slow and do not present regioselectivity. Hence, the process catalyzed by copper is still preferred.
Intending to improve the green chemistry procedure to synthesize triazoles, considering that electrons as redox reactants instead of polluting reducing/oxidizing reagents, it is propose to assist a conventional click reaction by electrochemical methods. Since a metallic species as Cu is relatively easy to oxidize by an electrolysis, the main objective is to generate ionic species of Cu as Cu+1 serving to catalyze the click reaction. For this purpose a suitable electrolytic media as well as a proper electrochemical cell configuration (Cu-working electrode, Ag/AgCl/Cl-
(tert-butylalcohol/water) reference electrode and Pt-counter electrode) were used to test the reaction improvement by the in-situ electro-oxidation of Cu.
The synthesis of 1-benzyl-4-phenyl-1H-1,2,3-triazole, 3-(1-benzyl-1H-1,2,3-triazol-4-yl)phenol and 1-benzyl-4-(naphthalen-1-yl)-1H-1,2,3-triazole derivatives via the in-situ preparation of Cu+1 by an electrochemical process, was very efficient, safe and inexpensive, since catalyst was obtained under soft conditions reaction generating extremely small amounts of electrooxidized Cu (~4.3x10-3 mol in one hour).
Conventional and electrochemical methods were compared, the last method yielded 78-90% in one hour of reaction and the conventional method produced only 56-60% at the same time, therefore, the electro-Click reaction is faster and more efficient.
Single Synaptic Observation of Cholinergic Neurotransmission on Living Neurons: Concentration and Dynamics
Authors: Shen Mei 
Published: February 2020

Acetylcholine, the first neurotransmitter identified in 1914, plays key role in human health and its defects have been associated with neurodegeneration. Elucidating its release dynamics and concentration profiles at the source of its release, the synaptic cleft, is instrumental in understanding neurodegenerative diseases. Here we present our study of acetylcholine synaptic release with a nanoITIES electrode of ~15 nm in radius, unveiling unprecedented details on its release dynamics and concentration profiles around single synaptic cleft. We employed nanoresolved scanning electrochemical microscope (SECM) (1-4) to position the nanoelectrode around the synaptic cleft. We further demonstrate the quantification of acetylcholine single exocytotic events from Aplysia californica neuron cells using a nanoITIES pipet electrode. Development of nanoITIES electrodes for non-redox active transmitter detection will be presented as well. (5-8)
Acknowledgement: This research was supported by the National Institute Neurological Disorders and Stroke of National Institutes of Health under Award Number R21NS085665.
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Electrodeposition of Si in Molten CaCl2 Above 1300K
Authors: Takenaka Toshihide , Shimokawa Ryoya , Okada Haruka , Morishige Taiki 
Published: February 2020

Metallic Si is produced by carbon reduction of SiO2 in an arc furnace above 2000K, and the energy consumption and CO2 exhaustion in the process are very large. The authors reported that TiO2 could dissolve in molten CaCl2 containing CaO above 1300K, and that Ti metal was electrodeposited in the bath. This result implies the possibility of electrolytic production of liquid metallic Si in molten CaCl2-CaO-SiO2 above its melting point, which can lead the innovative production process of metallic Si with lower energy consumption and lower CO2 exhaustion. To realize this process, the electrochemical behavior of Si in molten CaCl2-CaO-SiO2 at a very high temperature has to be studied in detail. In this study, the cathodic reaction has been investigated in molten CaCl2-CaSiO3 above 1300K, and the electrodesipotion of metallic Si has been attempted.
Based on our previous studies on Ti electrolysis, calcium silicate was used instead of CaO and SiO2. Calcium chloride containing 0~10 mol% CaSiO3 in a Mo crucible was fused in an air-tight furnace, and electrolysis was carried out at 1373 ~ 1573 K under a pure Ar flow. The working electrode was mainly a Mo wire with an Al2O3 sheath, and a SiC rod was also used. Another Mo wire electrode was used as quasi-reference electrode, and its potential was calibrated with Mo dissolution potential in the bath. Cyclic voltammetry was performed to investigate the electrode reactions in the bath, and then potentio-static electrolysis was carried out to obtain electrodeposit. The electrode surfaces after electrolysis as well as the electrodeposit were analyzed by XRD and SEM-EDX.
The cathodic current obviously enlarged with the CaSiO3 addition, and the CaSiO3 solubility seemed to increase with the bath temperature. A sharp cathodic current peak appeared around -1.1 V (vs. Mo dissolution potential) at the Mo electrode, while no cathodic current peak was observed at the SiC electrode. Electrodeposit as shown in Fig.1 was obtained at the Mo electrode, and metallic Si was detected in it. Although a MoSi2 layer was also formed on the surface by electrolysis as shown in Fig. 2, the amount of Si in the layer was limited considering the quantity of electricity during the electrolysis. Since CaSi2 was sometimes found in the deposit, the suitable electrolytic potential needs to be revealed.
It was shown that metallic Si was obtained by electrolysis in molten CaCl2-CaSiO3 under the proper condition. However, the amount of metallic Si on the electrode could not be determined yet because of the powdery morphology of deposit. It should be desirable to obtain liquid metallic Si by electrolysis above its melting point.

Figure 1
Electrochemical and Spectroscopic Insight into the Interfacial Structure of Ionic Liquids
Authors: Klein Jeffrey Michael , Gurkan Burcu 
Published: February 2020

Supercapacitors, or electrical double layer capacitors, are energy storage devices that offer higher power when compared to batteries. EDLCs are ideal for applications that can utilize a fast charge/discharge cycle and require long cycle lifetimes and are used in electronics, home appliances, and in some large-scale energy regeneration for automobiles and industrial equipment. Charge is stored in an EDLC by the accumulation of ions in the electrode-electrolyte interface. Aqueous and organic based systems create a well understood structure of accumulated ions where solvated ions pack into the interface and balance the charge of the electrode. Ionic liquids are a new class of electrolyte being considered for application in EDLCs. Ionic liquids are composed only of ions and do not form a structure at the interface that is readily understood. In order to successfully utilize Ionic Liquids for energy storage such as with supercapacitors, the structure of ion accumulation must be understood at a fundamental level. We investigated the structure of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [EMIM][TFSI], on two different electrodes and quantified the interfacial rearrangement thereby opening the door to begin a rational study of the interface through modification of the ionic liquid.
Differential capacitance of [EMIM][TFSI] on glassy carbon and silver electrodes has been measured by electrochemical impedance spectroscopy (EIS). The interfacial rearrangement was further characterized using electrochemical surface enhanced Raman spectroscopy (SERS). Potential dependence of the differential capacitance demonstrates the camel-like structure indicating formation and collapse of ion structure in the interfacial layer. The EIS data suggest that the formation of the structure occurs through multiple processes which change as the capacitance maximum is approached. On the silver electrode distinct shifts in the vibrational energies of the interface are shown via SERS to occur as the cell potential is forced away from open circuit potential which is associated with local changes in polarizability of molecular interactions associated with the interfacial structure. The series of techniques presented in this work open the path for different ionic liquids to be studied.