bluuebunny/crossref_metadata_2025_split huggingface dataset:
Band Gap Engineering in Luminescence Thermometry – Pros and Cons
Authors: Sójka Małgorzata , Bolek Paulina , Kulesza Dagmara , Brites Carlos Delgado Sousa , Zeler Justyna , Jedoń Joanna , Carlos Luís D , Zych Eugeniusz 
Published: December 2020

Luminescence thermometry and 2D imaging using luminescence thermometric phosphors are of growing interest as these non-contact and non-invasive techniques may offer important advantages in some applications. The requirements such thermometers have to fulfill depend on considered use. It is obvious that bio and medical applications points on different parameters than measurements in cryo-range and measuring high temperatures point on yet different needs. Nevertheless, high-sensitivity and low inaccuracy are always appreciated, as well as chemical stability in conditions the thermometers are to be used.
One of the limitations of known luminescence thermometers is their limited range of temperatures they may measure. Obviously, some applications do not need a broad range of thermometer usability. On the other hand, presenting a good performance over a wide range of temperatures would give a versatile “all-purpose” thermometer. This might open a door for truly broad usage of such a phosphor.
Trying to deliberately manage the performance of luminescence thermometers for a broad-range and accurate temperature measuring we paid attention to the bandgap engineering as a tool to achieve this goal. In this presentation, we shall focus on Lu2(Ge,Si)O5:Pr and Y3(Al,Ga)5O12:Pr powders with different Ge:Si and Al:Ga ratios, respectively. We shall discuss the advantages of bandgap engineering in luminescence thermometry and will point to possible complications this may cause. Among others, we shall show that managing the bandgap cause at the same time changes in phonons energies and these affect radiative and non-radiative processes, so important when luminescence over a broad range of temperatures is considered. Last but not least, a side effect of bandgap engineering is the change of the phosphor refractive index, also an important parameter for luminescence properties.
This research was supported by the Polish National Science Centre (NCN) upon the grants #UMO-2017/25/B/ST5/00824 and UMO-2018/29/B/ST5/00420 and the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by Portuguese funds through the Portuguese Foundation for Science and Technology (FCT)/MCTES. Financial support from FCT (PTDC/CTM-NAN/4647/2014, NANOHEATCONTROL - POCI-01-0145-FEDER-031469) is also acknowledged. E. Z. and L. D. C. are grateful to the Polish National Agency for Academic Exchange (NAWA) for support under the NAWA-Bekker #PPN/BEK/2018/1/00333/DEC/1 and NAWA-Ulam #PPN/ULM/2019/1/00077/U/00001 projects, respectively.

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Sodium Stripping and Plating from Na-β"-Alumina Ceramics Beyond 1000mA/cm2
Authors: Landmann Daniel , Graeber Gustav , Heinz Meike , Battaglia Corsin 
Published: December 2020

Dendrite formation limits the cycle life of lithium and sodium metal anodes and remains a major challenge for their integration into next-generation batteries, even when replacing the liquid electrolyte by a solid electrolyte. Recent studies have pointed out that lithium and sodium metal creep rather than lithium and sodium diffusion is the primary mechanism for replenishing the voids forming in solid metal anodes at the interface to a solid electrolyte upon stripping. Void formation upon stripping causes current constrictions upon plating, promoting dendrite formation. Here we investigate plating and stripping of liquid sodium metal from a ceramic Na-β"-alumina electrolyte at 250 °C, thereby eliminating mass transport limitations due to creep. Employing a porous carbon electrode coating to (1) prevent dewetting of plated liquid sodium from and (2) to supply liquid sodium upon stripping to the sodiophobic Na-β"-alumina surface, we demonstrate extremely high current densities above 1000 mA/cm2 and cumulative plated capacities of 10 Ah/cm2 without dendrite formation [1]. These values are two orders of magnitude larger than the corresponding values measured at room temperature [2]. We further show that liquid sodium occupies 60% of the porosity of the carbon coating, while excess sodium accumulates on top of the coating. Increasing the thickness of the carbon coating from 50 μm to 200 μm does not affect the Coulombic efficiency, but reduces the constant current rate capability due to the increased flow resistance for liquid sodium in the porous coating. Our results confirm that eliminating void formation is effective in suppressing dendrite formation.
[1] D. Landmann, G. Graeber, M. V. F. Heinz, C. Battaglia, Materials Today Energy, in press
[2] M.-C. Bay, M. Wang, R. Grissa, M. V. F. Heinz, J. Sakamoto, C. Battaglia, Adv. Energy Mater. 2019, 201902889
Improving Energy Storage and Ion Transport of Soft Nanostructured Complexes Using Regulated Crystallization
Authors: Chen Jihua 
Published: December 2020

Electron and Ion transport systems often rely on a balanced hierarchical boundary structure that spans from millimetre to nanometer scales. Systematically varied polymers and organic crystals are used to fine-tune the growth of soft nanostructured complexes. (1-2) The underlying intermolecular interactions between crystallization mediator and small molecule crystals can lead to thin films of largely enhanced performance for charge transport and energy storage purposes. In this work, controlled solution deposition was used to self-assemble a number of novel organic capacitors and solid electrolyte systems based on semicrystalline polymers, whose capacitance and ion conductivity are examined as a function of the resultant nanostructures and regulated crystallization conditions. Electrochemical impedance measurements, equivalent circuit modelling, as well as Vogel-Tamman-Fulcher relations are performed in light of microscopy studies including low-dose TEM to provide insights on capacitance enhancement and ion transport mechanism.(3)
References:
1. J. Chen et al., Chem. Mater. 25 (21) 4378
2. S.Bi, J.Chen et al, J. Polym. Sci. B, 53 (20) 1450
3.This research was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.
(*** This manuscript has been authored in part by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).)
The Development of High-Throughput Methods in the Study of All-Solid Li-Electrolytes
Authors: Jonderian Antranik , McCalla Eric 
Published: December 2020

High-throughput experimentation is a fast and efficient methodology for materials discovery, screening, and optimization. It has, therefore, garnered a lot of attention from battery researchers as a potential way to accelerate the development of next-generation Li-ion batteries and battery systems beyond Li-ion. However, its successful use in battery materials discovery has been extremely limited due to a variety of challenges including: (i) difficulties in synthesizing mg-scale samples that are comparable to bulk samples made by industrial methods, (ii) limited high-throughput characterization acting like a bottleneck even after high throughput synthesis is developed, and (iii) high cost of commercially available high-throughput instrumentation. Here, we develop high throughput techniques for solid-state electrolytes.
First, a novel synthesis approach is used to make 64 mg-scale solid electrolytes simultaneously. The powder samples are prepared by a citrate sol-gel method using an automated dispensing system. These powders were formulated into sixty-four pellets using a home-made high-throughput pellet press die. The samples are then sintered at high temperature to yield the solid electrolytes. The proof of concept here is performed on the Li-La-Ti-O pseudo-ternary system that includes the perovskites Li3xLa2/3-x‰1/3-2xTiO3, considered candidates for solid-state electrolytes for high energy lithium-ion batteries. Given that vacancies and other defects play an essential role in ionic conductivity, the screening of complete phase diagrams has the potential to reveal phases with optimized defect contents and thus yield improved solid electrolytes.
We have therefore developed a high-throughput characterization suite for solid electrolytes. First, we use a high throughput X-ray diffractometer capable of producing Rietveld quality patterns for mg-scale samples in 10 min such that 64 patterns can be obtained in under 12 h. This system is readily used to produce structural phase diagrams in ternary or even quaternary systems. Next, a high throughput electrochemical impedance spectrometer is used to map the ionic conductivities onto the phase diagrams. Finally, high throughput electrochemistry is used to determine the stability window of the electrolytes. All aspects of this workflow are demonstrated on the Li-La-Ti-O system. This now permits the synthesis and full characterization of approximately 192 compositions per week with one researcher only. This approach is well suited to determine the structure-property relations in complex composition spaces.
The complete ternary Li-La-Ti phase diagram synthesized at 1200 °C with slow cooling was determined and will presented in detail. The bulk and total conductivities of the phase diagram was mapped by electrochemical impedance spectroscopy. Quenching was performed to verify that transformations during slow cooling are moderate in this system. Consequences for the development of other solid electrolytes will also be discussed.
Next Generation of Separator Coatings Beyond Ceramics for Fast Charging
Authors: Roumi Farshid , Liu Jingjing 
Published: December 2020

High rates of charge or discharge generates extensive heat, which gets trapped inside the battery, creating hot spots and leading to premature failure when the battery is used for long periods of time. Today’s solutions to this problem involve coating the separator with an aluminum oxide, or alumina coating – which increases melting temperature and improves safety. This has been one of the major breakthroughs in the battery industry over the past several decades. However, ceramic-coated separators do not provide enough thermal performance needed for fast charging and high power applications specially in large cell where the heat dissipation is challenging.
To address that problem, stating 2012, we have been developing a new class of separators coating, carbon-based coating, that is comparable in cost to ceramic coated separator but has 10 times the thermal conductivity and is safer – increasing the separator melting temperature by 100 deg C. This enhanced thermal conductivity will remove more heat during cycling, reduces hot spots and results in cell temperatures as much as 11 deg C lower during operation. PCS’s ability to remove heat will result in longer cycle life for EV batteries. The increased thermal performance means that PCSTMis safer than ceramic-coated separators, but the more important difference is the x10 thermal conductivity, which means that PCSTMfacilitates heat removal from the center of the cell substantially more than other separators. The benefit is likely to be increased cycle life and higher rate capability.

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Quantitative Analysis of Electrode Gaps in Prismatic Format Lithium-Ion Cells
Authors: Spray Ryan , Cai Zhuhua , Goodman Johanna 
Published: December 2020

Inside a lithium-ion cell, many layers of positive and negative electrodes are separated by an electrolyte-soaked separator. The positive and negative electrodes are engineered to be parallel so that the current distribution is uniform between each set of electrodes. This uniform current density further leads to uniform and predictable operation of the cell. During manufacturing, gaps can be introduced between the electrode layers. This is especially prevalent in prismatic cells because the cell manufacturing process involves inserting the pliable cell windings into a rigid cell housing and applying vacuum during electrolyte filling. These electrode gaps lead to non-uniform current densities, resulting in adverse effects such as incomplete lithiation, electrolyte degradation and possibly lithium plating.
One method of non-destructively visualizing internal cell features is computed tomography (CT) scanning. Collecting data via this method is relatively fast with a typical cell scan takes ~1 hr and multiple cells being scanned at once. The output is commonly a set of 16-bit .tiff images that can be loaded and analyzed by a variety of software packages, with Volume Graphics Studio and Avizo being two common programs. These programs can be used to make a variety of measurements on individual datasets, but they lack the ability to conduct high-throughput analysis of many datasets.
In this work, we have collected computed tomography data on prismatic cells cycled at a series of temperatures throughout their cycle life of up to 500 cycles. This data is analyzed for electrode gap features using a python code written to extract the number of gaps, gap locations, and gap volume for each dataset. This data is then aggregated for all datasets and analyzed for macroscopic trends. One finding from the study is that cells cycled at lower temperatures showed less expansion/contraction because of kinetics and less capacity passed overall, while cells cycled at higher temperatures showed increased gap volume due to material growth between layers. Additional findings and opportunities for future work will be presented.

Image upload:

Horizontal mapping of gap locations in individual cells from the three different temperature groups, where the size of the bubble correlates to the size of the gap. (0 Cycles: yellow, 100 & 200 cycles: blue, 500 cycles: purple)

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Application of Thin Film As Polymer Gel Electrolyte for 3D Li-Ion Battery
Authors: Tolganbek Nurbol , Serik Nurassyl , Batrygali Nursaule , Naizakarayev Miras , Mentbayeva Almagul , Bakenov Zhumabay 
Published: December 2020

Three-dimensional materials can improve the performance of energy storage systems by providing large active surface. Thus, the research was focused on designing a full 3D battery based on electrodeposited Ni3Sn4 (Ni-Sn) anode and polymer gel electrolyte/separator that was coated via layer-by-layer (LbL) technique. Advantages of the LbL approach was appliance of polymer material onto a rough surface of 3D structured electrode material, and thickness control of the coated gel polymer electrolyte. The structure of deposited electrode material was confirmed by XRD. The thickness estimation of coated layers, and cross-section view of 3D battery were depicted via SEM. Electrochemical activity of Ni-Sn alloy with LbL coated gel electrolyte demonstrated redox couples for lithiation and delithiation processes. LbL technique proved that polymer can be coated uniformly onto 3D structure electrode and function as the electrolyte and separator.
Acknowledgement
This research was supported by the research grants #091019CRP2114 “Three-dimensional all solid state rechargeable batteries” from Nazarbayev University.
Visualization of Ion Transport and Electrode/Electrolyte Interaction in Electrolytes for Lithium Metal Batteries
Authors: Yang Yuan , Cheng Qian , Min Wei 
Published: December 2020

Visualization of ion transport in electrolyte provides fundamental understandings of electrolyte dynamics and electrolyte-electrode interaction, shedding light on material designs to enhance device performance, such as batteries and fuel cells. However, this task is challenging for existing techniques, since it is difficult to capture the low ionic concentration (<1 M) and the fast dynamics (1-10 s) of the electrolyte. Here we show that an emerging Stimulated Raman Scattering (SRS) microscopy offers the required spatial (sub-micrometer optical resolution), temporal (faster than 1 s per frame) and chemical (around mM) sensitivities to address this challenge.
The SRS microscopy has been used to study ion depletion and lithium dendrite growth in both liquid and polymer electrolyte, and distinct behaviors are observed. In liquid electrolyte, we observe a three-stage lithium deposition process, each corresponding to no-depletion, partial-depletion and full-depletion regime of Li+, respectively. A positive feedback mechanism between the inhomogeneous growth of lithium and the local ionic concentration or flux. In polymer electrolyte, we clearly see phase separation due to ion depletion and observe the accompanying transport of plasticizer inside, which was not observed in the past. The new phase has significantly higher modulus than the bulk electrolyte. These new understanding also leads to new strategies to suppress lithium dendrites. This study shows that SRS microscopy is a powerful technique for imaging ion transport and will open various applications in materials and energy fields.
References:

Qian Cheng et al., Operando and three-dimensional visualization of anion depletion and lithium growth by stimulated Raman scattering microscopy, Nature Communications 9, Article number: 2942 (2018) .
Control of Electrolyte Reactivity: A New Design of Electrolyte Additives for High Voltage Lithium Ion Batteries
Authors: Liao Chen , Yang Jianzhong , Shkrob Ilya A , Liu Kewei , Dietz Rago Nancy L. , Connell Justin G. , Zhang Zhengcheng 
Published: December 2020

To reach a higher energy density, lithium ion batteries have been pushed to cycle at a higher voltage. The development of new high voltage electrolytes and additives are essential as the fading mechanism at high voltages is tied up with exacerbating oxidation, cathode electrolyte interface formation, as well as the blockage of accessible active Li+. The additive development strategy has mostly followed the trial and error principle, and a paradigm shift is hard.
Here we report a development strategy which tames the spontaneity of electrolyte reactivity and opens an avenue to new additives that would be impossible to achieve otherwise. The talk will cover the recent development of a series of in-situ additives that utilize the reactivity of bistrimethylsilyl carboxylates with two -OSiMe3 groups to react with LiPF6 and form highly moisture sensitive lithium carboxylato phosphate additive (Figure 1).1,2 These additives targets at alleviating cathode impedance rise and show exceptional performance with NMC 532//Gr cell at 4.4 V.
Figure 1. Structure of in-situ additives and the exchange reaction between -O-TMS and LiPF6.

Recently we were also able to use a rational design to expand the family of in-situ additives to include functionality of - N-SiMe3 (TMSML, see Figure 1).4 High nickel cathodes show better performance with the -N-SiMe3 containing additive as they prevent the hydrolysis of LiPF6 caused by traces of water in a carbonate electrolyte, both ex and in situ. It also inhibits oxidative decomposition of electrolytes on the energized cathode through deactivation of the Transition Metal-Oxide (-TM-O.) radical center. We trace these beneficial functions to the ease of nucleophilic substitution and the formation of TM-O.N< that reduce electrolyte oxidation.
Overall, a new design of additives has been implemented with invention of two classes of new additives that improve the performance of high voltage lithium ion batteries.
References

I. Shkrob, B. Han, R. Sahore, A. P. Tornheim, L. Zhang, D. P. Abraham, F. Dogan, Z. Zhang, C. Liao,* Chemistry of Materials 2019, 31, 2459-2468.

Yang, I. Shkrob, Q. Liu, N. L. Dietz Rago, Y. Liu, K. Liu, Z. Zhang, C. Liao,* Journal of Power Sources 2019, 438, 227039.

Yang, I. Shkrob, K. Liu, J. Connell, N. L. Dietz Rago, Z. Zhang a and C. Liao*, J. Electrochemical Society, 167 (7), 070533

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Electrochemical Evaluation of the Application of Hydrogel Electrolytes to Rechargeable Zn|MnO2 Alkaline Batteries
Authors: Cho Jungsang , Huang Jinchao , Yadav Gautam Ganapati , Nyce Michael , Weiner Meir , Upreti Aditya , Messinger Robert J. , Banerjee Sanjoy 
Published: December 2020

Zinc-manganese dioxide (Zn|MnO2) alkaline batteries have been widely studied as the active materials exhibit high theoretical capacities (820 mAh/g for Zn and 620 mAh/g for MnO2), low cost, and are inherent safety. Furthermore, the active materials are electrochemically active in aqueous alkaline electrolytes, such as potassium hydroxide (KOH), which is beneficial from a cost and safety perspective. It is widely known that one of the issues with this system is active MnO2 poisoning by zincate anions during the 2nd electron reaction of MnO2. As a result, an electrochemically inert material, ZnMn2O4 (hetaerolite), is formed, which reduces the capacity and cycle life of Zn|MnO2 batteries. Another issue is associated with high depth-of-discharge (DOD) of each material. For example, at high DOD, Zn will undergo shape change, dendritic growth and passivation, while MnO2 will form inactive phases like Mn3O4. Therefore, the 1st electron reaction range of MnO2 is normally accessed in rechargeable Zn|MnO2 batteries with low DOD.
We have observed that the use of alkaline-based hydrogel electrolytes can significantly increase the cycle life of Zn|MnO2 batteries. Large-scale Zn|MnO2 cells were tested with either hydrogel or conventional alkaline electrolytes, whose nameplate capacities were 95 Ah based on the 1st electron capacity of MnO2. The hydrogel electrolytes were formed by mixing KOH solution, acrylic acid, and potassium persulfate solution as an initiator. Galvanostatic tests were carried out at cycling rates of C/20 (4.75 A) with 20% DOD of the capacity (19 Ah). The single full discharge performance to 0 V with hydrogels was compared to that with KOH aqueous electrolytes. The cell with the KOH electrolyte showed two sigmoidal curves, which means that two steps of electrochemical reactions were undergone, achieving 131 Ah. After recharging it, the single full discharge was conducted again, but nevertheless it attained less than 4 Ah to 1 V onwards. On the contrary, the cell with the hydrogel presented one sigmoidal curve with 40 Ah to 0 V, and it was continuously able to extract discharge capacities ≥28 Ah to 1 V during 40 cycles. Thus, the hydrogel electrolytes significantly enhanced the electrochemical performance of Zn|MnO2 cells, compared to conventional KOH electrolytes, the reasons for which will be discussed. The results suggest that hydrogels could help preserve active materials without the aforementioned issues and make rechargeable Zn|MnO2 batteries achieve better performance while accessing the 1st electron reaction of MnO2.