bluuebunny/crossref_metadata_2025_split huggingface dataset:
Degradation Mechanisms of a Cermet Anode for Aluminum Production
Authors: Meyer Pauline , Gibilaro Mathieu , Chamelot Pierre , Massot Laurent 
Published: February 2020

Aluminum production is made by alumina electrolysis (Al2O3) in a molten mixture of cryolite (Na3AlF6-AlF3-CaF2-Al2O3) at high temperature (960°C), between a liquid aluminum cathode and a carbon reactive anode:
2Al2O3(cry) + 3C(s) → 4Al(l) + 3CO2(g)

As the production of one ton of aluminum causes emission of 1.2 tons of CO2 [1], an inert anode is under development to form O2.
Anodes made of iron and nickel mixed spinel oxides have been studied since the 80's. As spinel oxides have no sufficient electrical conductivity, addition of a metallic phase was proposed in the 80's, creating the so-called CERMET (CERamic – METal), with a metallic phase (Ni, Cu and Fe) and a conductive oxide phase (NixFe3-xO4 & Ni1-xFexO). In the spinel structure, tetrahedral and octahedral sites are occupied by ions of different valences (eg: Fe2+/Fe3+), creating an electrical conduction thanks to an electron hopping phenomenon.
CERMET anodes were tested at 0.8A/cm² for different durations (from 30min to 8h) and analyzed by SEM, coupled with the energy-dispersive x-ray spectroscopy (EDX). First experiments revealed both chemical and electrochemical degradation: dissolution of the oxide phase and oxidation of the metallic phase.
To investigate this complex system, experiments without polarization were firstly performed. Results showed that the dissolution of oxide phase is due to a significant substitution phenomenon between Al3+ in the electrolyte and Fe3+ in the spinel phase [2], leading the formation of a soluble aluminate NixFe3-x-yAlyO4. To study the Al3+ impact on the aluminate formation, LiF-CaF2 solvent was selected and Al3+ ions were added as a solute at different concentrations. It was demonstrated that the degradation rate of the oxide phase increases with the Al3+content and was estimated by measuring the amount of dissolved oxide phase (Optical Microscopy) vs the immersion duration in the electrolyte.
Then, studies under galvanostatic electrolysis were carried out and new phases were identified: FeF2, Cu2O and Ni1-x-yFexCuyO monoxide.
Thanks to these observations and thermodynamic calculations, a global degradation mechanism of the anode was proposed.
[1] K.C. Grjotheim, C. Krohn, M. Malinovsky, K. Matiasovsky, J. Thonstad, "Aluminium electrolysis: the chemistry of the Hall-Heroult process", Aluminium Verlag, Düsseldorf, 1977.
[2] B. Gillot, A. Rousset, "On the limit of Aluminum substitution in Fe3O4 and γ-Fe2O3", Phys. Stat. Sol, 1990.
Macroporous Carbon Nanotube (CNT) Foams As Lithium Air Battery Cathodes
Authors: Shen Chao , Liu Teng , Zhang Mei , Zheng Jim P. , Hendrickson Mary A. , Plichta Edward J. 
Published: February 2020

In recent years Lithium air (Li-air) battery has attracted considerable attention mainly due to its extreme high specific energy1,2. The theoretical specific energy is estimated up to 3,000 Wh kg-1, which is approximately one order of magnitude higher than that of conventional Li-ion battery3. The cathode of Li-air battery is chosen as porous carbon material in most studies, which plays a significant role of Li2O2 storage and electron transfer. Good electronic conductivity, fast oxygen diffusion, stable mechanical integrity and sufficient surface area and porosity are required for Li-air battery cathode4.
In this study, a simple and scalable method for manufacturing three-dimensional carbon nanotube (CNT) foams as the Li-air battery cathode was being reported. CNT foams were synthesized using poly(methyl methacrylate) (PMMA) microspheres as a template and Polyacrylonitrile (PAN) as a precursor to create crosslinks among CNTs5,6. The tunable porosity and major pore size afford the opportunity to estimate the influence of cathode pore structure with controlled configuration and properties. A series of CNT foams with high porosity and desired major pore size were tested as cathodes in Li-air cells for single galvanostatic discharge performance. As shown in Fig. 1, the cathode with major pore size of 6 μm achieved a specific capacity over 10,000 mAh g-1 at a current density of 0.13 mA cm-2. Meanwhile, a direct inverse correlation between cathode major pore size and cell discharge specific capacity was observed. The electrochemical performance was combined with microscopy, porosimetry and modeling for further discussion. The results revealed that discharge product of Li2O2 were mainly deposited in micro-size pores and the reduced pore size favored the discharge reaction due to the increased volume specific surface area.
1. N. Akhtar and W. Akhtar, Int. J. Energy Res., 39, 303–316 (2015).
2. N. Imanishi and O. Yamamoto, Mater. Today, 17, 24–30 (2014).
3. J. P. Zheng, R. Y. Liang, M. Hendrickson, and E. J. Plichta, J. Electrochem. Soc., 155, A432-A437.
4. J. Lu, L. Li, J. Park, Y. Sun, F. Wu and K. Amine, Chem. Rev., 114, 5611–5640 (2014).
5. Y. Cui and M. Zhang, ACS Appl. Mater. Interfaces, 5, 8173–8178 (2013).
6. Y. Cui and M. Zhang, J. Mater. Chem. A, 1, 13984-13988 (2013).

Figure 1
Stabilization of Li Metal Anode in DMSO-Based Electrolytes Via Optimization of Salt-Solvent Coordination for Li-O2 Batteries
Authors: Liu Bin , Xu Wu , Yan Pengfei , Kim Sun Tai , Engelhard Mark H , Sun Xiuliang , Mei Donghai , Cho Jaephil , Wang Chongmin , Zhang Ji-Guang 
Published: February 2020

Stabilization of Li Metal Anode in DMSO-Based Electrolytes via Optimization of Salt-Solvent Coordination for Li-O2 Batteries

Bin Liu,† Wu Xu,†,* Pengfei Yan,‡ Sun Tai Kim,∥ Mark H. Engelhard,‡ Xiuliang Sun,§ Donghai Mei,§ Jaephil Cho,∥ Chong-Min Wang,‡ Ji-Guang Zhang†,*

† Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA 99354, United States

‡ Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354, United States

§ Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99354, United States

∥ Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, South Korea.
*E-mails: jiguang.zhang@pnnl.gov; wu.xu@pnnl.gov
The conventional DMSO-based electrolyte (1 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in DMSO) is unstable against the Li metal anode and therefore cannot be used directly in practical Li-O2 batteries. Here, we demonstrate that a highly concentrated electrolyte based on LiTFSI in DMSO (with a molar ratio of 1:3) can greatly improve the stability of the Li metal anode against DMSO and significantly improve the cycling stability of Li-O2 batteries. This highly concentrated electrolyte contains no free DMSO solvent molecules, but only complexes of (TFSI–)a-Li+-(DMSO)b (where a+b=4), and thus enhances their stability with Li metal anodes. In addition, such salt-solvent complexes have higher Gibbs activation energy barriers than the free DMSO solvent molecules, indicating improved stability of the electrolyte against the attack of superoxide radical anions. Therefore, the stability of this highly concentrated electrolyte at both Li metal anodes and carbon-based air electrodes has been greatly enhanced, resulting in improved cyclic stability of Li-O2 batteries. The fundamental stability of the electrolyte with free-solvent against the chemical and electrochemical reactions can also be used to enhance the stability of other electrochemical systems.

Acknowledgement

This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies, of the U. S. Department of Energy (DOE) as part of Battery Materials Research (BMR) program.

Figure 1
XPS Comparative Analysis of the Chevrel Phase Mo6S8 and the Analogous Mo6Se8 during Mg Insertion
Authors: Richard Julien , Colin Jean-Francois , Benayad Anass , Martinet Sebastien 
Published: February 2020

Since the earlier works in 2000 by Aurbach et al
1, magnesium-ion batteries emerged as an alternative to lithium-ion batteries thanks to many advantages: magnesium is the 5th most abundant metal in the earth crust, its divalent character and its ionic radius similar to lithium ionic radius gives it a volumetric capacity higher than lithium (3833 Ah/L and 2046 Ah/L respectively). Eventually the absence of dendritic growth on metallic magnesium is a plus in term of security.
Several cathode materials were proposed for Mg-ions battery, nevertheless the reference positive electrode material in Mg-Ion technology remained the Chevrel Phase with the formula Mo6S8. The Chevrel phase, synthesized by R. Chevrel et al
2 in 1974, was described as an octahedral cluster of molybdenum located in a cube of sulfur that forms a Mo6S8 pattern. Structural analysis3 (X-Ray Diffraction) showed the existence of 12 insertions sites localized inside a cube of sulfur surrounded by Mo6S8 clusters.
The electrochemistry highlighted 2 types of insertion sites able to host Mg2+ at different potentials.
Mg trapping into the Chevrel Phase was also noticed but curiously this phenomenom doesn’t occur in the analogous phase Mo6Se8
4 thanks to the lower ionicity of Se compared to S.
The anionic framework plays a major role in the redox process during Mg insertion, this study is a comparative analysis of Mo6S8 and analogous Mo6Se8 using electrochemistry and X-ray Photoemission Spectroscopy to get a direct observation of the redox mecanism during charge/discharge of the material.
We performed ex situ XPS core peak analyses on Mo6S8 and Mo6Se8 analogous electrodes at different states of charge to probe the molybdenum, the sulfur and the selenium oxydation states and the environment (polarized or metallic) of inserted magnesium ions.
These results will be discussed based on a step-by-step XPS study before and after cycling, and will be correlated with the electrochemical performances.
References:
(1) D. Aurbach, Z. Lu, A. Schechter, Y. Gofer, H. Gizbar, R. Turgeman, Y. Cohen, M. Moshkovich & E. Levi, Nature vol 407 (2000) 724

(2) R. Chevrel et al, Mat. Res. BuLl. Vol. 9, pp. 1487-1498, 1974.
(3) R. Chevrel, M. Sergent Superconductivity in Ternary Compounds I
Volume 32 of the series Topics in Current Physics pp 25-86
(4) M.D. Levi et al, Solid State Ionics
Volume 176, Issues 19–22, June 2005, Pages 1695–1699
The Anode - Magnesium Monocarborane Interface for Metal Deposition and Dissolution
Authors: Arthur Timothy S , Singh Nikhilendra , Glans Anders , Liu Yi-Sheng , Guo Jinghua , Kisslinger Kim , Li Jing , Stach Eric A. , Alsem Daan Hein , Salmon Norman , Tutusaus Oscar , Suto Koji , Takechi Kensuke , Mohtadi Rana 
Published: February 2020

The future of green mobility depends on continued research into alternative energy storage such as batteries, fuel cells and super-capacitors. However, to exceed the demands of current hybrid, plug-in hybrid and electric vehicles, new battery systems with high energy density are required. Magnesium (Mg) is an attractive alternative to current lithium-ion technologies because of the transfer of 2 electrons per magnesium-ion, higher volumetric capacity of magnesium metal compared to lithium metal (3833 mAh/cm3 Mg vs 2061 mAh/cm3 Li), and greater natural abundance [1]. Many challenges must be met to promote magnesium batteries as a practical candidate for the next generation of batteries. One of the pivotal issues is a complete understanding of the Mg deposition and dissolution interface.
Recently, advances in electrolyte synthesis has encouraged continued research into high energy density materials for magnesium batteries. Our group introduced a new family of electrolytes for Mg battery based on anions incorporating the B-H motif [2]. Among them, magnesium borohydrides (Mg(BH4)2) provides a segue between classic electrolytes based on Grignard reagents and the new electrolytes, such as magnesium monocarborane (MMC), which stands out as the first simple-salt magnesium compound stable to Mg metal, providing high anodic stability, non-corrosive electrochemistry, and chemically robustness [3]. However, the mechanism of deposition and dissolution of magnesium remains a complex process.

Operando electrochemical cells coupled with spectroscopic and microscopic tools are powerful techniques to understand the dynamic processes in batteries. Previously, we have used Operando electrochemical/X-ray absorption to identify the active species in organohaloaluminate electroltyes [4-5], and here we extend that research for (Mg(BH4)2) electrolytes. In combination with electrochemical impedance spectroscopy, we identify the presence of an active interphase required for magnesium deposition and dissolution. For MMC, we have determined that magnesium deposition and dissolution to be able to sustain high-current (10 mA/cm2), high-charge (5 mAh) and cold temperature (0oC) without the presence of magnesium dendrites. We utilize electron microscopy and X-ray photoelectron spectroscopy to elucidate the chemistry and mechanism of the promising anode / electrolyte interphase.
[1] Muldoon, J.; Buccur, C.; Gregory, T. Chem. Rev.
2014, 114, 11683.
[2] Tutusaus O.; Mohtadi, R.; ChemElectroChem
2015, 2, 51.
[3] Tutusaus, O.; Mohtadi, R.; Arthur, T.S.; Mizuno, F.; Nelson, E.G.; Sevryugina, Y.V. Angew. Chem. Int. Ed.
2015, 54, 7900.
[4] Arthur et al., Electrochem. Comm., 2012,
24, 43.
Dynamic Pulse Charging Equalization Scheme for Series Connected Cells Using Matlab/Simulink
Authors: Stephens Jamal Frederon , Morris Larry , Moss Pedro L. , Weatherspoon Mark H 
Published: February 2020

Pulse charging has shown some very appealing advantages that can maintain the battery’s optimal performance during cycling. It has been shown that pulse charging can reduce the build-up of film at the solid electrolyte interface (SEI), allowing ions to flow back into the electrolyte, provide shorter equalization cycles, and allows more of an efficient charge after each short relaxation period than the conventional constant current charge method [1]. Some pulse charging strategies use a high voltage pulse with a relaxation period, this can result in an unexpected variation of charge current which can lead to performance loss in the cell and error in state-of-charge (SOC) estimation [2,3]. In this study, we propose a current pulse charge topology that can charge and equalize a series connected battery string.
Methodology
This system uses a dc-dc converter mainly to maintain a constant current in each cell, 2N low resistance solid state switches are used to control the pulse current with short relaxation periods for each cell as shown in figure 1. Where N is the number of cells. During the charging process, the individual batteries in series are connected to the power and ground bus via a microcontroller to be charge one at a time. This configuration provides a means of isolation or bypassing capabilities for each cell in the stack without the need of a solid-state transformer (SST). The pulses are precisely controlled by varying the duty cycle for a specific switching period which is based on the average current represented by equation (1).
Equation (1)
Iavg is the average current, T is the period of the pulse and i(τ) is the pulse current induced in battery. The duration for each pulse is given by equation (2).
Equation (2)
Using this approach, constant-current/constant-voltage can also be achieved by using pulse charging simply by varying the duty cycle. Furthermore, this approach allows each battery to receive its own independent charge and increasing the equalization rate for the pack itself. Figure (1)
References
[1] Beh, Hui Zhi, Grant A. Covic, and John T. Boys. "Effects of Pulse and DC Charging on Lithium Iron Phosphate (LiFePO4) Batteries." IEEE 315.(2013): 315-20. Print.
[2] Yin, Meng Di, Jeonghun Cho, and Daejin Park. "Pulsed-Based Fast Battery IoT Charger Using Dynamic Frequency and Duty Control Techniques Based on Multi-Sensing of Polarization Curve." Energies (2016): 1-20. Print
[3] Li, Jun, Edward Murphy, Jack Winnick, and Paul A. Kohl. "The Effects of Pulse Charging on Cycling Characteristics of Commercial Lithium-ion Batteries." Journal of Power Source (2001): 302-09. Print.

Figure 1
High Performance GeO2 Inverse Opal Anode Materials for Long Cycle Life Li-Ion Batteries
Authors: McNulty David , O'Dwyer Colm 
Published: February 2020

With the rapid and ever increasing growth in portable electronics, such as smartphones and tablet computers, and the growing need for safer and longer range electric and hybrid powered vehicles, there has never been a more prevalent demand for light weight, high performance batteries with high power and energy densities. Commercial Li-ion batteries are just about keeping up with advancements in electronics. However, the limited performance of today’s commercial batteries is common knowledge, with the majority of hand held electronic devices requiring charging every day. Identifying and preparing battery materials which are capable of high performance, fast charging, and stable, safe capacity retention during operation would significantly advance portable device power technology.
Germanium based anode materials have attracted a lot of attention due to the high theoretical capacity of Ge (1384 mAh/g) with various nanostructures such as nanowires, nanotubes and nanoparticles being investigated as anode materials. (1-3) However the cost of preparing pure Ge nanostructures can be quite high due to the use of expensive anhydrous precursors such as diphenylgermane and the need to perform synthesis under an inert atmosphere. These factors would also impede scaling up the synthesis of these materials for industrial applications. To circumvent these issues we are investigating the electrochemical performance of GeO2 with an inverse opal (IO) morphology, which can be prepared in air using cheaper precursors.
In this work we detail the preparation of GeO2 IOs with application as anode materials for Li-ion batteries. The IO samples are initially structurally characterised via electron microscopy, electron diffraction and X-ray diffraction. We demonstrate the electrochemical evaluation of our GeO2 IO samples with cyclic voltammetry, rate capability testing and long cycle life (>1000 cycles) galvanostatic testing. Previous reports on the electrochemical performance of GeO2 as an anode material have indicated that the capacity values obtained from the oxide are lower than those obtained from pure Ge. However, we demonstrate that by preparing a highly ordered, porous, three dimensionally interconnected network of GeO2 in the form of an IO, we can obtain capacity values which are comparable to the highest values previously reported for pure Ge.
Acknowledgements
This work was also supported by Science Foundation Ireland (SFI) through an SFI Technology Innovation and Development Award under contract no. 13/TIDA/E2761. This publication has also emanated from research supported in part by a research grant from SFI under Grant Number 14/IA/2581.
References
1. T. Kennedy, E. Mullane, H. Geaney, M. Osiak, C. O’Dwyer and K. M. Ryan, Nano Lett., 14, 716 (2014).
2. L.-F. Cui, R. Ruffo, C. K. Chan, H. Peng and Y. Cui, Nano Lett., 9, 491 (2009).
3. D.-J. Xue, S. Xin, Y. Yan, K.-C. Jiang, Y.-X. Yin, Y.-G. Guo and L.-J. Wan, ‎J. Am. Chem. Soc., 134, 2512 (2012).
Advanced Silicon Anode Enabled By Simple Pouring of Bifunctional Gel Polymer
Authors: Song Jiangxuan , Zhang Li 
Published: February 2020

Electrode structure deterioration and unstable solid-electrolyte-interphase (SEI) are crucial issues hindering the application of silicon anode in high energy lithium-ion batteries.[1-3] Here, we report a simple way to construct a stable silicon anode enabled by pouring branched polyurethane gel that comprise ion-conductive ethylene oxide (EO) soft segment into electrode. This tough gel conformably coated on the electrode components and strongly bonded them together through the chemical bonding and hydrogen bonding, forming a robust electrode. Additionally, it provides mechanical and chemical protection while Li+ transport, behaving as an artificial SEI layer. The harness of bifunctional gel polymer lead to a significant improvement of electrochemical performance with an capacity retention of 90% within 150 cycles and achieve a high areal capacity over 4 mAh/cm2 when micro-sized silicon-based materials was evaluated.
References
[1] C.-M. Park, J.-H. Kim, H. Kim, H.-J. Sohn, Chem. Soc. Rev.
2010, 39, 3115.
[2] J. Song, M. Zhou, R. Yi, T. Xu, M. L. Gordin, D. Tang, Z. Yu, M. Regula, D. Wang, Adv. Funct. Mater.
2014, 24, 5904.
[3] J. Song, Z. Yu, M. L. Gordin, D. Wang, Nano Lett.
2016, 16, 864.
Multifunctional SnO2/3D Graphene Composites for Lithium-Ion and Sodium-Ion Batteries
Authors: Lee Jung-In , Song Junhua , Cha Younghwan , Lin Yuehe , Song Min-Kyu 
Published: February 2020

Although both Li-ion batteries (LIBs) and Na-ion batteries (NIBs) were investigated in the similar era (1980’s), LIBs are a current technology of choice for portable electronics and electric vehicle applications due to NIBs’ lower gravimetric/volumetric energy density. Recently, NIBs have gained another momentum for grid-scale energy storage systems (ESS) where the weight and volume limitations are relatively low. The most important requirements of EES would be the cost, reliability and long service life, while the high-energy density would be still viewed as an advantage. While looking slightly similar, Li and Na metals (and their cations) have distinct physical and chemical properties. It would be interesting to develop the multifunctional materials which can be used as effective electrode materials for both batteries.
SnO2 is an attractive material due to high theoretical capacity (for both LIBs and NIBs), low cost, abundance and ease of synthesis. But there are many drawbacks that need to be overcome for SnO2 to be applied to actual batteries. Various technical issues include the large volume expansion during discharge/charge process in batteries, the formation of unstable solid electrolyte interface (SEI), and the aggregation of Sn particles during battery operation, all of which can lead to the rapid capacity fading of batteries.
In this work, ultra-fine SnO2 nanoparticles dispersed within unique 3D-graphene structure (SnO2/3D GS) were synthesized by easy and simple hydrothermal process. These 3D-graphene structure could accommodate large volume change, prevent aggregation of Sn, and provide much facile electron transfer during battery operation. The SnO2/3D GS material exhibited outstanding electrochemical performances as anodes for both LIBs and NIBs. The structure-property-performance relation was investigated by various methods including SEM, TEM, EIS, CV, and XRD. The focus was on comparative studies of the internal resistance and diffusivity of Li-ions and Na-ions in SnO2/3D GS composites. Furthermore, the direct conversion from SnO2 to amorphous Sn during discharge/charge of 1st cycle in LIBs and NIBs was monitored by in-situ XRD.

Figure 1