bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elucidating the Requirements for Reversible Magnesium Electrodeposition and Dissolution
Authors: Barile Christopher J. , Barile Elizabeth C. , Spatney Russel , Zavadil Kevin R , Nuzzo Ralph G. , Gewirth Andrew A. 
Published: February 2020

We compare the electrochemistry of Mg deposition and stripping from three Mg-battery electrolytes: EtMgBr, Mg(AlCl2EtBu)2, and MgCl2-AlCl3. These electrolytes represent three generations of progress in Mg-battery development, and include a simple Grignard reagent, an organohaloaluminate, and an all inorganic system, respectively. Our electrochemical measurements coupled with surface and bulk analytical techniques elucidate the requirements for reversible Mg deposition and definitively establish that voltammetric cycling of the electrolyte significantly alters their composition and performance.
In the cases of EtMgBr and Mg(AlCl2EtBu)2, electrochemical quartz crystal microbalance measurements demonstrate that mass is gained and lost from the electrode with relatively high efficiency. However, the charge passed during stripping is consistently less than that passed during deposition, resulting in chronoamperometric charge efficiencies between 80-100% for EtMgBr and 50-70% for Mg(AlCl2EtBu)2. SEM-EDS analysis of electrode surfaces demonstrates irreversible Mg deposition and stripping. GC-MS and NMR analysis of electrolytes reveal decomposition of the solvent-electrolyte system.
For the all inorganic system containing MgCl2-AlCl3 in THF, elemental analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy (SEM-EDS) results demonstrate that irreversible Mg and Al deposits form during early cycles. Electrospray ionization-mass spectrometry (ESI-MS) data show that inhibitory oligomers develop in THF-based solutions. These oligomers form via the well-established mechanism of a cationic ring-opening polymerization of THF during the initial synthesis of the MgCl2-AlCl3 electrolyte and under resting conditions. In contrast, solutions containing MgCl2-AlCl3 in 1,2-dimethoxyethane (DME), an acyclic solvent, do not evolve as dramatically at open circuit potential. From these results, we propose a mechanism describing how the conditioning process of MgCl2-AlCl3 in THF improves its performance by both tuning the Mg:Al stoichiometry and eliminating oligomers. We also explore the role that other solvents and metal chlorides play in the properties of inorganic Mg-battery electrolytes.
Direct Observation of Magnesium Ion Intercalation into a Spinel-Structured Î»-Manganese Oxide at the Multi Length Scale
Authors: Kim Chunjoong , Phillips Patrick J , Yi Tanghong , Key Baris , Key Baris , Yu Young-Sang , Klie Robert F , Cabana Jordi 
Published: February 2020

The growing market of electric vehicles and grid storage requires the current battery technology to be further advanced. However, LIBs, the best energy storage system based on redox reactions, are intrinsically limited in their charge storage capacity by structural and/or electronic factors. Multivalent ion storage systems are attractive among the alternative systems because, while they closely resemble systems using Li-ion, they can store more charge per mol of intercalated species. In particular, Mg-ion batteries are of great interest to surpass the current performance barriers of Li-ion technology. There is only one proven working positive electrode material, Chevrel phase, for Mg ion battery at a relatively low working voltage window.1, 2 When searching for high voltage Mg-intercalation positive electrodes, most previous studies of the possible electrochemistry of oxide compounds Mg2+ electrolytes have provided little information on the reaction mechanisms leading to the electrochemical data.3 In this work, direct evidence of the reversible intercalation of Mg2+ into a spinel host was obtained. The structural changes observed after intercalation/deintercalation into the cubic spinel structure, λ-MnO2, and from tetragonal Mg
x
Mn3-x
O4 nanoparticles will be discussed. Experimental observations by XRD, XAS, STEM-EDX, PDF and NMR were used to provide a robust understanding of the electrochemical reactions (see representative STEM-EDX in Figure 1). The results confirm that spinel oxides are a potential cathode material for Mg batteries. They point at needs in the understanding of the mechanisms involved in multivalent ion storage, as well as the most efficient ways to characterize these reactions.
ADDIN EN.REFLIST 1. D. Aurbach, Z. Lu, A. Schechter, Y. Gofer, H. Gizbar, R. Turgeman, Y. Cohen, M. Moshkovich, and E. Levi, Nature,
407 (6805), 724-727 (2000).
2. H. D. Yoo, I. Shterenberg, Y. Gofer, G. Gershinsky, N. Pour, and D. Aurbach, Energ Environ Sci,
6 (8), 2265-2279 (2013).
3. C. Yuan, Y. Zhang, Y. Pan, X. Liu, G. Wang, and D. Cao, Electrochimica Acta,
116 (0), 404-412 (2014).

Figure 1
Electrolyte Additives for Reducing the Irreversible Capacity Loss, Impedance and Polarization of a Doped LiCoPO4 Cathode
Authors: Allen Joshua L. , Allen Jan L. , Delp Samuel A. , Jow T. Richard 
Published: February 2020

High voltage cathode materials show promise for improving the energy density of the state-of-the-art lithium ion battery. One notable cathode material that displays a discharge voltage of ~4.8V, and has the potential to improve the specific energy to ~802Wh/kg, is the olivine-structured LiCoPO4. One significant issue, however, that has plagued LiCoPO4-based systems is the irreversible electrolyte decomposition that occurs at higher voltages. The electrolyte decomposition is further perpetuated by the requirement of a constant voltage charging step (trickle charge) that is necessary due to a lower electronic conductivity of the material and increasing interfacial impedance from the unstable electrolyte.
We have previously demonstrated that Fe-doped LiCoPO4 performs significantly better than neat LiCoPO4 by stabilizing the cathode structure and improving the electronic conductivity of the material (1). These structural changes, however, do not solve the problem of perpetual electrolyte decomposition that leads to polarization and loss of cycleable lithium.
In order to promote a low resistance passivation layer that prevents electrolyte decomposition, many researchers have incorporated electrolyte additives (2-3). We previously demonstrated that using electrolyte additives improves the performance of doped-LiCoPO4 half cells by forming a protective passivation layer on the cathode (4). The cathode half-cell performance can be somewhat misleading, however, because it does not take into consideration the loss of cycleable lithium due to irreversible redox reactions on the electrodes.
The present study serves as a next-step for demonstrating the viability of our doped-LiCoPO4 cathode for the production of high specific energy Li-ion batteries. Full coin cells were fabricated and tested, including a next-generation LiCoPO4-doped cathode (developed by ARL) and a standard graphite anode. Various electrolyte additives were examined with the new cathode to minimize the first cycle irreversible capacity loss, reduce the interfacial impedance, and promote a long cycle life. These additives include tris(hexafluoro-iso­-propyl)phosphate (HFiP), lithium difluoro(oxalato)borate (LiDFOB), lithium bis(oxalato)borate (LiBOB), fluoroethylene carbonate (FEC), trimethylboroxine (TMB), and other ARL-proprietary additives. These additives significantly improved the performance when compared to the baseline electrolyte.

ACKNOWLEDGEMENT

The authors wish to express their gratitude to the DOE ABR program for partial financial support.

REFERENCES

J.L. Allen, T.R. Jow and J. Wolfenstine, J. Power Sources,
196, 8656 (2011).

R. Sharabi, E. Markevich, K. Fridman, G. Gershinsky, G. Salitra, D. Aurbach, G. Semrau, M.A. Schmidt, N. Schall and C. Bruenig, Electrochem. Commun., 28, 20 (2013).

M. Hu, J. Wei, L. Xing and Z. Zhou, J. Appl. Electrochem., 42, 291 (2012).

J.L Allen, J.L. Allen, S.A. Delp, T.R. Jow, ECS Trans.
27, 63-68 (2014)
Invesitgation of the Gas Generation in Lithium Titanate Anode Based Lithium Ion Batteries
Authors: Fell Christopher Ryan , Sun Liyuan , Hallac Peter B , Metz Bernhard , Sisk Brian C 
Published: February 2020

Lithium ion batteries containing lithium titanate (LTO), Li4Ti5O12 are promising energy storage systems for their high rate capabilities, safety, and long cycle-life. However, gas generation and associated swelling, which can be observed under high-temperature operation, present a challenge to the large-scale application of lithium ion batteries made from LTO anodes. Research has suggested various causes for gas generation, including residual moisture in the electrodes and electrolyte [1] and catalysis involving the Ti3+/Ti4+ redox couple combined with water electrolysis.[2,3] It is important to understand the source of gas generation so as to avoid it with proper manufacturing conditions, such as tight control over moisture levels. However, at this time the mechanism of gas evolution from LTO anode based lithium ion battery systems is not well established.
Here we analyzed LTO cells following high temperature (80ºC) calendar life storage at 100% SOC. We explored the relationship between volume expansion and impedance increase following high temperature storage. The results in Figure 1 indicate that with increasing gas volume expansion, the performance of the cells degrades. The gas species and quantities resulting from the cell volume expansion were collected and analyzed post-mortem using quadrupole mass spectrometry (MS) and combined gas chromatography / mass spectrometry (GC/MS). With this method, we introduced varying levels of water content into the cathode and anode, as well as the electrolyte. To facilitate determination of the origin of gas generation, we utilized deuterated water (D2O) introduced into the electrodes and electrolyte as well as 5% deuterated dimethyl carbonate (DMC) and ethylene carbonate (EC) based electrolytes. Figure 2 illustrates a comparison of gas compositions obtained from cells with 1600ppm D2O added to the electrolyte and 5wt% deuterated DMC in the electrolyte. The preliminary results illustrate that deuterated DMC in the electrolyte shows negligible breakdown to yield D2 based gas when compared to samples that contain heavy water (D2O) added into the electrolyte. This indicates that the primary source of gas generation in LTO based cells originates from residual moisture in the electrodes and electrolyte. This result reinforces the importance of maintaining low-moisture processing conditions for LTO-based lithium ion batteries.
(1) Belharouak, I.; Koenig, G. M.; Tan, T.; Yumoto, H.; Ota, N.; Amine, K. Journal of the Electrochemical Society
2012, 159, A1165.
(2) He, Y.-B.; Li, B.; Liu, M.; Zhang, C.; Lv, W.; Yang, C.; Li, J.; Du, H.; Zhang, B.; Yang, Q.-H.; Kim, J.-K.; Kang, F. Sci. Rep.
2012, 2.
(3) Bernhard, R.; Meini, S.; Gasteiger, H. A. Journal of the Electrochemical Society
2014, 161, A497.

Figure 1
Tuning Particle Morphology of Lithium-Ion Battery Electrode Particles
Authors: Koenig Gary , Robinson Pierce 
Published: February 2020

Improving energy density and performance of lithium-ion battery electrodes is highly dependent on improvements in electrode and electrolyte chemistry, however, the morphology of the active materials also can play a major role. Particle morphology has a major impact on factors such as the packing of particles into electrodes and the relative amount of surface area exposed to the electrolyte per mass of material. In this presentation, we will describe our current efforts to synthesize lithium-ion battery electrode particles that are relatively monodisperse and have tunable overall shape and surface morphology. Our group is taking advantage of inorganic solution chemistry methods and understanding particle nucleation and growth to control the final resulting particle morphology that will eventually serve as lithium-ion battery active materials. This work will focus on our first efforts investigating a model system for building a library of particle morphologies for a single battery chemistry, in this case LiMn2O4.
Prussian Blue As Negative and Positive Electrode in Lithium and Sodium-Ion Batteries
Authors: Piernas-Muñoz María José , Castillo-Martínez Elizabeth , Armand Michel , Rojo Teófilo 
Published: February 2020

Prussian Blue, ideally KFeIIIFeII(CN)6·xH2O, and its analogues, KMIIFeIII(CN)6·xH2O (M=Mn, Fe, Co, Ni, Cu, Zn), have been successfully proved to work as cathodes in lithium ion-batteries (LIB) or sodium ion-batteries (NIB), both in organic or aqueous media.[1],[2],[3],[4] The combination of the transition metals redox properties presents in the PB structure along with the large available channels for ion diffusion[5] make it a good candidate both for positive and negative electrode either in LIB or NIB.
We recently reported the performance of Prussian Blue (from now on abbreviated as PB) acting as anode versus lithium in organic media. In the low voltage window of 1.6 - 0.005 V, it exhibits a plateau at ca. 0.9 V and capacities comparable to those observed for graphite (450 mAh/g in the first cycle and 350 mAh/g after 50 cycles at 8.75 mA/g), which are 5 times higher than the theoretically expected for the insertion of 1 Li+ per formula unit through an intercalation mechanism. Based on several evidences observed when ex-situ experiments are carried out in the discharged electrodes, we proposed a conversion (or displacement) mechanism, for the first time reported, as the reaction probably taking place.[6]

On the other hand, the already contrasted performance of the potassium PB as cathode, in combination with the increasing interest in new alternatives to lithium, providing less expensive and more environmentally friendly materials, such as the NIB, led us to consider the sodiated phase of PB, ideally NaFeIIIFeII(CN)6·xH2O, to work as cathode material versus sodium in organic media. The presence of sodium ions in the crystal structure of the pristine material could facilitate the insertion/deinsertion of these alkali ions.[7] Herein, we will present the study on the optimization of the electrochemical behaviour of the sodium system, which shows 2 plateaus at 2.7 and 3.45 V and capacities up to 140 mAh/g, in NIB. The mechanism of insertion/deinsertion will be also discussed.

[1] J. Electrochem. Soc., 2012, 159, A98. Colin D. Wessells, S.V. Peddada, M.T. McDowell, R.A. Huggins and Y. Cui.
[2] Inorg. Chem., 2002, 41, 5706. A. Widmann, H. Kahlert, I. Petrovic-Prelevic, H. Wulff, J.V. Yakhmi, N. Bagkar and F. Scholz.
[3] Chem. Commun.,
2012, 48, 6544. Y. Lu, L. Wang, J. Cheng and John B. Goodenough.
[4] Chem. Commun. 2013,49, 2750. T. Matsuda, M. Takachi and Y. Moritomo.

[5] J. Phys. Chem.
1981
, 85, 1225. D. Ellis, M. Eckhoff and V.D. Neff.
[6] J. Power Sources, 2014
, 271, 489. M.J. Piernas-Muñoz, E. Castillo-Martínez, V. Roddatis, M. Armand and T. Rojo.
[7] Energy Environ. Sci.,
2014
, 7, 1643. Ya You, Xing-Long Wu, Ya-Xia Yin and Yu-Guo Guo.
Simulations with an Accurately Calibrated Electrochemical Model of Li-Ion Battery to Determine Additional Aging Mechanisms
Authors: Edouard Clément , Forgez Christophe , Revel Renaud , Bernard Julien , Petit Martin 
Published: February 2020

The growing number of electrified vehicles remains particularly constrained by the performance of the energy storage system, which is a complex and expensive component in the vehicle. Li-ion batteries seem to be the best candidates due to their suitable performances for plug in or full electric vehicle application. However, the aging phenomena in those batteries will have a direct impact on the autonomy, power and maintenance costs of the vehicle and are not yet clearly understood. For automotive industry, this kind of information is critical in determining the performance and durability of the battery in traction applications. For that reason, there is an urgent need of validated predictive models for the long term behavior of those electrochemical components, ensuring an optimal battery sizing on one hand, and a proper energy management onboard on the other hand.
The aging of a Li-ion battery is mainly due to a modification of its electrochemical properties which will lead to a loss of capacity (decrease of the autonomy) and an increase of its internal impedance (loss of power). A simplified electrochemical model has already been developed at IFP Energies Nouvelles[1] taking into account the loss of cyclable lithium due to the growth of the Solid electrolyte Interphase (SEI) and the modification of the porosity of the graphite electrode as aging mechanisms. This model allows us to estimate the evolution of the performance (power and autonomy) of a Graphite/LiFePO4-based battery as if it was used on a typical hybrid or electric vehicle. In order to ensure the reliability of this model, a sensitivity analysis based on Zhang et al. work[2] has been performed to find out the impact of the variation of each parameters on the model output (Voltage, Temperature) and determine the optimal testing conditions for this model calibration.
Moreover, the discrepancies observed during the validation of our properly calibrated model with experimental data highlighted an additional capacity loss due to another aging mechanism than SEI growth. According to our previous research and to the literature, we decided to add a mechanical stress based mechanism involving cracking into the electrode that leads to a loss of active materials or enhances the loss of lithium inventory. Therefore, specific experiments inducing stress during intercalation of lithium ions in the negative electrode have been carried out to gather data to identify parameters of the new mechanism added to our model. Afterwards, the behavior of this new aging model will be validated on dynamic PHEV duty profiles to ensure its good reliability.

References

[1] E.Prada, Di Domenico D., Creff Y., Bernard J., Sauvant-Moynot V. et al., J.Electrochem.Soc. 160 (2013) A616-A628.
[2] L.Zhang, Lyu C., Hinds G., Wang L., Luo W. et al., J.Electrochem.Soc. 161 (2014) A762-A776.
Electrophoretic LiFePO4/ Graphene Composite for Li-Ion Battery Cathode Application
Authors: Li Quan 
Published: February 2020

LiFePO4 (LFP) is a most promising cathode material for lithium ion batteries (LIBs) due to its high theoretical capacity (170 mAh g-1), flat voltage plateau, long cycle life, abundant material supply, and excellent safety. However, it suffers from low electronic conductivity, which results in sacrificed capacity and low rate performance of the cathode. Finding efficient additives that enhances the electronic conductivity of LFP, while at the same time minimizing the content of both additives and binders, become a tempting goal as it would lead to high performance cathode with high packing density.
In the present work, we demonstrate a binder free composite electrode of LiFePO4/ graphene with ultrahigh LiFePO4 mass ratio (91.5 wt% of LiFePO4) using electrophoresis. No additional additive (other than graphene) is introduced. Enhanced capacity and improved rate performance have been demonstrated in the electrophoretic composite cathode, when compared to either the conventional one or composite cathode formed by mechanically mixing LiFePO4 and graphene. A number of key material/processing parameters have been investigated in a systematic manner in order to understand their effect on the final cathode electrochemical performance as well as identify the optimum composite cathode configuration. We also extend our discussion onto the beneficial effect of using three dimensional current collectors and the role of different ions employed during the electrophoresis process. The present methodology is simple and does not disturb the active material growth process. It can be generally applied to a variety of active material systems for both cathode and anode applications in Li-ion batteries. This work is supported by General Research Funding of the National Natural Science Foundation of China/ Research Grants Council Joint Research Scheme under project No. N_CUHK448/13.
Studies on LiMn1.5Ni0.4Cr0.1O4 Cathode Spinel Combined with Graphene for Lithium Ion Batteries
Authors: Katiyar Rajesh K. , Shojan Jifi , Puli Venkata S , Sahoo Satyaprakash , Morell Gerardo , Weiner Brad R. , Katiyar Ram S. 
Published: February 2020

The low-cost development of rechargeable lithium ion batteries is of considerable technological importance. In this context, the use of active cathode LiMn1.5Ni0.4Cr0.1O4 material has attracted much attention due to its stable structure while intercalation and de-intercalation of lithium ions. The necessity of such battery material is that the energy density stored electrochemically in the electrodes is quite high. They combine high theoretical energy storage capability with low weight and good mechanical strength. Here we report the development of a rechargeable lithium ion battery with homogeneous mixing of graphene powder (with 10, 15 and 20%) in active cathode materials for high energy applications. The reduced graphene oxide was synthesized using modified Hummers method with high purity concentrated of H2SO4 (50 ml), oriented pyrolytic graphite, KMnO4 (7 g) and H2O2 (30 wt %). The resultant mixture was stirred well and then filtered with the help of a glass filter. The obtained precipitates were dried for 30 h in a vacuum oven at room temperature. Highly conducting reduced graphene powder was obtained using hydrazine treatment. The redox behavior of the cell, which is normally too slow for practical applications, is accelerated with highly conductive powder of the graphene (which itself functions as an active cathode material). Intimate mixing of the two materials is achieved by a slurry maker using an organic solution for a cathode paste. The resulting electrode can be repeatedly charged to near its theoretical limit and discharged. The gravimetric energy density of our composite cathode materials exceeds that of the LiMn1.5Ni0.4Cr0.1O4 oxide electrodes in lithium-ion batteries, a feature that is likely to prove advantageous in applications where weight, rather than volume, is a critical factor. The aforementioned results will be discussed.