bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lu2O3:Mn Ceramics for Thermoluminescence and Thermometry Dual Functionality
Authors: Kulesza Dagmara , Zeler Justyna , Zych Eugeniusz 
Published: February 2020

Manganese is capable of exist in many oxidation states from +1 to +7. In research of phosphors especially attractive and intensively studied in last years is a d-d emissions from Mn2+ and Mn4+. In both cases the luminescence may appear in red spectral range, greatly attractive for WLEDs.1 Yet, being strongly dependent on the host lattice the Mn2+ emission can vary from green to deep red with decay time in the order of ms.
This presentation is devoted to Mn2+ emission in cubic Lu2O3 host lattice which offer two nonequivalent site symmetry, C2 and C3i, for the dopant ion.2 A successful technology of effective permanent stabilization of Mn2+ in this host will be presented.
The preliminary spectroscopic investigation showed that the title system is able to produce thermoluminescence after irradiation with X-rays or UV-rays. Furthermore, in PL measurements detected in wide temperature range the system is able to produce 2 or even 3 different emissions whose intensities change in a complex way. These observations tells to consider the possible usefulness of the system to serve as a prospective luminescence thermometer working over a broad range of temperatures.
This research was supported by Polish National Science Centre upon the grant #UMO-2017/25/B/ST5/00824.

Q. Zhou, L. Dolgov, A. M. Srivastava, L. Zhou, Z. Wang, J. Shi, M. D. Dramićanin, M. G. Brik and M. Wu, Mn2+ and Mn4+ red phosphors: Synthesis, luminescence and applications in WLEDs. A review, J. Mater. Chem. C, 2018, 6, 2652–2671.

E. Zych, Concentration Dependence of Energy Transfer between Eu3+ ions occupying two symmetry sites in Lu2O3, J. Phys.
Condens. Matter, 2002, 14, 5637–5650.
Electrochemical Investigations of L-Tryptophan
Authors: Cheek Graham T. , Choi Pyung O. 
Published: February 2020

Introduction
Recent activity in this laboratory has involved the electrochemistry of amino acids such as L-cysteine and L-histidine in aqueous buffers (1-4). The effect of zinc ions, which are involved in determining the structures of “zinc finger” proteins (5), on the electrochemistry of amino acids has also been investigated. The present work has extended these studies to L-tryptophan and some of its derivatives.
Experimental
MOPS (3-(N-morpholino)propanesulfonic acid) was obtained from Sigma-Aldrich Corporation, and L-tryptophan was obtained from Nutritional Biochemical Systems. Electrochemical experiments were carried out under nitrogen using a Gamry Instruments Interface 1000 potentiostat and Gamry Framework software. Working electrodes were obtained from BASi (Glassy carbon, 3.0 mm diameter; platinum 1.6 mm) and eDAQ (gold, 1.0 mm diameter). Potentials were measured with respect to a silver/silver chloride saturated KCl reference electrode (eDAQ).
Results and Discussion
Electrochemical studies of L-tryptophan have been carried out in pH 7.4 phosphate buffer, and we have found that L-tryptophan undergoes oxidation more easily than does L-histidine (4). Complexation studies of Zn(II) by L-tryptophan in pH 7.4 MOPS buffer have shown that the extent of complexation is generally similar to that of L-histidine (4). Similar experiments were also carried out on 5-fluoro-tryptophan and 6-fluoro-tryptophan, revealing that they underwent oxidation at somewhat more positive potentials than does L-tryptophan. This observation reflects the electron-withdrawing effect of the fluorine atom. Despite this positive potential shift, the fluorinated tryptophans were found to effectively complex zinc(II) in pH 7.4 MOPS buffer. Finally, initial experiments in the voltammetric behavior of L-tryptophan in the very polar solvent formamide have been initiated.
References
1. G. T. Cheek and M. A. Worosz, ECS Transactions, 2016, 72(27), 1-8.
2. M. Y. Doan, M. A. Worosz, and G.T. Cheek, ECS Transactions, 2017, 77(11), 1537-1544.
3. G. T. Cheek, M. A. Worosz, M. Y. Doan, and D. C. Clark, ECS Transactions 2017 80(10), 1159-1166.
4. D.C. Clark and G.T. Cheek, ECS Transactions, 2018, 85(13), 1123-1131.
5. C.K. Mathews, K.E. Van Holde, D.R. Appling, and S. J. Anthony-Cahill, Biochemistry, 4th Edition, Pearson Canada, Toronto, 2013.
Influence of Electrode Design and Lithium Source Format on the Performance Metrics of Pre-Lithiation of Anodes in an Energy Storage Device
Authors: Shellikeri Annadanesh , Zheng Jim P. 
Published: February 2020

Energy storage devices like batteries and supercapacitors, have become the crucial part of electrification of transportation. Better and more efficient energy storage devices are the need of the hour, critical to achieving this goal. In our earlier work [1,2], we have shown that several fabrication and design measures, like an advanced dry method of electrode fabrication, an optimized design of anode to cathode capacity ratio, an array of pre-lithiation methods, a composite cathode, etc., can be ingeniously combined to enhance the performance characteristics of energy storage devices in terms of specific energy (Wh.kg-1), specific power (W.kg-1), cycle life and cost.
Among these performance enhancing measures, the process of pre-lithation is a necessary measure on multiple fronts, namely, to compensate for the initial cycle loss from solid electrolyte interface formation on anodes, to improve first cycle coulombic efficiency, to prevent the loss of active Li content in electrolyte and to achieve an improved cell working voltage range by initially driving the anode potential to lower permissible limits. We have also shown in our previous work [3] that an array of Li metal sources can be employed for achieving pre-lithiation through the internal short method in carbon electrodes. Over a time limited condition, we demonstrated the importance of different lithium source structures and their effect on the rate of pre-lithiation and pre-lithiation capacities that can be achieved.
In our present work, we have eliminated the time limiting condition, allowing for the complete ionization of the Li-sources employed, hence enabling a complete pre-lithiation process in all Li-source formats that were employed. We have also performed a comparative study between the internal short circuit method of pre-lithiation and the external short circuit method. Different Li-source formats, based on their surface area and structure, exhibit different ionization and pre-lithiation speeds, capacities and efficiencies. Fig. 1 presents an illustration of different pre-lithiation methods organized based on their speed of pre-lithiation, with the fastest process being stabilized Li-metal powder (SLMP - leftmost) and slowest of the pre-lithiation processes occouring in lithium strip in electrode gap method and in an external short circuit method using an appropriate current limiting resistor (rightmost). On account of spherical micro nature of SLMP particles, they possess a larger active surface area for the ionization process to continue more vigorously and hence faster speed of pre-lithiation. Our analysis of reversible capacities after pre-lithiation, electrode cycle life, DC life, safety and cost aspects, etc., will also be presented.

Figure 1
Investigating the Origin of Cation Mixing in Nickel Rich Cathodes
Authors: Muralidharan Nitin , Essehli Rachid , Self Ethan Craig , Nanda Jagjit , Belharouak Ilias 
Published: February 2020

*corresponding authors email: muralidharan@ornl.gov and belharouaki@ornl.gov
Lithium Ion Batteries Have Been the Catalyst That Brought about the Revolution of Portable Electronic Devices and Electric Vehicles. with the Ever-Increasing Promise of Novel Anode Formulations Delivering Higher Capacities, the Present-Day Energy Densities Are Limited By the Choice of Cathode Used. with Recent Research and Development Trends Focused Heavily on the Class of Layered Nickel Rich Cathodes (LiNixM1-xO2, where M=Transition Metal Cation, x>0.6), It Is of Categorical Importance to Understand the Limiting Mechanisms Hampering the Performance of Such Cathode Systems. of Particular Importance Is the Intermixing of Cations, Ni2+ and Li+ between the Lithium and Transition Metal Slabs in These Layered Cathodes Owing to Their Similar Ionic Radii. These Ni2+ions in the Lithium Slab Creates Li+ Ion Migration Bottlenecks Thus Resulting in the Under-Utilization of the Total Available Storage Capacity of These Cathode Materials. Our Work, Utilizing in-Situ X-Ray Diffraction and Mossbauer Spectroscopy during the Synthesis Procedures Aims to Reveal the Role of Specific Transition Metal Cation Dopants in Lowering/Increasing the Extent of Cation Mixing and the Resulting Electrochemical Behavior of Nickel Rich Cathode Systems Such As the LiNi0.8CoxAlyO2(NCA class) and the LiNi0.8CoxMnyO2 (NCM class). Overall, This Work Provides a Broad Framework to Understand, Isolate and Mitigate This Limiting Phenomena in the Development of Next Generation Lithium Ion Battery Cathodes.
Reduction of Electronic Conductivity within Secondary Particles Revealing a Degradation Mechanism of Ni-Rich Cathode for Lithium Ion Batteries
Authors: Kim Jae-Hyung , Nam Gyeong Won , Sun Yang-Kook 
Published: February 2020

A locally reduction in electronic conductivity in the core region of secondary particles is proposed as a capacity-fading mechanism of a Ni-rich cathode. This is investigated by measuring the electronic conductivity of the secondary particles of Li[Ni0.98Co0.01Mn0.01]O2 using the scanning spreading resistance microscopy (SSRM) mode of atomic force microscopy. SSRM analysis reveals that a much thicker rocksalt phase, which is transformed from the original layered structure, on the surface of the primary particles in the core region electronically disconnects the primary particles from the neighboring particles. Intercalation and deintercalation of Li are hindered in the electronically insulated primary particles. Thus, detecting of the local electronic conductivity in the secondary particles confirms that the loss of electronic conductivity in the core region of the secondary particle is a important factor in the degradation mechanism of a Ni-rich cathode for lithium ion batteries.
References:
[1] H.-J. Noh, S. Youn, C. S. Yoon, Y.-K. Sun, J. Power Sources
2013, 233, 121.
[2] K.-J. Park, H.-G. Jung, L.-Y. Kuo, P. Kaghazchi, C. S. Yoon, Y.-K. Sun, Adv. Energy Mater.
2018, 8, 1801202.
[3] C. S. Yoon, D.-W. Jun, S.-T. Myung, Y.-K. Sun, ACS Energy Lett.
2017, 2, 1150.
[4] C. S. Yoon, H.-H. Ryu, G.-T. Park, J.-H. Kim, K.-H. Kim, Y.-K. Sun, J. Mater. Chem. A
2018, 6, 4126.
Investigating the Effects of Magnesium Doping in Various Ni-Rich Materials
Authors: Liu Aaron , Li Hongyang , Zhang Ning , Inglis Julie , Dahn Jeff R 
Published: February 2020

As lithium ion battery technology expands into more demanding applications such as electric vehicles, attention has shifted towards nickel-rich positive electrode materials, namely LiNi1-x-yMnxCoyO2 (NMC) and LiNi1-x-yCoxAlyO2 (NCA).1 Aims to improve energy density and reduce costs of NMC and NCA can be achieved by increasing the Ni content of the material, but at the cost of shorter cell lifetimes.
Besides Al, Co and Mn, research has tried substituting Ni with many different metals.1 Mg has repeatedly come up as a beneficial dopant from positive electrode material doping studies that try to improve material cycling performances. Mg has been shown to improve cycling performances of various positive electrode materials including LiCoO2 (LCO), NMC, and NCA when doped into the material in small amounts.1–4 Doping the material with Mg slightly reduces the specific capacity of the material since Mg is an inactive constituent, but it has been shown that a Mg content of as low as 1 mol% can improve cycling.3

LiNiO2 (LNO) and some other Ni-rich materials undergo phase transitions as Li gets removed during charging. In particular, when the material transitions from the H2 phase to the H3 phase at low Li, it experiences a large volume change. It is believed that this contributes to a poor lifetime of the material. Mg doping has been shown to suppress these phase transitions and related volume changes.2,4 Mg has also been shown to reduce the amount of Ni migration to the Li layer.1

As research continues to increase the Ni content of NMC and NCA, the compositions will invariable converge towards LNO. Additionally, efforts are being made to reduce the Co content of Ni-rich materials due to cost and sourcing issues.4 Co is believed to reduce the amount of Ni in the Li layer and also to stabilize cycling performance, which are similar benefits that Mg imparts. This work studies the effect of Mg doping in LiMO2 (M = Ni, Ni+Al, Ni+Co+Al, Ni content > 0.8) at a dopant level of less than 5 mol%. Structural and electrochemical characterization of the materials was carried out to understand how Mg affects the materials and whether the presence of Al or Co influences the dopant effects of Mg. Figure 1 shows the initial half-cell voltage vs capacity and differential capacity vs voltage curves for a series of LiNi0.88-xCo0.09Al0.03MgxO2 (x = 0, 0.01, 0.02, 0.04) materials, showing a trend of how Mg affects the electrochemical performance of the materials.
(1) Kim, J.; Lee, H.; Cha, H.; Yoon, M.; Park, M.; Cho, J. Adv. Energy Mater.
2018, 8, 1–25.
(2) Sasaki, T.; Godbole, V.; Takeuchi, Y.; Ukyo, Y.; Novák, P. J. Electrochem. Soc.
2011, 158, A1214–A1219.
(3) Huang, B.; Li, X.; Wang, Z.; Guo, H.; Xiong, X. Ceram. Int.
2014, 40, 13223–13230.
(4) Li, H.; Cormier, M.; Zhang, N.; Inglis, J.; Li, J.; Dahn, J. R. J. Electrochem. Soc.
2019, 166, A429–A439.

Figure 1
Strategy of Enhancing Energy Density of Layered Ni-Rich Li[Ni1-2xCoxMnx]O2 Cathodes (x = 0.05, 0.1, 0.2)
Authors: Kim Jae-Hyung , Nam Gyeong Won , Park Nam-Yung , Aishova Assylzat , Yoon Dae Ro , Sun Yang-Kook 
Published: February 2020

Recently, Ni-rich layered Li[Ni1-2xCoxMnx]O2 (NCM, x ≤ 0.2) cathodes show high capability for increasing the energy densities which is essential to facilitate the penetration of electrified transportation systems into the automobile market. However, the poor thermal stability of these cathodes is retarding their commercialization. In this study, the effect of Ni content and upper cut-off potential on the electrochemical and thermal properties of Ni-rich NCM cathodes (NCM-622, 811, 90) is evaluated to identify the optimum composition of the cathodes and the cycling conditions. This research shows that operating Ni-rich cathodes at higher cut-off potentials (> 4.3 V) rather than progressing to highly nickel enriched compositions can be a better method of enhancing their energy densities and maintaining adequate thermal stability. It is shown that a Li[Ni0.6Co0.2Mn0.2]O2 (NCM-622) cathode cycled up to 4.5 V exhibits a discharge capacity of 200 mAh g-1 and capacity retention of 93% after 100 cycles, which are similar to the ones of Li[Ni0.8Co0.1Mn0.1]O2 (NCM-811) cycled up to 4.3 V. Similar volume change during cycling and comparable NiO-like rocksalt impurity layer after 100 cycles in both of the cathodes may be the reason for their similar cycle lives despite operating at different charge cut-off potentials. In spite of the comparable capacity and retention, NCM-622 cathode exhibits superior thermal stability, in which the occurrence of the exothermic reaction is delayed by 50 °C, than NCM-811. In addition, analogous trends are observed in the cathodes with higher nickel compositions, i.e., NCM-811 and Li[Ni0.9Co0.05Mn0.05]O2 cycled up to 4.5 V and 4.3 V, respectively.

Reference
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:

[1] Y.-K. Sun, S.-T. Myung, H. J. Bang, B.-C. Park, S.-J. Park, N.-Y. Sung, J. Electrochem. Soc.
2007, 154, A937.
[2] H.-H. Ryu, K.-J. Park, C. S. Yoon, Y.-K. Sun, Chem. Mater.
2018, 30, 1155.
[3] U.-H. Kim, E.-J. Lee, C. S. Yoon, S.-T. Myung, Y.-K. Sun, Adv. Energy Mater.
2016, 6, 1601417.
[4] C. S. Yoon, H.-H. Ryu, G.-T. Park, J.-H. Kim, K.-H. Kim, Y.-K. Sun, J. Mater. Chem. A
2018, 6, 4126.
Molecular Dynamics Simulation Study of Ion Transport, Structural and Mechanical Properties of Li2CO3 and Mn-Li-CO3
Authors: Ebrahiminia Mahsa , Wang Cun , Hooper Justin B. , Bedrov Dmitry 
Published: February 2020

In this study, we focus on understanding properties of the Solid Electrolyte Interphase (SEI), which plays an important role in the performance of Li-ion batteries. SEI has a complex structure including domains and blends of different organic (such as LEC, LMC, Li2EDC, etc.) and inorganic compounds (such as LiF, Li2O, etc.) which are byproducts of single and double electron reduction processes of electrolyte solvent and ions. Because of this complexity, the detailed structure and characteristics of SEI are still not well understood.
Dilithium carbonate, Li2CO3, is known to be one of the important and stable compounds in the SEI structure. While there were some studies considering crystal phase of Li2CO3, the properties of amorphous glassy phase that can form at the domain boundaries within SEI or under fast rates of electrolyte reduction has not been investigated. In addition to SEI, amorphous blends of Li2CO3 with other oxides have been considered as potential materials for solid electrolytes. To the best of our knowledge, we present the first study considering the amorphous phase from theoretical point of view.
Using atomistic MD simulations and a polarizable force field, we investigated properties of amorphous Li2CO3 phase and predict structural, dynamical, and mechanical properties of Li2CO3 as a function of temperature as well as the content of Mn2+ in the SEI. The latter investigates the influence of SEI “contamination” by divalent cations dissolved from high-voltage cathods or intentional introduction of sacrificial divalent cation salts to promote formation of denser and stronger SEI.
According to our study, Mn0.2Li1.6CO3 forms the glassy state below 600 K, which is a 150 K increase compared to Li2CO3 system. Besides, Mn0.2Li1.6CO3 shows 15% higher density. From mechanical property calculations, shear modulus value for Li2CO3 is around 8 GPa, while it increases significantly with the addition of Mn2+.
Small Functional Molecules As Slurry Additives for Si-Alloy Coatings with CMC/SBR Binder
Authors: Wei Congxiao , Obrovac M. N. 
Published: February 2020

Si-alloy based anodes are attractive for use in Li-ion batteries because of their high volumetric capacity. Polyacrylic acid (PAA) [1] binder is often used in such anodes, which contains carboxyl groups that bind to alloy surfaces, maintaining electrode integrity and forming an artificial SEI layer [2]. Aromatic binders like PI can decompose during lithiation, forming a conductive carbon network [3]. However, these binders have disadvantageous for their practical use, including superhydrophilicity, in the case of PAA; and high irreversible capacity and the cost and use of NMP solvent, in the case of PI. Sodium carboxymethyl cellulose/styrene-butadiene rubber (CMC/SBR) is currently the binder system of choice for Li-ion cell makers. Enabling the use of CMC/SBR binders with alloys could enable wider implementation of alloy electrodes.
In this work, several small molecule compounds containing carboxyl groups were evaluated as slurry additives. It was found that some slurry additives could significantly improve alloy cycle life in CMC/SBR coatings. Figure 1 shows the capacity retention versus cycle number for each slurry additive. Tremendous variations in capacity retention are observed for different additives. In particular, the addition of 5% sodium mellitate and sodium citrate resulted in a large increase in cycling performance of the CMC/SBR coating beyond even that of a coating with PAA binder. This work shows that the cycle life of alloy coatings using CMC/SBR binder can be improved by the use of small molecule slurry additives. This could help enable the use of alloy based electrodes in Li-ion batteries using practical binder systems.

Reference
s
:

[1] Magasinski, Alexandre, et al. "Toward efficient binders for Li-ion battery Si-based anodes: polyacrylic acid." ACS applied materials & interfaces 2.11 (2010): 3004-3010.
[2] Chen, Hao, et al. "Exploring chemical, mechanical, and electrical functionalities of binders for advanced energy-storage devices." Chemical reviews 118.18 (2018): 8936-8982.
[3] Wilkes, B. N., et al. "The electrochemical behavior of polyimide binders in Li and Na cells." Journal of The Electrochemical Society 163.3 (2016): A364-A372.

Figure 1
Investigation on Formation Process of Lithium-Ion Batteries
Authors: Kim Youngmin , Jeong Kyeong-Min 
Published: February 2020

To increase the energy density and the power density of lithium ion battery cell, it is important to design the capacity of each electrode accurately. Ideal lithium-ion battery should be formed SEI film through the first charge/discharge, after then should maintains 100% coulombic efficiency1. In reality, such a perfect formation cannot be achieved within one cycle, and reduction in cell capacity occurs with repeating charge/discharge cycle. This makes hard to measure the irreversible capacity accurately, so it is important to finish formation process in one cycle for cell design and process design.
In this work, we confirmed that the 0.1C charge as the formation protocol does not complete the formation with electrochemical impedance spectroscopy using graphite half-cell. In addition, we investigated how the cell capacity and the coulombic efficiency changes as the cell is cycled by varying the current applied in the CC process or time taken for the CV process during CC-CV charging protocol by graphite half-cell and Li [Ni0.6Co0.2Mn0.2] O2 / graphite cells.
We investigated whether we could accelerate the formation of lithium-ion batteries with variation of charging protocol. According to the experimental results, the film resistance of the graphite electrode decreased as the cell formation completed. When the film resistance of graphite decreases, equilibrium potential increases so the utilization of graphite active material would be increased in the subsequent cycles. This is followed by the abnormal behavior of capacity and coulombic efficiency. In charging/discharging graphite half-cell, we confirmed that higher portion time taken of charging with CV in first charge leads to earlier completion of formation. Change in film resistance, capacity, and coulombic efficiency will be discussed.

References

Principles and Applications of Lithium Secondary Batteries, Jung Ki Park.