bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Nucleation and Growth of Small Atomic Aggregates into Superatom Nanoclusters
Authors: Nakajima Atsushi 
Published: July 2022

One of the challenges in nucleation and growth of small atomic aggregates is to develop the novel research field of solid-state chemistry and material science using gas-phase-synthesized superatom nanoclusters. Among various superatoms, the greatest advantage of the central-atom-encapsulating binary superatoms, such as M@Si16, is that their electronic structures can be designed by optimizing the central metal atom M while retaining the geometrical symmetry of the Si16 cage [1], as shown in the figure below. We have systematically investigated the nucleation and growth of M@Si16 superatoms with gas-phase mass spectrometry, and then performed the surface immobilization of the M@Si16 cations and anions on a substrate monodispersively with the size-selective soft-landing. Initial products prepared via the surface immobilization of M@Si16 superatoms on solid surfaces decorated with monolayer films of C60 molecules were investigated using scanning tunneling microscopy (STM) [2] and X-ray photoelectron spectroscopy (XPS) [3]. Furthermore, we have developed a large-scale synthesis method for M@Si16 (M = Ti and Ta) by scaling up the clean dry-process with a high-power impulse magnetron sputtering (HiPIMS, nanojima®) [4] and by a direct liquid embedded trapping (DiLET) method [5]. The spectroscopic results reveal that the structures of soft-landed and isolated M@Si16 superatoms are the metal-encapsulating tetrahedral silicon-cage (METS) [5,6].
Furthermore, superatoms of group-5 metals (M = V, Nb, and Ta) encapsulating Si16 cage nanoclusters (M@Si16) can be efficiently generated to form assembled films [7]. Temperature-dependent current–voltage (I–V) characteristics of the M@Si16 assembled films revealed that the electrical conduction mechanism is not band transport, but hopping transport with Efros–Shklovskii variable range hopping for all central M atoms [8]. The results show that electrons involved in conduction are strongly correlated to localized electronic states.
[1] K. Koyasu, A. Nakajima, et al. J. Am. Chem. Soc. 127, 4998 (2005).
[2] M. Nakaya, A. Nakajima, et al. Nanoscale, 6, 14702 (2014).
[3] M. Shibuta, A. Nakajima, et al. J. Am. Chem. Soc. 137, 14015 (2015).
[4] C. H. Zhang, A. Nakajima, et al. J. Phys. Chem. A 117, 10211 (2013).
[5] H. Tsunoyama, A. Nakajima, et al. J. Phys. Chem. C 121, 20507 (2017).
[6] H. Tsunoyama, A. Nakajima, et al. Acc. Chem. Res. 51, 1735 (2018).
[7] M. Shibuta, A. Nakajima, et al. J. Phys. Chem. C, 124, 28108 (2020).
[8] T. Yokoyama, A. Nakajima, et al. J. Phys. Chem. C, 125, 18420 (2021).

Figure 1
(Invited) Charge Attachment–Induced Transport: Toward New Paradigms in Solid State Electrochemistry
Authors: Weitzel Karl-Michael 
Published: July 2022

Modern applications in solid state electrochemistry, e.g. in the field of energy storage and conversion, involve the transport of charge carriers through surfaces or interfaces as a key aspect. Many of the electrochemical concepts in fact originate from the field of liquid state electrochemistry. The transfer of concepts from the liquid to the solid state causes some problems which have been addressed in a recent review [1]. This contribution coveres some of the topics from ref. [1] e.g. (i) electrode potentials and half-cell potentials, (ii) charge carrier blocking and dielectric breakdown, and (iii) activities versus particle densities. Additional topics to be discussed are transfer of charge carriers across interfaces, work functions and electrodeposition.
Many of these topics can be addressed by the charge attachment–induced transport technique developed in the authors group. The discussion involves modifying some of the paradigms we became acquainted to in the liquid state.
[1] K.-M. Weitzel, Current opinion in electrochemistry, 26:100672, (2021)
(Invited) Electrochemical Nucleation and Growth of Lithium Fluoride at Lithium Battery Interfaces
Authors: Gallant Betar M. 
Published: July 2022

Lithium fluoride (LiF) is a commonly observed phase in many battery interfaces including at the solid-electrolyte interphase (SEI) of graphite and Li metal, and the cathode electrolyte interphase (CEI) of many high-voltage cathode materials in Li-ion batteries, given the battery field’s reliance on fluorinated salt anions and increasingly, on fluorinated solvents. For Li electrodeposition, LiF formation has been proposed to correlate with high Coulombic efficiency (CE) of Li plating/stripping, which still remains below 99.9%. Analytical methodologies to study LiF within the SEI have historically been limited, relying on techniques such as X-ray photoelectron spectroscopy that can detect presence of LiF and quantify bulk-average amounts, but lack spatial or morphological information. Meanwhile, the processes by which LiF nucleates and grows at battery interfaces, the morphology and properties of LiF particles formed in relevant battery electrolytes, and the relation to their properties and functionality remain poorly understood.
In this talk, I will present insights gained into the physicochemical properties and nucleation and growth behavior of electrochemically formed LiF under highly reducing conditions such as those found at Li anodes. We first studied a series of exemplar conversion reactions based on cathodic reduction of fluorine-rich carrier molecules (dissolved-gas or liquid solutions up to 5 M) that yield LiF upon reduction, with redox potentials ranging from 2–3 V vs. Li. The resulting particle size, morphology and crystallinity are highly sensitive to solvent donor number and discharge rate, evidencing a solution-mediated growth pathway involving supersaturation and precipitation of LiF crystallites onto a carbon or Cu substrate. The LiF growth modes are altered from cubic particles with large average particle sizes (> 1 µm) and sparse coverage in DMSO-based electrolytes to < 50 nm in carbonate- and ether-based electrolytes more relevant to battery applications. Next, we investigated how pre-nucleated LiF particles of varied morphologies and coverage influences Li plating on Cu current collectors. Nucleation overpotentials, Coulombic efficiencies as a function of plated/stripped capacity, and resulting Li deposition morphology are investigated to shed light on structural-electrochemical interplays relevant to those occurring at a Li metal interface.
Depolarization of Cu Electrodeposition in the Presence of Ag: A Cyclic-Voltammetry Study
Authors: Sun Yunkai , Shao Wenbo , Xu Yin , Zangari Giovanni 
Published: July 2022

During our investigation of Cu-Ag alloy electrodeposition from acidic sulfate bath, peculiar behavior of Cu reduction was found in the CV profiles when the Cu deposition overpotential is very small. An early Cu(II) reduction peak, which is revealed to be a full reduction of Cu(II) to Cu(0) based on the EQCM-CV measurement, was observed in addition to the main Cu(II)/Cu(0) deposition peak. To our surprise, this early Cu deposition peak occurs when the deposition bath contains Ag(I) cations, or the substrate contains Ag metals.
EQCM-CV profile shows that the early Cu deposition peak is associated with a 65% deposition efficiency, slightly smaller than that of the main Cu(II)/Cu(0) reduction peak (~78%). The amount of Cu deposited associated with the early Cu reduction peak is estimated based on the total charge associated with this peak. The early Cu reduction peak is associated with Cu deposit thicker than 3 nm, with the thickness increases with decreasing scan rate or increasing Ag(I) concentration in the electrolyte. Meanwhile, from the CV profiles, the early Cu reduction peak is associated with a Tafel slope ~30mV/dec. We hypothesize that by the catalytic effect of Ag, either in the substrate or in the initial deposit, on the intermediate reduction step of Cu(II)/Cu(I) causes the early Cu reduction peak by shifting rate determining step of Cu(II)/Cu(0) deposition from Cu(II)/Cu(I) to Cu(I)/Cu(0).

Disclaimer:

This work has been submitted at Electrochimica Acta (manuscript id: EA21-4167RR1), with title "Depolarization of Cu electrodeposition in the presence of Ag: a cyclic-voltammetry study". Figure attached is chosen from this manuscript.

Figure. Cyclic voltammograms at electropolished Cu substrate from 0.3 M CuSO4 + 0.5 M H2SO4 (a) with or without 0.5 mM NaNO3, and (b) with 0-0.5 mM AgNO3.

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The Distribution of Nucleation Activities: A New Local Perspective with Scanning Electrochemical Cell Microscopy
Authors: Torres Daniel , Bernal Lopez Miguel , Ustarroz Jon 
Published: July 2022

Electrodeposition is a convenient strategy for the synthesis of functional nanostructures, for which electrochemical nucleation and growth (EN&G) processes need to be well understood [1]. As a heterogenous process, understanding the distribution of nucleation sites on a substrate is fundamental to relate the microscopic events to the macroscopic properties of the new deposit. In this work, we have explored the EN&G process on a glassy carbon substrate with a local electrochemical approach based on the Scanning Electrochemical Cell Microscopy (SECCM), using copper as a case of study [2]. Since the studies of EN&G are extremely sensitive to the state of the surface, the diversity of the nucleation process is revealed by performing hundreds of spatially resolved experiments on the heterogeneous surface of the glassy carbon [2,3]. The spatially-resolved characterization opens up the opportunity to correlate the electrochemical information to the local surface state, which can be modified with common surface pretreatments (i. e., polishing and preanodization). This unique perspective of the EN&G can help to deconvolute the individual contributions to the overall process, bringing forward information on nucleation sites that is unavailable with the conventional macroscopic approach.
[1] J. Ustarroz, Current atomic-level understanding of electrochemical nucleation and growth on low-energy surfaces, Curr. Opin. Electrochem. 19 (2020) 144–152.
[2] D.Torres, M. Bernal, J. Ustarroz, distribution of copper nucleation activities on glassy carbon: a new local perspective, to be submitted 2022
[3] M. Bernal, D. Torres, S. Semsari, M. Čeh, K. Žužek Rožman, S. Šturm, J. Ustarroz, Diversity matters: Influence of surface heterogeneities in the electrochemical nucleation and dissolution of Au nanoparticles, under revision.

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(Digital Presentation) The Evolution of Composition and Morphology during the Initial Growth of Electrodeposited Ni-Fe Films
Authors: Lin Qiyuan , Zangari Giovanni 
Published: July 2022

The anomalous codeposition of Ni-Fe tends to develop a composition gradient zone along the growth direction within the near-substrate region. Although it has been shown that such a composition gradient can be mitigated by the pulsed deposition method, a fundamental understanding of this behavior based on the anomalous codeposition mechanism has not been achieved yet. In this work, the evolution of the composition and the morphology during the (pulsed) electrodeposition of Ni-Fe films was reported. A theory based on the Fe deposition mechanism originally described by Bockris, Drazic, and Despic [1] was proposed and described in detail, which was used to rationalize not only the occurrence and the decline of the composition gradient, but also the opposite signs of the composition gradient observed under the potentiostatic mode and the pulse-reverse potential mode.
[1] O’M. Bockris, D. Drazic, A. R. Despic, The Electrode Kinetics of the Deposition and Dissolution of Iron, Electrochimica Acta 4, no. 2 (1961) 325–361.
Elucidation of Discharge Mechanism in CFx As a High Energy Density Cathode Material for Lithium Primary Battery
Authors: Sayahpour Baharak , Bai Shuang , Cheng Diyi , Zhang Minghao , Li Weikang , Meng Ying Shirley 
Published: July 2022

Fluorinated graphite (CF
x
) is a class of cathode materials with the high theoretical capacity (865 mAh g-1 in case of x=1) for primary (non-rechargeable) batteries. When using Li metal as the anode material, the system possesses a very low self-discharge rate (< 0.5% per year at 25 °C) compared to other current alternative chemistries. This system, with the proposed general governing reaction of CF
x
+Li→LiF+C, is one of the best candidates for a wide range of applications, such as implantable medical devices and equipment for extreme environment.
Although the lithium fluorinated graphite system has been under investigation for a few decades, there is still a lack of fundamental understanding of the reaction mechanism in this system. Here, a multiscale investigation on the CFx discharge mechanism was performed using a novel cathode structure to minimize the carbon and fluorine additives for precise cathode characterizations. Titration gas chromatography (TGC), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), cross-sectional focused ion beam (FIB), high-resolution transmission electron microscopy (HRTEM), and scanning transmission electron microscopy with electron energy loss spectroscopy (STEM-EELS) were utilized to investigate this system.
The results demonstrated that: (i) There is no lithium deposition or intercalation through the entire discharge. (ii) The CFx structure transforms to a hard-carbon like structure with less sp2 content by increasing depth of discharge. (iii) The crystalline LiF particles uniformly covered the layers of CFx structure with a size range of < 10 nm. A three-step discharge reaction mechanism is proposed in agreement with our electrochemical performances. This work deepens the understanding of CFx as a high energy density cathode material and highlights the need for future investigations on primary battery materials to advance performance.

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(Invited) John B. Goodenough's Centenarian : Success Story of LiFePO4 (LFP) As Cathode Material for Rechargeable Lithium Batteries
Authors: Zaghib Karim , Trudeau Michel L. , Reddy M.V. , Mauger Alain , Julien Christian , Armand Michel 
Published: July 2022

Lithium-ion and solid-state battery (SSB) are now playing a central role in consumer electronic, energy storage and electric vehicles thanks to their excellent cycle life and high energy density. One of the key components that have paved the way for this success story in the past 27 years is LiFePO4 (LFP) which has served as a lithium-ion host structure for the cathode electrode. Today only LFP is used in both commercial Li-ion and SSB batteries, due their safety, low cost (cobalt free), fast charge and discharge, and over 20 years of calendar life.
In this presentation, we will show the progress of the physical chemistry of the olivine compounds since the pioneering work of Prof. John B. Goodenough. This major improvement has positioned LiFePO4 as the active cathode element of a new generation of Li-ion batteries from cell to pack, hence making a breakthrough in the technology of energy storage and electric transportation. This achievement is the fruit of about 27 years of intensive research in the electrochemical community during which chemists, electrochemists, physicists, and engineers added their efforts to understand the properties of the material, to overcome the obstacles that were met on the way, and finally to reach the state of the art enabling its ubiquitous use in technology today and in the future.
Improving High-Nickel Cathode Active Material Performance in Lithium-Ion Batteries with Functionalized Binder Chemistry
Authors: Matts Ian L , Klementov Andrei , Sisco Scott , Kumar Kuldeep , Lee Se Ryeon 
Published: July 2022

As the lithium-ion battery (LIB) market expands, driven mostly by the mass adoption of electric vehicles, LIB development is continually being pushed in the direction of higher energy density and lower cost. Both of these trends are leading to widespread development of LIB formulations using high-nickel cathode active materials, such as NMC811. In these materials, the high nickel content increases the amount of electrochemically accessible lithium in the cathode, increasing the cell energy density, while decreasing the amount of cobalt used, which decreases the cost of the cathode material. However, these materials also have drawbacks. First, NMC811 suffers from lower cycle life than higher-Co NMC materials such as NMC111 or NMC622. Second, NMC811 has poorer safety characteristics than lower energy density materials. Finally, NMC811 cathodes are known to experience gassing issues during cycling, which creates challenges in commercialization, especially for pouch cell battery designs.
Many approaches have been explored in the industry to address these shortcomings, including active material modification, electrolyte design, etc. In this presentation, binder functionalization will be presented as an alternative pathway to improve high-Ni cathode performance. LIB cathode binder is commonly high molecular weight PVDF, which provides good mechanical properties at low weight fractions as well as high electrochemical stability, but it is predominantly inert. Here, approaches of introducing novel binders tailored for high-Ni cathode systems will be discussed. Effectiveness of modifications, specifically their impact on LIB cycle life and safety, will be discussed.
(Invited) Elucidating the Structure and Function of the Electrode-Electrolyte Interface By New Solid State NMR Approaches
Authors: Leskes Michal 
Published: July 2022

The development of high-energy, long-lasting energy storage systems based on rechargeable batteries relies on our ability to control charge storage and degradation processes in the bulk of the electrode materials and at the electrode-electrolyte interface. NMR spectroscopy is exceptionally suited to follow the electrochemical and chemical processes in the bulk of the electrodes and electrolyte, providing atomic scale structural insight into the charge storage mechanisms and ion transport properties. However, interfacial properties, such as the processes governing charge transport between the electrode and the electrolyte, are much harder to study. These processes typically involve thin, heterogeneous and disordered layers that are formed chemically/electrochemically in the battery cell or artificially through coating the electrode material. While NMR is in principle an excellent approach for probing disordered phases, its low sensitivity presents an enormous challenge in the detection of interfacial processes.
In this talk I will describe recent approaches to overcome the sensitivity limitation by the use of Dynamic Nuclear Polarization (DNP). In DNP, the large electron spin polarization is used to boost the sensitivity of NMR spectroscopy by orders of magnitude. I will show how we can use this approach to detect the solid-electrolyte interphase (SEI), electrode coatings as well as the electrode’s bulk, with unprecedented sensitivity. Furthermore, I will present new approaches to probe ion transport properties of various interfaces. These allow us to get insight into the functional role of interfaces, which along with the chemical and structural insight, can provide design rules for beneficial interfaces, an essential aspect for developing long-lasting energy storage systems.
On the Study of Lithium Diffusivity in Lithium Nickel Manganese Cobalt Oxide Cathodes
Authors: Jaberi Ali , Trudeau Michel L. , Song Jun , Gauvin Raynald 
Published: July 2022

Climate change, population growth, and rising fossil fuel prices have encouraged governments and scientists for alternate energy resources. This energy transition requires a high-performance energy storage device to satisfy the high energy and power demand and lithium-ion battery (LIB) is one of the promising one. The performance of these batteries ultimately relies on the properties of their components. In this regard, to meet the high-power demand in high-power applications (such as electric vehicles (EVs) and hybrid EVs), materials with rapid lithium transport are required. Lithium Nickel Manganese Cobalt Oxide (NMC) has attracted scientists’ attentions due to its outstanding performance as a cathode material. Therefore, understanding the effect of various factors on lithium diffusivity in NMC is critical to develop high-performance LIBs for high-power applications.
Electrochemical methods such as potentiostatic and galvanostatic intermittent titration techniques (PITT and GITT) have been frequently utilized to experimentally quantify lithium diffusivity in NMC. These techniques need the knowledge of electrode particle shape and dimension, and uncertainty about these parameters leads to substantial errors in predicting the diffusion coefficient. In addition, because these techniques consider the response of the whole electrochemical cell, it is hard to distinguish the effect of different structural factors on Li diffusivity in a single NMC active material. Therefore, an appropriate method still needs to be developed to capture the structural effects on lithium diffusivity in NMC. For this purpose, a multi-level modelling from Density Functional Theory (DFT) to kinetic Monte Carlo (KMC) should be implemented.
In this study, we will use DFT to find the ground state energy of NMC at different lithium concentrations and configurations. Also, the minimum energy path of lithium migration and the related activation barrier will be found by Climbing Image-Nudge Elastic Band (CI-NEB) method. Then by implementing the configurational dependent activation barrier into the KMC simulation, the lithium diffusivity will be studied. This atomistic simulation gives insight about the structural effects on lithium diffusivity in NMC to further develop this cathode material for high performance LIBs.
Impact of Laser Structuring and Calendering on Electrode Characteristics and Cell Performance of Li-Ion Battery Graphite Anodes
Authors: Hille Lucas , Schriever Charlotte , Zaeh Michael F. 
Published: July 2022

The strong compression of electrode coatings is a common approach to enhance the volumetric energy density of Li-ion batteries (LIBs). However, it results in a deterioration of the charge and discharge performance due to an increase in the ionic resistance of the electrodes. This conflict can be addressed by microscopic ion diffusion channels in the electrode coatings, which reduce the ionic resistance and thus enhance the performance of a LIB.
In this study, the impact of laser micro structuring on different electrode properties was experimentally investigated for graphite anodes with varying initial porosities. All electrodes showed higher porosities after laser structuring, which can be attributed to an increase in the electrodes’ thicknesses and the removal of material. An equivalent circuit was fitted to the electrochemical impedance spectra of symmetric coin cells consisting of structured and pristine graphite anodes, respectively, to determine the ionic resistances, MacMullin numbers and tortuosities. The values were found to increase for decreasing initial porosities. Laser structuring significantly reduced the ionic resistances, MacMullin numbers and tortuosities of the electrodes in comparison to their pristine counterparts. Furthermore, the different graphite anode configurations were paired with NMC cathodes in coin cells and examined in a discharge rate test. At rates over 1 C, a significant increase in the discharge capacity through laser structuring was observed especially for cells with highly compressed anodes. Conclusively, this study empirically quantifies how laser structuring and calendaring influence different electrode characteristics of graphite anodes and the respective performance in LIBs.