bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxidation Controlled Anode Materials for Li Ion Battery
Authors: Jeong Je Jun 
Published: February 2020

Silicon is considered one of the best candidates as an anode material for the next generation of Lithium ion batteries due to its enormous capacity of 3579 mAh/g (Li15Si4) compared to that of graphite (372 mAh/g). However, Lithium ion insertion and extraction results in a volumetric expansion of 300 ~ 400%, which can lead to fracture that cause the capacity fading and poor cycle efficiency of the silicon anode during electrochemical cycling.
In this study, we introduce a Si-based alloy covered with oxide layer on the surface of particles. Inactive oxide layer component plays a structural buffering role to minimize the mechanical stress induced by huge volume change of active silicon. Si-Fe powders from ferrosilicon and Fe2O3 were synthesized by a high-energy mechanical milling process. The electrochemical properties were measured using coin cell with LCO as the counter electrode. From the electrochemical cell test, we observed the smaller degradation of the initial capacity and better efficiency compared to that of Si-Fe, and the capacity retention rate is also improved compared to that of Si-Fe alloy. A high-resolution transmission electron microscope and X-ray diffraction were used for detailed phase analysis of Si-Fe-O compounds.

Figure 1
Nucleation and Growth Controlled Polyol Synthesis of Size-Focused Nanocrystalline LiFePO4 Cathode for High Performance Li-Ion Batteries
Authors: Baboo Joseph Paul , Gim Jihyeon , Song Jinju , Kim Sungjin , Alfaruqi Muhammad Hilmy , Jo Jeonggeun , Lee Jun , Kim Jaekook 
Published: February 2020

Mono-dispersed and densely packed, LiFePO4 cathodes with high rate performance versus lithium were synthesized using a two-step polyol process. The particle-size distribution and packing density of LiFePO4 nanoparticles were fine-tuned via separation of the nucleation and particle growth processes in the polyol medium by varying reaction time and temperature. Precisely, the LiFePO4 samples were synthesized by heating the reaction mixtures at 200 °C for various reaction times (0, 1, 3 and 6 h) to facilitate nucleation and thereafter the solution temperature was raised and maintained at 320 °C to facilitate the crystal growth process. XRD studies confirmed the formation of olivine phase in all the samples. The FE-SEM, FE-TEM and particle-size distribution studies illustrate that the particle-size of olivine nanocrystals may be tuned to approximately 200 nm by controlling the aging time at 200 °C or in other words separating the nucleation and crystal growth process. The olivine cathodes synthesized by maintaining 3-6 h aging time demonstrate improved discharge capacities and cycle performances in comparison to those of the remaining samples. In particular, the 6 h olivine cathode registered average discharge capacities of 130, 87 and 64 mAh/g at 5 C, 10 C and 15.7 C current rates respectively.
Sealed Recombinant Flow Batteries
Authors: Selverston Steven , Wainright Jesse S. 
Published: February 2020

Flow battery systems were developed in the late 1970s, and have received renewed interest for grid-scale energy storage [1]. No flow batteries, though, have achieved mature commercial status, and this is partly because of poor stability and lifetime. Many flow battery systems have complications that results from electrolyte imbalances that result from undesired side reactions.
Commercial lead-acid batteries have well-developed recombination systems that help extend battery lifetime and reduce maintenance [2]. This has not been the case for flow batteries though. For flow (and hybrid flow) batteries, there have been many proposed systems to deal with the electrolyte imbalances, but they are typically complicated open systems that require the continuous supply of rebalancing reactants such as hydrogen or chlorine, and which allow gas venting or the formation of other waste products. Typically, the reaction is carried out in a fuel cell or trickle-bed reactor, and it requires careful monitoring of state-of-charge, as well as a control system. Here, we show the behavior of all-iron flow battery systems [3] designed to be sealed and valve-regulated just like modern lead acid batteries. All-iron flow batteries charge and discharge according to Equation 1, and the undesired side reaction at the negative electrode is given by Equation 2.
3Fe2+ + 4e ↔ Fe0 + 2Fe3+ (1)
2H+ + 2e
→ H2 (2)
The recombination reaction in the all-iron battery, which is the same reaction originally used by NASA’s rebalancing fuel cell, is given by Equation 3.
H2 + 2Fe3+ → 2Fe2+ + 2H+ (3)
This reaction is spontaneous (E0 = 0.77 V), and occurs readily at room temperature over a catalyst. In the all-iron flow battery system, recombination can also function as a pH control system, mitigating problems associated with the formation of iron hydroxide precipitates such as those given by Equations 4 and 5.
Fe2+ + 2OH
− → Fe(OH)2
, (4)
Fe3+ + 3OH
− → Fe(OH)3
. (5)
In this study, we show that recombination in a sealed system can be used to keep the electrolyte balanced in terms of both iron and hydrogen species, without the need for an external reactants or control systems (see Figure 1). The pressure in the electrolyte reservoir and the pH of the electrolytes rise during charge, and fall during discharge as the recombination occurs. These results represent a major step forward toward sealed recombinant flow batteries and shed new light on flow battery electrolyte dynamics.
Figure 1: System dynamics in a recombinant all-iron hybrid flow battery during charge/discharge cycling. System pressure – blue curve, Negative electrolyte pH – green curve, Positive electrolyte pH – red curve.

Figure 1
Interrogation of Alkaline AA Batteries Using in Operando Electrochemical ­Acoustic Time-of­-Flight Analysis and in Operando energy Dispersive X-Ray Diffraction
Authors: Bhadra Shoham , Steingart Daniel A , Hertzberg Benjamin Joseph , Hsieh Andrew , Gjeltema Peter J 
Published: February 2020

Recently, in operando Electrochemical ­Acoustic Time-of­-Flight (EAToF) analysis has been shown to provide information about the state of charge (SoC) and state of health (SoH) of a number of battery geometries and chemistries using ultrasonic interrogation of the density and modulus shifts that occur during charge and discharge. The technique has thus far offered a general understanding of these batteries, but has not been used for in depth analysis of individual battery chemistries.
In this work, we performed EAToF measurements on commercially available alkaline Zn/MnO2 AA batteries of a number of different brands under discharge and charge conditions. The data from this method were compared to in situ energy-dispersive x-ray diffraction (EDXRD) data from comparable alkaline AA batteries. Changes in the waveforms in the ultrasonic time-of-flight measurements were shown to correlate with phase transitions in the MnO2 cathode and densification and dehydration of the Zn anode, as shown by peak evolution in the EDXRD data. The mechanisms by which the phase and morphology transitions can change the transmission and reflection of an ultrasonic pulse and the utility of EAToF analysis in determining material differences between different brands of alkaline cells are discussed.
Towards High Performance Non-Aqueous Flow Cells
Authors: Milshtein Jarrod David , Darling Robert M. , Brushett Fikile R. 
Published: February 2020

Non-aqueous redox flow batteries (NRFB) have opened a new pathway towards achieving economically viable grid-level energy storage1. As such, a number of studies have reported on the electrochemical behavior of newly developed active species, salt, and solvent combinations (i.e. Brushett et al.2, Escalante-Garcia et al.3, etc.). Most of these redox chemistries, however, have been demonstrated only in beaker cells or un-optimized flow cells; system-level studies toward grid-scale applications have yet been realized. In order to meet aggressive grid storage cost targets, NRFB’s must meet the following power requirements: 3.5 V, 130 mA cm-2, 91% voltaic efficiency4. Hence, designing high performance non-aqueous flow cells tailored for different chemistries becomes a daunting task given the breadth of available chemistries and lack of materials properties (i.e. viscosity) knowledge required for cell design.
To ease the design process, this study demonstrates a chemistry-agnostic design cycle for non-aqueous redox flow batteries. Specifically, this design cycle will specify flow field geometries and porous electrode materials properties, which optimize the power output and voltaic efficiency of an unspecified NRFB chemistry. First, transport through interdigitated flow fields is modeled (Figure 1) to predict polarization as a function of various dimensionless groups. This modeling study develops guidelines for geometry and flow conditions as a function of materials properties in order to optimize electrochemical performance. Second, a single-electrolyte study5 (Figure 1) is employed to verify the impact of cell design on the cell performance for model active compounds (i.e., TEMPO6). The single-electrolyte configuration also allows us to study cell performance at fixed states of charge by collecting polarization and impedance data at varying flow rates. Ultimately, this experimental technique will verify trends discovered through the transport modeling. This modeling-experimental approach creates a tool for predicting optimized cell architectures given a set of input materials and chemical properties.

Acknowledgments

We gratefully acknowledge the financial support of the Joint Center for Energy Storage Research and the National Science Foundation Graduate Research Fellowship Program.

References

1. R. M. Darling, K. G. Gallagher, J. A. Kowalski, S. Ha, and F. R. Brushett, Energy Environ. Sci., 7, 3459–3477 (2014).
2. F. R. Brushett, J. T. Vaughey, and A. N. Jansen, Adv. Energy Mater., 2, 1390–1396 (2012).
3. I. L. Escalante-García, J. S. Wainright, L. T. Thompson, and R. F. Savinell, J. Electrochem. Soc., 162, A363–A372 (2015).
4. R. M. Darling, K. G. Gallagher, W. Xie, L. Su, and F. R. Brushett, Transport Property requirements for flow battery separators, submitted.
5. R. M. Darling and M. L. Perry, J. Electrochem. Soc., 161, A1381–A1387 (2014).
6. X. Wei et al., Adv. Mater., 26, 7649–7653 (2014).

Figure 1
Graphite-Based Non Precious Metal Catalyst for Oxygen Reduction Reaction
Authors: Dumont Joseph H , Martinez Ulises , Mohite Aditya , Purdy Geraldine M , Atanassov Plamen , Zelenay Piotr , Gupta Gautam 
Published: February 2020

The high cost of Pt-based catalysts for the anode and cathode has greatly limited the distribution and the commercialization of polymer electrolyte fuel cells (PEFCs). Non-precious metal catalysts (NPMCs) have shown high activity and low hydrogen peroxide yields [1, 2], and are a possible alternative to Pt-based catalysts for oxygen reduction reaction (ORR) in the PEFC cathode. In this work, we explore the development of graphite-based catalysts for fuel cell applications. The desired mechanical and chemical stability of graphite could improve durability of NPMC systems. However, implementation of graphite as a catalyst precursor presents new challenges as it is chemically inert. Given the fact that NPMCs are composed of carbon, nitrogen, and transition metals, a systematic approach will be presented to incorporate transition metal and nitrogen precursors into graphite structures. Graphite as a starting material will be treated with high temperature and pressure to intercalate transition metals and/or nitrogen compounds. The formation of active sites will be induced by the increase of defects in the material by harsh acid treatments and by microwaved synthesis. Structural, chemical, and morphological information will be presented via X-ray (XRD and XPS) techniques along with electron microscopy (SEM, TEM). The electrochemical activity for the ORR using RRDE for these graphite-based catalysts will be presented in both alkaline and acidic media. Our preliminary results indicate an improvement of the catalytic activity upon addition of defects, metal and nitrogen compounds.

References:

[1] Wu, G., More, K. L., Johnston, C. M., Zelenay, P., Science, 332, 443-447 (2011).
[2] Bashyam, R., Zelenay, P., Nature, 443, 63-66 (2006).
Graphene-Supported ' Core-Shell ' Carbon Nitride Fe- and Sn-Based Electrocatalysts for the Oxygen Reduction Reaction (ORR)
Authors: Bach Delpeuch Antoine , Negro Enrico , Vezzù Keti , Nawn Graeme , Bertasi Federico , Pagot Gioele , Di Noto Vito 
Published: February 2020

One of the major obstacles for the development of feasible low-temperature fuel cells (e.g., proton-exchange membrane fuel cells, PEMFCs, and anion-exchange membrane fuel cells, AEMFCs) is the sluggishness of the oxygen reduction reaction (ORR) kinetics. As of today, carbon-supported Pt-based nanocrystals are the most efficient electrocatalysts (ECs) for the ORR. However, the low abundance of platinum and the insufficient durability of these ECs, which results from the degradation of the carbon support, constitute some of the major obstacles for large-scale commercialization of PEMFC and AEMFC technology [1, 2].
In this study, new "Pt-free" electrocatalysts are prepared and studied for the ORR process. These ECs consist of alloyed Fe-Sn nanoparticles embedded in a carbon nitride “shell” a few nanometers thick, supported on conducting micrometric graphene sheets that act as the “core”. The electrocatalytic precursors are prepared by a sol-gel/gel-plastic process following a protocol previously developed in our laboratory [3]; afterwards, they undergo suitable pyrolysis and activation processes. The proposed electrocatalysts, both pristine (e.g., FeSn0.5-CNl 900/Gr) and activated (e.g., FeSn0.5-CNl 900/Gra) are extensively characterized in order to gain a full understanding of their structural features, proprieties and electrocatalytic performance [4]. The chemical composition is determined by inductively-coupled plasma atomic emission spectroscopy (ICP-AES). The structure is elucidated by powder X-Ray diffraction (XRD); the morphology is inspected by high-resolution scanning electron microscopy (HR-SEM) and high-resolution transmission electron microscopy (HR-TEM) (Fig. 1). Finally, “ex situ” cyclic voltammetry with the rotating ring-disk electrode (CV-TF-RRDE) and “in situ” single fuel cell measurements are carried out to evaluate the electrocatalytic performance as well as to study the ORR mechanism. The preliminary CV-TF-RRDE investigations in an alkaline medium exhibit promising results. Indeed, the catalysts exhibit an overpotential ca. 70 mV higher with respect to a 20 wt.% Pt/C reference (Fig. 2).

Acknowledgements

The authors would like to thank the European Union for the financial support provided by the GRAPHENE Flagship, project “GRAFUS - Graphene and related materials as supports for innovative metal carbon nitride electrocatalysts for anion-exchange membrane fuel cells”.

REFERENCES

[1] R. Othman, A. L. Dicks, Z. Zhu, Int. J. Hydrogen Energy
37, 357 (2012).
[2] S. Zhang, X.-Z. Yuan, J. N. C. Hin, H. Wang, K.A. Friedrich, M. Schultze, J. Power Sources
194, 588 (2009).
[3] V. Di Noto, E. Negro, R. Gliubizzi, S. Lavina, G. Pace, S. Gross, C. Maccato, Adv. Funct. Mater.
17, 3626 (2007).
[4] V. Di Noto, E. Negro, S. Polizzi, F. Agresti, G.A. Giffin, ChemSusChem
5, 2451 (2012).

Figure 1
Towards Realizing Wearable Batteries: Dual Ion Prussian Blue Analog/Zinc Battery Architecture with Long Cycle Life and High Energy Efficiency
Authors: Gupta Tanya , Kim Andrew , Biswas Shaurjo , Steingart Daniel A 
Published: February 2020

In recent years Prussian Blue Analogues (PBA) have attracted a lot of interest as a battery material due to their relative safety to skin contact and exceptionally high cyclability. Their open cage structure allow a variety of ions to shuttle in and out and thus store energy. This can be done very rapidly as there is no phase change associated with this process, which makes them stable for over thousands of cycles.(Pasta et al. 2012) Recent developments in this field show the use of zinc to act as the anode, which can exhibit a PBA vs. Zn cell potential as high as 1.7 V. But the performance of such a system reported thus far show less than 10% cycle life as that of highly reversible PBA half cells. (Zhang et al. 2014)

In this work we demonstrate a high potential aqueous Sodium ion battery with high cycle life, to achieve as much as 500 cycles with over 80% cell capacity retention, which is five times of the maximum reported in literature. (Trócoli and La Mantia 2015)The high potential of Zn and high reversibility of Na+ ion cycling in Copper Hexacyanoferrate lattice is exploited in making a considerable improvement over previous Zn/ Zinc Hexacyanoferrate system. We validate the hypothesis that the slow kinetics of zinc intercalation compared to sodium in Hexacyanoferrates enables preferential intercalation of sodium ions and hence reduce zinc poisoning. We further show the use of Hyper Dendritic Zinc (HD Zn) to improve capacity retention and overall kinetics of the system. Prussian Blue has been used as a fabric dye for over 80 years. The relative safety of the dual ion PBA/HD Zn system that we demonstrate helps us step closer to realizing batteries on fibers woven integrated with wearable electronics.
Metal Oxides Nanoparticles Encapsulated in 3D Porous Carbon Microspheres for High Performance Lithium Storage
Authors: Li Ying , Liu Lianjun 
Published: February 2020

Nanostructured metal oxides (e.g., ZnO, CoO, SnO2) have been considered as alternative anode materials for next-generation of lithium-ion battery (LIB) because of their higher reversible capacities (500–1500 mAh g−1) than conventional graphite of 372 mAh g−1. However, the metal oxide particles suffers from fast capacity decay due to its poor electrical conductivity, limited ions transport kinetics, serious aggregation, and large volume expansion (> 200%) and contraction during the charge/discharge process. To address these issues, we synthesized novel 3D porous carbon microspheres (PCM) from low cost raw materials (i.e., sucrose) via a spray pyrolysis method, and developed a new architecture of metal oxides nanoparticles decorated into the PCM by a simple one-pot hydrothermal method. The developed metal oxide/PCM hybrids (e.g., SnO2@PCM, ZnO-CoO@PCM) demonstrated a high reversible capacity, good rate performance, and excellent cycling stability. The superior electrochemical performance is because (1) the continuous and large surface area carbon framework greatly enhanced the electrical conductivity and dispersion of metal oxides nanoparticles, (2) the porous structure with multi-modal pores could warrant good electrolyte diffusion and fast li-ion transport and provide sufficient space to buffer the large volume expansion of the metal oxides,and (3) the nano-sized metal oxide particles (less than 10 nm) are uniformly confined in the pores that avoid the strong aggregation. Our low-cost, eco-friendly and multifunctional materials may hold a significant promise for the construction of advanced electrodes for high performance energy storage devices.Furthermore, the 3D porous nanocomposite architecture could shed light on the design and synthesis of other advanced electrodes for energy conversion and storage.
A Hybrid Dual-Type Sulfur Cathode and a Lithiated Si/SiOx Nanosphere Anode for Li-Sulfur Full Cells
Authors: Lee Sang-Kyu , Park Eunjun , Scrosati Bruno , Hassoun Jusef , Park Min-Sik , Kim Young-Jun , Kim Hansu , Belharouak Ilias , Sun Yang-Kook 
Published: February 2020

Lithium−sulfur batteries could become an excellent alternative to replace the currently used lithium-ion batteries. 1 The natural abundance and low cost of sulfur, coupled with the high theoretical energy density of sulfur-based cathodes, namely, 1675 mAh g-1 and 2600 Wh kg-1, are the major advantages of this sulfur battery.2 However, commercialization of lithium−sulfur batteries has so far been limited due to the cyclability problems associated with both the sulfur cathode and the lithium−metal anode.3 Herein, we demonstrate a highly reliable lithium−sulfur battery showing cycle performance comparable to that of lithium-ion batteries; our design uses a highly reversible hybrid dual-type sulfur cathode (solid sulfur electrode and polysulfide catholyte) and a lithiated Si/SiOx nanosphere anode. Our result shows superior battery performance in terms of high specific capacity, excellent charge−discharge efficiency, and notable cycle life, delivering a specific capacity of ∼750 mAh g−1 over 500 cycles (85% of the initial capacity). These promising behaviors may arise from a synergistic effect of the enhanced electrochemical performance of the newly designed anode and the optimized layout of the cathode.

References

1. B. Scrosati, J. Hassoun, Y-K. Sun, Energy Environ. Sci., 4, 3287 (2011).
2. E. Peled, A. Gorenshtein, M. Segal, Y. Sternberg, J. Power Sources, 26, 269 (1989).
3. Y-V. Mikhaylik, J. R. Akridge, J. Electrochem. Soc., 151, A1969 (2004).
(Invited) Characteristics of a Wire-Bonding-Less SiC Power Module Operating in a Wide Temperature Range
Authors: Sato Shinji , Tanisawa Hidekazu , Anzai Takeshi , Takahashi Hiroki , Murakami Yoshinori , Kato Fumiki , Watanabe Kinuyo , Sato Hiroshi 
Published: February 2020

Introduction

Using high-speed switching, wide bandgap semiconductor devices can reduce on-resistance in the on-state to realize low power converter losses. In addition, SiC power devices can be operated in high temperatures; thus, their cooling systems can be reduced in size or removed all together, thereby increasing the power density of the power converter. In this study, we designed and fabricated a SiC power module with a built-in snubber circuit. This power module is operable in high temperatures over 200 degrees C.

Design of Power Module for High-Temperature Operation

The manufactured power module, its components, and its circuit diagram are shown in Fig. 1. The module size is 30 × 44 × 29 mm3. Active metal brazing copper (AMC) substrates sandwich the four SiC-metal–oxide–semiconductor field-effect transistors (MOSFETs) in this structure. Two AMC substrates connect via the metal block. The C–R snubber circuit is built-in on the surface of AMC1 (Fig. 1(b)). The SiC-MOSFET and AMC1 are joined by a flip-chip-bonding technique using an Al bump. The others are joined by Au–Ge solder. Fig. 2 shows the 50-kHz switching waveforms. Fig. 3 shows the circuit configuration for the Fig. 2 waveforms. This power module can realize high-speed switching in a fall time tf @ 25 ns. Surge voltage and ringing are suppressed by the built-in snubber circuit.

Acknowledgment

This work was supported by Council for Science, Technology and Innovation (CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP), "Next-generation power electronics/Consistent R&D of next-generation SiC power electronics", and "the Novel Semiconductor Power Electronics Project Realizing Low Carbon Emission Society" (funding agency: NEDO).

Figure 1