bluuebunny/crossref_metadata_2025_split huggingface dataset:
Understanding the Electrochemical Performance of Rechargeable LiFePO4/Li4Ti5O12 Design Using Mathematical Model
Authors: Ma Miaomiao , Hendricks Christopher E. , Mansour Azzam N. , Ko Jonathan K. , Waller Gordon H. , Fuentevilla Daphne A. 
Published: February 2020

A lithium-ion cell utilizing LiFePO4/Li4Ti5O12 electrodes has attracted interest as a result of its safe and fast charging performance. A commercially available software package, Battery Design Studio, was utilized to simulate the electrochemical performance of an LFP/LTO cell at different rates and temperatures to understand the charge transfer and diffusion processes of this electrode pairing. Open circuit potential curves for each electrode were obtained using galvanostatic intermittent titration technique (GITT) as a base for modeling. Simulation of the High Pulse Power Characterization (HPPC) test data on a 26650 cell showed that the pulse discharge was affected by six parameters, including ohmic resistance, capacitance, SEI resistance, electrode conductivity, electrolyte diffusion, and electrode diffusion. These parameters were obtained by comparing the experimental data with the model predictions at various SOC and temperatures to demonstrate their SOC and temperature dependence. Sensitivity of parameters was evaluated within the range of the reference values.
To further evaluate the dependence of these parameters on SOC and temperature, AC impedance measurements were performed on the full cell at different SOC and temperatures during both charge and discharge processes as shown in Figure 1. Analyses of impedance results indicated the charge and discharge processes undergo different charge transfer processes and diffusion in both the electrolyte and solid phase. AC impedance on half-cell coin cells was performed to understand the contribution from each electrode.
Finally, the electrochemical model was utilized to understand the performance limitations and failure mechanisms of the LFP/LTO cell though the current and concentration distributions throughout the electrode thickness.
Figure 1. AC impedance measurement on LFP/LTO 26650 cell at different SOC during charge and discharge processes at room temperature.

Reference:

[1] M. Doyle, T. F. Fuller, and J. Newman, J Electrochem Soc, 140, 1526 (1993).
[2] V. Ramadesigan, P. Northrop, S. De, S. Santhanagopalan, R. Braatz, and V. Subramanian, J Electrochem Soc, 159, R31 (2012).

Acknowledgement:

This work is funded by the Office of Naval Research under award N0001419WX01258.

Figure 1
X-Ray Absorption Spectroscopy of SrTi0.65Fe0.35O3-Δ : Understanding Local Structure Evolution during Crystallization
Authors: Skiba Emily , Ma Qing , Perry Nicola H. 
Published: February 2020

Mixed ionic and electronic conductors (MIECs) serve as active materials and electrodes in a variety of electrochemical energy conversion, storage, processing, and sensing devices. Compared to composites of an ionic conductor and electronic conductor, single phase perovskite-structured MIECs that conduct both oxide ions and electronic species extend the reaction site for surface oxygen exchange beyond the triple phase boundaries and can exhibit high efficiencies. There has been increasing interest in lower temperature processing and application of MIECs. Therefore, there is a significant need to understand the local structure of amorphous and crystallizing MIECs so that structure-property relationships pertaining to electrode function (surface exchange kinetics, conductivity) can be established. To this end, we have studied the model MIEC SrTi0.65Fe0.35O3-d (STF).
To better understand the role of crystallization on local structure evolution of STF films, X-ray absorption spectroscopy (XAS) studies at Argonne National Laboratory’s DND-CAT beamline were carried out on films at various stages of crystallization. Three films were deposited using PLD at several temperatures to control crystallinity: 1) room temperature (amorphous), 2) room temperature and subsequently annealed for 2h at 550 °C (semi-crystalline), and 3) at a substrate temperature of 700 °C (highly crystalline). Our experiments observed the Sr, Fe, and Ti K-edges using XAS to compare the local structure (valence states, coordination environment, and bond lengths) of amorphous, semi-crystalline, and crystalline STF thin films. Our results to date suggest significant differences in the first shell mean bond length and coordination environment of Fe and Ti polyhedra. Although it is widely assumed that the local environment of amorphous and crystalline materials is similar, with the main distinction being in the long-range ordering, our results show that the amorphous samples are significantly undercoordinated relative to their crystalline counterparts. Furthermore, we observe that the Ti-O and Fe-O coordination number increases with increasing crystallinity. However, it appears that even in the fully crystalline samples, there remain tetrahedrally coordinated cation centers with Fe atoms having, across all samples, more oxygen vacancies than Ti atoms within the same film.
Compositional Dependence of Mössbauer Spectra for Mechanically Milled (Fe1-xAlx)2O3
Authors: Nakaishi Hayato , Takai Shigeomi , Yabutsuka Takeshi , Yao Takeshi , Kitao Shinji , Seto Makoto 
Published: February 2020

Introduction

Although α-Fe2O3 is promising anode material of LIB for excellent theoretical capacity as 1007 mAhg-1, it shows the severe cycle deterioration due to conversion reaction during the charge-discharge process. We have considered that the formation of Fe2O3-Al2O3 solid solution allows the Fe ions to react reversibly around the original site in the corundum-type structure. Although both α-Fe2O3 and α-Al2O3 have the corundum-type structure, solid solution ranges are restricted within 10% from the both end components [1]. In recent years, we have successfully obtained the Fe2O3-Al2O3 solid solution for all the compositional range through the mechanochemical synthesis method. It was also found that the obtained solid solution shows good cycle characteristics as an anode material of LIB [2]. Nevertheless, this solid solution has just been newly found and any magnetic property has not been clarified yet. In this study, we have carried out the Mössbauer measurement to discuss the magnetic properties of Fe2O3-Al2O3 solid solution.

Experimental

The solid solutions of (Fe2O3)1-x(Al2O3)x (x = 0, 0.1, 0.25, 0.33, 0.50 and 0.67) were prepared by mechanical alloying method. About 0.5 g of the stoichiometric mixtures of γ-Fe2O3 and γ-Al2O3 were put into a silicon nitride milling vessel with 20 ml in volume accompanied by 10 silicon nitride balls with 10 mm in diameter without any solvent. A planetary ball milling machine has been operated with the rotation speed of 800 rpm for 240 min. Mössbauer measurement was performed on the obtained samples of (Fe1-xAlx)2O3 (x = 0, 0.1, 0.25, 0.33 ,0.50 and 0.67) at room temperature. 57Co was used as a gamma ray source for Mössbauer measurement.

Results and Discussions

Fig. 1 shows the Mössbauer spectra of (Fe1-xAlx)2O3 measured at room temperature for x = 0, 0.1, 0.25, 0.33, 0.5 and 0.67. For the Fe2O3 (x = 0) obtained by milling, the sextet spectrum was observed. This would correspond to weak ferromagnetism appearing from a cant structure, in which the spin of Fe is slightly inclined from 90° to the c-axis direction. This spectrum is essentially similar to the α-Fe2O3 reagent without milling. The Mössbauer spectra gradually changed into doublet with increasing the concentration of aluminum x and the change is almost completed to the x = 0.5. Fourier transform of the EXAFS signal shows that |χ| peak value around 1.5 Å corresponding to Fe-O distance did not vary significantly, while that around 2.5 Å for Fe-Fe distance decrease with x. Dilution of Fe3+ with Al3+ would result in the change in spin interaction, or (Fe1-xAlx)2O3 changes from weak ferromagnetism to the paramagnetic state by reducing spin interaction.

References

[1] A. Muan, C.L. Gee, J. Am. Ceram. Soc., 39 207-214 (1956).
[2] S. Takai, E. Sawada, J. Harada, S. Park, M. Oda, S. Esaki, M. Nishijima, T. Yoshie, T. Yabutsuka, T. Yao, Solid State Ionics, 313 1-6 (2017).

Figure 1
Investigation of Chemical Corrosion and Electrochemical Charge/Discharge Behavior of Preferentially Faceted Zinc Particles for Battery Applications
Authors: Faegh Ehsan , Ng Benjamin , Hayman Dillon , Cook Kaitlyn , Mustain William E. 
Published: February 2020

Zinc-based batteries have been reliable energy storage device in primary batteries for decades due to their intrinsic safety, resulting from the use of aqueous and non-flammable electrolytes, low cost and high natural abundance of Zinc. For many years, Zinc-based electrodes have been sought as a promising option for secondary batteries, though the cycling performance of Zinc electrodes is still limited by shape change and dendrite formation – especially in alkaline electrolytes.
To address this issue, shape-controlled electrolytic Zinc particles were synthesized. Using scanning electron microscopy (SEM), it was observed that these micron-sized Zinc particles possess preferentially-faceted, hexagonal shape, which allowed us to explore the morphological variation of synthesized well-faceted Zinc particles during corrosion and charge/discharge in alkaline media. It was found that both chemical corrosion and electrochemical discharge of single Zinc particle happens from the basal plane in alkaline media and step-edge planes were more corrosion resistant for an individual Zinc particle. X-ray diffraction patterns showed that by heat-treatment of electrodeposited Zinc particles the degree of crystallinity, and thus, the number step-edge planes were increased which resulted in creation of “terraced” Zinc structures. Higher capacities were achieved during discharge using “terraced” Zinc particles. Such highly faceted particles also led to significantly improved cyclability compared to traditional Zinc structures.
Commercial 18650 Lithium-Ion Cells for High-Energy, High-Power, and Radiation Applications
Authors: Krause Frederick C. , Bugga Ratnakumar V , Billings Keith J. , Ruiz John Paul , Brandon Erik J. 
Published: February 2020

Interest in commercial off-the-shelf (COTS) cylindrical lithium-ion cells for NASA missions has increased in recent years due to their increasing performance and demonstrated reliability. There is particular interest in cells in the 18650 format, due to their wide availability from well-established vendors. Multiple commercial products are available, offering greater than 250 Wh∙kg-1 and/or 3 kW∙kg-1 at the cell level. High specific energy has made small cells competitive with heritage large-format prismatic lithium-ion cells for spacecraft power systems; high power capability could offer an alternative to thermal batteries in some applications.
The descent stage of the Europa Lander mission concept was baselined with a combination of a high specific energy lithium primary battery and thermal batteries to provide the required energy content and high-power pulse capability during deorbiting and landing. High specific energy and power lithium-ion cells could fulfill the functions of both of these, while also allowing for cell pre-screening and testing, unlike primary or thermal batteries. In support of this concept and future NASA missions, we have performed extensive evaluation of the components and performance characteristics of a number of COTS 18650 Li-ion cells, including destructive physical analysis, cycle life, rate capability, and ionizing radiation tolerance.
ACKNOWLEDGEMENT

The work described herein was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Support from the Europa Lander Mission concept and the NASA Engineering Safety Commission is gratefully acknowledged. Pre-Decisional Information – For Planning and Discussion Purposes Only.
Tailoring of Liquid Electrolytes for Room-Temperature Fluoride Shuttle Batteries
Authors: Kawasaki Mitsuo , Morigaki Ken-ichi , Kano Gentaro , Minato Taketoshi , Abe Takeshi , Ogumi Zempachi 
Published: February 2020

Fluoride ion shuttle batteries (FSBs), alternatively referred to as fluoride ion batteries (FIBs), are anion-based rechargeable batteries with fluoride (F-) ions as charge transporting and redox active species, and potentially offer a high electrochemical energy storage capability that overwhelms those of the state-of-the-art lithium ion batteries. The theoretical gravitational capacities for some typical metal/fluoride combinations, e.g., Ag/AgF, Cu/CuF2, Bi/BiF3, and Al/AlF3, amount to 249, 844, 385, and 2980 mAh/g, respectively.
Nevertheless, despite some considerable efforts in the past decade or so, FSBs are still far from practical, because of a number of technical limitations to overcome no matter which type of FSB, all-solid type or liquid type, is of major interest. In particular, liquid-electrolyte based FSBs suitable for room-temperature cell operation require high-quality fluoride ion transporting electrolytes ensuring both high enough reactivity of the fluoride ions with the active material of interest and sufficient electrochemical stability of the electrolyte as a whole. Unfortunately, normally none of alkali fluorides are soluble in whatever high boiling battery-oriented organic solvents. One way to solve this problem has been to use organic fluoride salts. Another sophisticated way out has been to utilize a so-called anion acceptor (AA) that makes alkali fluorides substantially soluble even in low polarity solvents such as the glyme series. AA can also play another important role to facilitate the dissolution and re-deposition of the active materials into and from the electrolyte, which are unique pathways available in liquid-electrolyte based FSBs. However, the overall cell performances so far reported in the literature are still limited in capacity and cyclability.
In this paper, we introduce lactone-based liquid electrolytes tailored for room-temperature FSBs, where either CsF or KF is dissociated without the help of any special addenda to offer strong electrolytes. Although the maximum fluoride ion concentration achieved by this method is around 0.05 M, it affords the ionic conductivity more than 0.5 mS/cm and the fluoride ions transported between the cathode and anode exhibit high reactivity with various metals to sustain reversible redox reactions to and from their fluoride counterparts. We have also achieved some successful battery operations using practical polymer-composite electrodes. Together with a superior cyclability, the thus tailored liquid fluoride electrolytes offer the opportunity to make a big step forward to establish the room-temperature rechargeable FSBs.
Acknowledgement.
This work was supported by the Research and Development Initiative for Scientific Innovation of New Generation Battery 2 (RISING2), financially supported by New Energy and Industrial Technology Development Organization (NEDO).
Crosslinked Quaternized Poly(arylene ether benzonitrile) Membranes for Vanadium Redox Flow Batteries
Authors: Park Eun Joo , Maurya Sandip , Kim Yu Seung , Mukundan Rangachary 
Published: February 2020

Development of membrane separators is important to decrease cross-over and enhance efficiency and durability of non-aqueous redox flow batteries. Desired properties of the membranes for the application include (a) selective ion permeability, (b) high conductivity and (c) good chemical and mechanical stability in operating conditions of redox flow batteries. Our approach to satisfy these criteria is synthesizing cation-functionalized nitrile-containing polyaromatics, poly(arylene ether benzonitrile)s, for membrane separators. While these membranes exhibited good performances in an aqueous vanadium redox flow battery (VRFB) system, in non-aqueous systems where acetonitrile is used as electrolytes, the membranes could not be utilized due to their limited mechanical strength. To endure the harsh operating condition of non-aqueous VRFB, we developed crosslinked quaternized poly(arylene ether benzonitrile)s. A series of high molecular weight polymers with tertiary amine groups were synthesized via aromatic nucleophilic substitution polycondensation followed by the simultaneous quaternization and crosslinking reactions. In this presentation we will discuss the membrane properties and the electrochemical performance of these membranes in terms of cycling efficiencies, vanadium permeation and membrane durability. The applicability of crosslinked quaternized poly(arylene ether benzonitrile) membranes in non-aqueous VRFB systems will be summarized.
Acknowledgement
This work is fully supported by Laboratory Directed Research & Development, Los Alamos National Laboratory.
The submission of the manuscript is approved by LANL (LA-UR-19-23557)
Controlling Electrochemical Lithium Deposition and Sulfur Reduction Mechanism through Liquid Electrolytes
Authors: Lin Tzu-Yun , Wang Chun-Yao , Wu Heng-Liang 
Published: February 2020

Lithium metal anode has been regarded as the "Holy Grail" of next-generation battery technologies. In order to stabilize the electrodeposited Li metal for safe and high energy batteries, highly concentrated electrolytes (solvate electrolytes) have been proposed to suppress the formation of Li dendritic structure and polysulfide dissolution in lithium-sulfur (Li-S) batteries. (1-5) In this talk, we use in situ transmission X-ray microscopy (TXM) to study the effect of solvate electrolyte on Li plating/stripping process. In situ TXM images show that electrodeposited Li particles with uniform density are formed in solvate electrolyte during initial plating process. The effect of solvate electrolyte on the mechanism of Li growth is studied in detail. Additionally, in situ spectroscopy including Raman and X-ray spectroscopy (X-ray diffraction and X-ray absorption spectroscopy) are used to investigate sulfur reaction mechanism and the interaction between polysulfide and solvate electrolyte. We found that the sulfur species formed in the solvate electrolyte are different from the sulfur species formed in conventional DOL/DME electrolyte. These results suggest that solvate electrolyte changes both polysulfide solubility and sulfur reaction mechanism. We next propose different solvate electrolytes with low polysulfide solubility and high stability toward Li metal to enhance the capacity retention of Li-S batteries.
References:
[1] L. Suo et al., Nat. Commun. 2013, 4, 1481.
[2] K. Dokko et al., J. Electrochem. Soc. 2013, 160, A1304.
[3] M. Cuisinier et al., Energy Environ. Sci., 2014, 7, 2697.
[4] Y. Yamada et al., J. Electrochem. Soc. 2015, 162 (14), A2406.
[5] L. Cheng et al., ACS Energy Lett. 2016, 1, 503.
Lithium Air Batteries; Challenges and Opportunities
Authors: Salehi-Khojin Amin 
Published: February 2020

Metal-air batteries are greatly considered as an advanced solution for future energy requirements due to their remarkably high-energy density. For instance, the theoretical energy density of Li-air batteries (3500 Wh/kg) is about one order of magnitude higher than that of commonly used Li-ion batteries (~400 Wh/kg). In terms of cruising-speed range on passenger cars, the performance of Li-air batteries is comparable to that of internal combustion engines. Thus far, the research on the Li-air battery has been limited to the short life study of lithium oxygen (Li-O2) batteries where the O2, as the oxidant in Li–air cells, needs to be extracted from air to eliminate the side reactions of N2, CO2 and water with lithium or cell components. Hence although oxygen is an abundant and freely available element, its use will require on-site purification, which is energetically expensive and reduce the energy density of practical cells.
In this presentation, I will overview our recently developed Li-air battery system that operates with the actual air components (N2, O2, CO2 and H2O) with a superior cycle life and energy efficiency that can operate up to 700 continuous cycles with the capacity of 500 mAh/g [1]. This Li-air battery benefits from a novel protected Li-anode, an air cathode based on MoS2 catalyst and a mixture electrolyte including DMSO and EMIM-BF4 ionic liquid. Various characterizations including differential electrochemical mass spectroscopy (DEMS), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy on the cathode reveal that the only discharge product in our system is lithium peroxide (Li2O2) with no evidence of side products such as lithium hydroxide (LiOH) and lithium carbonate (Li2CO3). Nuclear magnetic resonance (NMR) results also show the stability of the electrolyte. Density functional theory calculations suggest that the combination of MoS2 cathode and ionic liquid in the electrolyte provides a kinetically favorable system for Li2O2 formation. The study of this Li-air system is a key step toward the development of next generation lithium batteries with higher energy density and cycle life for transportation and grid scale applications.
[1] A. Salehi-Khojin et al., A lithium–oxygen battery with a long cycle life in an air-like atmosphere, Nature, 555 (7697), 502, 2018.
A Novel Eutectic Aluminum-Silicon Alloy Doped Li7La3Zr2O12 Garnet-Type Solid Electrolytes for Solid State Lithium Ion Batteries
Authors: Anand Rohit , Pathak Anil Daliprasad , Sahu Kisor Kumar 
Published: February 2020

Lithium ion batteries are considered as a promising candidate for electric vehicles and other similar demanding applications. Electrolyte is one of the main components of a rechargeable battery and safety of a battery largely depends on it. Various types of liquid electrolytes were developed over time to enhance the performance of the battery. However, liquid electrolytes promote the growth and formation of lithium dendrites, which cause short circuit in the battery which eventually leads to fire hazard. Solid state electrolyte was found to be a better alternative, because it suppresses the growth and formation of the lithium dendrites between the electrodes. Garnet-type Li7La3Zr2O12 (LLZO) has been considered as a promising candidate for next-generation solid-state electrolyte in lithium batteries because it possesses high ionic conductivity, wider electrochemical and thermal stability window.
This is the first report of doping LLZO by eutectic Al-Si alloy. Al-Si alloy is added because Al is considered as a cubic phase stabilizer and Si helps in modifying the path of lithium ions in LLZO. Further, lithium based solid state batteries are fabricated by using lithium foil anode, LLZO based electrolyte and LiFePO4 cathode material. The doped Ai-Si LLZO solid electrolyte showed better electrochemical performance over the bare LLZO solid electrolyte. Thus, the Al-Si doped LLZO could be a candidate material for solid electrolyte for next generation all solid state lithium batteries.