bluuebunny/crossref_metadata_2025 huggingface dataset:
Microplasma Fabrication of Three-Dimensional Porous Au/Ag Nanostructures on Disposable Strip for the Applications of Surfaced-Enhanced Raman Scattering and Catalysis
Authors: Yeh Yi-Jui
Published: May 2020

Surface enhance Raman scattering (SERS) has been demonstrated a useful technology for biological and chemical sensing. In general surface plasmonic resonance metals such as Au and Ag have been reported the efficient materials with SERS properties. Recently theoretical and experimental works have suggested that AgAu bimetallic can further provided enhanced SERS properties. The development of simple, effective, and controlled method to fabricate AgAu nanostructures is important for fundamental and commercialization of SERS-based detection. Here we present an one-step fabrication of three-dimensional porous bimetallic Au/Ag nanostrutures deposited on filter paper using microplasmas at ambient conditions. Microscopic characterization indicates that three-dimensional porous Ag/Au-based microstructures composed with Ag/Au nanoparticles with a particle density of ~2000 particles/mm2 were synthesized and deposited on filter papers in a single microplasma process. MicroRaman study suggests that the as-fabricated Ag/Au porous structures exhibit exceptional SERS properties with a low detection limit for Rhodamine 6G (R6G), and high signal uniformity and stability. Moreover, the as-prepared Ag/Au porous structures can be directly employed for 4-nitrophenol reduction with high catalytic ability. Our work provides a simple method to fabricate three-dimensional porous multi-metal nanostructures

Figure 1
Monodisperse FeF2 Nanorods in Ionic Liquid Electrolytes: A Comprehensive Study of the Conversion Mechanism
Authors: Xiao Albert Wang , Lee Hyeon Jeong , Capone Isaac , Robertson Alex W , Fawdon Jack , Pasta Mauro
Published: May 2020

Transition metal fluorides display the combination of high capacity and high electrode potential that are essential to boosting the energy density of lithium ion batteries. However, their application as cathode materials has been hindered by an incomplete understanding of their electrochemical capabilities and limitations. Herein, we present a system of single crystalline, monodisperse iron (II) fluoride nanorods and detail how their morphology and uniformity make them ideal for mechanistic study. High-resolution analytical transmission electron microscopy reveals intricate morphological features, lattice orientation relationships, and oxidation state changes that redefine the conversion reaction with unprecedented spatial resolution. We first introduce the presence of surface specific reactions and examine how they critically influence phase evolution, diffusion kinetics and cell failure. Next, we examine how the reversibility of the conversion reaction is governed by topotactic cation diffusion through an invariant lattice of fluoride anions and the nucleation of metallic particles on semi-coherent interfaces. We will focus on how each mechanistic feature establishes new principles for improving reaction hysteresis, kinetics and reversibility and how this new holistic understanding can inform the more effective application of metal fluorides. To ensure a pertinent result, ex-situ data was extracted from coin cells that deliver near theoretical capacity (570 mAh g-1) and extraordinary cycling stability (>90 % capacity retention after 100 cycles). This exceptional performance was enabled solely through the use of an ionic liquid electrolyte. Using a combination of impedance spectroscopy, TEM, and X-ray photoelectron spectroscopy, we explain how the solid electrolyte interphase forming ability of this electrolyte precludes the major failure mechanisms associated with transition metal fluorides. We conclude this talk by examining the complementary nature of this cathode electrolyte pairing, particularly with regards to high-temperature cycling.

Figure 1
Birnessite-Type Layered Manganese Oxides Nanosheets for 18650-Type Cylindrical Aqueous Supercapacitors
Authors: Chomkhuntod Praeploy , Sawangphruk Montree
Published: May 2020

The manganese oxide (MnO2) is one of the promising pseudocapacitive materials due to its high specific capacitance, low-cost, and low-toxicity.1 Especially, the birnessite-type MnO2 with 2D-layer structure demonstrates a high specific capacitance because the charge storage can occur at the active site within the interlayer region. Herein, the influence of hydration energy of structural cations (Li-, Ca-, Sr-, and Ba) within the birnessite-type MnOx is demonstrated on charge storage mechanisms via de-/intercalation processes upon redox reaction with ion-exchange process. Interestingly, the Ca-MnOx demonstrates the superior specific capacitance even though the Li-MnOx has higher redox activity and Mn utilization as observed by the ex situ X-ray absorption spectroscopy. The Ca-MnOx has higher hydration energy of Ca2+ (500 kcal mol-1) as compared to -465, -436 and -204 kcal mol-1 of Sr- MnOx, Ba-MnOx and Li-MnOx, respectively, which for the higher hydration energy leads to the easier cation exchange.2 Hence, the ion-exchange affinity within the birnessite structure is dominant which can further confirm by inductively coupled plasma - optical emission spectrometry technique. Moreover, the cycling stability of the as-prepared sample is retained at 96% after 11,000 cycles at current density of 5 A g-1. Up to now, there is no Ca-MnOx-based electrode material in real practical supercapacitor devices; therefore, we fabricated the first prototype of cylindrical-cell as well as further studied its performance.
(Invited) In Situ Studies of the Atomic Structure/Charge Distribution at the Electrochemical Interface
Authors: Grunder Yvonne , Lucas Christopher A. , Joly Yves , Soldo Yvonne -
Published: May 2020

The presence of specifically adsorbed anions can significally affect the electrochemical reactivity of a metal electrode which is of major interest for galvanic deposition, etching, corrosion and electrocatalysis. Halogens on metal surfaces are prototypic adsorbate systems but the adsorption of halide ions especially on copper is also of major importance for on-chip metallization in ULSI microchip production. Halide ions on Cu surfaces form an inhibiting adsorbate layer with polyethylene glycol (PEG). Even though the influence of the additives combination on the shape evolution of the Cu deposit was subject of numerous studies, their precise role during the elementary steps of the deposition with regards to altering the charge distribution and dipole moment at the interface is largely not understood.

To obtain insights into the influence of the applied potential and the screening by the electrolyte to better understand electrochemical processes and charge transfer during adsorption and deposition is a major goal .[1]

Thus combining x-ray spectroscopy and x-ray diffraction to gain site-specific information about the charge distribution at buried interfaces is a promising tool. [2,3]

We will present studies on the metal-halide interface and how the use of surface x-ray scattering techniques can help to characterise electrochemical interfaces in-situ in order to link, structure and stability. [3] Advances in these directions offer possibilities in elucidating atomic scale models of the electrochemical interface and thus will help to establish structure-stability-reactivity relationships which will help to understand growth kinetics.

References:

[1] Y. Gründer, P. Thompson, A. Brownrigg, M. Darlington, and C. A. Lucas, Journal of Physical

Chemistry C, 2012,116, 6283

[2] Y. Gründer and C. A. Lucas, Physical Chemistry Chemical Physics, 2017, 19, 8416

[3] Y. Joly et al., J. Chem. Theory Comput,. 2018, 14, 973−980
Adsorbate-Driven Electrode Processes, Part 2: Order to Disorder Transitions
Authors: Schwarz Kathleen , Moffat Thomas P. , Groenenboom Mitchell C.
Published: May 2020

Adsorbates on metal electrodes change the step formation energies and preferred step orientations relative to those of clean electrodes. We apply previously developed approximate density functional theory potential energy surfaces from Behler-Parrinello neural networks. We investigate the adsorbate order to disorder transition on terraces and monolayer and bilayer steps. We identify how the adlattice disorders with changing adsorbate coverage for these surfaces.
(Invited) The Tool-Box Concept for the Synthesis of Surfactant-Free Colloidal Nanoparticles As Electrocatalysts
Authors: Quinson Jonathan , Arenz Matthias
Published: May 2020

Our research concept is presented, which focuses on a design approach for supported electrocatalysts in order to optimize their properties independent of each other. In supported electrocatalysts, the active phase consists of metal or alloy nanoparticles distributed over a conducting support, mostly carbon based. Our aim is to elucidate the role of
mesoscopic properties – such as the interparticle distance on the support – for their performance in a comprehensive and systematic manner by combining catalyst synthesis, electrochemical measurements with (ex-situ and in operando) spectroscopy and microscopy. Mesoscopic properties have so far received only little attention in academic electrocatalyst design, yet some few studies demonstrate that they bear significant potential for improving the electrocatalyst performance. A proof of concept has been our pioneering work on the particle proximity effect on size-selected Pt clusters where we could decouple the particle size from the particle loading (interparticle distance).

In the talk focus on the catalyst synthesis via a so-called toolbox concept of surfactant-free colloidal nanoparticles, which plays an important role for the ability to investigate such mesoscopic effects. Different colloidal catalyst synthesis strategies are discussed which consist of two steps: the preparation of the active phase (nanoparticle) as well as the deposition of the nanoparticles onto a suitable substrate (support). To obtain well-defined catalysts, a stable colloidal nanoparticle suspension is key. In the presentation the classic use of surfactants in the colloidal synthesis to obtain stable suspensions is compared to so-called surfactant-free methods, in particular a recent approach from our group using low boiling point solvents [1].

[1] Jonathan Quinson, Sara Neumann, Tanja Wannmacher, Laura Kacenauskaite, Masanori Inaba, Jan Bucher, Francesco Bizzotto, Søren Simonsen, Luise Theil Kuhn, Dajana Bujak, Alessandro Zana, Matthias Arenz, Sebastian Kunz; Angewandte Chemie International Edition 57 (2018) 12338-12341
(Invited) Controlling Multi-Component Colloidal Nanocrystal Surface and Interface for Enhanced Electrocatalysis
Authors: Zhang Sen
Published: May 2020

Nanocrystals with well-controlled surface and interface structures as well as multi-component interactions present new opportunities to tune and optimize nanocatalyst properties for many energy and environmental applications. In this talk, I will highlight the colloidal approach for the synthesis of well-defined nanocrystals with these surface and interface features for enhanced electrocatalysis. These multicomponent nanocrystals play critical roles in maximizing the benefit of oxygen-mediated energy conversion reactions: oxygen reduction reaction (ORR) for fuel cells and oxygen evolution reaction (OER) for water electrolyzer. The first example is M-Pt (M=non-precious metals) core-shell nanocrystals within which desirable/undesirable interfaces between non-precious metal M core and precious metal Pt shell are identified by density functional theory (DFT) calculations and are practically balanced by nanocrystal synthesis. The optimized core-shell nanocrystals exhibit favorable interfacial interaction at nanometer scale through properly coupled electronic and strain effects, leading to an enhanced electrocatalytic efficiency toward oxygen reduction reaction (ORR). In second example, we take advantage of single-atom Co's synergy with various oxide support for electrochemical oxygen evolution reaction (OER). By choosing the proper oxide supporting nanocrystals, single atom Co conversion and stabilization at high valence OER active site can be controlled through its interaction with supporting materials. The relevant theoretical calculation, controlled synthesis and structural/catalytic characterization of nanocrystals will be discussed.
(Invited) Investigations of Interaction and Molecular Structure of Additives on the Copper Electrodeposited Layer By Combination of Cyclic Voltammetry with Time-of-Flight Secondary-Ion Mass Spectrometry (TOF-SIMS)
Authors: Mroczka Robert , Ładniak Agata , Przykaza Kacper , Słodkowska Agnieszka
Published: May 2020

Appropriate additives, such as polyethylene glycol, play the essential role of metal deposition suppressors and are required to control the fabrication process of copper electrodepositionon micro and nanoscale devices. Moreover, brighteners, accelerators and levellers are involved in adjusting of functional properties of the electroplating bath influencing roughness and waviness of deposited copper layer. Our recent studies [1] show that TOF-SIMS measurements under static regime can be conducted successfully for the identification of additives such as PEG, SPS, and Cl, accumulated on the copper electrodeposited layer.Especially, evaluation of molecular structure of the large molecules such as polyethylene glycol is very challenging and out of range for techniques such as SERS, widely applied for in situ studies under copper electrodeposition regime. On the other hand, traditional mass spectroscopy such as electrospray mass spectrometry are oriented on evaluation of composition of electroplating bath. Recently, we have developed a new approach for evaluation of additives on the copper layer by combination of cyclic voltammetry (CV) with TOF-SIMS. To determine the molecular structure of polyethylene glycol and its interaction with chloride and acceleratorson the copper electrodeposited layer CV experiment was conductedwhile a nitinol wire as a working electrode was withdrawn at constant speed from a copper electroplating bath. In that way applied potential during CV corresponds to position of the wire withdrawn from the electroplating bath. This approach allows to evaluate of distribution of chemical species in a function of the applied potential by ex situ TOF-SIMS measurements. Moreover,the thickness of the copper layer was controlled by laser scan micrometer. In the presence of brightener and leveler, the roughness was evaluated by atomic force microscopy in a function of length of wire. In that fashion, CV experiment combined with a molecular analysis, thickness and roughness of copper layer measurements bring complementary knowledge to comprehensively understand the processes occurring on the copper surface. This will have an application for the real-world samples in a wide range of thickness copper layer, applied potential and concentration of additives and copper sulfate.

[1] R. Mroczka, R. Łopucki, G. Żukociński, Molecular analysis of additives and impurities accumulated on copper electrodeposited layer by time-of-flight secondary ion mass spectrometry, Applied Surface Science 463 (2019) 412–426
Uniformity in Bottom-up Cu and Au Filling of High Aspect Ratio Features
Authors: Josell Daniel , Moffat Thomas P.
Published: May 2020

Bottom-up metal deposition arising from variation of adsorbate coverage can be strongly impacted by modest variation of local concentrations and potential associated with deposition in other features. As a result, bottom-up copper filling of fully metallized features in suppressor-based electrolytes can be made to occur in all, none, or only a subset of recessed features on a substrate. Furthermore, and to the greater detriment of uniformity, localized deposition can continue over filled features, further retarding deposition in still unfilled features. In contrast, accelerator-based bottom-up gold deposition, as well as copper filling using different concentrations of the suppressing additives that yielded inhomogeneity, exhibit not only excellent uniformity during feature filling but also self-termination of deposition at a controllable depth within the filling features. This presentation will discuss the origins of these different behaviors in light of the underlying filling mechanisms. History, transport, potential-dependent kinetics and even cell impedance can all play a role.
In-Operando characterization of Electrochemical Interfaces Via Shiners: Shell-Isolated Nanoparticle Enhanced Raman Spectroscopy
Authors: Raciti David , Hight Walker Angela R. , Moffat Thomas P.
Published: May 2020

The advent of SERS created a new avenue for investigating interfacial phenomena by coupling the localized surface plasmon resonance (LSPR) of metal nanostructures to the inelastic scattering properties of molecules. Seeing a 104-fold enhancement in Raman signals, SERS scattering events were used to identify adsorbed molecules and substrate-surface structural conformations. But, even with the advent of SERs, Raman spectroscopy was still confined to LSPR active materials with roughened surfaces. However, recent technical modifications to SERS, such as shell-isolation and localized probe modes, have shown potential for the in-operando investigation of flat non-plasmon active single-crystal surfaces. Shell-isolated Nanoparticle Enhanced Raman Spectroscopy(SHINERS) provides two parallel paths for electric field enhancement of non-plasmon active surfaces while minimizing chemical perturbations by encasing reporters in a chemically inert shell (Figure 1). This technique can be used to perform in-operando measurements during electrochemical processes to bridge the gap between observing and understanding the state of metallic interfaces under an applied bias. This serve as a great utility to not only understand surface adsorbates, but to also characterize dynamic surfaces (e.g. Cu) that undergo reconstruction in response to the applied biases. Such metastable surfaces can impede capturing surface structure information, preventing accurate structure-activity assignments necessary to further understanding of the system. Furthermore, a lack of in-operando technology has inhibited the characterization of active sites and surface phenomena via in-situ measurements. These limitations have resulted in uncertainty of how novel findings are interconnected and ways to design refined interfaces. Herein, I report the synthesis of SiO2 encapsulated Au NPs and their application in-operando to track the state of Cu interfaces under varying electrochemical and chemical conditions.

Figure 1
Superconformal Cu Electrodeposition
Authors: Moffat Thomas P , Liu Guokun , Zou Shouzhong , Ou Yang Liang Yueh , Braun Trevor Michael , Wheeler Daniel , Richter Lee , Josell Daniel
Published: May 2020

State-of-the-art manufacturing of semiconductor devices involves electrodeposition of copper interconnects The process depends on additives that affect the local deposition rate to yield void-free superconformal, or bottom–up filling of trenches and vias. Chemical process models describing the filling of high aspect ratio features, from nanometers (on-chip wiring) to micrometers (through-silicon-vias) to millimeters (printed circuit boards) are available. Nevertheless, much remains to be known about the molecular nature and competitive, co-adsorption dynamics of the additives and their impact on metal deposition. This lecture will detail experiments that reveal the important role of competitive, coadsorption of polyether, Cl-, SPS and LEV additives in controlling the hydrophilicity of the interface and thereby the rate of metal deposition during superconformal film growth.
(Invited) Electrochemical Liquid-Liquid-Solid Deposition of Microwires, Nanowires, and Nanoparticles
Authors: Cheek Quintin , Pattadar Dhruba , Maldonado Stephen
Published: May 2020

This presentation will describe our group's latest efforts to advance the concept of electrochemical liquid-liquid-solid (ec-LLS) deposition of inorganic nanomaterials. A brief historical overview of the concept and relevant precedents in the literature will be presented, followed by advances on two separate fronts. First, in-situ TEM studies of nanowire and nanoparticle growth will be detailed. These measurements describe the initial stages of the ec-LLS process. The cumulative data suggest that ec-LLS nanowire growths are typically performed under conditions of extreme supersaturation and this has a large influence on the resultant crystal quality. Second, the prospects for using ec-LLS to synthesize intermetallic nanoparticles and films will be documented for the first time. An important aspect of this work is describing the fate of initial electrodeposited adsorbates at the liquid metal/liquid electrolyte interface.
Anisotropic Copper Electrodeposition on Microelectrodes
Authors: Braun Trevor Michael , Moffat Thomas P
Published: May 2020

Copper electrodeposition is critical to electronics manufacturing, ranging across lengthscales from nanometer damascene plating to 100s of micrometers for through-silicon-vias in 3D interconnect packaging and even millimeter-scale in printed circuit board manufacturing. Essential to this process is formation of void-free copper structures in high aspect ratio cavities, which is achieved with various additives that enable superconformal or bottom-up electrodeposition. When the additive package consists of only a suppressor (polyether) and chloride, the superconformal phenomenon is driven by S-shaped negative-differential resistance (S-NDR), which promotes spatial bifurcation of the electrode surface into active and passive depositing regions. All S-NDR systems involve kinetic suppression, polyether-chloride adsorption in this case, and kinetic activation, potential-driven disruption of the polyether-chloride adlayer. The term S-NDR is derived from the s-shape the i-V curve expresses when cyclic voltammetry (CV) is post-experimentally corrected for ohmic resistance, resulting in a system that expresses a multiplicity of reaction rates (current) for a given driving force (potential).

Electroanalytical measurements using microelectrodes (UMEs) offer an avenue for exploring S-NDR systems without significant iR-drop in solution. In other reaction systems, the reduced electrode dimension of UMEs has shown the ability to frustrate active-passive bifurcation, resulting in a homogeneously reacting electrode surface. Nonetheless, potential-controlled measurements such as cyclic voltammetry restrict S-NDR behavior from fully expressing itself, as the potential is the control parameter throughout the experiment. Current-controlled techniques, however, allow the thermodynamic state (i.e., potential) to dynamically shift as the polyether-chloride suppressing layer is formed and disrupted. In this work, current-controlled measurements in the form of linear galvanodynamic sweeps (GDS) are utilized to explore S-NDR behavior and electrode bifurcation during copper electrodeposition. GDS and CV measurements on UMEs are compared across a range of additive concentrations and polyether types. Influence of the operating mode on pattern formation is evaluated by in-situ optical microscopy on UMEs ranging from 10 μm to 25 μm in diameter. Spatial bifurcation during GDS measurements is further exploited to grow anisotropic copper deposits.
Programmable Electrodeposition of Ptni Alloy Porous Film for Oxygen Reduction
Authors: Yang Yang
Published: May 2020

Oxygen reduction reaction (ORR) is a critical process in many emerging energy technologies, such as fuel cells and metal-air batteries, determining the energy conversion efficiency of devices.However, the complex electron transfer pathways involved in the oxygen-oxygen (O-O) bond cleavage makes ORR kinetically sluggish. Platinum (Pt)-based materials are the state-of-the-art ORR catalysts due to their proper surface electronic structures toward efficient cleavage of O-O bond. However, the high cost and limited natural availability of Pt severely hinder its large-scale commercial application for ORR. Even though many Pt-free catalysts have been claimed in recent years as alternatives to Pt, their ORR performances and production costs still can not really compete with Pt. Hence, it is of vital importance but very challenging to develop efficient ORR catalysts with low Pt loading. In this work, we used O2 bubbles as gaseous templates to fabricate PtNi nanoporous films with ultra-low Pt loading, which could be achieved through controlling oxygen evolution reaction (OER) during the programmable synthesis process. The rationally designed nanoporous PtNi catalysts have selectively exposed Pt (111) facets with ultra-low Pt loading (0.015 mg cm-2) for ORR. We discovered that the adsorbed O2 bubbles on the Pt surfaces act as protection agents, preventing Pt oxidation and dissolution. As a result, the enriched Pt (111) facets are preferentially exposed on the surface of PtNi PFs, showing superior ORR activity to other low-Pt catalysts.
Stretchable Organic/Hybrid/Organic Multi-Layer Electrodes Prepared By Co-Sputtering for Wearable, Stretchable Sensors and Touch Panels
Authors: Yoon Sunyoung , Kim Han-Ki
Published: May 2020

We demonstrate an Organic (PTFE)/Hybrid (AgPdCu-PTFE)/Organic (PTFE) multi-layer electrodes on Polyurethane (PU) substrate using co-sputtering for wearable and stretchable sensor. Co-sputtering process of the polytetrafluoroethylene (PTFE) of Organic/Hybrid/Organic (OHO) multi-layer electrodes improved mechanical flexibility and stretchability in AgPdCu (APC)-PTFE hybrid layer which coated at the middle of OHO electrodes. We applied the power in the DC 10 W and RF 40 W for APC and PTFE, respectively. PTFE single layers of OHO electrodes are deposited to improve mechanical stability and transmittance. To investigate a mechanical and electrical characteristics of OHO electrodes, we measured sheet resistance, and stretchability depending on individual PTFE thickness. Average transparency towards visible light was measured ≥ 45% for OHO multi-layer structure. The average value of sheet resistance is 32.6 Ohm/square without significant change in the thickness of PTFE, which means that this uniform conductive network is formed in the hybrid layer. The stretching test was conducted 40 % strain under all conditions and reversible to confirm that hysteresis and stretchability were good for 30 nm of PTFE thickness. Minimal changes to resistance even after 20000 cycles under 20 % strain. In addition, a very small critical inner/outer bending radius below 1 mm indicates that the OHO multi-layer structure could also be applied as highly wearable devices. In addition, applicability is further verified by using it as commercial EL/LED interconnector and strain sensor. We confirmed the high electrical stability and feasibility by applying OHO multi-layer structure electrodes to the touch panels and electromyography (EMG) sensor.
Electrochemical Re-Functionalization of Spent FePO4 Originating from LiFePO4 Battery Recycling
Authors: Larouche Francois , Demopoulos George P. , Amouzegar Kamyab , Bouchard Patrick , Houlachi Georges , Zaghib Karim
Published: May 2020

Lithium-ion batteries (LIBs) find many applications from powering multitudes of portable electronics, to automotive, and stationary energy storage. The current rapid market growth, more specifically in mobility and stationary energy storage, has made the consumption of LIBs to increase exponentially since year 2000. It is predicted that this market will be multiplied by ten in the next decade. Inevitably, the quantity of spent LIBs will follow the same trend, causing important challenges to the waste management system. However, while end-of-life (EOL) management of portable batteries is established in North America and Europe, collection of industrial and vehicle batteries is just starting. Consequently, we expect an important increase of spent lithium battery available for recovery during the next decade raising the pressure on the recycling industry. In addition to the rapid increase in volume of spent batteries, the wide range of chemistries and types make recycling of LIBs more complex compared to other types of batteries. Until now, the industry has focussed on recovering the most valuable metals like cobalt and nickel while sending to the waste elements such as lithium, iron, and phosphorus from lithium iron phosphate (LiFePO4, LFP) batteries. Hydro-Québec has developed a new low environmental footprint process to recover efficiently high value product from spent LiFePO4 batteries. The process includes a dismantling and sorting step from which the active cathodic material is recovered as a black mass. A hydrometallurgical process extracting selectively Li ions as lithium bicarbonate from the black mass follows this preparation stage. The leaching residue is a carbon-coated iron (III) phosphate (FePO4 -C) which is re-functionalized as fully restored cathodic active material by taking advantage of highly reversible lithium intercalation into the FePO4 hosting structure. The final product is suitable for reuse in new LiFePO4 battery manufacturing.
Highly Efficient and Air Stable Ternary Organic Solar Cell Enabled By Employing a Perylenediimide-Based Acceptor
Authors: Ting Yu , Izquierdo Ricardo , Welch Gregory Charles , Ma Dongling
Published: May 2020

Organic solar cells (OSCs) are regarded as one of the promising photovoltaic technologies to address the issues of energy crisis and environmental pollution all over the world, and are thus considered as the next generation of solar cells. 1 However, the devices power conversation efficiency and stability of the devices are still important factors to limit the commercial application of OSCs. 2 To this end, enhancement of photon absorption is an attractive strategy for the increase of PCE. Recently, developing the ternary OSCs with three materials of complementary absorption spectra is an efficient method to enhance the photon harvesting of single junction devices while having a fairly simple fabrication process. Meanwhile, the morphology of active layers can be finely optimized by selecting the third component and adjusting its contents to improve performance of ternary OSCs. 3 Herein, we synthesized highly air-stable perylenediimide (PDI)-based non-fullerene material and integrated it into common organic solar cells as the third component to form the ternary OSCs. This cascade band structure showed a better energy level alignment and the complimentary absorption, thus demonstrating a high ternary device efficiency of 8.71% that represented 14.6% enhancement with respect to the corresponding binary OSCs. Besides, morphology was characterized by two-dimensional grazing-incidence X-ray diffraction (2D-GIXRD) and photo-induced force microscopy (PiFM) and results suggest improved compatibility between organic materials in OSCs, which could reduce the electronic trap states to inhibit the charge recombination and increase the stability of devices. The ternary OSCs thus exhibited good air stability, photo-stability and humidity. Our work provides a very promising approach to enhance the photovoltaic performance while demonstrating highly stable devices, which could contribute to the future development of the large area manufacturing in an ambient condition and roll-to roll processing on flexible substrates.

Reference

1. Yu T., Xu X. P., Zhang G. J., Wan J. H., Li Y., Peng Q., advanced functional materials, 2017, 1701491.

2. Li P. D., Mainville M., Zhang Y. L., leclerc M., Sun B. Q., Izquierdo R., Ma D. L., small, 2019, 1804671.

3. An Q. S., Zhang F. J., Gao w., Sun Q. Q., Zhang M., Yang C. L., Zhang J., nano energy, 2018, 45, 177-183.
Crystalline-to-Amorphous Phase Transformations As a Key Ingredient to Enhanced Rate Performance and Cycle Life in Mg- and Na-Ion Battery Anodes: Operando X-Ray Scattering Studies
Authors: Welborn Samuel S. , Wang Lin , Li Manni , Qiu Tian , Stach Eric A. , Rappe Andrew , Detsi Eric
Published: May 2020

The increasing popularity of Li-ion batteries in new applications such as electric vehicles is expected to cause the key resources (Li, Ni and Co) used in these batteries to become scarce. Alternative battery technologies, including Mg-ion, Na-ion, and metal-air batteries are therefore desirable. In this talk, I will discuss the use of operando wide-angle X-ray scattering (WAXS) to study the crystalline to amorphous phase transformations that are key to the outstanding performance of state-of-the-art alloy-type Mg- and Na-ion anodes. The 1st part of the talk will be on the impact of the crystalline-to-amorphous transformation on batteries cycle life. Here I will discuss our novel self-healing Ga/Mg anode, which holds the current record for cycle performance and rate capability in alloy-type Mg-ion battery anodes, owing to a crystalline Mg2Ga5 to amorphous liquid Ga phase transformation occurring near room temperature, preventing the well-known pulverization issue in alloy-type anodes.[1] The 2nd part of the talk will detail the impact of the crystalline-to-amorphous transformation on the rate capabilities of batteries. Here, I will present our nanoporous Sb/Na system, which transforms from crystalline Na3Sb to crystalline Sb, going through an amorphous intermediate. It will be shown using a combination of WAXS, electrochemical characterization, and computational study based on ab initio grand canonical (aiGCMC) simulations that the amorphous intermediate phase favors high rate Na storage in Sb.[2]

[1] Wang, L., Welborn, S. S., Kumar, H., Li, M., Wang, Z., Shenoy, V. B., Detsi, E.: High‐Rate and Long Cycle‐Life Alloy‐Type Magnesium‐Ion Battery Anode Enabled Through (De)magnesiation‐Induced Near‐Room‐Temperature Solid–Liquid Phase Transformation.
Adv. Energy Mater. 2019, 1902086. https://doi.org/10.1002/aenm.201902086

[2] M. Li, T. Qiu, S. S. Welborn, A. Foucher, B. Lesel, E. Stach, A. M. Rappe, E. Detsi: Understanding the Fast Kinetics of Sodium Storage in Antimony (unpublished)
Structural and Electrochemical Relationships of Bicontinuous Polysorbate-20 Microemulsions
Authors: Imel Adam , Barth Brian , Nelms K. McKensie , Hayes Douglas G. , Zawodzinski Thomas A.
Published: May 2020

Research and discovery of new electrolytes is crucial for advancing the fundamental understanding and development of new opportunities in electrochemical systems. Through an Energy Frontier Research Center (EFRC) for Breakthrough Electrolytes for Energy Storage (BEES), the approach we are taking is to establish a system for decoupling the nature and solubility of electroactive material from the conductivity and transport of ions in the surrounding solution. We accomplish this with microemulsions as a technique to solubilize hydrophobic redox active materials in an aqueous solvent. Microemulsions are isotropic, nanoscale dispersions of two immiscible liquids, stabilized by a surfactant, and cosurfactant. Microemulsions are an interesting electrolyte because they possess several properties that make them useful as an energy storage medium – they are thermodynamically stable, have fast dynamics, possess large interfacial areas, and can solubilize large concentrations of hydrophobic redox-active compounds in an aqueous electrolyte solution. Cyclic voltammetry experiments have shown reversible behavior in microemulsions up to 22 V/s with a double layer capacitance less than expected with such high scan rates. In order to understand the electrochemical behavior, we have begun with understanding the nanoscale structure of the microemulsion. Presented here are the small angle neutron scattering results on microemulsion systems with increasing surfactant loading and how the nanostructure correlates with the electrochemical response. That is as the strength of the amphiphile increases the maximum current density peak decreases and the half-wave potentials shift to lower potentials suggesting the local environment of the redox active species changes as the composition of the microemulsion is varied.

Figure 1
Performance Modeling of Hybrid Battery/Supercapacitor Energy Storage Systems Under Charge-Discharge Regimes
Authors: Zabara Mohammed Ahmed , Uzundal Can Berk , Ulgut Burak
Published: May 2020

The hybridization of batteries and supercapacitors shows advantages in energy storage applications by improving the power density, energy efficiency and cycle life [1]. Applications involving rapid changes in power consumption/production, such as electric vehicles, wind and solar energy systems benefit the most from the hybridization.

The enhancement is due to the power distribution among the hybrid systems. In a hybrid connection the load distributes according to the electrochemical properties of the energy storage system. Batteries are high specific energy systems (Figure 1(b)) which suffers degradation and capacity fade if utilized in high and oscillating specific power applications. The parallel connection of a battery to a high specific power system such as Super-Capacitor (SC) distributes the power among the two systems in which high currents are presumably handled by the SC.

Accurately predicting the power distribution among the hybrid systems is critical for their utilization in any projected applications. Conclusions regarding the best combination of battery/SC to specific condition or application is dependent on the knowledge of power distribution among them.

In this work, we demonstrate how the current distribution between the battery/supercapacitor systems and their voltage responses to random charge-discharge regimes can be modeled using optimization algorithm and Electrochemical Impedance Spectroscopy (EIS) of each system. First, the current distribution for each system is optimized using Differential Evolution algorithm. Second, the voltage is calculated by complex multiplication of the current by the impedance of each system [2]. The predicted current distributions and the calculated voltage responses show high accuracy with the experimental measurements Figure 1(c).

After obtaining the current distributions and the voltage response, performance parameters such as, peak power and energy efficiency are computed to determine the best combination of battery/SC under the charge-discharge condition. Furthermore, EIS of SC systems with different capacitances are simulated and used to predict the performance of the hybrid combination with Lithium Iron Phosphate (LFP) battery. The results demonstrate the ability to accurately predict the power distribution between the LFP/SC system for any capacitance value. It also enables for the determination of the best capacitance to choose for any charge-discharge condition.

References:

[1] L. Kouchachvili, W. Yaïci, and E. Entchev, “Hybrid battery/supercapacitor energy storage system for the electric vehicles,” J. Power Sources, vol. 374, no. November 2017, pp. 237–248, 2018.

[2] E. Özdemir, C. B. Uzundal, and B. Ulgut, “Zero-Free-Parameter Modeling Approach to Predict the Voltage of Batteries of Different Chemistries and Supercapacitors under Arbitrary Load,” J. Electrochem. Soc., vol. 164, no. 6, pp. A1274–A1280, Apr. 2017.

Figure 1
High Energy and Power Density Dense and Deterministically Mesostructured Electrodeposited Lithium and Sodium Battery Electrodes
Authors: Braun Paul V
Published: May 2020

Electrodeposition of electrode materials has the potential to grow anode and cathode materials with unprecedented energy and power densities for both Li-ion and Na-ion rechargeable batteries and to broaden the scope of available electrode form factors. I will present our work on the electrodeposition of high performance silicon and tin-based Na and Li-ion anodes and LiCoO2, NaCoO2, LiMn2O4, and Al-doped LiCoO2-based Na and Li-ion cathodes. The electrolytically active materials were formed either as solid films, or where significant volume changes upon cycling are present, as a 3D mesostructured film. The capacities are near-theoretical, and in the case of the electroplated oxides, the crystallinities and electrochemical capacities are comparable, or in some cases, even better than powders synthesized at much higher temperatures.
Electrodeposition of Li Metal onto an Ulta-Micro-Electrode
Authors: Nishikawa Kei , Shinoda Keisuke
Published: May 2020

Li metal is very attractive candidate for a negative electrode of next-generation rechargeable batteries because Li metal has very large theoretical capacity and the lowest standard electrode potential. In order to utilize Li metal for negative electrode, it is indispensable to control the morphological variation during charging and discharging. However, Li metal forms dendrites very easily in the electrodeposition process. In general, the distribution of the current density will induce the dendrite formation in the electrochemical system. In addition to that, SEI (solid electrolyte interphase) should play an important role for the morphological variation of the electrodeposited Li metal. Many researches were conducted based on the surface chemistry in order to reveal the relationship between the nature of SEI layer and the morphology of electrodeposited Li metal. However, the localization of the electrodeposition sites is an obstacle for the quantitative analysis in order to discuss the dendrite initiation and growth.

In this study, ultra-micro-electrode was utilized to observe the morphological variation of the electrodeposited Li metal. Constant current electrodeposition was conducted to observe the electrodeposited Li metal. All electrochemical experimental was done in super dry room. The dewpoint of the room was kept lower than 213K. After the electrodeposition, the ultra-micro-electrode was rinsed with some solvents very carefully, and transferred to FE-SEM or TEM with transfer vessel without air exposure. Ex-situ SEM and TEM observation was done to discuss the electrolyte effects to the morphology of electrodeposited Li metal. For SEM observation, not only the observation of morphology but also the chemical composition of SEI layer was analyzed by EDS spectra. The SEM observation was conducted in room temperature. For TEM observation, the sample was cooled to be about 100 K in order to minimize the electron beam damage. STEM-EELS analysis was also conducted for analysis of SEI layer on the electrodeposited Li metal.

The electrodeposited Li metal onto a ultra-micro-electrode in 1M LiPF6-EC:DEC=1:1 electrolyte was very smooth and uniform column shape. The chemical composition of the SEI layer on the electrodeposited Li metal was confirmed to be mainly LiF and Li2O by SEM-EDS and STEM-EELS analysis. In this presentation, we would like to discuss the relationship between the SEI layer and morphological variation based on the SEM and TEM observation results.
Progress on Primary Electrodeposition of Lithium Metal: Attempting to Decouple Effects of Solvent and Substrate
Authors: Steingart Daniel , Chang Wesley
Published: May 2020

A continued challenge and paradox of the lithium metal secondary battery is that we cannot, currently, make it of sufficient quality through primary metal electrodeposition. If we cannot make the lithium for the battery via electrochemistry, why should we expected a plating / stripping cycle to be sufficiently different. In this presentation we review our work and the work of others to provide some answers to this question, and perhaps some hope, by examining and decoupling the role of solvent and the role of substrate on the qualities and features of lithium metal, and the subsequent cycling performance.
Electrodeposition of Dense Tungsten Films from Molten KF-KCl-WO3 and Csf-Cscl-WO3
Authors: Nohira Toshiyuki , Meng Xianduo , Ide Tatsuya , Norikawa Yutaro , Yasuda Kouji
Published: May 2020

Tungsten metal is known for its robustness, especially high melting and boiling points and hardness. However, its hardness and brittleness make it difficult to work. Thus, electrodeposition of dense tungsten films is worth investigating. There are a number of reports on the electrodepositon of tungsten from high temperature molten salts such as fluorides, chlorides, oxides, etc. It is known that dense and coherent tungsten deposits are more easily obtained from molten fluorides compared to molten chlorides. Although good tungsten deposits can be electrodeposited from molten oxides, the operation temperature tends to be high, typically over 1123 K. One drawback of typical fluoride melts like LiF-NaF-KF is difficulty in removing the adhered molten salts by water washing because LiF and NaF have limited solubility to water.

From this background, we proposed new electrolyte baths, molten KF-KCl and CsF-CsCl. Since all the components salts of KF, KCl, CsF and CsCl have large solubility to water, adhered salts to deposited films can be easily removed by water washing.

First, electrodeposition of tungsten was investigated in eutectic KF–KCl melt to which WO3 was added at 923 K. Cyclic voltammograms at copper and gold electrodes indicated the deposition of tungsten metal at more negative potential than 1.55 V vs. K+/K. The effects of electrolysis conditions on the morphology of deposits were studied by changing the cathodic current density from 12.5 to100 mA cm-2. As shown in Fig.1 (a), a dense tungsten film with a thickness of approximately 20 µm was obtained on a copper substrate electrode at 12.5 mA cm−2 for 120 min. From the Raman spectra of molten KF–KCl and molten KF–KCl–WO3 at 923 K, the coordination structure of W(VI) complex ion was indicated to be fac-[WO3F3]3−.

Secondly, eutectic CsF-CsCl melt was used to lower the operation temperature. After adding 2.0 mol% of WO3, the electrodeposition was investigated using copper and gold electrodes at 823-923K. As shown in Fig.1 (b), a dense and smoother tungsten film was obtained by galvanostatic electrolysis at 12.5 mA cm−2 for 120 min at 873 K.

Figure 1
Electrochemical Growth and OER Catalytic Activityof Ultrathin Epitaxial Cobalt Oxide Films
Authors: Pacheco Ivan , Bouvier Mathilde , Wiegmann Tim , Qiu Canrong , Reikowski Finn , Stettner Jochim , Magnussen Olaf M. , Allongue Philippe , Maroun Fouad
Published: May 2020

Iron-group oxides are among the best earth abundant catalysts for the oxygen evolution reaction (OER) in alkaline and neutral electrolytes [1],[2]. Such oxides have been prepared with an amorphous or a crystalline structure, using thermal salt decomposition [3], autoclave synthesis [4], photochemical reactions [5], sol-gel synthesis [6], metal electrodeposition and subsequent oxidation, [7] and direct oxide electrodeposition [1], [8].

This work focuses on well-defined epitaxial CoOx [9] electrocatalysts grown by direct electrodeposition on Au(111) according to an approach similar to that introduced by Switzer [8]. The growth modes of catalysts and the mechanisms of deposition will be discussed based on electrochemical characterizations, XRD characterizations and microscopic observations. In particular to explain that CoOOH may be obtained at a potential of +1V/RHE by oxidation of a Co(II) complex diluted in an alkaline solution while thermodynamics predicts that Co3O4 should be formed. The electrochemical properties in pre-OER and within OER will be discussed as a function of the surface structure and morphology of layers. In particular to show that the large pseudocapacitance measured at the electrode is not related to its ECSA but to electrical charging within the bulk of the electrode.

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[2] C. C. L. McCrory, S. Jung, I. M. Ferrer et al., Journal of the American Chemical Society 137, 4347 (2015).

[3] C. Pirovano and S. Trasatti, Journal of Electroanalytical Chemistry and Interfacial Electrochemistry 180, 171 (1984).

[4] D. Yuming, H. Kun, Y. Lin et al., Nanotechnology 18, 435602 (2007).

[5] S. R. Alvarado, Y. Guo, T. P. A. Ruberu et al., The Journal of Physical Chemistry C 116, 10382 (2012).

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[7] M. W. Louie and A. T. Bell, Journal of the American Chemical Society 135, 12329 (2013).

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[9] F. Reikowski, F. Maroun, I. Pacheco et al., ACS Catalysis 9, 3811 (2019).