bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling and Experimental Studies of Zn Dendrites Formation and Growth
Authors: Yurkiv Vitaliy , Foroozan Tara , Ramasubramanian Ajaykrishna , Paoli Roberto , Ragone Marco , Shahbazian-Yassar Reza , Mashayek Farzad 
Published: February 2020

Li-ion batteries (LIBs) have shown the tremendous success over past decade for various application starting from portable electronics up to large grid storage solutions. There are many advantages of LIBs comparing to other rechargeable energy storage devises. However, safety concerns originated from the toxic/flammable electrolyte, high materials/manufacturing costs, and relatively low energy density hinders LIBs’ widespread applications. In this regard, metal-air batteries with a light metal (e.g., Li or Zn) as a negative electrode and a porous cathode are very favorable candidates. Among various metal-air batteries, the Zn-air battery is one of the most promising concepts due to Zn’s low cost, low equilibrium potential, abundance, environmental benignity, and long shelf-life.
In the present contribution, we combine modeling and experimental work to study Zn-metal electrodes under various conditions. Experimentally, a novel substrate is suggested to modify the electrodeposition morphology of Zn electrode and its behavior under different cycling conditions. The electrode is characterized using various electrochemical, microscopy and spectroscopy techniques. It is found that Zn dendrites formation can be controlled by a proper choice of current density and current collector material, thus allowing for stable and long-lasting operation. In order to understand the underlying mechanism of Zn dendrites formation and their suppression a phase-field model (PFM)1,2 is developed and applied. In addition, density functional theory (DFT) calculations are used to derive the appropriate parameters needed in the PFM. A detailed description of the relevant electrochemical and mechanical processes is incorporated into the PFM allowing to predict ion concentration field, electrical potential variation as well as elastic-plastic properties of the electrodeposited Zn. The results of the combined PFM and the DFT study show a significant local stress development indicating a direct correlation between the stress field and the origin of the undesired Zn dendrites initiation. In addition, the effects of the solid electrolyte interface (SEI) on Zn electrodeposition is studied.
Thus, the present combined multi-scale modeling methodology and experimental work allows a mechanistic interpretation of the origin of Zn dendrites formation, growth as well as their interdependence with interfacial mechano-electrochemical processes.

References:

[1] V. Yurkiv, T. Foroozan, A. Ramasubramanian, R. Shahbazian-Yassar, F. Mashayek, Electrochim. Acta. 265 (2018) 609 –619.
[2] M.R. Tonks, D. Gaston, P.C. Millett, D. Andrs, P. Talbot, Comput. Mater. Sci. 51 (2012) 20–29.
Durability and Reliability of Commercial Lithium-Ion Cells As a Function of Chemistry and Cycling Conditions
Authors: Preger Yuliya , Barkholtz Heather Marie , Fresquez Armando , Mier Frank Austin , Chalamala Babu R. , Ferreira Summer 
Published: February 2020

Energy storage systems (ESS) utilizing Li-ion batteries are increasingly deployed to maintain a robust and resilient grid and facilitate the integration of renewable energy resources. For this application, ESS are expected to last for a decade or even longer. To ensure long-term system safety and reliability, batteries must be selected based on application specific requirements and performance characteristics. However, suitable cell selection is made difficult by the dearth of data comparing popular commercial chemistries under comparable operating conditions. To address this gap, we initiated a large-scale, multi-year aging study of commercial LiFePO4/LFP, LiNixCoyAl1-x-y­O2/NCA, and LiNi0.80Mn0.15Co0.05O2/NMC cells, varying the discharge rate, depth of discharge (DoD), and environment temperature. Though all cells were cycled within manufacturer specifications, the time to reach 80% capacity varied by thousands of hours among cells of different chemistries and cycling conditions. Analysis of variance was performed to determine what variable levels or combinations of variables contribute most to degradation. Notable results included the resilience of LFP cells to full discharge (in contrast to the sensitivity of NCA and NMC cells), and the inverse temperature dependence of LFP and NMC cells. The source of differences in aging behavior was investigated through electrochemical impedance spectroscopy and differential capacity analysis. Efforts were made to identify markers of degradation that could be translated beyond high-precision lab equipment to field instrumentation. The next phase of this study involves monitoring the abuse response of aged cells to determine if the aging pathway influences the severity of the failure.
Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. SAND2018-13934 A
(Invited) Spectroscopy of Nanocarbon Structures Synthesized in the One-Dimensional Core of Carbon Nanotubes
Authors: Wenseleers Wim , Martinati Miles , Cambré Sofie , Kuzmany Hans , Shi Lei , Rohringer Philip , Ayala Paola , Pichler Thomas 
Published: February 2020

The hollow core and well-defined diameters of carbon nanotubes (CNTs) make them the ideal template for ordering one-dimensional (1D) arrays of molecules and for the controlled synthesis of 1D carbon nanostructures from suitable precursor molecules. For instance, we previously demonstrated that in this way dipolar dye molecules can be naturally aligned in an ideal head-to-tail arrangement to create assemblies with a giant total nonlinear optical response,[1] and that the optical properties of dye molecules encapsulated in SWCNTs can be strongly modulated by the SWCNT diameter, indicating very specific diameter-dependent stacking and interactions of the molecules.[2] By thermal conversion also well-defined carbon structures such as long 1D carbon chains (carbyne) or graphene nanoribbons can be synthesized inside the hollow core of CNTs. Here we show that the structure and properties of such 1D carbon chains are strongly modulated by the interaction with the host tube, which greatly modifies the chains’ bond-length alternation.[3] We also show how the band-gap and electronic spectrum of the encapsulated carbon structures can be measured in detail, even in heterogeneous mixtures, through extensive wavelength dependent resonance Raman (excitation) spectroscopy, disentangling the vibrational and electronic spectra of the different structures.
[1] S. Cambré, J. Campo et al., Nature Nanotechnol.
10, 248 (2015).
[2] S. van Bezouw, D. H. Arias et al., ACS Nano
12, 6881 (2018).
[3] L. Shi et al., Phys. Rev. Mater.
1, 075601 (2017).
(Invited) Thermo-Excitonic Properties of Semiconducting Single-Walled Carbon Nanotubes
Authors: Miyauchi Yuhei 
Published: February 2020

Because of the large binding energy of one-dimensional excitons on the order of 0.5 eV, excitons are stable in semiconducting single-walled carbon nanotubes (SWNTs) even at high temperatures more than 1000 K. This unique exciton property, with the very high intrinsic thermal stability of the materials, enables thermal generation of excitons in semiconducting SWNTs; this results in thermal radiation with very narrow spectral bandwidth even at 1000-2000 K [1]. We will report our recent progress in the study on the thermal exciton radiation from SWNTs.
[1] T. Nishihara, A. Takakura, Y. Miyauchi, and K. Itami, Nat. Commun. 9, 3144 (2018).
(Invited) Challenges for the Electrochemical/Electroless Metallization of Additive Manufactured Polymer Parts
Authors: Dietz Andreas 
Published: February 2020

Additive manufacturing is a well-known technology for manufacturing components with complex geometries. Materials for this process are mainly metals, but also ceramics and polymers. Many components that are produced in large series are still produced today using traditional manufacturing methods such as turning or milling. This also limits their design. In the case of small series or individual parts, additive processes are being used more and more frequently, for which there are no such restrictions. In these cases, the design of these components can be optimally adapted to the required function. Another advantage is often a considerable weight saving.
A major disadvantage of this process is often the insufficient surface quality, which can lead to problems when using the component.
Particularly with polymer components, galvanic metallization can create additional advantages, e.g. mechanical reinforcement, electrical conductivity or the prevention of outgassing.
However, components manufactured by different AM processes have different surface structures depending on the manufacturing process. For example, powder bed-based processes (SLM - Selective Laser Melting) provide a very rough surface. Filament-based methods (FDM - Fused Deposition Modeling), on the other hand, produce a very smooth surface when viewed microscopically, and a very rough surface when viewed macroscopically (half wave profile).
For the electroless and electrochemical metallization of polymer components, this can lead to a major problem with the adhesion of the metal layer to the polymer. In addition, AM-manufactured components are geometrically very complex, so Faraday shielding must be taken into account in galvanic metallization.
The lecture discusses the basics and latest findings on galvanic metallization of plastic components with special consideration of AM-manufactured components and Cr(VI)-free pre-treatment.

Figure 1
Correlating Catalyst Ink Rheology with Fuel Cell Performance and Durability
Authors: Yang Fan , Spinetta Magali , Zhong Sichen , Xu Hui 
Published: February 2020

In polymer electrolyte membrane (PEM) fuel cells, catalyst ink formulation and mixing processes are closely related to catalyst layer coating quality, thus affect the fuel cell performance. Therefore, it would be important to understand these complex solvent-catalyst-ionomer interactions to control the ink properties for coating requirements and performance targets. Ink rheological characterization and particle size distribution (PSD) analysis are two powerful tools that can help to extract valuable information of the catalyst ink. This information can be used to optimize electrode morphology and structure to maximize fuel cell performance. In addition, it can also be used to monitor the ink quality and consistency from batch to batch, and from small lab scale to subsequent scale-up as well.
To establish the correlation between the ink property and MEA performance, the electrode made of catalyst inks with various rheology have been tested for fuel cell performance and durability. The catalyst inks are varied by ionomer, solvent, catalyst, mixing approach and time. The selection of a variety of non-aqueous solvents for catalyst ink preparation will also be investigated as the solvents impact the catalyst particle morphology and structure, and thus electrode performance.
This work will provide a comprehensive understanding of interactions among Pt, carbon, ionomer and their impact on the electrode structure and fuel cell performance. The attained information can be used for better fuel cell electrode design.

Acknowledgement: The project is financially supported by the Department of Energy’s Fuel Cell Technology Office under the Grant DE-SC0012049.
Pressure-Induced Control of Core-Shell Nanoparticles for Oxygen Reduction Reaction
Authors: Park Hyun-Uk , Jang Jeongyun , Seo Min Ho , Choi YongMan , Yim Sung-Dae , Park Seok-Hee , Park Gu-Gon 
Published: February 2020

Precious metal-based active metals are mainly used as electrocatalysts for ORR (Oxygen Reduction Reaction), and cost and durability are major research and development issues in fuel cell applications. In order to obtain high performance in electrocatalysts, composition, dispersion, structure and particle size have been studied as key parameters. A number of researchers have been reporting enhanced ORR performance by alloying approaches. Platinum-based alloy nanoparticles are typically prepared through a heat treatment process, which can result in significant levels of specific activity and mass activity improvements. However, the high temperature of the alloying process leads to size growth of the nanoparticles, resulting in a reduction in active area. In order to prevent growth of nanoparticle size during heat treatment, various approaches have been reported such as forming a protective layer by using physical barriers using inorganic and organic materials [1-3]. However, in this case, post-treatment or additional process is required to remove the protective layer, which limits the mass production.
In this work, we propose a method to easily control the size of the core-shell nanoparticles by controlling the pressure of the inert gas during the heat treatment process. As synthesized M@Pt/C (M = Co, Fe, etc.) catalysts were conducted heat treatment with varied pressure control (1, 40, 80 bar) under inert atmosphere. The average size of the metal nanoparticles was distributed in the range of about 3 to 5 nm, and the particle size was clearly reduced in inverse proportion to the pressure. By scanning transmission electron microscopy (STEM) analysis, we also confirmed that the catalysts show clear M core-Pt shell structure. Theoretical calculations show the correlation between the size of metal nanoparticles and external pressure. Herein, we introduce a novel particle size control method (Pressure-induced particle size control). Furthermore, we believe that our unique synthetic approach can be a promising way to obtain intermetallic structure NPs with controlled particle size.

References

1. L. Guo, W.-J. Jiang, Y. Zhang, J.-S. Hu, Z.-D. Wei and L.-J. Wan, ACS Catal.,
5, 2903-2909 (2015).
2. N. Cheng, M. N. Banis, J. Liu, A. Riese, X. Li, R. Li, S. Ye, S. Knights and X. Sun, Adv. Mater., 27, 277-281 (2015).
3. D. Y. Chung, S. W. Jun, G. Yoon, S. G. Kwon, D. Y. Shin, P. Seo, J. M. Yoo, H. Shin, Y. H. Chung, H. Kim, B. S. Mun, K. S. Lee, N. S. Lee, S. J. Yoo, D. H. Lim, K. Kang, Y. E. Sung and T. Hyeon, J. Am. Chem. Soc., 137, 15478-15485 (2015).

Figure 1
In-Situ XAFS Study to Monitor the Degradation of an Fe/N/C Cathode Catalyst in PEMFC
Authors: Nabae Yuta , Nagata Shinsuke , Kusaba Keizo , Aoki Tsutomu , Yuan Qiuyi , Takao Naoki , Itoh Takanori , Arao Masazumi , Imai Hideto , Higashi Kotaro , Sakata Tomohiro , Uruga Tomoya , Iwasawa Yasuhiro 
Published: February 2020

Understanding the degradation mechanism of Fe/N/C cathode catalysts in proton exchange membrane fuel cells (PEMFCs) is extremely important. In this study, an Fe/N/C catalyst prepared from polyimide nano-particles were placed in an in-situ cell for X-ray absorption spectroscopy, and its Fe K-edge adsorption spectra were recorded during a continuous operation of the fuel cell.
The Fe/N/C catalyst used in this study was prepared by pyrolyzing Fe-containing polyimide nano-particles, which were synthesized by the precipitation polymerization of Pyromellitic dianhydride and 1,3,5-tris(4-aminophenyl)benzene. The Fe content after the preparation procedure was 0.6 wt%. This catalyst was used to fabricate a membrane and electrode assembly (MEA) with a Pt/C anode and a Nafion 212 membrane. This MEA was installed in a test cell for in-situ X-ray adsorption fine structure (XAFS) measurements, and operated at 0.5 V and 80°C for 8 h monitoring its Fe K-edge adsorption spectra.
Fig. 1 shows the changes in the spectra during the fuel cell operation. The valence of the Fe specie at the initial stage was 3+. The spectra gradually changed during the fuel cell operation, suggesting that the dissolution of the Fe species from the active sites. This change could be relevant to the degradation of the cathode catalyst.
Acknowledgements
This study is financially supported by NEDO. The in-situ XAFS study was carried out at BL36XU in SPring-8 (No. 2016B7907, 2018A7840 and 2018B7907).

Figure 1
Electrochemical Characterization Methods of Fe-Based Oxygen Reduction Reaction Electrocatalysts for Polymer Electrolyte Fuel Cells
Authors: Park Jaehyung , Ferrandon Magali , Myers Deborah J. , Chung Hoon T , Komini Babu Siddharth , Zelenay Piotr 
Published: February 2020

Transition metal-nitrogen-carbon (TM-N-C) materials are now regarded as the most promising class of platinum group metal-free (PGM-free) oxygen reduction reaction (ORR) catalysts for polymer electrolyte fuel cells catalysts [1]. An Fe catalyst with atomically-dispersed FeNx sites imbedded in a graphene matrix (Fe-N-C), derived from an iron-doped zeolitic imidazolate framework (ZIF), has recently been shown to have outstanding ORR activity and to be a relatively durable PGM-free catalyst [2,3]. This presentation will describe methods to quantify the amount and relative adsorption energies (i.e., desorption temperatures) of nitric oxide (NO), a molecular surface probe, adsorbed on different surface sites on Fe-N-C catalysts. Catalyst powder samples are electrochemically reduced and oxidized using an electrochemical cell specially designed for easy retrieval of the powder after electrochemical treatment. Using a commercial temperature-programmed reactor (TPR), as-prepared and electrochemically-reduced catalyst samples are exposed to gas-phase NO followed by temperature-programmed desorption (TPD) with mass spectrometric detection of NO and thermal conductivity detection of all desorbed species. The TPD results quantify the amount and relative adsorption energies (i.e., desorption temperatures) of NO adsorbed on different surface sites on the Fe-N C catalyst. In addition, following NO exposure, the powders are also transferred to the above-mentioned electrochemical cell or incorporated into a catalyst-ionomer ink and deposited onto a rotating disk electrode (RDE) tip for electrochemical stripping of the adsorbed NO and for ORR activity and selectivity measurements. The potentials and stripping charges and desorption peak temperatures and areas for both the as-prepared and electrochemically-reduced forms of the catalyst are compared and used to provide insight into the active site identity and density of the Fe-N-C catalysts.
References

S.T. Thompson, A.R. Wilson, P. Zelenay, D.J. Myers, K.L. More, K.C. Neyerlin, and D. Papageorgopoulos, Solid State Ionics, 319 (2018) 68-76.

H. Zhang, S. Hwang, M. Wang, Z. Feng, S. Karakalos, L. Luo, Z. Qiao, X. Xie, C. Wang, D. Su, Y. Shao, Gang Wu, J. Am. Chem. Soc., 139 (2017) 14143-14149.

H. T. Chung, D. A. Cullen, X. Yin, S. Komini Babu, K. L. More, D. J. Myers, P. Zelenay, 234th Electrochemical Society Meeting Abstract 1540, Oct 4 2018, Cancun, Mexico.

This work was supported by the U.S. Department of Energy, Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office under the auspices of the Electrocatalysis Consortium (ElectroCat). Argonne National Laboratory is managed for the U.S Department of Energy by the University of Chicago Argonne, LLC, also under contract DE-AC-02-06CH11357.
Hydrogen Oxidation Reaction on Pt and Pt Alloys and the Role of Cations in Alkaline Media
Authors: Weber Daniel Jochen , Oezaslan Mehtap 
Published: February 2020

Hydrogen oxidation/evolution reactions (HOR/HER) are the main key for the hydrogen economy in the
future. The control of an efficient hydrogen generation from water and of its reverse reaction, particularly
in fuel cells, is still insufficient. For instance, very low Pt loadings are required for the HOR in proton
exchange membrane fuel cells,1 whereas the HOR kinetics change tremendously in alkaline media and
become at least two order of magnitudes slower.2 To design catalyst materials with improved HOR/HER
performance in alkaline conditions, a deeper understanding about the reaction mechanism and kinetics is
needed. This includes to uncover the significant role of cations during the HOR in alkaline media.3

Firstly, we have studied the effect of monovalent cations on the HOR kinetics on polycrystalline and nanosized
platinum in different alkaline solutions (MOH, M = K+, Na+, Li+). Depending on the cations, we
observed a significant change of the HOR activity and activation energy for the Pt. More precisely, the
HOR activity of Pt increases in the order of K+ < Na+ < Li+, respectively, while the activation energy
simultaneously decreases in the same order. We suggest that the catalytic properties of the Pt are strongly
influenced by non-covalent interactions of the hydrated cations with the adsorbed hydrogen by the hydrogen
bond formation. In the second part, various Pt-Co alloys were investigated for the HOR/HER in alkaline
media using rotating disc electrode set up. Our results show that the HOR/HER performance can be tuned
by variation of atomic Pt & Co arrangements like core-shell, segregation and alloy nanoparticles. We
developed a multi-dimensional matrix to clarify the relationship between structural parameters and catalytic
HOR activities for the Pt-Co nanoparticles.
The combination of both works allows to provide a deeper understanding about the mechanism and kinetics
of the HOR/HER for Pt and Pt alloys in alkaline media.
References
1. H. A. Gasteiger, S. S. Kocha, B. Sompalli and F. T. Wagner, Applied Catalysis B: Environmental,
56(1-2), 9–35 (2005).
2. J. Durst, A. Siebel, C. Simon, F. Hasché, J. Herranz and H. A. Gasteiger, Energy Environ. Sci., 7(7),
2255–2260 (2014).
3. D. J. Weber, M. Janssen and M. Oezaslan, Journal of the Electrochemical Society, 166(2), F66-F73
(2019).