bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation By NMR Spectroscopy of the Structural Characteristics of Modified Oligo-Nucleotides with Pendant Porphyrins
Authors: Solladie Nathalie 
Published: July 2021

Exerting control over the position and distance of the porphyrins along a specifically designed oligonucleotidic scaffold was our main goal over the past years. Indeed, in naturally occurring light-harvesting complexes, biopolymer scaffolds hold pigments at intermolecular distances that optimize photon capture, electronic coupling, and energy transfer. We thus focused on the synthesis of four uridine-porphyrin conjugates (a monomer, dimer, tetramer and octamer) dedicated to adopt a pre-organized conformation with face-to-face porphyrins, and capable to self-organize in a stable sandwich type complexe with bidentate base such as DABCO. Using a similar strategy as the one used in antisense research, an artificial nucleotidic backbone was built from modified deoxy-uridine units linked with a more rigid linker than the phosphodiester moieties found in natural oligonucleotides. Antisense research uses modified oligonucleotides, less flexible than natural strands, to pre-organize the system toward the obtaining of stable double helices between synthesized and natural oligonucleotides. A modified oligonucleotidic backbone was here used to target a parallel conformation of the porphyrins appended to each deoxy-uridine moiety. To provide a rigid environment for the porphyrins, the uridine units were coupled in 3’-5’ stepwise fashion using ether-ester type of spacer of suitable length, and porphyrins were anchored to the uridine by means of robust carbon-carbon bonds.
To investigate the conformation of our four uridine-porphyrin conjugates, they were subjected to a comprehensive conformational analysis by using NMR spectroscopy. The collected NOE NMR data highlighted characteristic and strong interactions indicating that the glycosidic angle between the ribose and uracil base is anti. In order to further invastigate the conformation of this family of molecules, NMR experiments were carried out at variable temperature. At low temperature, the signals of the porphyrinic protons decoalesce showing two sets of b-pyrrolic protons. Similar observations are made for the signals corresponding to the sugar moieties and especially the H1’ protons, indicating molecular motions within our porphyrin-uridin arrays. These results testify in favor of the existence of a dynamic process between C3’-endo and C2’-endo conformations.
We thus document the fact that the choice of rigid spacers is not the only way to pre-organize bis-porphyrins, and that some well-chosen nucleosidic linkers offer an interesting option for the synthesis of such devices. Furthermore, the chirality and enantio-purity of the nucleosidic linkers paves the way toward the selective complexation of enantio-pure bidentate guests and the resolution of racemates.

Acknowledgements

This work was supported by the CNRS and the French Ministry of Research.

References

Merkas, M. Zinic, R. Rein, N. Solladié, J. Porphyrins Phthalocyanines
2019, 23, 797-812.

Figure 1
Dualbeam Platform Applications in Lithium Battery Research
Authors: Liu Zhao , Zhang Minghao , Randolph Steven J , Winiarski Bartlomiej , Shojaee S. Ali , Pelapur Rengarajan , Wu Devin , Lemmens Herman , Meng Shirley 
Published: July 2021

Lithium batteries are energy storage systems with highly complex microstructures. To understand the performance of the battery it is essential to accurately characterize the battery microstructure at multiple length scales. However, there are multiple challenges in battery characterization such as beam damage, imaging liquid phases and getting to representative volumes.
The DualBeam, also known as focused ion beam–scanning electron microscope (FIB-SEM) technique is an analytical method combining an ion beam for materials processing and an electron column for imaging to enable 2D and 3D characterization at the nanometer scale. In this presentation the application of three different DualBeam techniques for battery characterization and how to handle the imaging challenges are discussed for different sample types.
A battery separator is a beam sensitive sample and imaging conditions need to be optimized to avoid damaging the separator morphology. By using cryo techniques in a Ga-based FIBSEM, the cross-section and 3D structure of a separator sample is analyzed. The second example deals with a thick NMC electrode sample. Considering the thickness of the cathode (>70 µm) and the active particle size (~10 µm) particle size, a field of view >100 um is needed to get to a representative volume. The combination of Xe-plasma FIB (PFIB) with Avizo software is used to study the electrode microstructure evolution during cycling to better understand the degradation mechanism. The final example is about accessing the liquid-solid interphase inside of the electron microscope. By using a laser PFIB under cryogenic condition, the interphase of the liquid-solid in a Li-metal battery is explored, which is critical to decipher the root cause for cycling inefficiency.
DualBeam technology enables new analytical capabilities for materials research while opening up exciting opportunities for advancing battery development. It is expected to remain an indispensable technique for supporting battery innovation in both academic and industrial environments.
Development of Charge Transport Model to Study the Diffusion-Controlled Dissolution and Multi-Pit Interaction in Pitting Corrosion
Authors: Nguyen Van Anh , Newman Roger 
Published: July 2021

Recently, we developed a reaction-transport model that incorporates diffusion, migration, and complexation to examine the charge transport inside a one-dimensional corrosion pit [1]. In this presentation, we will demonstrate the application of this model to study the “diffusion-controlled” dissolution of a metal in a pit from a more advanced point of view, such that the limiting anodic current density varies with the bulk NaCl concentration. An analytical result on anodic limiting current density as functions of pit depth, diffusivity, and chloride concentration was derived explicitly and coupled with artificial pit experiments. In a dilute chloride solution with low conductivity, the limiting current density is increased due to the increase of the migration flux near the pit mouth. On the other hand, the presence of Na+ at the bottom of the pit is significant for moderate to high bulk NaCl concentrations, which increases the limiting current density to some degree. The proposed full mass transport model can be used to predict limiting current densities at different ranges of bulk NaCl solutions. At above 2.5 M NaCl, the conventional diffusion-only model can give reasonably accurate results, but the effect of Na+ at the bottom of the pit on the solubility of metal ions and the limiting current density should be considered.
Finally, we will discuss the extension of the current work to the two-dimensional pit model to investigate the propagation and the interaction mechanism of multiple pits. The 2D multi-pit simulation under galvanostatic conditions shows the interaction between pits of different sizes. Due to the increase of the local chemistry inside the larger pit, the dissolution rate at the surface is faster and suppresses the growth of the neighboring pits.
Reference:

V. A. Nguyen, A. G. Carcea, M. Ghaznavi and R. C. Newman, The Effect of Cation Complexation on the Predicted “B” Value in Galvele’s Pit Model, J. Electrochem. Soc., 166, C3297 (2019).
Investigation of 2-Way Injection Method on Cu CMP Process
Authors: Kim Juhwan , Bae Chulwoo , Kwak Donggeon , Oh Seungjujn , Kim Taesung 
Published: July 2021

Chemical mechanical polishing (CMP) is one of the process for planarization in semiconductor manufacturing. With the decrease of device size, copper (Cu) has been accepted as the material of interconnect for good performance. After electroplating process of Cu, overburden Cu surface is polished for planarization using CMP process. Generally, oxidants, dispersants, abrasive particles, chelating agents, and corrosion inhibitors are used in the Cu CMP slurry, and planarization of Cu is achieved by reaction of slurry components. Hydrogen peroxide is one of the oxidants which is widely used in Cu CMP slurry and react with Cu surface to form a passivation layer. In general, it is known that hydrogen peroxide is easily decomposed in the alkaline state. Therefore, in the alkaline slurry, decomposition of hydrogen peroxide can occur, which leads to deterioration of CMP performance.
In this study, a new slurry injection method is proposed as an alternative to prevent the decomposition of hydrogen peroxide that may occur when hydrogen peroxide and slurry are mixed. The concentration of hydrogen peroxide decreased when hydrogen peroxide and slurry are mixed, and accordingly, the removal rate decreased (Fig. 1(a)). It indicates that hydrogen peroxide is decomposed in alkaline state, and this affects the CMP performance. In order to prevent the decomposition of hydrogen peroxide, hydrogen peroxide and slurry were separately injected (2-way injection) during the CMP process. Fig. 1(b) shows the comparison of the removal rate between the general method and the 2-way injection method in the slurry supply system. As shown in the graph, when using the 2-way injection method, the removal rate is almost similar to that of the general injection method. Therefore, the 2-way injection method can replace the general injection method.
Figure 1. (a) the removal rate and concentration of hydrogen peroxide with slurry aging time, (b) the removal rate of general and 2-way injection method

Figure 1
Direct Observation of Adsorption of Ceria Particles on the Silicon Dioxide Surfaces and Their Removal
Authors: Seo JIhoon , Ranaweera Charith , Gowda Akshay , Babu S.V. 
Published: July 2021

We demonstrated that the movement of the single ceria particles located at the glass interface could be imaged in situ using evanescent wave (EW) microscopy. (1,2) Here, the flat glass surface of the lens became our model for the SiO2 film surface of interest. 3D trajectories, diffusion coefficients, and interactions of ceria particles with a glass surface at pH 3, 5, and 7 were investigated using EW microscopy. We also defined the types and characteristics of particle motions by analyzing the mean-square displacement (MSD) versus time curves. (1)
The removal of single ceria particles from the glass films in the cleaning solution was monitored in situ using EW microscopy coupled with a brush set-up. In situ measurement data collected during cleaning are likely to provide more important insights into the underlying mechanisms of various complex reactions that occur at the particles/brush–wafer interface. (3)
This talk will also introduce lateral force microscopy (LFM) mode in the atomic force microscopy (AFM) to obtain the removal force of single ceria particles from the SiO2 film. LFM is a powerful tool to monitor the torsion bending (or twisting) of the cantilever with contact mode, which is corresponding to the removal force. Types of particle removal mechanism depending on the characterization of single particles (size, shape, and surface) will be discussed. Our results will provide a better understanding of how the abrasive particles, the additives, and the film surfaces interact together during cleaning.
(1) Seo, J., Gowda, A., Khajornrungruang, P., Hamada, S., Song, T., & Babu, S. (2020). Trajectories, diffusion, and interactions of single ceria particles on a glass surface observed by evanescent wave microscopy. Journal of Materials Research, 35(3), 321-331.
(2) Seo, J., Gowda, A., Khajornrungruang, P., Hamada, S., & Babu, S. (2020). 3D trajectories and diffusion of single ceria particles near a glass surface and their removal. Journal of Materials Research, 1-10.
(3) Seo, J. (2020). A review on chemical and mechanical phenomena at the wafer interface during chemical mechanical planarization. Journal of Materials Research, 1-23.
Three-Dimensional Mapping of Cycling Changes in Silicon-Graphite Composite Anodes Via Scanning Probe Microscopy
Authors: Huey Zoey , Ha Yeyoung , Finegan Donal P. , Norman Andrew , Al-Jassim Mowafak , Jiang Chun-Sheng , Han Sang-Don , DeCaluwe Steven C. 
Published: July 2021

Silicon (Si) anodes have the potential to greatly improve the energy density of lithium-ion batteries due to the greater specific capacity of Si relative to standard graphite (Gr) anodes (1). However, Si anode implementation is limited by issues such as volumetric expansion during cycling and an unstable solid-electrolyte interphase (SEI). Composite anodes with Si and Gr particles can increase capacity while mitigating Si anode degradation. However, these electrodes can be challenging to characterize (and therefore optimize) due to their multiple components, heterogeneous surfaces, and the complex processes occurring there. Scanning spreading resistance microscopy (SSRM) is a form of scanning probe microscopy that measures local resistivity in a sample. By removing material with the probe tip while measuring resistivity, three-dimensional resistivity maps can be determined (2). For Si-Gr composite anodes, the different resistivities of the electrode components (e.g., Si, Gr, carbon, and lithium polyacrylate binder) allows direct identification through SSRM. 3D nanoscale volumes can then be created for both the whole electrode and the individual components.
This presentation will demonstrate 3D SSRM mapping of pristine and cycled anodes with three compositions – Si, Gr, and Si-Gr. By comparing changes in the morphology, thickness, and resistivity in the active material and SEI in each single-component electrode, the component distribution and evolution of the Si-Gr composite anode is better understood. SSRM results will be compared to chemical analysis techniques such as scanning transmission electron microscopy, energy dispersive x-ray spectroscopy, and electron energy loss spectroscopy to verify the component identification and to correlate chemical composition to resistivity. These data will then be correlated to electrochemical performance and used to further the development of Si-Gr electrodes with enhanced performance.

W.-J. Zhang, Journal of Power Sources, 196, 13 (2011).

C. Stetson, Z. Huey, A. Downard, Z. Li, B. To, A. Zakutayev, C. S. Jiang, M. M. Al-Jassim, D. P. Finegan, S. D. Han and S. C. DeCaluwe, Nano Lett (2020).

Figure 1
In Situ Investigations on LiNiO2 during Post-Synthesis Heating in Air
Authors: Li Hang , Hua Weibo , Indris Sylvio 
Published: July 2021

Enhancing cathode materials with high energy density and low cost has become the main direction of development in battery industry [1]. In order to achieve this goal, LiNi
x
Co
y
Mn1-x-y
O2 (NCM) and LiNi
x
Co
y
Al1-x-y
O2 (NCA) cathode materials with increased Ni contents (0.6 ≤ x ≤ 1) have been gradually put into mass production and applied in electric vehicles [2]. If the Ni content is being increased continuously, finally we will probably go back to LiNiO2, a well-known yet traditional material. Numerous efforts have been made to improve its stability and usability up to now [3, 4]. Nevertheless, an easy and effective method is still waiting to be discovered. For this purpose, we study the structural changes of LiNiO2 during the heat treatment process in air using nuclear magnetic resonance, synchrotron radiation diffraction and absorption spectroscopy. Various reactions such as oxygen loss, lithium transport and phase transitions take place in different temperature regions. During the thermal treatment, a thin layer is formed in-situ on the surface of LiNiO2 as a consequence of oxygen loss. The thickness of this layer could be precisely adjusted through changing the heating temperature. A thicker layer has positive effects on protection of LiNiO2 but it blocks the migration of Li ions, resulting in larger over-potential and lower capacities. After heating to 400 °C an excellent stability has been observed with 93% capacity retention after 180 cycles. In summary, the properties of LiNiO2 could be adjusted through a post-synthesis treatment without additional chemicals. This method could also be applied to a larger class of NCM or NCA materials as a new modification strategy.
References:
[1] Li, Wangda, Evan M. Erickson, and Arumugam Manthiram. "High-nickel layered oxide cathodes for lithium-based automotive batteries." Nature Energy (2020): 1-9.
[2] Bianchini, Matteo, et al. "There and back again—the journey of LiNiO2 as a cathode active material." Angewandte Chemie International Edition 58.31 (2019): 10434-10458.
[3] Li, Hongyang, et al. "An unavoidable challenge for Ni-rich positive electrode materials for lithium-ion batteries." Chemistry of Materials 31.18 (2019): 7574-7583.
[4] Jung, Sung Hoo, et al. "Ni‐Rich Layered Cathode Materials with Electrochemo‐Mechanically Compliant Microstructures for All‐Solid‐State Li Batteries." Advanced Energy Materials 10.6 (2020): 1903360.
(Invited) Cation Transport across Interfaces in Solid-State Li Batteries
Authors: Rettenwander Daniel 
Published: July 2021

Despite all the progress made in the development of solid-state Li batteries (SSLB), interfaces arise as the main bottleneck impeding their practical realization. In particular, the interfacial regions between the individual components of a cell comprising those formed between ceramic electrolytes and Li metal and ceramic high-voltage cathodes as well as interfaces between ceramic particles and the polymeric matrix in composite electrolytes are identified to be challenging.1 For example, current constriction that arise from inhomogeneous electrical field distributions at the Li metal | solid-electrolyte interface leads to the formation of dendritic structures at high current rates.2 Forming a good interface between the solid electrolyte and cathode material requires high temperature treatments that leads to the formation of an interphase layer that impedes the ion transport across the interface.3 To unroll the beneficial properties of a composite membrane both components, ceramic particles and polymer matrix, must contribute to the long-range ion transport. Due to the high interface resistance between the components, ionic transport does not take place in ceramic particles; hence, the ceramic has only the role of a passive filler rather than improving the membrane properties.4

Inspired by these challenges, mitigation strategies to overcome these bottlenecks will be presented. For example, strategies that (i) enable cycling at very high rates up to 6 mA cm-2 using different surface treatments and current waveforms, (ii) change the mechanical properties at the interface to potentially avoid crack formation that ultimately leads to short circuits, and (iii) lower the interfacial resistance between ceramics and polymers by orders of magnitude.5 Moreover, we show that Co interdiffusion not only lead to the formation of resistive interphases, but is also detrimental for the electrical transport properties and electrochemical stability of solid electrolytes.

References

(1) A. Banerjee, et al. Chem. Rev.
2020, 120, 6878–6933.
(2) J. Kasemchainan, et al. Nat. Mater.
2019, 18, 1105-1111.
(3) K. Park, et al. Chem. Mater.
2016, 28, 8051–8059.
(4) J. Zheng, et al. Angew. Chemie Int. Ed.
2016, 55, 12538–12542.
(5) E. Kuhnert, et al. Cell Reports Phys. Sci.
2020, 1, 100214.

Acknowledgement

Financial support by the Austrian Federal Ministry for Digital and Economic Affairs, the National Foundation for Research, Technology and Development and the Christian Doppler Research Association (Christian Doppler Laboratory for Solid-State Batteries) and the Austrian Science Fund (FWF) (project no. P25702) is gratefully acknowledged.
Determination of Lithium Diffusion Coefficient in FeS2 through Improved Galvanostatic Intermittent Titration Technique (GITT) Modeling
Authors: Horner Jeffrey Scott , Whang Grace , Ashby David , Dunn Bruce S. , Talin Alec Alec , Roberts Scott A. 
Published: July 2021

Significant, recent efforts have been directed towards modeling lithium-ion batteries to optimize their performance and design. These models depend highly on physical parameters that must be evaluated experimentally for the system of interest. One of the most critical of these parameters is the chemical diffusion coefficient for lithium inside the active cathode material. Galvanostatic Intermittent Titration Technique (GITT) is a commonly used technique that can evaluate the diffusion coefficient, as well as other important information about the cell such as the reaction rate constant and open circuit potential. Despite its popularity, there remain several issues with the existing method of analyzing GITT data. Notably, the conventional method for extracting diffusion coefficients from GITT data relies on numerous assumptions, applies only at short discharge times, and lacks evidence validating the obtained coefficients.
In this work, we describe a new method of extracting diffusion coefficients from GITT data. This method involves directly fitting a GITT pulse to a one-dimensional, single particle electrochemical model and can be applied for both ideal and non-ideal solution theory. We apply this approach to experimental measurements at two temperatures for the intercalation regime of FeS2, a conversion cathode material. Results are compared to the conventional method of evaluating diffusion coefficients from GITT data as well as diffusion coefficients obtained from electrochemical impedance spectroscopy. Diffusion coefficients are found to be higher for direct fitting, and more than an order of magnitude difference is observed between ideal and non-ideal diffusion coefficients. The modeling is also extended to a distribution of particles, and we show that the distribution behaves as a single particle with an effective particle radius proportional to the total volume to surface area ratio. Finally, the new diffusion coefficients are validated against discharge data for the cell, and it is shown that a reasonable prediction to the experimental data can be achieved using a single particle model. However, this is only possible with a non-ideal diffusion model, and high variation is observed across predictions obtained using other diffusion coefficient evaluation methods. This work demonstrates the susceptibility of electrochemical modeling to transport parameters and offers a simple, yet improved, method for evaluating diffusion coefficients from experimental GITT measurements.
Supported by the Laboratory Directed Research and Development program at Sandia National Laboratories, a multimission laboratory managed and operated by National Technology and 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-NA-0003525.
Modeling First Stages of Solid-Electrolyte Interphase (SEI) in LiPF6/EC Electrolytes Using Molecular Dynamics Simulations
Authors: Alzate-Vargas Lorena , Allu Srikanth , Fattebert Jean-Luc 
Published: July 2021

The performance of lithium-ion batteries(LiB) using organic electrolytes depends strongly in the formation of a stable solid electrolyte interphase (SEI) film. Elucidating the dynamic evolution and spatial composition of the SEI can be very useful to study the stability of the structures and could also optimize the formation cycles of LiB. We propose a classical molecular dynamics simulation protocol for predicting the first stages of the SEI using a reaction method involving the decomposition of EC and LiPF6 molecules in the electrolyte. We are able to accelerate, on the order of nanoseconds, the formation of SEI components near the anode surface, such as gases (C2H4), inorganic (Li2CO3, and LiF) and organic (LEDC). We expect to expand this protocol to explore different electrolyte compositions and additives and for further advances in Li-ion battery technology
This research is supported by the U.S. Department of Energy's Vehicle Technologies Office.