bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Method to Optimize 3D Microbatteries
Authors: Miyamoto Kaito 
Published: December 2020

The rapid development of information technology (IT) since the end of the 20th century and the technological progress of sensors and devices have familiarized the concept of the Internet of Things (IoT). So far, the miniaturization of the sensors and devices has significantly contributed to the rapid growth of the IoT ecosystem. However, compared with such technological progress on the sensors and devices, the miniaturization technology of the power sources for the off-grid operation of the electronics has not been well established, which hinders further prevalence of the IoT. Especially, for the integration with microelectronics, the high areal energy density is recognized as one of the key properties for such power sources.
As one of the promising candidates for such IoT-enabled power sources, lithium-ion microbatteries have attracted attention. Especially, the three-dimensional design of the microbattery at full cell level has been investigated in order to improve the areal energy density while maintaining high power density. The benefit of the geometrical modification is the lowering of the internal resistance due to the reduction of the ion transport distance without reducing the battery capacity. Indeed, the recent advancement of a variety of 3D manufacturing technologies has allowed the realization of the 3D microbattery. However, the 3D electrode structure is limited to simple shapes such as interdigitated plate or cylindrical electrodes and, therefore, the battery performance is restricted by such electrode shapes. To design the 3D battery architecture beyond the interdigitated configuration, the 3D battery optimization method at the full cell level is vital. Also, the 3D battery optimization method is crucial from the point of view of industrial demand since there are a variety of IoT devices that have different functions, and it is demanding to optimize the battery following the requirements of each IoT device by hand. However, there are no reports regarding the 3D battery optimization methods at the full cell level.
In this talk, we propose a novel battery optimization system at the full cell level, which consists of an automatic geometry generator and performance simulators. The geometry generator designs the full cell based on the random sampling by only receiving the size and the resolution of the 3D battery cell as the input data. For compatibility with the geometry generator, as one of the performance simulators, we newly propose the transmission line model, the so-called 3D porous electrode model, to compute the internal resistance of the 3D battery quickly. To demonstrate the effectiveness of our approach, the tradeoff frontier for the internal resistance and capacitance is created by plotting 200,000 data points as shown in Fig. 1 (a). From the figure, we successfully find new battery geometry (Geometry D in Fig. 1 (b)), which has both higher power and energy densities than the interdigitated plate configuration (Geometry C in Fig. 1 (b)).

Figure 1
Area-Perimeter Relation for Si-Based Anode Materials Using Cross-Sectional SEM Analysis
Authors: Qin Si 
Published: December 2020

Silicon is one of the promising anode materials for next generation high energy density batteries due to its high theoretical capacity. However, its large volume expansion during lithiation hinder its practical application. Here, we report a relation of cross-sectional area and particle perimeter of lithiated silicon using cross-sectional SEM analysis in order to discuss volume expansions and surface degradations of Si-based materials.
The silicon electrodes were prepared by a mixture of Si-based materials, conductive materials and binders in a weight ratio of 80:10:10. After gently fabricating cross-sectional electrodes with an ion-milling, cross-sectional SEM images before and after lithiation were obtained. A software, ImageJ was utilized to process the SEM images and calculate length of X-axis and Y-axis, cross-sectional areas and particle perimeters.
Figure 1 shows SEM images of a Si-based electrode before and after lithiation. Si expanded uniformly with X-axis and Y-axis expansion ratio of 128%. The cross-sectional area was the expansion ratio of 165%. Since volume expansion is uniform, volume should be calculated by setting to 3 power of X-axis (or Y-axis) or 3/2 power of cross-sectional area. According to the above data, we achieved similar volume expansion rates those were 210% (calculated by X-axis) and 214% (calculated by cross-sectional area). With this method, expansion rate of graphite was shown to be 112%, which is similar to previous Schweidler’s report (113%) [1]. Figure 2 shows processed images of high resolution SEM before and after cycling in order to calculate precise perimeter of Si-based material. The perimeter after the initial lithiation increases to 1.2 times larger than the pristine electrode, which is equivalent to the volume expansion. However, a perimeter after cycling is 3 times larger and it could be caused by a surface erosion. It suggests that the perimeter relates the surface erosion with SEI formation, not only the volume expansion.We will demonstrate the detailed results of cross-sectional SEM analyses on several other Si-based materials.

References

[1] S. Schweidler, L. d. Biasi, A. Schiele, P. Hartmann, T. Brezesinski, and J. Janek, J. Phys. Chem. C 2018, 122, 8829.

Figure 1
(Invited) Pseudocapacitive Energy Storage Using 2D Nanomaterialsunder Extreme Conditions
Authors: Park Ho Seok 
Published: December 2020

With increasing demand for high performance energy storage devices, the feasibility of reliable and functional energy storage devices that well operates under extreme conditions is of prime importance for expanding applicative fields as well as for understanding materials’ intrinsic and extrinsic properties and device physics.1-4 In this talk, I will introduce the control in the physical structure and chemical composition of 2D nanomaterials for ultracapacitive energy storage devices under limited circumstances, where conditions are classified into thermodynamic (e.g. pressure, volume and temperature) and kinetic (e.g. high rate and frequency) variables.1-10 In addition, a fundamental foundation via in-situ spectroscopic techniques will be presented to understand charge storage phenomenon of new materials and devices occurring on a nanoscale under various circumstances.8-10

Reference

[1] Ho Seok Park*, et al. Adv. Energy Mater., 2015, 1500959.
[2] Ho Seok Park*, et al. ACS Nano., 2015, 9, 8569-8577.
[3] Ho Seok Park*, et al. Adv. Funct. Mater., 2015, 25, 1053-1062.
[4] Ho Seok Park*, et al. ACS Nano, 2011, 5, 5167-5174.
[5] Ho Seok Park*, et al. Nano Lett., 2015, 15 (4), 2269-2277.
[6] Ho Seok Park*, et al. Adv. Energy Mater., 2016, 6, 1501115.
[7] Ho Seok Park*, et al. Adv. Energy Mater.,
2018, 8, 1702930.
[8] Ho Seok Park*, et al. ACS Energy Lett., 2018, 3, 724.
[9] Ho Seok Park*, et al. Joule, 2019, 3, 1-13.
[10] Ho Seok Park*, et al. Nature Materials,
2019, 18, 156-162.
Understanding Cell Degradation As a Function of Fast Charging
Authors: Raj Abhishek , Rodrigues Marco-Tulio , Abraham Daniel P. 
Published: December 2020

The results of this work aim to inform development of charging protocols that are less damaging to cell health. To that end, degradation during fast charging is observed through capacity limited charging with rates ranging from 1C to 8C and SOCs ranging from 10-100%. This test matrix probes various failure modes including metallic deposition of lithium at the anode, continued formation of SEI, and full cell impedance rise. Reference electrode testing and harvested electrodes transferred to half cells are used in order to deconvolute these degradation modes.
Through these experiments, we find that impedance rise is a function of charging rate alone and not on the amount of capacity passed at each cycle. Accordingly, limiting charging to a narrow SOC can delay cell aging, but not prevent eventual degradation. Particle cracking in the cathode is identified as the likely mechanism for impedance rise, supporting the notion that electrode design is essential to enabling fast charging.
Reversible Capacity Losses in LiFePO4 / Graphite Cells
Authors: Spingler Franz B. , Naumann Maik , Jossen Andreas 
Published: December 2020

This investigation focuses on significant capacity losses that have been found to occur in commercial lithium-iron phosphate (LFP) / graphite cells after repeated shallow cycling around medium states of charge (SOCs). Many combinations of cycle depth, medium SOC and temperature are examined over up to 10,000 full cycle equivalents. Up to 1000 full cycle equivalents, the capacity loss rate is four times higher when the cells are cycled between 40% and 60% state of charge than it is with full cycles. It is shown that these extraordinary losses occur in three different lithium-iron phosphate / graphite cell models, two 26650-type and one 18650-type, but do not occur in a nickel-manganese-oxide / graphite 18650-type cell. Most of the apparently lost capacity is shown to be recoverable by holding the cells at either 0 % or 100 % state of charge over a period of several days. Differential voltage analysis and visual post-mortem inspection as well as coin cell experiments with harvested electrode material suggest that these capacity losses are caused by strongly non-uniform lithium distributions in the electrodes. Hypothetical mechanisms are presented and discussed that could lead to such non-uniform distributions of lithium forming preferentially in lithium-iron phosphate based cells. The findings presented in this study are believed to be particularly relevant for grid applications like primary control reserve or in other scenarios where the battery mainly serves as a peak power buffer, e. g. in hybrid drivetrains.
The graph shows the capacity evolution of LFP / graphite cells cycled with full cycles and with 20 % cycle depth around three different medium SOCs. Capacity loss is largest when cycling between 40 % and 60 % SOC. The photographs show post-mortem views of the graphite anodes of three different LFP / graphite cell models that were cycled using this procedure until reaching ca. 80 % remaining capacity. Gold colored stripes at the top and the bottom of the electrodes indicate a non-uniform distribution of intercalated lithium.

Figure 1
Electrochemical Synthesis of Fused Indole Alkaloids By Controlling Radical Cation Reactivities
Authors: Okamoto Kazuhiro , Chiba Kazuhiro 
Published: December 2020

Pyrrolophenanthridone alkaloids are isolated from Amaryllidaceae and it has fused N-benzoyl indole as core structure. Many researchers targeted this simple alkaloids to demonstrate various synthetic method1), such as palladium- or hypervalent iodine-mediated intramolecular cross-coupling, tetrazine-promoted inverse electron-demand Diels-Alder reaction. All examples required DDQ oxidation to convert indoline to indole.
We established metal- and oxidant-free electrochemical intramolecular C(sp2)-H cross-coupling and indole synthesis reaction. These reactions were initiated by same anodic oxidation for electron-rich indoline ring, but different electron-transfer pathway was occurred in both cyclization and indole forming reaction. Moreover, non-coordinative medium has crucial role to control reactivity of radical cation. Increasing electrophilicity of radical cation is key strategy to accomplish intramolecular cross-coupling. MeNO2-LiClO4 and HFIP (1,1,1,3,3,3,-hexafluoro-2-propanol), which known as suitable medium for radical cation-mediated reaction2), had not worked well for this reaction. However, MeNO2-HFIP (9:1) mixed solvent strongly enhanced the reactivity of radical cations. This phenomenon was occurred by synergetic stabilization effect of MeNO2 and HFIP3). The low donor number of MeNO2 and anion trapping ability of HFIP made non-coordinative environment and resulting electrophilic radical cation was maintained in this medium. Dehydrogenative indole forming reaction was accomplished in Lewis-basic condition (MeCN-Bu4NClO4), and collidine additive enhanced benzylic deprotonation from radical cation.
Finally, we applied both reactions for the synthesis of seven naturally occurred pyrrolophenanthridone alkaloids4).

References

(1) (a) Black, DC.; Keller, PA.; Kumar, N. Tetrahedron Lett.
1989, 30, 5807-5808; (b) Ganton, MD.; Kerr, MA. Org. Lett.
2005, 21, 4777-4779; (c) Boger, DL.; Wolkenberg, SE. J. Org. Chem.
2000, 65, 9120-9124.
(2) (a) Okada, Y.; Chiba, K. Chem. Rev.
2018, 118, 4592-4630; (b) Kirste, A.; Nieger, M.; Malkowsky, IM.; Stecker, F.; Fisher, A.; Waldvogel, SR. Chem. Eur. J.
2009, 15, 2273-2277.
(3) (a) Shida, N.; Imada, Y.; Nagahara, S.; Okada, Y.; Chiba, K. Commun. Chem.
2019, 2, 24; (b) Shida, N.; Imada, Y.; Okada, Y.; Chiba, K. Eur. J. Org. Chem.
2020, 2020, 570-574.
(4) Okamoto, K.; Chiba, K. Org. Lett.
2020, accepted (DOI: 10.1021/acs.orglett.0c01082).

Figure 1
Evaluation of Matching Ratio Impact on Reduced Charging Time
Authors: Yourey William , Fu Yanbao , Li Ning , Battaglia Vincent , Tong Wei 
Published: December 2020

As electric vehicles (EV) show an increased penetration into the transportation market, a challenging hurdle to overcome is a vehicle “refuel” time similar to that of refilling a gasoline vehicle tank. One pathway to accomplish this is fast charging lithium-ion cells. The majority of commercial Li-Ion cells manufactured today contain various positive electrode active materials, coupled with a graphite negative electrode. An advantage of graphite electrodes is that the lithiated graphite voltage lies close to that of Li/Li+, resulting in in increased cell voltage. This benefit also has a detrimental effect on fast charging cells with graphite electrodes, where a small polarization of the negative electrode can result in a condition favorable to lithium metal plating on the negative graphite electrodes1.
While modified high rate charging procedures for commercial lithium-ion cells with conventional graphite negative electrodes, such as multistage constant current charging and boost charging, have been implemented. These procedures rely on reducing charging currents when cell voltage limits are reached 2,3. Following the development of an accelerated charging procedure based solely on negative electrode lithiation rate and polarization 4, the presented work evaluates the effect of negative to positive (N:P) matching ratio on cell fast charge performance. Two varying N:P matching ratios of 1.2:1 and 1.7:1 are evaluated and the resulted impact on fast charge performance will be presented. Utilizing an accelerated charging procedure based solely on the limiting negative electrode results in an identical charging procedure being used for multiple cell designs when charging to the same degree of negative electrode lithiation. Theoretically the applied procedure should result in a reduction in recharge time to 80% state of charge from 58 minutes to 34 minutes by altering the cell N:P ratio. Actual cell performance is altered as increased irreversible capacity loss occurs in cells with increased N:P rations, but improvements in cell charge times can be accomplished from design changes, namely cell N:P ratios.

References

C. Uhlmann, J. Illig, M. Ender, R. Schuster, and E. Ivers-Tiffée, Journal of Power Sources, 279, 428–438 (2015).

D. Anseán et al., Journal of Power Sources, 321, 201–209 (2016).

P. H. L. Notten, J. H. G. O. het Veld, and J. R. G. van Beek, Journal of Power Sources, 145, 89–94 (2005).

W. Yourey, Y. Fu, N. Li, V. Battaglia, and W. Tong, J. Electrochem. Soc., 166, A1432–A1438 (2019).
Modeling of Calendar Capacity Loss of Graphite-NMC Li-Ion Battery
Authors: Su Boman , Ke Xinyou , Yuan Chris 
Published: December 2020

Nowadays lithium ion batteries (LIBs) have been widely used in various portable electronic devices and electric vehicles, owing to their high power and energy densities1. The most popular LIB is using graphite anode and NMC(Lix[MnNiCo]O2) cathode2. However, battery aging is a critical issue for graphite-NMC LIBs, and currently studies on examining their capacity losses through modeling are few3-5.In this presentation, we will first introduce an electrochemical model that was developed for simulating the calendar capacity loss of a graphite-NMC Li-ion battery during the storage period. We will then present our modeling results on investigating the effects of state of charge (SOC), cell working temperature and electrode particle size on calendar capacity loss of a graphite-NMC Li-ion battery. In the end, we will discuss some strategies on reducing the calendar capacity loss and extending the graphite-NMC battery life.

Acknowledgement

This work was partially supported by U.S. DOE Industrial Assessment Center at Case Western Reserve University.

References

[1] Blomgren, G. E. (2016). The development and future of lithium ion batteries. Journal of the Electrochemical Society, 164(1), A5019.
[2] Wu, S. L., Zhang, W., Song, X., Shukla, A. K., Liu, G., Battaglia, V., & Srinivasan, V. (2012). High rate capability of Li (Ni1/3Mn1/3Co1/3) O2 electrode for Li-ion batteries. Journal of the Electrochemical Society, 159(4), A438.
[3] Lee, Y. J., Choi, H. Y., Ha, C. W., Yu, J. H., Hwang, M. J., Doh, C. H., & Choi, J. H. (2015). Cycle life modeling and the capacity fading mechanisms in a graphite/LiNi0.6Co0.2Mn0.2O2 cell. Journal of Applied Electrochemistry, 45(5), 419-426.
[4] Schmitt, J., Maheshwari, A., Heck, M., Lux, S., & Vetter, M. (2017). Impedance change and capacity fade of lithium nickel manganese cobalt oxide-based batteries during calendar aging. Journal of Power Sources, 353, 183-194.
[5] Jana, A., Shaver, G. M., & García, R. E. (2019). Physical, on the fly, capacity degradation prediction of LiNiMnCoO2-graphite cells. Journal of Power Sources, 422, 185-195.
Ionic and Thermal Transport in the Nasicon System Na1+XAlxTi2-X(PO4)3 (NATP)
Authors: Rohde Magnus , Seifert Hans , Ziebert Carlos 
Published: December 2020

Phosphate based ceramic electrolytes are promising candidates of all-solid-state Na-ion cells. Specifically, the NASICON (Na SuperIonic Conductor) structured electrolytes can be tailored by doping and structural tuning. Therefore, our studies were focused on the evaluation of possible interrelations between mechanisms of ionic and thermal transport, thermodynamic properties as well as morphology and microstructure of ceramic Na+ ion conductors.
Within this work, we have studied the ionic and thermal transport properties along with the thermodynamic key properties of Na-ion conducting phosphate ceramics. The system Na1+xAlxTi2-x(PO4)3 with x=0.3 was taken as a Na-ion conducting model system.
In addition to the ionic transport also the thermal transport properties were measured by a Laser Flash Apparatus (LFA 427, Netzsch GmbH), which enables the direct determination of the thermal diffusivity. The specific heat capacity of the NASICON systems were measured in a differential scanning calorimeter (DSC 404, Netzsch GmbH for the high temperature range 220 to 900 °C and DSC 204, Netzsch GmbH for the low temperature range from 0 to 320 °C). The thermal conductivity was calculated from data of the thermal diffusivity, the heat capacity and the density.
In contrast to the ionic conductivity, which increases in both NASICON systems about two orders of magnitude from RT to 200 °C the thermal diffusivity and conductivity, respectively, varies only slowly in this temperature due to strong phonon scattering at point defects. Changes of the thermal transport properties within a given material system can be directly related to a variation in the phonon mean free path, which is affected by scattering processes at grain and phase boundaries, respectively, but also by defects. This is important for solid electrolytes since the number and distribution of point defects i.e. vacancies are crucial for the transport of ions within a lattice structure.
(Invited) Doping and Composition Optimization of Electrocatalysts for Water Splitting and Metal-Ion Batteries
Authors: Fan Hong Jin 
Published: December 2020

Water electrolysis, fuel cells, and metal-air batteries all require efficient and cheap electrocatalysts that can significantly lower the reaction overpotentials. Bimetallic alloys and their oxides or nitrides compounds are particularly interesting as non-precious metal electrocatalyst materials for HER, OER, and ORR because of their tailorable electronic structure, conductivity, and surface chemistry. Our group has been actively working on nanoarray materials directly grown on conductive substrates as electrodes for supercapacitor, batteries and electrocatalyst.
In this talk, I will present two main results about surface and interface engineering/functionalization of array-type electrocatalysts for water splitting and for meal-ion batteries. First, we demonstrate that dual anion doping, or metal-anion co-doping in alloy compounds (Ni2P, CoP) can simultaneously modulate key parameters in water dissociation and hydrogen adsorption energies, and thus leads to a significant enhancement in catalytic activities for both HER and OER in wide-pH solutions. Second, effective bi-functional catalysts (ORR and OER) supported on doped 3D carbon supports for cathode materials in Zn-air batteries will also be presented.
This work is supported by Singapore MOE (MOE2017-T2-1-073) and A*STAR (AMEIRG18-0006).
Morphological Heterogeneities of Stripped and Plated Lithium Metal Analyzed By X-Ray Tomography
Authors: Magnier Lucile , Devaux Didier , Lachambre Joël , Lecuyer Margaud , Deschamps Marc , Maire Eric , Bouchet Renaud 
Published: December 2020

Lithium (Li) metal is the most promising anode battery material to be implemented in stationary and electric vehicle applications [1]. For years, its use and subsequent industrialization was hampered because of the inhomogeneous Li electrodeposits onto Li metal leading to dendrite growth [2]. The use of solid polymer electrolyte is a solution to mitigate dendrite growth but the Li redox processes, stripping and plating, remain heterogeneous. Blue Solutions compagny is already commercializing lithium metal batteries using a solid polymer electrolyte to prevent dendrite growth. A precise characterization of the behaviour of these heterogeneities during cycling is essential to move towards an optimized anode. During our research, we have developed a characterization method based on X-ray tomography applied to model Li symmetric cells to
quantify and spatially probe the Li stripping/plating process. Ante- and post-mortem cells are recut in order to allow a 1µm voxel size
in a conventional laboratory scanner. The reconstructed cell volume is post-processed to numerically re-flatten the Li electrodes, allowing
us a subsequent precise measurement of the electrode and electrolyte thicknesses and revealing local interface modifications. This in-depth
analysis brings information on the location of heterogeneities and the impact on the electrode microstructure both at the electrode grains and
grain boundaries. This simple methodology permits to finely retrieve and then surface-map the local current density at both electrodes based
on the local thickness change during the redox process (see Figure 1a : 2D map of the cathode local current density variations overlaped with
grain boundaries pattern (image analysis of a cell after moving 22µm of lithium)). Thanks to quantitative data that can be extracted from the
2D maps (see Figure 1b: anode and cathode quantitative distribution of local current density variations), we show that the plating process
(reduction) induces more pronounced heterogeneous deposits compared to the stripping (oxidation) one. The existence of cross-talking
between the electrodes is also highlighted.

[1] Wu Xu et al., Energy Environ. Sci. 7, no 2 (2014): 513-37
[2] Xin-Bing Cheng et al., Chemical Reviews 117, n°15 (2017): 10403-73

Figure 1