bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plasma-Assisted Anion Exchange Reactions in Thermally Grown Copper Oxide Nanowires
Authors: Kosicek Martin , Zavašnik Janez , Cvelbar Uros 
Published: November 2022

Copper oxide nanowires represent a popular topic in recent research due to their potential use in gas sensors, batteries, supercapacitors etc. One of their advantages is facile synthesis, as they can be synthesized merely by heating metallic copper in the air. Moreover, their parameters, such as length and diameter, can be easily tailored by adjusting the conditions at which they are synthesized. Once obtained, nanowires can be further processed to enhance their properties. Common processing includes a partial or complete transformation of grown nanowires to another phase via cation or anion exchange. There are many existing methods for achieving such transformations, which are mostly solution-based. On the other hand, great unused potential lies in methods that exploit plasmas to achieve phase transformations in nanomaterials.
Even though there are a lot of reports on the synthesis of CuO nanowires, there are still a lot of knowledge gaps when it comes to their production and ion exchange reactions. In both cases, the challenges are associated with fundamental science behind processes during nanowire growth and phase transformations, as mechanisms behind NW growth and ion exchange reactions are not completely understood. In our present research, we tackle challenges connected to the thermal growth of CuO nanowires as well as the fundamental science behind phase transformations in them. In order to study mechanisms of nanowire growth, we performed thermal oxidation of copper to obtain nanowires at different times and temperatures. With detailed microstructural analysis of nanowires and oxide layers on which they grow as well as utilization of theoretical simulations, we obtained valuable information about growth of one dimensional metal oxide nanomaterials. Furthermore, mechanisms of anion exchange reactions were studied in the copper oxide – copper sulfide system. To achieve the oxide to sulfide transformations, copper oxide nanowires were subjected to plasma treatment with sulfur-containing gasses, which allowed us to study anion exchange in non-equilibrium plasma environments.
(Student Award, 2nd Place) Optical and Mechanical Properties of Europium-Doped Sicn Thin Films Prepared By Integrated Ecr-PECVD and Magnetron Sputtering
Authors: Azmi Fahmida , Ahammou Brahim , Bhattacharyya Paramita , Mascher Peter 
Published: November 2022

Silicon carbonitride (SiCN) is a wide bandgap semiconductor material that has drawn significant interest over the past few decades due to its excellent optical, electrical, and mechanical properties[1]. Rare earth doping in wide bandgap semiconductors has several prospective applications in the field of photoelectric devices, solid-state lasers, flat panel displays, and high-energy radiation detectors [2]. Among the various rare earth materials, europium (Eu) is particularly interesting due to its optically active divalent and trivalent states capable of emitting in different visible spectral ranges [3].
In this work, Eu-doped SiCN thin films were prepared by electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECR-PECVD) with integrated magnetron sputtering [4] on p-type 3” Si (100) substrates. Silane (diluted in 90% argon), nitrogen (diluted in 90% argon) and ethane (C2H6) were used as precursor gases, and a 99.9% pure Eu sputtering target was used as a sputtering source. To understand the effect of C incorporation in the Eu-doped SiCN matrix, we have prepared a set of samples without C. The as-deposited samples were annealed over a wide range of temperatures from 600 to 1100° C in an internet N2 environment. Rutherford backscattering spectrometry (RBS) was performed to determine the atomic concentration of the constituents. Variable angle spectroscopic ellipsometry (VASE) analysis was performed to investigate the optical properties of the films. The room temperature photoluminescence (PL) experiments were carried out with a laser diode excitation source, operating at a wavelength of 375nm. Finally, we performed nanoindentation measurements to understand the deformation behavior of SiCN films as a function of the incorporation of C. The indentation hardness and Young’s modulus of the films were investigated for different Eu and C concentrations.
References:
[1] Q. Li, Y. Wang, X. Shan, X. Wang, and W. Zhao, “Preparation and optical properties of SiCN thin films deposited by reactive magnetron sputtering,” J. Mater. Sci. Mater. Electron., vol. 28, no. 9, pp. 6769–6781, 2017.
[2] Z. Ma, J. Zhou, Z. Chen, and E. Xie, “Luminescence properties of terbium-doped SiCN thin films by rf magnetron reactive sputtering,” Diam. Relat. Mater., vol. 20, no. 4, pp. 475–479, 2011.
[3] X. Zhang, D. Yang, D. Li, and M. Wang, “Intense photoluminescence from Eu-doped silicon-rich silicon oxide films prepared by electron beam evaporation,” IEEE Int. Conf. Gr. IV Photonics GFP, pp. 66–68, 2009.
[4] J. W. Miller, Z. Khatami, J. Wojcik, J. D. B. Bradley, and P. Mascher, “Integrated ECR-PECVD and magnetron sputtering system for rare-earth-doped Si-based materials,” Surf. Coatings Technol., vol. 336, pp. 99–105, 2018.
Resisting Dendrites in Lithium Batteries, One Pinhole at a Time
Authors: Oyakhire Solomon , Zhang Wenbo , Cui Yi , Bent Stacey F. 
Published: November 2022

For humanity to successfully transition from fossil fuels, the mismatch in the demand and supply of renewable energy must be addressed by reliable, high energy storage systems. One promising energy storage system is the lithium metal battery (LMB), owing to the high gravimetric capacity of lithium (3860 mAh/g). The potential gain in volumetric and gravimetric energy density offered by LMBs could usurp today’s lithium-ion battery technology and revolutionize energy storage. However, the lifetime of LMBs is hindered by morphological instabilities experienced during the electrodeposition of lithium.
Modifications of the solid electrolyte interphase (SEI) and electrolyte are the most common strategies for improving lithium metal morphology. However, electrolyte and SEI engineering are often tedious, based on trial and error, and insufficient for enhancing lithium electrodeposition. Here, we demonstrate a new, alternative strategy for controlling lithium metal morphology and improving electrochemical performance that is independent of the electrolyte and SEI. By modifying the current collector with atomic layer deposited (ALD) thin films of ZnO, SnO2, and Al2O3, we show that lithium deposits atop, rather than beneath, the thin films, resulting in changes in lithium morphology and battery performance that are strongly dependent on the electrical resistance of the ALD films. The results show that low resistance copper modification films like SnO2 and ZnO provide numerous sites for lithium nucleation and promote the formation of high surface area (fast electrolyte consuming) lithium deposits, while the highly resistive Al2O3-modified copper reduces the available sites for lithium nucleation and promotes the formation of low surface area (slow electrolyte consuming) clusters of lithium deposits.
We propose and demonstrate the first recorded mechanism for the connection between electrical resistance and lithium growth - we propose that, in resistive substrates, lithium metal nucleates atop only pinhole sites, then grows laterally by the radial diffusion of lithium ions from the electrolyte. We prove this mechanism analytically, using diffusion controlled current equations, and experimentally by introducing patterned pinholes into a resistive, pinhole-free substrate. We generalize the concept of resistance-controlled morphology and demonstrate high battery performance in three distinct classes of electrolytes, culminating in anode-free pouch cells that retain 60% of their initial discharge capacity after 100 cycles. This work presents a new approach for understanding the electrodeposition of lithium and tuning the performance of lithium metal batteries.
In Situ Analytical Techniques: Solid Electrolyte Interface Analysis of Al Anode Materials for Al-Ion Batteries
Authors: Palanisamy Krishnaveni , Daboss Sven , Rahide Fatemehsadat , Dsoke Sonia , Kranz Christine 
Published: November 2022

Rechargeable post Li-ion batteries based on aluminum (Al) are gaining attention due to high abundance of Al, the high theoretical volumetric capacity, and high safety associated with the low flammability [1,2]. In comparison to Li-ion batteries (LiBs), where the solid-electrolyte interphase (SEI) has been studied for decades, little is known on SEI formation in dependence of the used electrolyte for Al electrodes.
In this study, we present the electrochemical performance of Al foils with two different thicknesses (0.025 mm and 0.075 mm), which were used as negative electrode in Al-ion batteries in AlCl3/1-ethyl-3-methylimidazolium chloride [EMIm]Cl electrolyte. Atomic force microscopy (AFM) was used to determine changes in the morphology of Al foils during the charge - discharge process to obtain information on the SEI and its microstructural morphology [3]. Spatially-resolved information on the electrochemical activity of interphase layers on cycled Al foils can be obtained via scanning electrochemical microscopy (SECM), which so far has only be studied at LiBs [4]. First results reveal the correlation between the morphological changes of SEI layer during cycling and its electrochemical behavior depending on the Al foil surface properties, which will be presented and discussed in this contribution.
Key words: Al foil, AFM, microstructure, SEI layer, SECM.

References:

Meng-Chang Lin, Ming Gong, Bingan Lu, Yingpeng Wu, Di-Yan Wang, Mingyun Guan, Michael Angell, Changxin Chen, Jiang Yang, Bing-Joe Hwang and Hongjie Dai, Nature, 520, 325–328 (2015).

Li, and N.J. Bjerrum, J. Power Sources, 110, 1–10 (2002).

Feng Wu, Na Zhu, Ying Bai, Yaning Gao, and Chuan Wu, Green Energy & Environment 3, 71-77, (2018).

Bastian Krueger, Luis Balboa, Jan Frederik Dohmann, Martin Winter, Peter Bieker and Gunther Wittstock. ChemElectroChem,7, 3590–3596, (2020).

This work contributes to the research performed at CELEST (Center for Electrochemical Energy Storage Ulm-Karlsruhe) and was funded by the German Research Foundation (DFG) under Project ID 390874152 (POLiS Cluster of Excellence).
(Invited) Photophysics of QDs Enabled By Gas-Phase PECVD Growth
Authors: Neale Nathan R. 
Published: November 2022

We have been exploring doping and alloying of semiconductor quantum dots (QDs) and the impact of chemical composition on the QD primary photochemical events including charge generation, separation, and recombination. Dopant incorporation and alloying without phase segregation are significant challenges using conventional colloidal growth methods. Nonthermal plasma-enhanced chemical vapor deposition (PECVD) growth is an attractive approach to overcome these challenges since it is controlled by kinetics rather than thermodynamics.
In this presentation, we will describe the PECVD synthesis of silicon quantum dots (Si QDs) that provides the ability to incorporate high concentrations (~1020 cm–3) of either p-type (B:Si) or n-type (P:Si) dopants. We also can use this synthetic technique to prepare co-doped QDs containing both P and B atoms in the same PB:Si QD. Whereas the optical absorption of singly P:Si and B:Si QDs exhibit plasmonic features characteristic of a high concentration of dopants, the co-doped PB:Si QDs instead exhibit photophysics that resemble those of intrinsic Si QDs, for example emission lifetimes of ~100 μs, but with size-dependent optical transitions that are tunable even below the energy of bulk Si (1.12 eV). Finally, we will describe new work on III–V semiconductors, in particular gallium nitride (GaN) QDs, that also exhibit tunable photophysics and serve as useful model systems for photochemically-driven small molecule conversion.
(Invited, Digital Presentation) Excited State Properties of Low-Dimensional Materials: Insight By Ab-Initio DFT + Mbpt Simulations
Authors: Palummo Maurizia 
Published: November 2022

The use of emerging low-dimensional materials in technological applications presupposes a detailed knowledge of their chemical and physical properties. In this context ab-initio theoretical methods and simulations are playing a fundamental role.
Here I aim to show how the use of parameter-free atomistic simulations can contribute to improve the microscopic understanding of the opto-electronic properties of nanomaterials and to predict new ones. I will show how ab-initio DFT and post-DFT (GW and BSE) calculations, based on Many-Body Perturbation Theory (MBPT), provide a very useful scheme to study i) giant electronic band-gaps renormalization due to low dielectric screening and large quantum confinement ii) strong light-matter interaction iii) fine structure of strongly bound excitons. iv) the influence of electron-phonon interaction on the electronic and optical spectra, v) how doping, molecular functionalization or strain can tune their opto-electronic properties. Main focus will be on different semiconducting 2D materials discovered after graphene, but other dimensionality examples will be discussed.
(Invited) Design and Synthesis of Colloidal QDs for Quantum Emitters
Authors: Fedin Igor 
Published: November 2022

On-demand generation of quantum photons is one of the four major targets of Quantum Information Science (QIS), identified by the NSF as one of the five “industries of the future.” Colloidal semiconductor quantum dots (QDs) are viable candidates for quantum materials, owing to their tunable, bright, and stable emission. Identifying a suitable semiconductor material and engineering long exciton coherence times is key to producing single coherent photons on demand. We show that colloidal compositionally-graded CdSe/ZnS QDs designed with a high degree of asymmetric internal strain demonstrate superior quantum emission properties compared to conventional sharp-interface CdSe/ZnS QDs. In comparison to conventional colloidal CdSe/ZnS core/shell QDs, we find that, in asymmetrically strained CdSe QDs, over six times more light is emitted directly by the bright exciton. Temperature-dependent PL dynamics and fluorescence line narrowing (FLN) spectroscopy reveals the radiative recombination rates of bright and dark excitons, the relaxation rate between the two, and the energy spectra of the quantized acoustic phonons in the QDs that can contribute to relaxation processes. We attribute the six-fold improvement to the four-fold deceleration of the bright-dark relaxation and the doubled radiative recombination rate in the strained QDs.
The next step in this research is to bring these improvement from the visible to the near-IR emission, where most communication bandwidths lie. This area has been traditionally dominated by III-V materials, which are chemically challenging in the colloidal state. We design, synthesize, and characterize alternative strong near-IR materials and assess them as potential quantum emitters. Last but not least, we demonstrate applications of electrochemistry in programmable hot syntheses of colloidal QDs.
Higher Energy Density Mediated Lithium-Sulfur Flow Batteries
Authors: Meyerson Melissa L , Maraschky Adam M. , Small Leo J. 
Published: November 2022

There is a need for safe, reliable, high-capacity storage for long duration energy storage. The low cost and high capacity of sulfur make Li-S batteries ideal for this purpose. However, sulfur has poor electrical conductivity and Li-S batteries are prone to polysulfide shuttling that decreases the battery life. Additionally, lithium metal cannot be cycled at high rates or dendritic growth is produced. We have previously addressed the issues with the S by combining aspects of a static Li-S battery with aspects of a redox targeting system and flow battery. With this system we demonstrated that fundamental Li-S chemistry and novel SEI engineering strategies can be adapted to the hybrid redox flow battery architecture, obviating the need for ion-selective membranes or flowing carbon additives, and offering a potential pathway for inexpensive, scalable, safe MWh scale Li-S energy storage. However, these tests were done at lab scale with low S loadings and limited charge rates, limiting both the energy and power density of the proof-of-concept system. In this study we present recent progress scaling up the system from 2.5 mgS cm-2 to over 50 mgS cm-2 and increasing the current density from 0.5 mA cm-2 to 10 mA cm-2 to decrease the charge/discharge time. The increase in S loading results in an increase in energy density and the increase in applied current increases the power density of the system.
To scale up the flow cell we address limitations of the small-scale architecture including examining the flow field used with the catholyte and the structure of the Li metal anode. We first tested high surface area scaffolds in Swagelok cells to examine the effect of the increased effective surface area and seeding with lithiophilic materials, like ZnO, on Li metal deposition independent of the flow cell or S chemistry. Using a high effective surface area anode support enables us to increase the applied current density from 0.5 mA cm-2 to 10 mA cm-2 greatly increasing the charge/discharge speed. Furthermore, the addition of a lithiophilic seed layer decreases the nucleation overpotential and encourages uniform Li electrodeposition. A tailored flow field also improves the uniformity of Li deposition on the anode by improving the uniformity of the catholyte flow velocity. These improvements are first evaluated separately and then combined in a mediated Li-S flow battery where cycling rate and capacity retention are compared against a traditional planar Li anode and open flow field.
Sandia National Laboratories is a multi-mission 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-NA0003525.
Simulation Strategies for Measuring Impedance Response of Lithium-Ion Batteries
Authors: Telmasre Tushar Khemraj , Jang Taejin , Goswami Neha , Concepcion Anthony , Subramanian Venkat R. 
Published: November 2022

The battery as an electrochemical system can be considered a Blackbox with no way of observing processes occurring within it in a nondestructive manner1. However, most physical, and chemical processes in electrochemical systems are shown to be distinguishable by their distinct characteristic time constant. Electrochemical impedance spectroscopy (EIS) can therefore be a valuable tool to distinguish between internal processes within batteries based on their frequency response2–4.
Numerical approaches for understanding battery systems have long been explored by researchers in academia and industry alike2,4,5. Generally, it is computationally expensive to develop a high fidelity multiscale and multiphysics model with high predictive capability that can estimate critical transport parameters and material decay. Thus, model development traditionally starts with simplistic models where more physics is added as per requirements. Many approaches to mathematical modelling of the battery at different length scales and complexity are available today6.
The impedance response of the battery can also be simulated coupled with various other parameters using the battery models7. Basic equivalent circuit models of the battery are commonly used for this but they suffer from lack of physical interpretability and model degeneracy8. The impedance response based on models are obtained in a physics-based model by linearizing the non-linear models and transforming equations in the time-domain into the frequency domain5,9. This generally is achieved by applying a Laplace transform to the system of linearized equations. Now, based on the complexity of the model, these equations can be solved analytically or after separating the real and imaginary parts for numerical simulation.
Therefore, there are varied solution strategies appropriate for individual battery models that depend on underlying scale and physics involved. Through this work we aim to comprehensively compile these solution strategies and present the best approach for the individual electrochemical model based on criteria such as faster convergence times and error minimization.

References:

R. S. Robinson, INTELEC, Int. Telecommun. Energy Conf., 654–661 (1996).

M. Gaberšček, Nat. Commun., 12, 19–22 (2021).

J. Xu, C. C. Mi, B. Cao, and J. Cao, J. Power Sources, 233, 277–284 (2013).

S. E. Li, B. Wang, H. Peng, and X. Hu, J. Power Sources, 258, 9–18 (2014).

J. P. Meyers, M. Doyle, R. M. Darling, and J. Newman, J. Electrochem. Soc., 147, 2930 (2000).

V. Ramadesigan et al., J. Electrochem. Soc., 159, R31–R45 (2012).

D. Andre et al., J. Power Sources, 196, 5349–5356 (2011).

S. Fletcher, J. Electrochem. Soc., 141, 1823–1826 (1994).

M. Pathak et al., J. Electrochem. Soc., 165, A1324–A1337 (2018).
Insights into the Lithium Nucleation and Plating/Stripping Behavior from Ionic Liquid-Based Battery Electrolytes
Authors: Stepien Dominik , Wolff Beatrice , Diemant Thomas , Kim Guk-Tae , Hausen Florian , Bresser Dominic , Passerini Stefano 
Published: November 2022

Lithium-metal batteries are anticipated to become the next-generation battery technology, allowing for substantially higher energy densities. To maximize the energy density, however, a “zero excess” of lithium in the cell is a must, e.g., by initially storing all electrochemically active lithium in the positive electrode.1 Nevertheless, this requires the fully reversible deposition of metallic lithium, i.e., a Coulombic efficiency of essentially 100%.2

Herein, the investigation of the lithium nucleation and plating/stripping from ionic liquid-based electrolytes composed of N-butyl-N-methyl pyrrolidinium bis(fluorosulfonyl)imide (PYR14FSI) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) on nickel current collectors is reported, involving a comprehensive set of electrochemical techniques coupled with operando and in situ atomic force microscopy and ex situ X-ray photoelectron spectroscopy. It was found that the morphology of the deposited lithium, the chemical composition of the interphase formed on the nickel current collector, and the reversibility of the lithium plating and stripping is highly dependent on the ratio of the ionic liquid and the lithium salt. Moreover, the addition of suitable film-forming additives allows for lower overpotentials and greater reversibility by tuning the interphase composition. The results are anticipated to contribute to the development of advanced electrolyte systems for “zero excess” lithium-metal batteries.
(1) Nanda, S., Gupta, A., and Manthiram, A. Anode-Free Full Cells: A Pathway to High-Energy Density Lithium-Metal Batteries. Adv. Energy Mater.
2021, 11, 2000804. DOI: 10.1002/aenm.202000804
(2) Hobold, G.M., Lopez, J., Guo, R. et al. Moving beyond 99.9% Coulombic efficiency for lithium anodes in liquid electrolytes. Nat. Energy
2021, 6, 951–960. DOI: 10.1038/s41560-021-00910-w