bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical Stability of Bipyridylimino Isoindoline Metal Complexes As Multi-Electron Anolyte Materials for Non-Aqueous Redox Flow Batteries
Authors: Laramie Sydney M , Sevov Christo S , Sanford Melanie S , Thompson Levi T 
Published: February 2020

The development of grid scale energy storage will facilitate the integration of intermittent renewable electricity sources, such as wind and solar, into the grid. However, available technologies are limited by high cost or location dependence. Non-aqueous redox flow batteries (NAqRFBs) offer a scalable, non-geographically limited technology with the potential to provide a low cost, high energy density solution to the energy storage problem. Despite these promising attributes, the limited solubility and stability of current NAqRFB active species hinders implementation. In this work we explored a series of metal complexes of tridentate bipyridylimino isoindoline (BPI) ligands as anolyte materials for NAqRFBs. The goal was to evaluate the electrochemical stability of this class of materials and identify trends between the metal center and stability. Each complex exhibits 2 quasi-reversible redox events at -1.73 V and -1.83 V vs. Ag/Ag+. Bulk electrolysis through these 2 couples was used to quantify the electrochemical stability of each material and the following trend was identified: Co(BPI)2 = Ni(BPI)2 = Fe(BPI)2 > Zn(BPI)2 = Mg(BPI)2 > Mn(BPI)2. Co(BPI)2, Ni(BPI)2 and Fe(BPI)2 were all identified to be highly stable with no capacity fade observed over 50 cycles. This high stability is attributed to the tridentate, anionic ligand structure, which affords a stronger bond between the ligand and the metal center. Extended cycling experiments revealed that Ni(BPI)2 is stable through 2 negative electron transfers for over 200 cycles. Zn(BPI)2 and Mg(BPI)2 were both moderately stable as they have full valence shells while the instability of Mn(BPI)2 is attributed to rapid ligand exchange kinetics, which is common for Mn MCCs. For each of the unstable materials, post-cycling analysis revealed that ligand shedding is a prominent degradation mechanism. The developed stability trends can be used to guide the exploration and design of future NAqRFB active species to aid in the identification of electrochemically stable materials. Since solubility is also a concern, ligand functionalizations were identified that successfully enhanced the solubility of Ni(BPI)2 by three orders of magnitude, up to a maximum solubility of 0.7 M in acetonitrile. In conclusion, BPI MCCs exhibit remarkable stability, along with relatively high solubility, and we present the first demonstration of a stable 2 electron transfer for NAqRFB applications. These complexes can be paired with a suitable catholyte material to achieve a stable, high energy density, multi-electron transfer NAqRFB.
Studies of Earth Abundant Metal Complexes for Near Neutral Aqueous Redox Flow Battery (RFB) for Grid Storage
Authors: Nagasubramanian Ganesan , Allcorn Eric , Ingersoll David 
Published: February 2020

Among the many options available for Large-Scale Grid Energy Storage, Redox Flow Batteries (RFB) are leading candidates because of the decoupled design of power and energy1 which offers tremendous design flexibility and modularity. As part of the Department of Energy’s Office of Electricity (OE) energy storage program at Sandia National Laboratories, we are investigating earth abundant transition metal coordination complexes for aqueous redox flow batteries at close to pH 7. The aqueous-based systems offer complete freedom from the thermal instabilities that plague non-aqueous systems, such as lithium-ion. Furthermore, the use of neutral pH electrolytes engenders intrinsic safety and low/no corrosion, unlike the highly corrosive and toxic electrolytes used for the vanadium redox flow battery or the zinc-bromine systems. In this abstract we discuss the electrochemical properties of some of the complexes under development, and the performance of full cells containing the optimized redox couples will be presented at the meeting.
Performance of Fe(2+)(tris-BPY)Cl2-0.4M Na2SO4
We have performed dc and ac voltammetry to characterize a number of iron coordination complexes, and Figure 1 shows the dc voltammetry curves at a 10 mV/s scan rate of one of these. As seen, the peak separation is ~60 mV, close to the theoretical value. We have also performed DC voltammetry at different scan rates up to 200 mV/s, and the peak separation varies between 60 and 64 mV which clearly demonstrate highly reversible behavior as well. Additionally, this couple exhibits higher redox voltage which will assure a RFB with a higher cell voltage and energy when appropriately configured with another redox couple.
Figure 2 shows a plot of redox peak potentials vs. square root of scan rate. The linear increase of peak value vs. square root of san rate indicates that this couple is highly reversible. We also performed AC voltammetry, which is more sensitive than the DC measurement, just to make sure that there are no other redox peaks buried around the solvent decomposition voltage. We observed only one reversible peak (Figure 3) which corroborates the DC measurement. Similar observations were observed for other couples and will be described in detail at the meeting.
Reference: B. Dunn, B., H. Kamath, H. & Tarascon, J.-M. “Electrical energy storage for the grid: a battery of choices” Science 334, 928–935(2011).
Acknowledgment: Sandia Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation for the U. S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL 85000. The authors would like to thank Dr. Imre Gyuk of the DOE Office of Electricity for the support.

Figure 1
Impact of Solvent Co-Intercalation in Cathodes: A Study on Mg-Xerogel V2O5
Authors: Gautam Gopalakrishnan Sai , Canepa Pieremanuele , Richards Will , Malik Rahul , Ceder Gerbrand 
Published: February 2020

The electrochemical performance of several known Li- and Na-ion cathode materials can be influenced by the presence of specific solvents, such as water, either in the electrolyte or the electrodes. Indeed co-intercalation of solvent molecules, along with the redox active ions, is an approach to potentially impact the voltage and mobility with which cation species intercalate into electrodes in energy storage systems. While Multi-valent (MV) ion intercalation batteries that replace the Li+ with a MV cation, such as Mg2+, provide a pragmatic approach to improve upon the energy densities of current cutting-edge Li-ion batteries, several cathode hosts suffer from sluggish MV ion mobility within the cathode structure. One of the approaches that has been deployed to mitigate poor MV ion migration so far, specifically in layered oxide cathodes such as Xerogel-V2O5, is to introduce solvent molecules (water) in the structure that electrostatically shield the high positive charge density around MV ions and lower the local structural distortions. However, the role of water during the process of Mg2+ (or MV) intercalation is not well known yet, specifically if the structural water in the cathode “shuttles” along with the Mg2+ ion or stays in the structure during Mg-cycling.
In this study, we use first-principles calculations combined with the framework of grand potential phase diagrams to gain insight into the thermodynamics of Mg-water co-intercalation into Xerogel-V2O5. Based on our calculations, we find that Mg-water shuttling depends heavily on the water concentration of the electrolyte, ranging from full co-intercalation in wet to none in superdry electrolytes. Also, the Mg insertion voltages depend on the activity of water in the electrolyte in regimes where water shuttles with the Mg2+, leading to important consequences in the design of electrodes and electrolytes. We believe that this study can be further extended to other complex solvent-electrode pairs to develop a general understanding of the phenomenon of solvent co-intercalation.
Studies of New Rechargeable Mg-Ion Battery Using Boron-Hydrogen Based Electrolytes
Authors: Aso Hikaru , Tutusaus Oscar , Arthur Timothy S. , Mohtadi Rana 
Published: February 2020

Mg-ion battery is one of the most promising candidates for a post Li-ion battery due to its high capacity, improved safety and potentially reduced cost. However, since the metallic Mg-anode is prone to passivation by electrolytes, we need to carefully use appropriate electrolytes which have high stability to the Mg metal. For example, common anions such as ClO4
-, BF4
- or TFSI- decompose on the Mg surface resulting in a highly resistive layer that partially or fully blocks Mg-ion transport. Although organo and chloride based reagents were found to be compatible with Mg metal, they still have severe issues such as highly corrosive nature and low Mg-ion transference number.1) We have been pioneering the development of a new class of electrolytes based on a novel design strategy and offering halogen free and non-corrosive boron-hydrogen salts, which can also improve the transport and solubility properties.2)

Another serious challenge facing Mg battery technologies is the limited choice of cathode materials due to the difficulty to reversibly intercalate divalent Mg-ion in host structures analogues to those used in Li-ion batteries such as transition metal oxides.3)Therefore, we have been studying alternative cathode chemistries beyond the intercalation types. The inertness and stability of the MMC electrolyte allow us to examine these new cathodes where fast and stable charge/discharge cycles can be performed with a relatively fine coulombic efficiency. In this presentation, we will unveil these new results and also show detailed mechanisms towards understanding the battery performance.
[1] J. Wook Choi, D. Aurbach, doi:10.1038/natrevmats.2016.13, Nature Reviews Materials, 2016

[2] a) R. Mohtadi, M. Matsui, T. S. Arthur, S.-J. Hwang, Angew. Chem. Int. Ed.
2012, 51, 9780 –9783; b) T. J. Carter, R. Mohtadi, T. S. Arthur, F. Mizuno, R. Zhang, S. Shirai, J. W. Kampf, Angew. Chem. Int. Ed.
2014, 53, 3173-3177; c) O. Tutusaus, R. Mohtadi, ChemElectroChem.
2015, 1, 51-57 d) O. Tutusaus, R. Mohtadi, T. Arthur. F. Mizuno, Angew. Chem. Int. Ed.
2015, 27, 8011-8015
[3] a) H. D. Yoo, I. Shterenberg, Y. Gofer, G. Gershinsky, N. Pour, D. Aurbach, Energy Environ. Sci. 2013, 6, 2265-2279; b) R. Mohtadi, F. Mizuno Beilstein J. Nanotechnol. 2014, 5, 1291–1311
Investigation of the Electrochemical Oxygen Reduction Reaction in Non-Aqueous, Magnesium-Ion-Containing Electrolytes for Magnesium Air Batteries
Authors: Fischer Philipp , Schwarz Rainer Martin , Pejic Marijana , Marinaro Mario , Wachtler Mario , Jörissen Ludwig 
Published: February 2020

Secondary magnesium-air batteries (MAB) hold great promise for cheap and highly dense energy storage as needed in automobiles and portable devices. While magnesium-ion-batteries1 and primary magnesium-air-batteries (magnesium air fuel cells, aqueous electrolyte)2 do already exist, there are difficulties in the development of the secondary magnesium air battery.
In principal, the work which was done on the Lithium-air-batteries (LAB) should also be usable in MABs. Therefore, in this work the system Mg(ClO4)2 + DMSO, first proposed by Shiga et al.3, was investigated. The equivalent electrolyte for LABs (LiClO4 + DMSO) is proven to work4.
It is shown that the oxygen reduction reaction (ORR) takes place (see Figure 1) within the stability window of the electrolyte and the electrochemical behavior of the system is discussed when using gold, platinum and glassy carbon as electrodes. It is shown that the ORR is not reversible and that passivating films are formed.
By using a change-disk-RRDE-setup, we could investigate those films with IR, Raman, XPS, SEM and EDX. It was possible to trace the electrolyte components (S-O-groups and Cl-O groups) on the surface and a quantitative analysis proves that oxygen is mainly contributing to the composition and structure of the surface film. The resulting decomposition products on the respective electrodes and a probable pathway of reaction are presented.

Acknowledgments

This work has been funded by the German Federal Ministry of Education and Research (BMBF) under the project “Mg-Air”, under the reference 03EK3027C.

References

1. H. D. Yoo et al., Energy Environ. Sci., 6, 2265 (2013)
2. I. C. Blake, J. Electrochem. Soc., 99, 202C–203C (1952)
3. T. Shiga, Y. Hase, Y. Kato, M. Inoue, and K. Takechi, Chem. Commun. (Camb)., 49, 9152–4 (2013)
4. M. M. Ottakam Thotiyl et al., Nat. Mater., 12, 1050–6 (2013)

Figures

Figure 1 Cyclic voltammograms of a 5mm diameter platinum disk (mirror polished) in 0.5 M Mg(ClO4)2 / DMSO electrolyte solution, argon saturated (red) and oxygen saturated (blue). Scan speed: 10 mV s-1

Figure 1
Low-Cost Modular Battery Fabrication System Based on 3D-Printed Parts and Microcontrollers
Authors: Kim Andrew , Raj Abhishek , Epstein Lindsay , Biswas Shaurjo , Steingart Daniel A 
Published: February 2020

Integrating energy storage into clothing would enable wearable electronics of a more comfortable form factor and weight distribution compared to traditional rigid cells. Work on LTO vs LCO systems by previous groups have demonstrated the material system’s ability to be flexed or produced with scalable methods. In this work we report a low-cost automated fabrication setup to produce flexible LTO/LCO batteries on carbon fiber substrates.
The modular thread-coating system reported here takes advantage of cheap Arduino microcontrollers and 3D printed structures for a highly customizable design allowing for rapid prototyping of different material systems. In this particular setup, a stepper motor pulls a fiber through a series of 3D-printed stages where the fiber substrate is subjected to slurry deposition, washing, heating or packaging to produce a functional LTO/LCO battery.
The modular system serves as a useful intermediary between initial lab scale research— in which artisanal manual skills are often required from the researcher— and the industrial production process— in which automation and high throughput are paramount. The modular intermediary allows one to mimic mass production at a lab scale to identify challenges and solutions to scaling up a battery architecture for wide use.
Revealing the Impact of Anions in Lithium Oxygen Batteries
Authors: Iliksu Merve , Yang Shuo , Sauer Dirk Uwe 
Published: February 2020

Despite their high theoretical capacity, lithium oxygen cells cannot be fully discharged to the limit of their theoretical energy density. The main reason for that is the insoluble and insulating character of the discharge product Li2O2, when it is formed as a thin film form on the cathode, creating the passivation layers, and causing a stop of the charge transport. Furthermore, the discharge/side products can block the cathode’s pores, therefore limiting capacity too. Capacity is also limited by oxygen transport especially at higher current rates. The solubility of oxygen in the electrolyte and the diffusion is important in that case, and can be increased with the right choice of salt.
A big challenge in building lithium oxygen batteries is choosing proper electrolyte for the system, which should be stable against species such as LiO2
-, LiO2, O2-, O2
2-. New combinations are necessary to improve issues such as minimizing electrolyte breakdown and/or enhancing the stability of the battery.
In this work the electrochemical performances are investigated using constant current measurements and cyclic voltammetry of the lithium nitrate and bis(trifluoromethane) sulfonamide lithium salt mixtures in tetragylme. Furthermore, post mortem analysis in the form of Raman Spectroscopy, Scanning Electron Microcopy, and Energy – dispersive X ray Spectroscopy is performed. The contribution of this work is an analysis of the effect of various lithium salts, by maintaining the activity of Li+ but changing the anion. This yields insights into the extent of ion pairing and its effects on the Li-O2 battery system. Higher capacity results are coming from the increased stability and solubility of ion pair species that are formed in the electrolyte between the initial oxygen reduction reaction product (superoxide), O2
- and solvated the Li+.
Figure 1. Constant current first discharge performances of LiNO3 and LiTFSI salt mixture concentrations and Scanning Electron Micrographs (scale 10µm) of their air cathode.

Figure 1
Performance Enhancement in Redox Flow Batteries Using Bismuth Based Catalyst
Authors: Kwon Yongchai , Suharto Yustian , Yang Seungwon , Kim Ki Jae 
Published: February 2020

Slow reaction rates of vanadium (V), iron (Fe), chrome (Cr) redox couples are a bottleneck to address for enhancing performance of vanadium and Fe-Cr redox flow battery (VRFB and Fe-Cr RFB) system. For promoting their reaction rates, new catalytic materials based on Bismuth (Bi) are suggested in this study. Reaction reversibility as well as catalytic activity of the catalysts is investigated using cyclic voltammogram (CV) and the results are compared with those of other catalysts. Performances and long term stabilities of VRFB and Fe-Cr RFB using Bi-based catalysts are evaluated by repetitive and cyclic measurements of charge-discharge step. Especially, energy efficiency (EE) and capacity loss rate are mainly inspected to determine superiority of the VRFB and Fe-Cr RFB. Their crystal structure, specific surface area and catalyst morphology are measured by chemical characterizations. The new Bi-based catalysts show high peak current ratio, small peak potential difference and high electron transfer rate constant, confirming that in both catalytic activity and reaction reversibility facets, the Bi-based catalysts play an important role. In terms of charge-discharge curves, VRFB and Fe-Cr RFB including new catalysts indicate high EE, low overpotential and low internal resistance. The results are attributed to role of Bi that activates Fe2+/Fe3
+, Cr2+/Cr3
+ and V4+/V5
+ redox reactions. Indeed, adoption of the Bi-based catalysts lead to improvement in performances and long term stabilities of VRFB and Fe-Cr RFB.
Single Wall Carbon Nanotube Modified with Nano Size Metal Oxides for High-Performance Cathode in Li-O2 Rechargeable Batteries
Authors: Jang Il-Chan , Ishihara Tatsumi 
Published: February 2020

Li-O2 batteries have a big potential for the application of future electrochemical power sources because of their much larger energy density than that of conventional Li ion battery. However, rechargeable Li-O2 batteries are still facing many challenges including large overpotential, low round trip efficiency, low power capability, and poor cycle stability. All these poor electrochemical performances are related with poor reversibility of air electrode, which can be improved by employing sophisticated and active cathode [1]. As confirmed in our early study [2], a mesoporous oxide can virtually reduce the overpotential and enhance the cycle efficiency with abundant active sites. In addition, as a carbon substrate, a CNT has high chemical and thermal stability, high tensile strength and excellent electrical conductivity resulting from their unique structures. Discharge capacity of 1200 mAh/g was achieved on Li-O2 battery using CNT for cathode, however, because of high charge potential, cycle performance was poor. In this study, therefore, we introduce combination of single wall carbon nanotubes (SWCNT) and mesoporous metal oxides as a cathode for Li-O2 batteries. It was found that discharge capacity was decreased by loading mesoporous MnO2, cycle stability was much increased, in particular, co-loading of Co3O4 and Cr2O3 shows much superior cycle stability and discharge capacity was sustained up to 100 cycles. Characterization techniques ranging from, electron microscopy, surface analysis have been applied for metal oxides. Large porosity formed in SWCNT electrode seems to be one reason for large discharge capacity and cycle stability.
References
[1] Z. Ma, X. Yuan, L. Li, Z.F. Ma, D. P. Wilkinson, L .Zhang, J. Zhang, Energy & Environmental Science, 8, 2044 (2015).
[2] A. K. Thapa, Y. Hidaka, H. Hagiwara, S. Ida, T. Ishihara, J. Electrochem. Soc., 158, A1483(2011)
the Role of Ceramic Filler in Microporous Gel Electrolytes for Sodium Ion Batteries
Authors: Kim Seokwoo , Nguyen Ngoc Anh , Kim Kyuman , Ryou Myung-Hyun , Lee YongMin 
Published: February 2020

Abstract

Due to the abundance in nature and the low price of sodium ions, sodium ion batteries have been considered as the promising candidate for the next generation high-capacity rechargeable battery system.
Herein, we investigate the effect of ceramic filler, alumina (Al2O3), in gel polymer electrolytes based on poly(vinylidenefluoride-co-hexafluoropropylene) porous membrane prepared through a simple phase separation process. Ceramic fillers improved not only the mechanical properties but also the electrochemical stability, resulting better cycle performance during electrochemical tests. We believe these results are attributable to the enlarged surface area and the improved wetting property of gel polymer electrolyte to liquid electrolyte, resulting larger amount of liquid electrolyte uptake. The surface and cross section structure images of composite membranes were investigated by field-emission scanning electron microscope (SEM) as a function of Al2O3 contents. Ionic conductivity of composite gel polymer electrolytes was measured using an impedance analyzer (VSP). The uptake amount of liquid electrolyte was determined by measuring the weight changes of composite gel polymer electrolytes. The unit cells employing the composite gel polymer electrolytes achieved significant improvements in rate capability.

Acknowledgements

This work was supported by the Human Resource Training Program for Regional Innovation and Creativity through the Ministry of Education and National Research Foundation of Korea (NRF-2014H1C1A1066977)

Refernces

Y.Q. Yang et al. / Solid State Ionics 269 (2015) 1 7 Y.Q. Yang et al. / Solid State Ionics 269 (2015) 1 7

Bella Federico et al. / ChemsusChem 8.21 (2015): 3668-3676.

Gao Hongcai et al. / Advanced Energy Materials 5.9 (2015).