bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinetic Equilibrium Study of CO2 poisoning Observed in Anion Exchange Membranes When Exposed to Ambient Air and Varying Levels of CO2 ppm
Authors: Divekar Ashutosh G , Pivovar Bryan S. , Herring Andrew M.
Published: February 2020

One of the hurdles in Anion exchange membrane fuel cell technology is weaker understanding of CO2 poisoning observed when they are exposed to air. Our previous work suggests that OH- ions depletes in approximately 15 min to form CO3
2- and HCO3
- ions when exposed to ambient air at 30 °C and 95%RH[1]. However, an actual fuel cell device is operated at a much higher temperature. In this study we have obtained the CO2 absorption data at different temperatures and different CO2 concentration environment. Our data suggest that the air equilibrated AEM concentration of CO3
2- increases at higher temperatures whereas HCO3
- concentration follows a decreasing trend. The OH- ion has a very insignificant change at higher temperatures but we observe that the equilibrium OH- concentration is higher at lower ppm level of CO2 environment. This indicates that the CO2 reaction is dependent on CO2 concentration in air. We have also studied the transient change in ionic conductivity of OH- AEM films in ambient air. Here, we observe the nature of drop in conductivity when exposed to air. We have attempted to fit the conductivity data to mathematical models that will give us more insights into absorption phenomenon of CO2.

Acknowledgements:

This research was funded by the Department of energy through NREL. The AEM samples were supplied by Dr. Bryan Pivovar’s group at NREL.

Reference

A.G. Divekar, A. M. Park, Z. R. Owczarczyk, S. Seifert, B. S. Pivovar and A. M. Herring, ECS Transactions, 80, 1005 (2017).

Figure 1
Reaction Mechanism of a Novel IrOx-Based OER Catalyst in Acidic Media
Authors: Cheng Junfang , Yang Jun , Kitano Sho , Cui Xuedong , Ghuman Kulbir , Juhász Gergely , Yamauchi Miho , Nakashima Naotoshi
Published: February 2020

The oxygen evolution reaction (OER) is of prime importance in multiple energy storage devices [1]. IrOx-based catalysts are thought to be the most promising candidates in acidic media, but have been limited by their high cost. Choosing suitable substrates for such catalysts are effective to reduce the Ir consumption as well as beneficial for the OER performance[2
-
4]. Here, we focus on the catalytic mechanism for a newly synthesized IrOx-based composite material which shows an excellent OER performance in acidic media. The catalytic mechanism has been revealed mainly based on in-situ measurements and DFT calculations. The detail mechanism will de presented at the meeting.

References

[1] A. Grimaud, A. Demortiere, M. Saubanere, W. Dachraoui, M. Duchamp, M. Doublet, J. Tarascon, Nature energy, 2016, 2, 16189.

[2] H. Oh, H. Nong, T. Reier, A. Bergmann, M. Gliech, J. Araújo, E. Willinger, R. Schlögl, D. Teschner, P. Strasser, J. Am. Chem. Soc. 2016, 138, 12552−12563.

[3] E. Oakton, D, Lebedev, M. Povia, D. Abbott, E. Fabbri, A. Fedorov, M. Nachtegaal, C. Copéret, T. Schmidt, ACS Catal. 2017, 7, 2346−2352.

[4] H. Casalongue, M. Ng, S. Kaya, D. Friebel, H. Ogasawara, A. Nilsson, Angew. Chem. Int. Ed. 2014, 53, 7169–7172.
Self-Activated Low-Dimensional Metal Halide Phosphors and Scintillators
Authors: Du Mao-Hua
Published: February 2020

We report theoretical studies of exciton excitation and emission in low-dimensional metal halides, (C4N2H14X)4SnX6 (X = Br, I), Cs4PbBr6, (Ph4P)2SbCl5 (Ph4P = tetraphenylphosphonium), (C9NH20)2SnBr4, and (C4N2H14)PbCl4. These are bulk crystalline materials, in which isolated metal halide clusters/wires are separated from each other by large inorganic or organic countercations, forming 0D/1D structures. For example, in (C9NH20)2SnBr4, the anionic (SnBr4)2- clusters are separated from each other by (C9NH20)+ molecular countercations. The metal halides shown above all have 0D structures except (C4N2H14)PbCl4, which has a 1D wire structure. High photoluminescence quantum efficiencies (PLQE) (close to 100% in some cases) have been reported for the 0D metal halides. We calculated exciton excitation and emission energies in these low-dimensional metal halides; the results are in excellent agreement with the experimental values. This enables us to study the luminescence mechanisms and suggest new compounds for synthesis. We show that exciton self-trapping in the metal-halide cluster/wire leads to localized excitons, which is important for efficient radiative recombination. The relatively low PLQE (6% - 18%) in 1D (C4N2H14)PbCl4 is likely due to the exciton diffusion along the wire and the subsequent nonradiative recombination at defects. The large organic countercations in hybrid organic-inorganic 0D halides plays the important role of decoupling metal halide clusters (which are luminescent centers), leading to highly immobile excitons and high PLQE. On the other hand, in all inorganic 0D Cs4PbBr6, the significant electronic coupling between PbBr6 clusters and the small Stokes shift should enable resonant transfer of excitation energy and the subsequent energy loss at defects, which explains the strong thermal quenching of luminescence in Cs4PbBr6. We further suggest that Cs4EuX6 (X = Br,I), which are analogs to Cs4PbBr6, should exhibit improved luminescent properties compared to Cs4PbBr6 due to stronger exciton localization at Eu2+ than at Pb2+. Indeed, recent synthesis and characterization of these compounds show high light yields under gamma-ray irradiation at room temperature. In particular, the light yield of Cs4EuBr6 (78,000 photons/MeV) is the highest among the self-activated scintillators.
(Invited) Water-Soluble Near-Infrared Fluorophores Emitting over 1000 Nm and Their Application to In Vivo Imaging in the Second Optical Window
Authors: Jin Takashi , Tsuboi Setsuko , Yamada Sayumi
Published: February 2020

Near-infrared (NIR) emitting fluorophores are widely used as bio-imaging probes for non-invasive visualization of deep-tissues at the whole body level, because of the high permeability and low absorption of NIR light in living tissues. Recently much attention has been paid for NIR fluorescence imaging at the wavelengths of 1000-1400 nm (second optical window) to obtain clearer deep-tissue images with high signal to background ratios. This is because that the NIR light with longer wavelengths (1000-1400 nm) is highly permeable with lower scattering compared with the conventional NIR light (700-1000 nm). In the second optical window, there are a very limited number of fluorophores that can be used for NIR fluorescence imaging. To date, single walled carbon nanotubes (SWNTs), PbS quantum dots (QDs) and Ag2S QDs, rare-earth metal doped nanoparticles (NPs) have been reported as NIR fluorophores for in vivo imaging in the second optical window. In this work, we synthesized several types of water-soluble NIR fluorophores, glutathione coated PbS QDs, glutathione coated Ag2S QDs, Er3+-doped NaYF4 nanoparticles (Er3+-NPs) and cholate-capped SWNTs that emit over 1000 nm. For the application of the NIR fluorophores to in vivo imaging, we examined their fluorescence brightness, particle size, and cytotoxicity. We found that among the NIR fluorophores, PbS QDs are the brightest fluorophore (quantum yield, 4 %) with no significant cytotoxicity. The fluorescence of Ag2S QDs, Er3+-NPs, and SWNTs was at least 50 times week compared with that of PbS QDs. We show the capability of the NIR fluorophores for in vivo imaging of cerebral blood vessels, tumor angiogenesis, lymph nodes, and phagocytic cell migration in mice.
(Keynote) Electrocatalysis for Electrosynthesis
Authors: Minteer Shelley D.
Published: February 2020

Over the last several years, there has been a renewed interest in electrosynthesis. However, frequently electrocatalysts are needed to improve the selectivity and lower the overpotential for product production. This paper will detail the use of electrocatalysts and electrocatalytic cascades for electrosynthesis. This talk will include a discussion of direct and mediated bioelectrocatalysis, as well as direct and mediated electrocatalysis. Special attention will focus on the need for proton coupled redox mediators, as well as the strategies for immobilization of small molecule redox mediators. This talk will discuss electrosynthesis applications that range from the production of ammonia to hydrocarbons to high value pharmaceutical pre-cursors.
In Situ Structural Determination of Underpotentially Deposited Pd Monolayer on Au(111) Surface
Authors: Masuda Takuya , Wakisaka Yuki , Kondo Toshihiro , Chun Wang-Jae , Takakusagi Satoru , Asakura Kiyotaka , Uosaki Kohei
Published: February 2020

Ultrathin metal films with well-defined atomic arrangements can be formed on surfaces of single crystal electrodes by underpotential deposition (UPD) technique in which metals can be deposited on a foreign metal substrate at potentials more positive than the reversible potential of the bulk deposition if the interaction between the deposited metal and the foreign metal substrate is stronger than that of the deposited metal itself. The structure of a Pd UPD layer prepared on a Au(111) surface has been studied with an atomic resolution in situ by scanning tunneling microscopy (STM) and surface x-ray scattering (SXS) and it was found that a pseudomorphic Pd monolayer is formed on the Au(111) surface.1-5 In addition, the Pd UPD layer on Au(111) surface is known to exhibit unique catalytic activities for oxygen reduction reaction (ORR).6 In the present work, the geometric and electronic structure of the Pd UPD layer on Au(111) surface during ORR were investigated by in situ XAFS measurements in the polarization dependent total reflection fluorescence (PTRF) configuration.7-12

1) Naohara, S. Ye, K. Uosaki, J. Phys. Chem. B
102, 4366 (1998).

2) Naohara, S. Ye, K. Uosaki, J. Electroanal. Chem.
473, 2 (1999).

3) Takahasi, Y. Hayashi, J. Mizuki, K. Tamura, T. Kondo, H. Naohara, K. Uosaki, Surf. Sci.
461, 213 (2000).

4) Naohara, S. Ye, K. Uosaki, J. Electroanal Chem.
500, 435 (2001).

5) Takahashi, Y. Hayashi, J. Mizuki, K. Tamura, T. Kondo, H. Naohara, K. Uosaki, Surf. Sci.
461, 213 (2000).

6) Naohara, S. Ye, K. Uosaki, Electrochim. Acta,
45, 3305 (2000).

7) W.-J. Chun, K. Asakura, Y. Iwasawa, J. Phys. Chem. B
102, 9006 (1998).

8) Masuda, H. Fukumitsu, S. Takakusagi, W.-J. Chun, T. Kondo, K. Asakura, K. Uosaki, Adv. Mater,
24, 268 (2012).

9) Masuda, K. Uosaki, J. Electron Spectrosc. Relat. Phenom.,
221, 88 (2017).

10) Masuda, Y. Sun, H. Fukumitsu, H. Uehara, S. Takakusagi, W.-J. Chun, T. Kondo, K. Asakura, K. Uosaki, J. Phys. Chem. C,
120, 16200 (2016).

11) Masuda, K. Uosaki, Chapter 6, “Novel In Situ Techniques”, Electrochemical Science for a Sustainable Society A Tribute to J.O’M Bockris, Springer International Publishing, 2017, 147-174.

12) Masuda, T. Kondo, K. Uosaki, Section 5.13, “Solid-Liquid Interfaces”, XAFS Techniques for Catalysts, Nanomaterials, and Surfaces, Springer International Publishing, 2016, 505-525.
Photoelectrochemical Methanol Oxidation on TiN@Au Core-Shell Nanoparticles Supported on TiO2
Authors: Baturina Olga A , Epshteyn Albert , Simpkins Blake
Published: February 2020

Refractory transition metal nitrides such as TiN and ZrN are a new class of plasmonic materials that exhibit plasmonic resonance in the visible and near-infrared regions [1, 2]. The similarity of optical appearance of TiN to gold makes one wonder whether inexpensive and chemically and mechanically robust TiN can replace Au in plasmon-mediated photocatalytic reactions. Prior research [3] has shown that cubic 50 nm TiN nanoparticles supported on TiO2 nanowires provide greater photocurrent enhancement for the photoelectrochemical water splitting compared to spherical Au nanoparticles. This has been attributed to more efficient hot carrier generation by TiN nanoparticles, followed by more efficient collection of hot electrons by TiO2. 50 nm TiN nanoparticles (NPs), however, proved to be inefficient in promoting photocatalytic activity of TiO2 towards methanol oxidation in the visible region [4]. This was likely due to a lack of catalytic activity of the TiN NPs’ surface for CH3OH oxidation.

Here, we explore the plasmon-mediated photocatalytic methanol oxidation on hybrid core-shell nanoparticles consisting of a thin gold shell and TiN core and compare the effect of TiO2-supported TiN@Au nanoparticles to that of Au on the photon-to-electron conversion efficiency.

The TiO2-supported TiN@Au photocatalysts were made by the deposition of a thin Au shell on 20 and 50 nm TiN NPs (PlasmaChem) followed by the dispersion of the TiN@Au NPs onto TiO2 nanoparticle support (Degussa). Electrochemical experiments were conducted in a three-electrode photoelectrochemical cell. The thin films of TiN@Au/TiO2 on FTO-coated glass served as working electrodes (WEs), while platinum foil and Ag/AgCl in 3 M NaCl (BioLogic, Inc) were used as counter and reference electrodes, respectively. LED lights were used as light sources. X-Ray Photoelectron Spectroscopy, Powder X-Ray Diffraction, and high resolution transmission electron microscopy were used for characterization of catalysts surface composition and morphology.

References

[1] G.V. Naik, J.L. Schroeder, X. Ni, A.V. Kildishev, T.D. Sands, A. Boltasseva, Optical Materials Express, 2 (2012) 478.

[2] U. Guler, A. Boltasseva, V.M. Shalaev, Science, 344 (2014) 263.

[3] A. Naldoni, U. Guler, Z.X. Wang, M. Marelli, F. Malara, X.G. Meng, L.V. Besteiro, A.O. Govorov, A.V. Kildishev, A. Boltasseva, V.M. Shalaev, Advanced Optical Materials, 5 (2017).

[4].O.A. Baturina, A. Epshteyn, B. Simpkins. Unpublished results
(Keynote) Conducting Redox Polymer Batteries
Authors: Sjödin Martin , Emanuelsson Rikard , Sterby Mia , Huang Hao , Wang Huan , Strømme Maria
Published: February 2020

Organic matter based battery materials have attracted large interest due to their inherent ability to provide an environmentally benign alternative to inorganic batteries because such materials can be produced from renewable resources via eco-efficient processes. Conducting redox polymers (CRPs) is an attractive class of materials for organic matter based electrical energy storage. CRPs are composed of a conducting polymer backbone with redox active pendant groups covalently linked to the polymer backbone. The conducting polymer backbone renders the material conductive and, due to the large molecular size, prevents material dissolution thus mastering two of the most significant obstacles in achieving powerful and stable battery materials from organic compounds. The pendant redox group, on the other hand, can provide high charge storage capacities to the material. Combining conducting polymers with high charge storage capacity pendants thus has the possibility to form powerful materials for battery applications provided that the individual properties of the backbone and the redox group can be preserved and operate in synergy in the CRP. This requires careful matching of the redox chemistry of the pendant group and the CP backbone as CPs are only conducting in specific potential regions. In this work design principles for CRPs are outlined and we present results suggesting that CRPs can show semi-metallic electron transport properties and that redox conversion rates on the sub-second time-scale can be accomplished with this type of materials [1]. In addition we present an all-organic proton battery composed of quinone CRPs as both anode and cathode [2].

[1] M. Sterby, et al., Electrochim. Acta, 2017, 235, 356-364

[2] R. Emanuelsson, et al., J. Am. Chem. Soc., 2017, 139 (13), 4828-4834.

Figure 1
A Rational Balance Design of Ionic Liquid Based Electrolyte for Advanced Li-S Batteries
Authors: Lu Hai , Chen Zhen , Du Huiling , Zhang Kai
Published: February 2020

Lithium-sulfur (Li-S) battery has attracted worldwide attentions by virtue of high theoretical energy density, abundant material source and good environmental friendliness. However, the dissolution and shuttle of the intermediate polysulfides always result in low sulfur utilization, bad cycle stability and severe self-discharge issue.

It is well known that room temperature ionic liquids (ILs) can reduce polysulfide dissolution owing to weak donor ability and delay polysulfide migration due to high viscosity. But high viscosity is a double-edged sword, which can also hinder the transport of Li ion, casing low capacity deliver and weak rate capability. Various low-viscous ethers (DME, DOL, TEGDME) has been attempted to cooperate with the IL, but most of them have a relatively high donor number and hence polysulfide dissolution is reversely promoted unavoidably.

Here, we put forward the introduction of linear fluorinated ethers (LFEs) in the IL-based electrolyte as co-solvent. By adding moderate content of LFEs into the IL, the increased capacity and improved rate capability are demonstrated. On the one hand, LFEs own relatively lower viscosity compared to ILs and hence improve the ion conduction in the electrolyte. On the other hand, they serve to minimize polysulfide dissolution due to low solvation ability. Besides, these F-contained solvents stabilize SEI on Li anode as well. However, the binary system consisting of IL and LFE leads to low active material utilization instead, despite high coulombic efficiency (CE, close to 100%) and stable cycle is obtained. In other words, excessive restriction to polysulfide dissolution is not necessary for the improvement of cell performance. In contrast, the ternary system consisting of IL, LFE and ordinary ether (such as DOL) contributes to more reversible capacity, although the CE value (~90%) is a bit lower than those binary or pure IL cases (Fig.1 as an example). Therefore, it should be emphasized that a rational balance design between the polysulfide dissolution and shuttle suppression is more significant for constructing advanced Li-S batteries.

Fig. 1 (a) Discharge capacities and (b) coulombic efficiencies of Li-S batteries in various electrolytes during cycling

Reference:

Lu, K. Zhang, Y. Yuan, et al, Electrochim. Acta, 2015, 161, 55-62

Lu, Y. Yuan, K. Zhang, et al, J. Electrochem. Soc., 2015, 162, A1460-A1465

Lu, Z. Chen, H. Du, et al, Ionics, DOI: 10.1007/s11581-018-2814-x

Acknowledgment:

This work was supported by the Natural Science Foundation of China (No. 51604221, 51372197 and 51574288), the Key Innovation Team of Shaanxi Province (2014KCT-04).

Figure 1
Multi-Site Redox Activities in Chemically Complex Sodium Layered Oxide Cathode Materials
Authors: Rahman Muhammad Mominur , Lin Feng
Published: February 2020

Sodium layered oxide cathode materials with high specific capacity, energy density, and long cycle life have been the bottleneck for the widespread market implementation of sodium-ion batteries. Even though sodium layered oxide materials share many similarities with their Li-ion counterpart, there are many dissimilarities between the two which can be utilized to design high performance sodium layered oxide cathode materials. Sodium layered oxide materials can incorporate almost all of the first row transition metals in the transition metal oxide layer. Herein, we have synthesized a sodium layered oxide material with five transition metals to demonstrate such concept. The material is synthesized following a simple co-precipitation method and is a mixture of P2 and P3 type crystal structures (P2/P3=1). The material has good electrochemical performance with excellent stability on long term cycling. It delivers a specific capacity in the range of 95 mAh/g at C/10 with no capacity fading after 100 cycles, 72 mAh/g at 1C with 95% capacity retention after 500 cycles, and 55 mAh/g at 5C with 85% capacity retention after 1000 cycles. We further demonstrate the surprisingly good performance of the material at low temperatures. For example, the material delivers a 60 mAh/g capacity at 1C and 0°C with no capacity fading after 100 cycles. We further studied the structural evolution and redox reaction mechanism of the cathode material at different states of charge. The reversibility of the Na (de)insertion is evident from the reversibility of the XRD pattern upon cycling. Hard XAS study has revealed that most transition metals contribute to some degree towards the redox reaction of the cathode material, with most energy derived from the redox of Ni2+ and Co3+. This study has demonstrated that selecting the ideal transition metal hosts and building up the compositional complexity can be a path towards further improving sodium cathode materials.
Key Features in the Manufacturing Process of Ultra-Thick Electrodes for High Energy Lithium Ion Batteries
Authors: Heider Emanuel , Hoffmann Alice , Kremer Lea Sophie , Dreer Christian , Pfeifer Claudia , Diehm Ralf , Kumberg Jana , Schabel Wilhelm , Wohlfahrt-Mehrens Margret
Published: February 2020

Energy density is one of the key challenges in the development of advanced lithium ion batteries for many applications. To address this issue, a considerable number of studies have been conducted on high capacity cathode materials1–3. Another approach, covered in this contribution, is reducing the amount of passive material in the cell via increasing the mass loading of the electrodes4,5. These ultra-thick electrodes, however, suffer from certain drawbacks like a low rate capability4–7, reduced adhesion and flexibility or crack formation8.

Numerous investigations on the development of electrodes for lithium ion batteries have been performed using preparation techniques typical for lab scale. In common studies, the electrochemical and mechanical properties of an electrode are attributed to mass loading, porosity and the distribution of passive materials in the binder-network9.

This study considers manufacturing procedures for NMC cathodes highly relevant to industrial production. A strong influence of the manufacturing process especially on the morphology and electrochemical performance of ultra-thick electrodes was observed.

As an example, ultra-thick electrodes with an areal capacity of 8 mAhcm-2 were prepared in pilot scale, yielding a significantly higher capacity than state of the art cathodes7,10.

It is demonstrated that the mixing strategy used for slurry preparation significantly alters the distribution of materials and the morphology of the electrode, consequently also influencing adhesion strength and flexibility. These properties are likewise strongly affected by the applied drying procedure. By an optimized mixing and drying procedure, crack-free, ultra-thick electrodes were obtained even in pilot scale. These electrodes, manufactured by the optimized process, show significantly higher flexibility, which is very important for roll-to-roll processing.

Scanning electron microscopy revealed the strong effect of the manufacturing process on the morphology of the material distribution within the electrode composite. Electrochemical measurements and impedance spectroscopy furthermore showed the decisive influence of electrode morphology on rate capability and Li+ transport properties.

As a result, only by applying an improved mixing process, the areal discharge capacity of ultra-thick cathodes at 1 C was increased by more than 50% compared to a common procedure.

Figure 1
Novel Alkyl Aluminum Coating Method for Lithium Ion Batteries Cathode Materials
Authors: Aoki Masahiro , Takemoto Yujin , Futagoishi Tsukasa , Inaba Koichirou , Nakajima Nami , Haraguti Tomohiro , Sakai Kentaro
Published: February 2020

Lithium ion batteries (LIBs) have high energy density compared with other batteries. However, LIBs require more energy density since mobile devices become high performance.

In order to increase the energy density of LIBs, it is effective that increase of the charge-discharge operating voltage. However, increasing voltage simultaneously induced the decomposition of electrolyte in LIBs and deteriorate safety and durability of batteries.

Coating positive electrode materials with the metal oxide has been developed as the effective techniques for improving the safety and durability of LIBs (1-3).

It was well known that the coating methods with metal oxide protect the surface from chemical reaction with the electrolyte. On the other hands, coating with a metal oxide leads to an increase in interfacial resistance.

We have been developing the Al materials for coating based on partially hydrolyzed alkyl aluminum wet process technology.

The partially hydrolyzed alkyl aluminum coated on LiCoO2 active material exhibited a capacity retention of 85.6% after 500 charge-discharge cycles in the 3.0-4.35V (vs. Li/Li+) range. In contrast, the bare LiCoO2 active material displayed only a 9.6% capacity retention.

The coating process with partially hydrolyzed alkyl aluminum can formed thin film on active materials in contrast to the sol-gel process.

Therefore, this process does not cause an increase in interfacial resistance.

In this presentation, we will report several battery characteristics using coating method with partially hydrolyzed alkyl aluminum.

H.-J. Kweon, J. Park, J. Seo, G. Kim, B. Jung, and H. S. Lim Journal of Power Sources, 126, 156 (2004).

J. Cho, Y. Kim, T.-J. Kim, and B. Park, Angewante Chemie International Edition, 18, 3367 (2001).

Y. S. Jung, A. S. Cavanagh, A. C. Dillon, M. D. Groner, S. M. George, and S.-H. Lee, Journal of Electrochemical Society, 157(1), A75 (2010).
Fabrication and Electrochemical Studies of Ncm Cathode Active Material with Nano-Grade Materials for All-Solid State Batteries
Authors: Park Sang-Jun , Yang Seung-Hoon , Kim Min-Young , Jung Ha-Young , Ban Hee-Jung , Song Young-Woog , Jeon Se-Hyeon , Nam Su-jeong , Kim Ho-Sung , Han Jong-Hun , Kim Yoong-Ahm
Published: February 2020

Recently, all-solid state batteries (ASSBs) are studied using hybrid solid electrolyte and composite cathode by wet process. NCM materials is suitable for high voltage and capacity of ASSBs. However, since the ASSBs are used under high-temperature (60~80°C), the initial capacity is lower than that of the liquid type lithium ion battery, and the discharge capacity tends to decrease according to the charge/discharge cycle.

In order to improve the thermal properties and the electrochemical reactivity of the NCM material, the surface was coated with nanoparticles of LFP or LMO material using liquid dispersion method. The surface of the active materials was observed by SEM and TEM analysis, and the lattice parameter was analyzed by XRD and Rietveld analysis. Furthermore, the coated NCM active materials were mixed with garnet LLZO, a polymeric binder, and a conductive material to prepare a cathode by a wet process. A 2032 coin cell was fabricated using Garnet LLZO composite solid electrolyte sheet (SE) as a solid electrolyte and Li-metal as anode to evaluate electrochemical characteristics. The characteristics of charge/discharge cycle of ASSBs will be described in more detail.
Li Ion Hopping Conduction in Highly Concentrated Liquid Electrolytes
Authors: Dokko Kaoru , Watanabe Daiki , Ugata Yosuke , Thomas Morgan L. , Ueno Kazuhide , Watanabe Masayoshi
Published: February 2020

We demonstrate here that Li+ ion hopping conduction emerges in highly concentrated liquid electrolytes composed of LiBF4 and sulfolane (SL). Self-diffusion coefficients of Li+ (D
Li), BF4
− (D
BF4), and SL (D
SL) were measured with pulsed field gradient (PFG) NMR. In the concentrated electrolytes with molar ratios of SL/LiBF4 ≤ 3, the ratios of diffusion coefficients, D
SL/D
Li and D
BF4/D
Li, become lower than unity, suggesting faster diffusion of Li+ than SL and BF4
−. X-ray crystallographic analysis of a single crystal of LiBF4:SL (1:1) solvate revealed that the two oxygen atoms of the sulfone group are involved in bridging coordination of two different Li+ ions. In addition, the BF4
− anion also participates in bridging coordination of Li+. Raman spectroscopy revealed that Li+ ions are bridged by SL and BF4
− even in the highly concentrated LiBF4/SL solution. The fact that D
Li is larger than D
SL and D
BF4 in the highly concentrated electrolytes strongly suggests that Li+ exchanges between the coordination sites formed by the ligands (SL and BF4
−) and moves forward leaving behind the ligands. The SL and BF4
− provide closely placed coordination sites in the highly concentrated electrolytes. The spatial proximity of coordination sites is assumed to enable Li+ hopping conduction. Furthermore, we found that Li+ hopping conduction occurs in the highly concentrated SL-based electrolytes containing other Li salts, such as LiClO4 and Li(NSO2F)2. The higher diffusion coefficient of Li+ than that of anion results in the higher Li+ ion transference number (> 0.5) in the electrolytes. The higher Li+ ion transference number was effective in suppressing the concentration polarization in a lithium battery, leading to increased limiting current density and improved rate capability compared to the conventional concentration electrolyte.

Acknowledgements

This study was supported in part by JSPS KAKENHI (Grant Nos. 16H06368 and 18H03926) from the Japan Society for the Promotion of Science (JSPS) and the Advanced Low Carbon Technology Research and Development Program (ALCA) of the Japan Science and Technology Agency (JST).

Reference

K. Dokko, D. Watanabe, Y. Ugata, M. L. Thomas, S. Tsuzuki, W. Shinoda, K. Hashimoto, K. Ueno, Y. Umebayashi, M. Watanabe, J. Phys. Chem. B, 122, 10736-10745 (2018).
Elucidating Interfacial Phenomena between Solid-State Electrolytes and the Sulfur-Cathode of Lithium-Sulfur Batteries
Authors: Camacho-Forero Luis E , Balbuena Perla B.
Published: February 2020

With the increasing demand for electric/hybrid vehicles, smart electronic devices, and rapid technological advancements, the need for batteries with improved properties to state-of-the-art Li-ion batteries has hastily grown over the last decade. In the screening of new technologies, Lithium-Sulfur (Li–S) batteries are one of the most promising candidates among rechargeable battery systems due to its reduced cost, low toxicity, and high theoretical specific energy and specific capacity. However, there are still several limitations that need to be overcome before Li-S batteries are feasible for commercialization. One of the main drawbacks of this technology is the “shuttle” effect – migration of soluble polysulfide species (PS) from the cathode to the anode, where are reduced to Li2S2 and Li2S, resulting in the formation of an SEI layer that can passivate the lithium anode. In addition, the use of liquid organic electrolytes rises safety concerns due to their flammability. For this reason, inorganic solid-state electrolytes (SSEs) are being explored as an alternative because unlike liquid organic-based electrolytes, SSEs are usually non-flammable and have the potential to suppress PS shuttle and Li dendrites. However, when working with SSEs, the compatibility between the electrodes and the SSEs is critical. Such compatibility is determined by the properties of the electrode/electrolyte interface. A good interface between an SSE and electrode requires fast ion transport, maximum contact area, and chemical stability during cycling. Therefore, it is imperative to gain insights regarding the SSE/Sulfur-cathode interface. In this work, we use density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations in order to study the SSE/S-cathode interface. Li3PS4, Li7P2S8I, and Li6PS5Cl were selected as representative materials of the sulfide-type family of SSEs, which has proven to exhibit high ionic conductivity and good mechanical properties. Here, two states of charge of the cathode (non- and fully-lithiated) in contact with the SSEs models are studied. Reaction mechanisms, the structure of the interface, and charge transfer evolution are carefully examined and characterized in detail. Finally, interfacial and surface energies are provided as descriptors of stability and compatibility of the electrode/cathode interfaces.
Morphology Controlled Fabrication of Nanostructured Molybdenum Oxides By Different Mineralizers Via Hydrothermal Synthesis Method
Authors: İnel Eren , Karahan Billur Deniz
Published: February 2020

Recently, the “chemistry of form” turns into an interesting subject for scientists of various disciplines. Thus, designing novel structured materials and controling their morphologies become an attractive and value-added research topic. Among alternative materials, molybdenum oxides have been researched in depth as they find a large variety of applications in electrochemistry. The evaluation of molybdenum oxide as anodes for Lithium Ion Batteries (LIBs) is an example for their various applications. Their higher discharge capacity (over the state-of-the-art anode, graphite) revealed upon cycling makes them a strong candidate for being the anode material of next generation LIBs.

So far, solid state reactions at temperatures up to 1000 °C, ball-mill, co-precipitation, sol-gel synthesis and hydrothermal processes have been used in the production of molydenum oxides.

In this study, hydrothermal method being environmental friendly process is chosen as production method due to its low investment cost, practical application and good control over the crystal structure as well as the morphology of the particles. Although, previously the effect of different mineralizers on the particle morphology has been studied a comparitive study based on investigating the effect of same cationic based mineralizers on the particule properties has not been done yet.

In this work, first in literature, three different sodium based mineralizers (sodium nitrate, sodium chloride and sodium acetate) has been added into the ammonium heptamolybdate (AHM) precursor solution, separetly (pH=0), and their effects on the crystal structure and morphology of molybdenum oxide particles have been investigated. Among alternatives mineralizers, alkali chemicals stand out as cationic ions are expected to be the most influencing factor on the nucleation and growth of molybdenum oxide particles. During the experiments, the hydrothermal reaction takes 12 hours and the temperature is set to 1800C. The resulting powders’ surface morphologies are analyzed by secondary electron microscope, and their structures are characterized based on X-ray Diffraction method. The results are used to propose a nucleation and growth mechanism of molybdenum oxide particles during the hydrotermal treatment, in the presence of different sodium based mineralizers. The possible use of the resulting molybdenum oxides as anode materials for lithium ion batteries has been also discussed based on electrochemical tests.
Room Temperature Fluoride Ion Batteries
Authors: Munnangi Anji Reddy , Mohammad Irshad , Fichtner Maximilian
Published: February 2020

Fluorine is highly electronegative (+2.84 V vs. SHE) element and possess low weight. Fluoride is monovalent, and it has high charge density. Consequently, it enables high ionic conductivity similar to Li+ in certain solids. However, fluorine is a corrosive and toxic gas, which forbids it as one of the electrodes. Nevertheless, fluoride ions can be transported between a metal and a metal fluoride through a fluoride transporting electrolyte, and fluoride-ion batteries (FIB) can be realized. FIB offers high specific energy, energy density, thermal stability, and safety compared to state of the art lithium-ion batteries (LIBs). Primary batteries based on fluoride transport were demonstrated earlier [1]. Recently we have demonstrated first rechargeable FIB that was operable at 150 °C [2]. Several challenges need to be addressed to realize its full potential of FIBs. We have been working on various aspects related to FIB with the aim of developing sustainable fluoride ion batteries [3-5]. Recently, for the first time, we have demonstrated room-temperature (RT) rechargeable fluoride-ion batteries using BaSnF4 as fluoride transporting solid electrolyte [6]. BaSnF4 shows high fluoride conductivity of 3.5x10–4 S cm–1, but limited electrochemical stability window. To be compatible with BaSnF4, we have utilized low electropositive Sn, Zn as anode materials to demonstrate RT FIB. However, to enable cells with high operating potentials, the electrolyte should be compatible with highly electropositive metals (e.g., Mg, Ce). Toward this, we developed a new interlayer electrolyte that is compatible with highly electropositive metals like Ce and Mg. Further, utilizing the interlayer electrolyte, we demonstrate the functioning of first high potential RT FIB.

References:

J. Schoonman, J. Electrochem. Soc. 1976, 123, 1772−1775.

M. Anji Reddy and M. Fichtner, J. Mater. Chem. 2011, 21, 17059.

C. Rongeat, M. Anji Reddy, R. Witter, and M. Fichtner, J. Phys. Chem. C, 2013, 117, 4943.

C. Rongeat, M. Anji Reddy, T. Diemant, J. Behm, M. Fichtner, J. Mater.
Chem. A, 2014, 2, 20861.

C. Rongeat, M. Anji Reddy, R. Witter, and M. Fichtner, ACS Appl. Mater. Interfaces, 2014, 6, 2103.

M. Irshad, R. Witter, M. Fichtner, and M. Anji Reddy, ACS Appl. Energy Mater. 2018, 1, 4766.

M. Irshad, R. Witter, M. Fichtner, and M. Anji Reddy, submitted.
A Materials Genome Approach for Discovery of Novel Li-Ion Cathodes
Authors: Shen Jimmy-Xuan , Persson Kristin A , Horton Matthew
Published: February 2020

With the advent of solid-state electrolytes enabling the safer use of Li-metal anodes, Li battery cathodes can operate from a non-Li-containing state-of-charge. This opens up the possibility for new families of cathode materials. First-principles predictions of cathode material performance (in terms of voltage and capacity) is well established [1] and requires calculating the energies of structures with varying amounts of Li in a given framework material. We have developed a robust method of identifying the stable and metastable Li-insertion sites based on analyzing the charge density. This allows us to successively populate any crystalline framework with Li atoms to obtain the voltage and capacity. Furthermore, the identification of all stable/metastable sites in the host material enables us to map-out possible Li diffusion pathways through the lattice and analyze the migration along those pathways. We demonstrate the approach on a test set of more than 10,000 compounds and show the reliability in comparing to known intercalation systems as well as systems that do not intercalate Li.
(Invited) Model Guided Design and Analysis of Experiment
Authors: Brady Nicholas W , Mayilvahanan Karthik , West Alan C
Published: February 2020

Batteries are complex, with phenomena emanating from multiple length scales that may impact performance and life. Advances thus require multiscale experimental inquiries, and mathematical models, including multiscale models, may be employed to design, analyze and integrate studies. In early-stage research efforts, close collaboration with experimental efforts may result both in dramatically improved model fidelity and in more optimal utilization of experimental resources.

We present approaches to augment physics-based models of Li-ion cathodes with applied statistics algorithms based on Markov-chain Monte Carlo simulations. Several examples are illustrated. The use of model regularization algorithms as a tool to efficiently introduce new physics in cathode-performance and degradation models is demonstrated. Additionally, model selection algorithms are demonstrated within the context of studies of mesoscale transport processes. Identification of the better model leads to an understanding of the dominant length scale in terms of impedance. Such tools can inform decisions in terms of where to focus experimental resources. Finally, the model-guided design of experiment (MGDOE) is discussed. Specifically, the use of simulation tools to identify experimental approaches to minimize parameter uncertainty is discussed, and the use of MGDOE for synchrotron-based operando experiments is considered.
(Invited) Effect of Gravitational Level on the Initial Stage of Cu Electrodeposition
Authors: Fukunaka Yasuhiro
Published: February 2020

Material tailoring of nanostructured devices emphasizes the importance to separately control the nucleation rate from the growth process. It is indispensable to uniquely create the heterogeneous interface to result in the required electronic or physical properties. Then, the multi-scale modeling to link the atomic scale process on the heterogeneous interface with the shape evolution phenomena based on the continuous media process is required.

It is well known that natural convection is accompanying with physicochemical reactions under ground level (1 G).　Microgravity experiments are conducted over 10 s with JAMIC drop tower in order to understand the effect of gravitational level on electrodeposition as well as electrochemical dissolution. Less nucleation rate was observed in μ-G. On the other hand, a centrifugal field has been applied widely in order to create high G environment in electrochemical processing. Various differences in physical and chemical properties were found as well as morphological variations.

The main purpose of this study is to clarify the effect of gravitational level from m-G to high G level on the coupling phenomena between the ionic mass transfer rate and the morphological variations of the electrodeposits. The possibility to control the nucleation phenomena, film morphology and nanostructure is explored.

In particularly, the effects on the electrodeposited copper are analyzed in a cavity-type electrolytic cell from microgravity field in parabolic flight to high G field in centrifugal field. Cathode over anode configuration simulates the ionic mass transfer rate under quasi-microgravity environment because no macroscopic natural convection is induced in this cell configuration. Copper electrodeposition is conducted in order to examine the nucleation rate of copper on TiN substrate. The effects of cell configuration and gravitational level are focused on these phenomena.
Sensitivity Analysis Based on Monte Carlo Simulations of a 1D Accelerated Mechanistic Model of a Proton Exchange Membrane Fuel Cell
Authors: Kannan Vishvak , Fisher Adrian Charles , Birgersson Erik Karl
Published: February 2020

Mathematical modelling of polymer electrolyte membrane fuel cells (PEMFCs) commenced with a one-dimensional (1D) model incorporating gas diffusion and chemical reaction mechanisms, movement at the membrane via electroosmotic drag and proton and water transport at the electrolyte membrane was developed. Subsequently more sophisticated two- and three-dimensional models incorporating the water and thermal management were established to improve the accuracy and thereby identify parameters that influence the performance of the PEMFCs. Recently, as the computational power improved, statistical analyses including sensitivity analyses of approximated models were carried out. However, employing a mechanistic model considering the conservation of charge, mass, momentum, species and energy, for sensitivity analysis is not trivial particularly because of the associated computational cost. In this study, a Monte Carlo based sensitivity analysis is carried out based on an accelerated, time-marched 1D mechanistic model of a PEMFC that captures the effects of dependent variables in all three dimensions. To achieve this, we investigate the effect of random, simultaneous, variation of over 30 normally distributed parameters (physical, geometric, operating electrochemical and fitting parameters) at different operating conditions of the PEMFC. Kolmogorov-Smirnov (KS) test is performed to ensure that the size of the drawn sample is reliable for stable results. An experimentally validated model is taken as the base case and all the parameters are varied with a standard deviation of 10%. The standard deviation in the current at different operating cell potentials is presented. Additionally, the contribution of each stochastic parameter to the current is ranked and quantified by multiple linear regression and sigma-normalized derivative method. Furthermore, a sample size of 10000 is chosen to generate enough variations to the model and identify optimal operating and physical parameters to improve the performance of PEMFC. Moreover, any artificial intelligence centered model predictor can estimate the best set of parameters by accessing the data generated from this study to fit an experimental curve at different operating cell potentials. This accelerated model prediction thereby enables improved accuracy of the predicted models, faster diagnosis and easier optimization of a PEMFC.
Investigation on the Role of Coating Layer Thickness in CeO2 Coated LiMn2O4 Particles for Li-Ion Batteries
Authors: Zhu Yaqi , He Yufang , Liang Xinhua , Park Jonghyun
Published: February 2020

Atomic layer deposition (ALD) coating technique is proved to be an effective and efficient strategy to improve the capacity and cycle capability of lithium-ion batteries. An ALD can deposit continuous, conformal and defect-free thin layers with a controllable coating thickness from sub-micrometer range to nanometer range. Recently, many studies using ALD techniques revealed that coating thickness was a crucial impact factor in improving battery performance and there existed an optimal value for coating thickness to obtain best property. However, the mechanism of its influence remains unclear. Here, we propose a new mechanism in which a thin coating layer can greatly improve battery performance. A demonstration based on a single particle model could explain the trade-off between providing a uniform layer path for diffusion and delaying the transport of the species. A parametric study of the flux area, coating thickness, and current density reveals their influences on the process of charge transfer and diffusion of lithium ions, as well as the capacity of battery.
Thermal Properties of Non-Volatile Phase Change Memories at Device Length Scale
Authors: Aryana Kiumars , Gaskins John , Nag Joyeeta , Grobis Micheal , Olson David , Hopkins Patrick
Published: February 2020

Chalcogenide materials such as Ge2Sb2Te5 (GST) which undergo structural transition between amorphous and crystalline phases with applied thermal load, have emerged as potential material candidates for new memory technologies due to prospective gain in speed, device lifetime, and capacity. In these devices, each memory cell is composed of various components with different material compositions and functionalities. Therefore, a solid understanding of how heat transfers between each component is pivotal in the enhancement of performance and minimization of power consumption. In this study using time-domain thermoreflectance, we measure thermal properties relevant to device operation, at material length scales (< 40 nm) similar to those used in actual devices, such as sound speed, thermal conductivity and thermal boundary conductance (TBC) for a temperature range from 25 °C to 400 °C. According to acoustic echoes obtained from picosecond acoustic measurements, the speed of sound in GST is calculated to be around 2,900 m/s. Moreover, we report the thermal boundary resistance (TBR) when different spacer compositions (W, SiO2, SiNx) are introduced to separate GST from the other components where SiNx/GST interface showed the highest TBR compared to both W and SiO2 interlayers. Additionally, the temperature dependent results indicate that the GST change phase from amorphous to cubic structure at 150 C and again from cubic to hexagonal at approximately 340 C. The thermal conductivity of GST experiences a significant jump at the transition temperature of 150 from 0.15 W/m/K to 0.30 W/m/K and continue to linearly increase by raising the temperature until its crystal structure completely transforms into the hexagonal where the thermal conductivity flattens out to the value of 1.4 W/m/K.