bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous Acquisition of Differential Electrochemical Mass Spectrometric and Infrared Spectroscopic Data for in Situ Characterization of Gassing Processes in Lithium-Ion Batteries
Authors: Berkes Balázs B. , Jozwiuk Anna , Sommer Heino , Brezesinski Torsten , Janek Jürgen 
Published: February 2020

A considerably contributing process to the capacity fading of lithium-ion batteries is gas evolution. The understanding of its mechanism is inevitable to develop better battery components. These are especially tailor-made electrolyte mixtures and additives, as well as cathode and anode structures/composites.
In the past, differential electrochemical mass spectrometry (DEMS) already served us with important facts on the gassing behavior of electrochemical systems, particularly in lithium-ion batteries. However, it cannot always unambiguously unveil certain important features of the ongoing gas evolution reactions. In the case of overlapping m/z values, like 28, the species can be either assigned to C2H4, CO as an individual reaction product or as a fragment of CO2 too. Furthermore, the quantification of the gaseous products might be extremely difficult due to matrix effects caused by the volatile electrolyte components. A hands-on supplementary technique is infrared spectroscopy (IR), since the majority of the products in question have characteristic absorption bands. Simultaneously acquired with the DEMS measurements, they give a more complete and unequivocal picture on the nature of gases. Additionally, with the help of IR, the quantification of the products is straightforward and more precise.
In this talk, we present the results on the development of a novel, combined in-situ DEMS-IR (DEIRS) analysis method. We show that our approach is unique with regard to long-term battery cycling tests as well. We compare different cathode materials or modified versions of the given material and demonstrate the effect of chemical composition/structure on the gassing behavior. The effect of solvent mixtures and some additives, like vinylene carbonate, on the stability of the electrolyte is elucidated. With the help of our setup, a method to optimize the amount of additives is suggested. Supported by precise pressure measurements, we give a comprehensive picture on the gassing processes in closed systems and compare those with the continuous flow DEMS-IR results. The quantification of the gaseous reaction products together with versatile, potential resolved electrochemical tests enables the establishment of kinetic models of the gas evolution, which will be illuminated. Unanticipated gas formation in certain cycling steps will be manifested too.
Enhanced Lithium Ion Conductivity in Lithium Lanthanum Titanate Solid Electrolyte Nanowires Prepared By Electrospinning
Authors: Yang Ting , Li Ying , Chan Candace K. 
Published: February 2020

Solid electrolytes have great potential to address the safety issues of Li-ion batteries, but better synthesis methods are still required for ceramics such as lithium lanthanum titanate (LLTO) since current techniques require high-temperature calcination for long times. Here we report a new approach that utilizes electrospinning to prepare phase-pure polycrystalline LLTO nanowires with well-crystallized tetragonal phase.
To synthesize LLTO nanowires, the electrospinning precursor was prepared by mixing a LLTO sol into a polymer solution [1]. In a typical electrospinning experiment, the voltage was set to 7 kV, the distance between the needle tip and the collector was kept at 10 cm, and the feed rate was 0.3 mL/h. The as-spun fibers were calcined at 1000 °C for 3 h to get the LLTO nanowires.
Pellets of electrospun LLTO and LLTO prepared with conventional sol-gel method [2] were made and sintered. Electrochemical impedance spectroscopy (EIS) was used for ionic conductivity measurement. Pellets prepared from the electrospun LLTO nanowires had higher density, less void space, and higher Li+ conductivity compared to those made from conventional sol-gel method. This work demonstrates the potential that electrospinning can provide towards improving the properties of sol-gel derived ceramics.

Acknowledgements

This work was supported by new faculty startup funds from the Fulton Schools of Engineering at ASU. We gratefully acknowledge the use of facilities within the LeRoy Center for Solid State Science and Goldwater Environmental Laboratory at ASU.

References

[1] T. Yang, Y. Li and C. K. Chan, Journal of Power Sources 287 (2015) 164-169.
[2] T. Wöhrle, P. Gómez-Romero, T. Fries, K. West, M.R. Palacín, N. Casañ-Pastor, Ionics 2 (1996) 442.
The Joint Center for Energy Storage Research (JCESR): A New Paradigm for Energy Storage Research
Authors: Crabtree George 
Published: February 2020

The Joint Center for Energy Storage Research (JCESR) pursues high performance, low cost beyond lithium ion electricity storage that will transform transportation and the electricity grid. JCESR will leave three legacies:

a library of fundamental knowledge of the materials and phenomena of energy storage at the atomic and molecular level

two prototypes, one for the grid and one for transportation, that, when scaled to manufacturing will be able to deliver five times the energy density at one-fifth the cost

a new paradigm for battery R&D that combines discovery science, battery design, research prototyping and manufacturing collaboration in a single highly interactive organization, accelerates the pace of discovery and innovation and significantly shortens the time from discovery to commercialization.

An introduction to JCESR’s vision, mission and legacies will be followed by research highlights illustrating its advances in fundamental science and the promising pathways to transformational battery designs and prototypes.
This work was supported as part of the Joint Center for Energy Storage Research, an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences

Contact information

George Crabtree
Director, Joint Center for Energy Storage Research (JCESR)
Argonne National Laboratory
9700 S. Cass Ave
Argonne, IL 60439
630 252 5509
crabtree@anl.gov
Departments of Physics, Electrical and Mechanical Engineering
University of Illinois at Chicago
845 W. Taylor St. M/C 273
Chicago, IL 60607
Tel 630 252 5509
crabtree@uic.edu

Executive Assistant

Bernadette (Nada) Petrovic
Joint Center for Energy Storage Research (JCESR)
Argonne National Laboratory
9700 S. Cass Ave
Argonne, IL 60439
(630) 252-1420
bpetrovic@anl.gov
Surface Reaction, Solvent Inhomogeneity, and Ion Transport in Electric Double Layers: Predictions from a Classical Density Functional Theory
Authors: Lian Cheng , Wu Jianzhong 
Published: February 2020

Electric double layers (EDLs) are formed at the interface of a charged fluid in contact with an electrified surface or an electrode leading to drastic changes in the fluid structure and local thermodynamic properties. Whereas conventional theories of EDLs are often concerned with the local inhomogeneity in terms of ionic distributions near a planar surface, the simplistic model is insufficient to capture many important properties relevant to emerging electrochemical processes for energy storage and conversion. In this talk, we present a few recent applications of the classical density functional theory (CDFT) that account for not only ionic excluded volume effects and electrostatic correlations ignored in conventional theories of EDLs but also electrode geometry and pore size distributions, the local solvent and dielectric inhomogeneity, surface reactions, and hydrodynamic effects. The CDFT calculations will be illustrated with practical examples for unusual ion transport in nanopores, optimization of capacitive energy extraction processes, design of nanostructured electrodes for flow supercapacitors and pseudo-capacitors. The theoretical predictions are validated with experiment results and provide insights for novel electrochemical behavior that are not captured in conventional EDL theories.
Acknowledgements: This research is sponsored by the Fluid Interface Reactions, Structures, and Transport (FIRST) Center and the U.S. Department of Energy (DE-FG02-06ER46296). The numerical calculations were performed at the National Energy Research Scientific Computing Center (NERSC).
Ionic Liquid Structure and Dynamics at Charged Graphene Interface
Authors: Uysal Ahmet 
Published: February 2020

Supercapacitors with room temperature ionic liquid (RTIL) electrolytes and graphene-based electrodes are promising candidates for small electronic devices, especially flexible and wearable ones. The theoretical upper limit for the electric double layer (EDL) capacitance of graphene is the highest in all carbon materials. Also, graphene-based electrodes open up novel designs that are free of binders and inert conductive additives [1]. Furthermore, RTILs stand out as safe, non-volatile electrolytes with a wide potential window. However, our knowledge of these highly dense ionic plasmas at electrified interfaces is still at its infancy due to the lack of in situ experimental data about their potential-dependent EDL structures and dynamics [2].
Here, we use in situ real-time X-ray reflectivity integrated with fully atomistic molecular dynamics (MD) simulations to elucidate the interfacial ionic liquid structure and dynamics at epitaxial graphene electrode during cyclic voltammetry and potential steps [3]. Our results suggest that the graphene-RTIL interfacial structure is bistable in which the EDL structure at any intermediate potential can be described by the combination of two extreme-potential structures whose proportions vary depending on the polarity and magnitude of the applied potential. This picture is supported by the EDL structures obtained by MD simulations at various static potentials [4]. The potential-driven transition between the two structures is characterized by an energy barrier (~0.15 eV) that is independent of temperature. The model nicely explains the coexistence of distinct anion and cation adsorbed structures and provides further insights to ultra-slow response of the interfacial structure to potential steps.

References

1- Y. Shao et al. Chemical Society Reviews DOI:10.1039/C4CS00316K (2015)
2- M. Fedorov and A. Kornyshev. Chemical Reviews 114, 2978-3036 (2014)
3- A. Uysal et al. Journal of Physical Chemistry C, 118, 569-574 (2014)
4- A. Uysal et al. Journal of Physics: Condensed Matter, 27, 032101 (2015)
* This effort was supported as part of the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. The research described here was done in collaboration with S. S. Lee, H. Zhou, P. Fenter (Argonne National Laboratory), G. Feng, S. Li, P. Cummings (Vanderbilt University), P. Fulvio, P. Zhang, S. Dai (Oak Ridge National Laboratory), J. McDonough, Y. Gogotsi (Drexel University)
Electronic Structure Calculations and Synergistic Experimental Work in the Nanostructures for Electrical Energy Storage (NEES) Energy Frontier Research Center
Authors: Leung Kevin 
Published: February 2020

In this presentation, we will review computational effort and synergistic experimental activities in the Nanostructures for Electrical Energy Storage (NEES) Energy Frontier Research Center, and discuss future research directions. Interfaces and interphases constitute a main theme of our research. Nanoscale structures exhibit enhanced surface areas, and fundamental understanding and smart design of interfaces can help exploit their kinetic advantages while mitigating undesirable parasitic reactions. Thus electrochemical reactions responsible for liquid electrolyte degradation are examined using both large scale ab initio molecular dynamics (AIMD) simulations and complementary ultrahigh vacuum (UHV) measurements. Electrolyte decomposition on lithium peroxide surfaces, a key obstacle in Li-air battery implementation, is examined using analytical/spectroscopic techniques and DFT calculations. Artificial "solid electrolyte interphase" are deposited on amorphous carbon electrodes via atomic layer deposition (ALD) processes, and its electrode-passivating property is characterized by microgravimetric measurements and modelled using DFT calculations coupled with Marcus Theory constructions. This ALD study highlights a second key theme in our research: that necessary fundamental science, computational- and nano-electrochemistry advances emerge naturally in the ostensibly "applied" field of energy storage. We will discuss other examples of method development, such as rigorous voltage calibration in AIMD/DFT calculations, and measurement/control of minute currents associated with single nanowires. Going forward, our new computational approaches will be applied to model solid-solid interfaces pertinent to solid electrolytes, artificially-coated, nanostructured interfaces, and electrode degradation studies.
This work was supported by Nanostructures for Electrical Energy Storage (NEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under award no. DESC0001160. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corpo ration, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
The Challenge of 3D All Solid State Li-Ion Battery
Authors: Talin A. Alec , Ruzmetov Dmitry , Haney Paul , Kolmakov Andrei , Kozen Alexander C , Pearse Alex , Gregorczyk Keith , Schmitt Tom , Rubloff Gary W 
Published: February 2020

Demonstration of all-solid state 3-dimensional (3D) Li-ion batteries has been a long standing goal for numerous researchers in the battery community interested in developing high power and high areal energy density storage solutions for variety of applications. The basic idea is to use the 3D geometry to maximize the volume of active material per unit area, while keeping its thickness sufficiently small to allow for fast Li diffusion. The 3D approach also leads to high electrode/electrolyte interface area, which should prove beneficial by lowering the local current density and therefore the charge transfer resistance, assuming that the interface is stable against parasitic reactions and breakdown. While simple conceptually, realizing working all solid state Li ion batteries has proven to be a significant challenge. Specifically, the physical vapor deposition processes which have been successfully implemented for planar, thin film solid state Li ion batteries, fail miserably when applied to 3D substrates, particularly with high aspect ratio features. In our presentation, we will describe the structure and performance of all solid state 3D Li ion batteries fabricated by physical vapor deposition. Although these can be charged and discharged at low C-rates, their capacity decreases rapidly at higher C-rates. In our presentation we will discuss the underlying reasons for the poor performance and demonstrate how these problems can be addressed using atomic layer deposition, a thin film deposition method compatible with high aspect ratio geometries.

Figure 1
Investigating Synthetic Effects on Ni-Based Oxide As a Cathode Material for Li-Ion Batteries
Authors: Xu Jing , Tong Wei 
Published: February 2020

Lithium-ion battery (LIBs) technology has already disrupted the consumer electronic industry that has a continuous requirement on lighter weight and smaller size. Nowadays, it has been considered as the most promising power source for electric vehicles (EVs) and hybrid electric vehicles (HEVs). However, the mass adoption is still hindered by the battery performance and cost. Therefore, there is a definitive focus on increasing the energy density and lowering the cost in addition to ensure the other performance metrics such as in lifetime and safety. In the commercial Li-ion batteries, the layered transition metal oxides, such as LiCoO2, are widely used. Despite of its high theoretical capacity (> 270 mAh/g), LiCoO2 can only deliver about 140 - 170 mAh/g. This limited capacity as well as the high cost originated from the usage of Co has driven the research focus from LiCoO2 to other potential alternatives.
The extensive research on the search of an alternative to LiCoO2 has identified LiNixMnyCozO2 (NMCs) (0 < x, y, z < 1) as a category of promising compositions for the use of cathode materials in Li-ion batteries in terms of energy density, cost and safety. Ni content has been recognized to play a key role in an effort to push towards the high-capacity end. There have been renewed interests in this research direction. However, high Ni content causes the tendency of lithium and transition metal cation mixing and propensity to catalyze the electrolyte oxidation. Additionally, there is an evidence of preferential segregation of Ni on the surface for both NMC and Li-rich NMCs. Here we are investigating the synthetic effects on the cation distribution, and electrochemical performance of Ni-based layered oxide in a battery. The influence of synthetic routes on the bulk and surface will be systematically investigated by synchrotron XRD and soft X-ray absorption spectroscopy. These findings will hopefully shed light on the further development of Ni-based electrode materials for Li-ion batteries.
Evolution of the Surface and Subsurface Chemical Environment of LixNi0.8Co0.15Al0.5O2 electrodes
Authors: Sallis Shawn , Pereira Nathalie , Huang Yiqing , Quackenbush Nicholas F. , Whittingham M. Stanley , Amatucci Glenn G , Piper Louis F.J. 
Published: February 2020

The nickel-based layered positive electrode, LiNi0.8Co0.15Al0.05O2 (NCA) has a high discharge capacity of ~ 200 mAhg-1 making it promising for potential electric vehicle applications. However, NCA displays drastic capacity fade with cycling. Accelerated cycling tests at elevated temperatures have shown that NCA electrodes undergo significant power fading. The significant power fading has been largely attributed to the formation of insulating and electrochemically inactive phases at the NCA surface. These include Li2CO3 surface species and a NiO-like rocksalt phase at particle surface due to oxygen loss. The literature of NCA surface and subsurface studies have highlighted the complexity of studying electrodes, with many reactions occurring that may not be inherent to NCA.
Here we report on our studies of the surface and subsurface of NCA electrodes with and without a binder additive (i.e. PVDF) as a function of initial charging and cycling. The chemical composition and transition metal oxidation states were determined from a combination of x-ray photoelectron and absorption spectroscopy techniques. Our results reveal dramatic differences in the surface environments between our NCA electrodes with and without binder. Our results suggest that the PVDF may play a more significant role in degrading the surface of the NCA i.e. oxygen loss, than previously thought. We also report our surface analysis of our extended cycled NCA binder free electrodes. This work was supported as part of NECCES, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001294.
Molybdenum Substituted Vanadyl Phosphate Îµ-VOPO4 with Enhanced Two-Electron Transfer Reversibility and Kinetics for Lithium-Ion Batteries
Authors: Wen Bohua , Wang Qi , Lin Yuh-Chieh , Chernova Natasha , Karki Khim , Chung Youngmin , Omenya Fredrick , Sallis Shawn , Piper Louis F.J. , Ong Shyue Ping , Whittingham M. Stanley 
Published: February 2020

Structural reversibility of multiple electron transfer cathodes is the key challenge for the consequent intercalation process, which can double the energy density of current commercialized lithium-ion batteries. VOPO4 is a promising cathode that can possibly involve two redox transitions of V3+/V4+ and V4+/V5+, while in fact the structure easily loses the reversibility with only ~1.2 lithium inserted1. Here, we report ε-VOPO4 from hydrothermal precursor with 5 % Mo substituted at V site with improved reversible initial capacity to as much as ~250 mAh/g (total ~1.6 Li) and ~80 % retention for up to 20 cycles at C/25. Faster kinetics and lower hysteresis of Mo substituted VOPO4 can be attributed to the smaller and less ordered particles as shown by HRTEM images. X-ray absorption and X-ray photoelectron spectroscopy show the Mo6+ oxidation state with the charge compensated by the corresponding amount of V4+ confirmed by the magnetic analysis. The Mo6+ coordination and charge compensation mechanisms are also confirmed by hybrid density functional theory calculations. This work was supported as part of the NorthEast Center for Chemical Energy Storage (NECCES), and Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0012583.
1. Z. Chen, Q. Chen, L. Chen, R. Zhang, H. Zhou, N. A. Chernova and M. S. Whittingham, J. Electrochem. Soc., 2013, 160, A1777

Figure 1
Designing Polyoxometalate Thin Films on Carbon Nanomaterials for Pseudocapacitive Electrodes
Authors: Genovese Matthew , Foong Yee Wei , Lian Keryn 
Published: February 2020

Multi-Walled Carbon Nanotubes (MWCNTs) modified with mixtures of polyoxometalate (POM) ions were investigated as pseudocapacitive electrodes for electrochemical capacitors. POMs undergo fast reversible multi-electron transfer reactions, and different POM molecules such as PMo12O40
3-
(PMo12) and PW12O40
3- (PW12) demonstrate characteristic electrochemical activity related to their chemical composition. However, we have discovered that when these molecules are combined in aqueous solutions, the resulting mixture shows unique electrochemical properties leading to cyclic voltammograms (CVs) very different from those of the constituent molecules. Further analyses revealed that these POM ions do not just mix physically in aqueous solutions, but instead react spontaneously to form PMo12-xWx mixed addenda chemistries. By simply mixing PMo12 and PW12 in different ratios, a variety of mixed addenda ions, each with unique electrochemical properties, can be easily synthesized.
This control over POM redox behavior afforded by the novel mixed addenda synthesis is used along with layer-by-layer (LbL) deposition to design molecular coatings that demonstrate desired pseudocapacitive characteristics. The best performance was achieved with a coating that superimposed a 3:1 PMo12O40
3−-PW12O40
3− mixed layer on a 1:1 GeMo12O40
4−-SiMo12O40
4− mixed layer, which resulted in an 11X capacitance enhancement over unmodified CNT. This dual layer electrode also demonstrated a close to rectangular CV profile due to the overlapping redox features of the POM combination (Figure 1). In this talk we will discuss the unique electrochemistry of various POM mixtures, the mechanisms of the novel mixed addenda synthesis, and our approach for using these molecules to design high performance composite EC electrodes.

Figure 1