bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three Dimensional Modeling of Dendrite Growth in Rechargeable Lithium Metal Batteries
Authors: Aryanfar Asghar , Brooks Daniel J , Cheng Tao , Merinov Boris V , Goddard William A , Colussi Agustin J , Hoffmann Michael R 
Published: February 2020

One of the most critical issues leading to failure in researchable batteries is the tendency to grow amorphous crystals called dendrites during charge periods. These microstructures cause the internal short circuit between electrodes and lead to possible ignition of organic electrolytes.[1] Lithium batteries, particularly are more prone to form dendrites due to low surface energy of lithium. The tendency for creating more surfaces leads to formation of isolated dendrites known as dead lithium. Particularly rechargeable lithium metal batteries suffer the most from this matter due to dominance of deposition over intercalation on crystalline and compact structure of the metal. [2]
Herein, we present a new three dimensional framework, extended from our previous Coarse Grained method[3], for predicting the intrinsic properties and internal structure of meta-stable lithium dendrites. A sample of dendrite is given in Fig. 1. We have investigated annealing of dendrites in various temperatures, resulting in stable atomic arrangements. (Fig. 2). We will characterize the physical and mechanical properties of acquired morphologies, such as porosity and compressive strength.
1. Armand, M. and J.M. Tarascon, Building better batteries. Nature, 2008. 451(7179): p. 652-657.
2. Li, Z., et al., A review of lithium deposition in lithium-ion and lithium metal secondary batteries. Journal of Power Sources, 2014. 254: p. 168-182.
3. Aryanfar, A., et al., Dynamics of Lithium Dendrite Growth and Inhibition-Pulse Charging Experiments and Monte Carlo Calculations. The Journal of Physical Chemistry Letters, 2014.

Figure 1
Li Vs. Na Batteries - Investigation of the SEI and Conversion Mechanisms of Nanostructured Fe2O3 Composites Electrodes Via Soft X-Ray Photoelectron Spectroscopy
Authors: Philippe Bertrand , Valvo Mario , Lindgren Fredrik , Rensmo Hakan , Edström Kristina 
Published: February 2020

The properties of the SEI layers formed on composite nanostructured iron oxide electrodes upon cycling in Li- and Na-half cells[1] containing analogous electrolytes (i.e. LiClO4, NaClO4) have been investigated by an advanced non-destructive analysis based on Soft X-ray Photoelectron Spectroscopy (PES). Using synchrotron radiation, this approach has enabled probing the corresponding SEI layers at different depths by varying the photon energy hν, in the range of 100-1200 eV. [2,3] This methodology has granted access to a careful study of both the intimate structure and the compositions of these passivating films formed upon initial lithiation/sodiation of the electrode.[4] In this respect, understanding the SEI features without causing any interference or damage during the PES measurement processes has proved crucial to obtain a deeper insight into the specific mechanisms that lead to the formation of such films. The latter have a crucial technological relevance, since they directly affect the electrochemical performances of the active materials undergoing a particular electrochemical reaction, e.g. in a Li or Na cell. The results of this study will be presented highlighting the differences and the similarities that exist between these two electrochemical systems. In particular, it will be shown that such step-by-step analysis conducted on various electrodes left in a defined state of charge upon reduction (i.e. Li+ or Na+ uptake) and oxidation (i.e. Li+ or Na+ release) has revealed interesting differences for the structure of their respective SEI layers, as well as different covering properties in both cases. Finally, the mechanisms of nanostructured iron oxide upon reaction with Li+ and Na+ ions will be discussed. Additional information will be provided on the conversion reaction occurring at low potentials vs. Li+/Li and Na+/Na when the thickness of the grown SEI layer was not critical and has allowed probing the underlying active material, its oxidation state and surrounding chemical environment.

References

M. Valvo, F. Lindgren, U. Lafont, F. Björefors, K. Edström, J. Power Sources 245 (2014) 967.

B. Philippe, R. Dedryvère, J. Allouche, F. Lindgren, M. Gorgoi, H. Rensmo, D. Gonbeau, K. Edström, Chem. Mater. 24 (2012) 1107.

S. Malmgren, K. Ciosek, M. Hahlin, T. Gustafsson, M. Gorgoi, H. Rensmo, K. Edström, Electroch. Acta 97 (2013) 23.

B. Philippe, M. Valvo, F. Lindgren, H. Rensmo, K. Edström, Chem. Mater., 26 (2014) 5028
Electrochemical Stiffness Measurements of Graphite Anodes for Li-Ion Batterie
Authors: Tavassol Hadi , Jones Elizabeth M. C. , Sottos Nancy R. , Gewirth Andrew A. 
Published: February 2020

We report on measurement of the electrochemical stiffness of the graphite anodes during Li exchange in Li-ion batteries. Graphite is the most common anode material used in commercial Li-ion batteries. During lithiation and delithiation of the graphite anodes, Li-graphite intercalation compounds with varying Li content (Li
x
C6, 0 ≤
x ≤ 1), and graphene layer spacing are formed. Hence, Li intercalation and de-intercalation causes considerable mechanical changes in the whole electrode.
We use curvature bending measurements to monitor stress changes in a thin graphite electrode constrained on an inert, rigid substrate. In a separate experiment, we employ digital image correlation to track strain changes in a free-standing, unconstrained graphite electrode. Combining in-situstress and strain analyses enables us to extract the potential-dependent stiffness of the graphite anodes during lithiation-delithiation cycles.
As expected, graphite anodes develop compressive stress during lithiation (ca. 10 MPa). The compressive stress is removed during delithiation. Strain response also corresponds with the Li deposition and removal, as graphite anodes expand during lithiation (ca. 1.5 % linear strain) and contract over delithiation. The electrode exhibits an initially stiff response at high potentials and low lithium contents, and then gradually softens during early formation of dilute stage I of the Li-graphite intercalation compound. As the potential is lowered and lithium content increases, several oscillations in the stiffness are observed, which correspond with the phase transitions during different stages of graphite lithiation. The evolution of stress, strain and stiffness data provides quantitative information on the coupled electro-chemo-mechanical response of the battery electrodes and insight on material strategies to increase battery reliability.
Interfacial Study of the Role of SiO2 on Si Anodes Using Electrochemical Quartz Crystal Microbalance
Authors: Hubaud Aude A. , Schroeder David J. , Yang Zhenzhen , Dogan Fulya , Vaughey John T. 
Published: February 2020

One of the challenges associated with silicon as an anode material for Li-ion batteries is the
formation of an unstable solid-electrolyte interphase which, forms continuously while consuming
lithium and other components; and consequently contributes to irreversible capacity. To elucidate
some of the details of the formation and subsequent dissolution of species that form during lithiation of
silicon anodes we have produced thin film silicon electrodes with and without an oxide layer and
analyzed these during lithiation and delithiation using an electrochemical quartz microbalance with in-
situ dissipation (EQCM-D). Measurements were conducted both in EC:EMC and EC:DEC:FEC based
electrolytes. Mass loss during lithiation was observed in both solvents systems when an oxide layer
was present on the electrode and this was found to be associated with Li2O dissolution using solution
and solid state NMR.
Semi-Empirical Study on Lithium Diffusion into Electrode Materials for Lithium Batteries
Authors: Kwon So-Yeon , Shin Heon-Cheol 
Published: February 2020

The decrease in power density of lithium batteries at low temperature is one of main obstacles for their widespread use in transportation systems. In spite of many works on low temperature performance, the key factors affecting the temperature-dependent power degradation still remain unclarified in many battery systems. Successful analysis of power performance is dependent critically on how to estimate accurately the resistances of the electrode reactions such as interfacial charge transfer and solid state lithium diffusion.
In particular, lithium diffusion is hard to be analyzed when the electrode materials undergo a phase transition during charge-discharge process. As a matter of fact, many researchers have still analyzed lithium transport phenomena by using typical relations derived on the assumption of atom diffusion into single phase. For instance, they carried out typical potentiostatic intermittent titration technique, cyclic/linear sweep voltammetry, or electrochemical impedance spectroscopy and then estimated the solid state diffusion coefficient from Cottrell, Randle-Sevcik, or Warburg equation, respectively. However, it is quite unlikely that such a method might give a reliable value of diffusion coefficient because the phase transition significantly influences the electrochemical response. Although a few works investigated lithium transport by considering the coexistence of two phases, the analysis of lithium transport kinetics through biphasic materials is still a great challenge.
In this work, a viable way to analyze lithium transport phenomena through the materials experiencing phase transition is suggested. The method includes the experimental determination of the charge amount transferred during the phase transition and the subsequent numerical estimation of apparent lithium diffusion coefficient for the same amount of charge in a hypothetic single phase.
The apparent diffusion coefficients of transition metal oxides undergoing phase transformation during charge-discharge process were determined at different temperatures to obtain the activation energy for lithium diffusion. The estimated values of diffusivity and activation energy are compared with those in the literatures and their validity is critically discussed. Furthermore, from the comparison with the activation energies for interfacial reactions estimated from the electrochemical impedance spectroscopy, main factors affecting power performance, esp. low temperature power decline of transition metal oxides are suggested.
Electrochemical Approach for the Synthesis of Carbon-Metal Fluoride Nanocomposites for Lithium Batteries
Authors: Munnangi Anji Reddy , Fichtner Maximilian 
Published: February 2020

Metal fluorides are assuming importance as electrode materials for rechargeable lithium batteries as they possess high gravimetric and volumetric energy densities and are thermally stable. However, metal fluorides are insulators, exhibits sluggish kinetics and undergo large volume changes during electrochemical discharge and charge. Mechanochemical synthesis of carbon metal fluoride nanocomposites (CMFNCs) was suggested to address these problems [1]. Recently we reported a facile chemical approach for the synthesis of C-FeF2 nanocomposites by reductive intercalation method using CFx as a precursor [2]. The C-FeF2 nanocomposites obtained by this method showed high reversible lithium storage due to the incorporation of nanocrystalline FeF2 in electronically well-connected graphitic domains.
Here we propose and demonstrate a rather general approach for the synthesis of CMFNCs at room temperature using CFx as precursor. CFx is known as a cathode material for lithium primary batteries. During discharge process lithium reacts with CFx and form C+LiF. In other words this is an electrochemical method for the synthesis of C-LiF nanocomposites. Fundamentally, it is possible to extend this approach for the synthesis of other C-MFx nanocomposites if the reaction of metal with CFx is thermodynamically feasible provided with suitable metal ion transporting electrolyte. Figure 1 show the discharge curve obtained with CFx cathode and Fe metal foil as anode and Fe2+ transporting liquid electrolyte. During the discharge process the Fe2+ is released into the electrolyte at anode and the CFx is reduced at cathode to form C-FeF2. The discharged electrode was analyzed by XRD and formation of FeF2 is confirmed. The as synthesized C-FeF2 nanocomposites showed excellent reversible lithium storage properties. Further, we have succeeded in the synthesis of various C-MFx nanocomposites by the proposed electrochemical approach.

References:

F. Badway, N. Pereira, F. Cosandey, G. G. Amatucci, J. Electrochem. Soc. 2003, 150, A1209.

M. Anji Reddy, B. Breitung, V.S.K. Chakravadhanula, C. Wall, M. Engel, C. Kübel, A. K. Powell, H. Hahn and M. Fichtner, Adv. Energy Mater.
2013, 3(3), 308.

Figure 1
Pore Collapse and Regrowth in Lithiated Si Anodes Determined By in-Operando Neutron Reflectometry
Authors: Dura Joseph A. , DeCaluwe Steven C , Dhar Bal-Mukund , Huang Liwei , Yang Kaikun , Owejan Jon , Zhao Yiping , Talin A. Alec , Wang Howard 
Published: February 2020

Structure and composition changes of an 11 nm thick amorphous silicon (a-Si) thin film anode, capped with a 4 nm thick alumina film are measured, in operando, by neutron reflectometry (NR) and electrochemical impedance spectroscopy in a lithium half-cell. NR data are analyzed to quantify the a-Si thickness and composition at various states of charge over six cycles. The a-Si anode expands and contracts upon lithiation and delithiation, respectively, while maintaining its integrity and low interfacial roughness (£1.6 nm) throughout the cycling. The apparently non-linear expansion of the a-Si layer volume versus lithium content agrees with findings from previous thin-film a-Si anode studies. However, a proposed pore collapse and regrowth (PCRG) mechanism explains apparently minimal volume expansion of the film as a whole for low Li content in terms of linear expansion of the solid domains within the initially porous amorphous Si. In the PCRG model, the porosity is first consumed by the expansion of solid domains upon lithiation, after which the film as a whole expands linearly with Li content with a proportionality factor found to be 8.48 cm3/mol-Li, which is similar to that of crystalline Si. Porosity is reversibly reestablished at 5-28% upon delithiation. Data also show that the alumina protective layer on the a-Si film functions as an effective artificial solid electrolyte interphase (SEI), which maintains its structural integrity, low interfacial roughness, and a relatively small transport resistance. No additional spontaneously-formed SEI is observed in this study.
Electrochemical Impedance Spectroscopy Study of Failure of Commercial LiFePO4 Cells Under Overcharge Conditions
Authors: Liu Yadong , Li Zhe-Fei , Liu Qi , Xie Jian 
Published: February 2020

One of the major problems remaining to be solved for the lithium-ion batteries (LIB) is the safety issue, especially, the failure of LIB cells under extreme conditions (overcharge, over-discharge, high temperature, low temperature, etc.). A Li-ion cell experiences overcharge/over-discharge when it is practically used in a battery pack for electric vehicles (EVs) hybrid electric vehicles (HEVs) because the capacity variation of different cells in the pack and difficulty to control the state of charge (SOC) of each single LIB cell/module in a battery pack exactly the same1,2.
Electrochemical impedance spectroscopy (EIS) was employed to investigate the failure phenomena of commercial 18650 Li-ion batteries at different states of charge (SOCs) under overcharge conditions. The change of voltage profile, discharge capacity, charge acceptance, temperature, and impedance were characterized and analyzed during overcharge cycles. During overcharge cycling, the charge acceptance, charging efficiency, cell temperature, and cycle life change dramatically with cycle numbers. The EIS results at different cycle numbers were characterized and analyzed (Fig. 1). Further study of the EIS for LiFePO4 cells at different SOCs (0, 50, and 100%) revealed that these de-convoluted parameters show similar patterns of changing with cycle numbers; and some of them, the Ohmic resistance, resistance of SEI, charge transfer resistance and Warburg coefficient, are associated with failure and can be used as indicators of incoming failures. EIS results from both the two-electrode system and the three-electrode system were compared, demonstrating that the direct application of EIS to the practical 18650 LiFePO4 cells can lead to results as reliable as those obtained from the three-electrode system. The three-electrode result showed that impedance of the cathode is much higher than the anode, and both the impedance of anode and cathode increase significantly when the cell is failed caused by overcharge, which indicates that both the SEI on the anode surface and CEI on the surface of the cathode are changed a lot during overcharge process (Fig. 2). In short, the EIS can be an effective tool to monitor the state of health (SOH) of the battery or pack and issue an early warning signal before the failure happens.

Reference

1. P. G. Balakrishnan, R. Ramesh and T. Prem Kumar, Journal of Power Sources, 155, 401 (2006).
2. J. Chen, C. Buhrmester and J. R. Dahn, Electrochemical and Solid-State Letters, 8, A59 (2005).

Figure 1
Dual-Function Air Cathode for Metal-Air Batteries: Integrating Oxygen Reduction Catalysis with Pulse-Power Capability
Authors: Rolison Debra R. , Long Jeffrey W. , Chervin Christopher N. , Kucko Nathan W. , Nelson Eric S. 
Published: February 2020

The air cathode in a metal–air battery is the lung of the energy-storage device—with power output limited by the transport of gas-phase molecular oxygen into the structure of the cathode, transport of dissolved molecular oxygen across the electrolyte-wetted electrode surface, and the rate at which that surface catalyzes electroreduction of O2. Too much electrolyte within the electrode structure confers pneumonia and an inability to sustain even moderate loads. Zinc–air at 400 W h kg–1 is an established battery technology with an energy density three times that of Li-ion, but its broader applicability is hampered by low specific power and limited rechargeability. We have solved the inability to recharge zinc without dendrite formation [1,2], but low specific power lies with performance limitations at the air cathode. We have solved this problem by departing from customary air-cathode fabrication approaches. We adopt a “multifunctional nanoarchitecture” design in which the solid and void components in a macroscale electrode structure are controlled and modified on the nanoscale to provide balanced pathways for electronic and ionic conductivity, facile permeation/transport of electrolyte and gas-phase O2 through a 3D interconnected void volume, and optimal electrocatalytic turnover for O2 reduction. We achieve this desirable blend of functionality by fabricating carbon-fiber paper filled with a pyrolytic carbon nanofoam. The nanofoam papers are produced in x–y scalable forms with variable electrode thickness (50–300 μm), tunable pore sizes (10–1000 nm), high specific surface areas (>400 m2 g–1), and a highly conductive carbon framework (>15 S cm–1) [3]. This electrode design not only improves performance for typical air-cathode operation via efficient O2 reduction catalysis at 10 nm–thick birnessite manganese dioxide (MnOx) “painted” onto the walls of the carbon nanofoam but also imparts new function: air-independent pulse power as derived from the pseudocapacitance of the MnOx coating. Manganese (III) sites in the post-pulsed oxide spontaneously recharge to Mn(IV) in the presence of oxygen—making the oxide ready and available for subsequent pulse-power discharge. The application of our “dual function” air cathode to alkaline Zn–air cells imparts pulse-power capability (>1 F cm–2for >10 s) otherwise absent in a battery that already provides the advantages of high energy density, low cost, and safety of operation.
This work was funded by the Office of Naval Research.
[1] D.R. Rolison, J.W. Long, J.F. Parker, U.S. Patent Application #20140147757.
[2] J.F. Parker, C.N. Chervin, E.S. Nelson, J.W. Long, D.R. Rolison, Energy Environ. Sci.
7(2014) 1117–1124.
[3] J.C. Lytle, J.M. Wallace, M.B. Sassin, A.J. Barrow, J.W. Long, J.L. Dysart, D.R. Rolison, Energy Environ. Sci.
4 (2011) 1913.
Mass Transfer Overpotentials in Dispersed Pt/C and De-Alloyed PtNi/C Polymer Electrolyte Fuel Cell Cathodes
Authors: Wang Xiaohua , Peng Jui-Kun , Ahluwalia Rajesh , Myers Deborah J , Yang Zhiwei 
Published: February 2020

While oxygen reduction reaction (ORR) mass activities, measured at high voltages, that exceed the DOE 2020 targets (>0.44 A/mg PGM @ 900 mV) have been demonstrated for carbon-supported Pt alloys and core-shell nanoparticle catalysts [1], the full performance of promising catalysts such as these have yet to be achieved in MEAs when operating at high current densities (> 1 A/cm2in air) [2]. To reach a high power output per gram PGM (8 kW/g, DOE 2017 Target), requires high utilization of the electrocatalytic sites as well as low oxygen transport resistance in the cathode catalyst layers. To determine the electrode properties limiting the performance of the de-alloyed PtNi/C based cathode, a standard Pt/C catalyst was annealed to grow the mean particle size to one that is comparable to that of d-PtNi/C catalysts (approximately 5.5 nm). Catalyst-coated membranes with cathodes comprised of a standard Pt/C, annealed Pt/C, and d-PtNi/C at loadings of 0.1 mg Pt/cm² with various ionomer to carbon ratios were fabricated, tested, and characterized under a variety of test conditions [3]. Modeling of these polarization curves to determine the sources of the observed voltage losses (i.e., purely resistive, kinetic, or mass transport) showed that mass transport losses are higher with d-PtNi/C and annealed Pt/C-based cathodes than standard non-annealed Pt/C, while the kinetic losses are lower for d-PtNi/C and standard non-annealed Pt/C as compared to the annealed Pt/C due to higher area-specific activity and higher enhanced surface area, respectively.

Acknowledgements

This work is part of a collaborative project with Johnson Matthey Fuel Cells, United Technologies Research Center, the University of Texas-Austin, and Indiana University-Purdue University of Indianapolis. The authors wish to thank the U.S. Department of Energy’s Fuel Cell Technologies Office for support. Argonne National Laboratory is managed for the U.S Department of Energy by the University of Chicago Argonne, LLC, under contract DE-AC-02-06CH11357.

References

Han, B.; Carlton, C.E.; Kongkanand, A.; Kukreja, R.S.; Theobald, B.R.; Gan, L.; O'Malley, R.; Strasser, P.; Wagner, F.T.; Shao-Horn, Y.; Energy Environ. Sci., DOI: 10.1039/c4ee02144d.

Debe, M.K.; Steinbach, A.J.; Hendricks, S.M.; Kurkowski, M.J.; Vernstrom, G.D.; Atanasoski, R.T.; Hester, A.E.; Haug, A.T.; Lewinski, K.A.; Deppe, S.K.; “Advanced Cathode Catalysts and Supports for PEM Fuel Cells”, DOE Hydrogen Program Annual Report 2012;

Myers, D.; Kariuki, N.; Ahluwalia R.; Wang X.; Peng J.-K.; “Rationally Designed Catalyst Layers for PEMFC Performance Optimization”, DOE Hydrogen Program Annual Report 2014;