bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study to Improve Electrolytes in Sodium Batteries
Authors: Walker Dejuante , Thai Edward , Higgwe Tamunotelema , Yu Ted H. 
Published: February 2020

With increasing need for batteries and energy storage, sodium batteries are of increasing demand. Lithium batteries are very popular but focus is being placed on sodium due to its higher abundance and subsequently, its lower cost. The human body also has a higher threshold for ingesting sodium than lithium as a nutrient, making it more biocompatible in ingestible battery1. The main focus of the study is to improve the electrolyte2,3. We test the electrolyte in a coin cell battery with sodium metal as the anode and the cathode.
A variety of solvents, electrolytes, and additives are tested to optimize the electrolyte. Several different solvents were tested: ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dimethoxyethane (DME), and dioxolane. These solvents were tested in different combinations with three electrolytes: sodium perchlorate (NaClO4), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), and sodium hexafluorophosphate (NaPF6). Lastly additives were tested in combination with above cases to test how they improve the electrolyte. The ionic liquid, 1-Butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI) and lithium nitrate (LiNO3) were tested as additives.
We look at the overpotential to gauge the effectiveness of the electrolytes by cycling symmetrical Na/Na cells. An example of the cycling with EC/PC/DEC and NaClO4 electrolyte is shown in the below Figure 1.
References:
1. L. Xin, X. Huang, H. Xu, Y. Zhang, J. Lam, J. Cheng and J. A. Rogers, Adv Mater
26, 3879-3884 (2014).
2. A. Ponrouch, D. Monti, A. Boschin, B. Steen, P. Johansson and M. R. Palacin, J. Mater. Chem. A, 3, 22 (2015).
3. Monti, Damien, Alexandre Ponrouch, M. Rosa Palacín, and Patrik Johansson. Journal of Power Sources, 324, 712-721 (2016).

Figure 1
Synthesis and Characterization of α-MnO2/Graphene Nanocomposites for Applications to in High Performance Super Capacitors
Authors: Singhal Rahul , Lemaire Peter , Omidwar Amir 
Published: February 2020

In recent years, supercapacitors have attracted a lot of attention due to their applications in portable electronic devices such as mobile phones, laptops, digital camera and also for power applications in hybrid electric vehicles, engine start, and solar energy storage, etc. [1-3]. Transition metal oxides and carbon materials are widely being used in supercapacitors. Among transition metal oxides, MnO2 has been one of the most studied electrode materials because of its cost effectiveness, natural abundance and environmental compatibility. In spite of its various advantages, MnO2 in its pure state is not very useful for supercapacitor applications because of its poor electrical conductivity and electrochemical dissolution upon cycling. On the other hand, graphene has drawn considerable interest because of its ultrahigh surface area (up to 2630 m2/g), and excellent conductivity. Up to now, composites of graphene and MnO2 have been used to improve their capacitance.
We have synthesized hetero-structured - nanorods using the low temperature hydrothermal technique [4]. Finally -/graphene nanocomposite was synthesized by sonochemical co-precipitation method as reported earlier [5]. Graphene oxide power, suspended in sulfuric acid solution (1mg/ml), and manganese sulfate (dissolved in sulfuric acid) were mixed together and potassium permanganate solution was added to this solution drop by drop. After 2 hours -/graphene nanocomposite was filtered using centrifuge, washed with DI water and ethanol and dried. The phase structure of - nanorods and -/graphene nanocomposites were studied using powder X-ray diffraction (XRD). The results of physical, thermal and electrochemical characterization of -/graphene nanocomposite will be presented during 231st Electrochemical Society Meeting.

References:

Z. Yang, J. Zhang, M.C. Kintner-Meyer, X. Lu, D. Choi, J.P. Lemmon, J. Liu, Chem. Rev. 111 (2011) 3577.

H. Zhang, G. Cao, Y. Yang, Energ. Environ. Sci. 2 (2009) 932.

X.H. Lu, X. Huang, S.L. Xie, T. Zhai, C.S. Wang, P. Zhang, M.H. Yu, W. Li, C.L. Liang, Y.X. Tong, J. Mater. Chem. 22 (2012) 13357.

Z.K. Ghouri, M.S. Akhtar, A. Zahoor, N. A. M. Barakat, W. Han, M. Park, B. Pant, P.S. Saud, C. H. Lee, H. Y. Kim, J. Alloy and Compounds
642 (2015) 210 .

B. Zhao, M. Lu, Z. Wang, Z. Jiao, P. Hu, Q. Gao, Y. Jiang, L. Cheng, J. Alloy and Compounds B 663 (2016) 180.
(Invited) Space-Confined Assembly of All-Carbon Hybrid Fibers for Capacitive Energy Storage
Authors: Chen Yuan 
Published: February 2020

Miniaturized portable and wearable electronics have diverse power requirements, ranging from one microwatt to several milliwatts. Fiber-based micro-supercapacitors are promising energy storage devices that can address these manifold power requirements. Here, we demonstrate a hydrothermal assembly method using space confinement fillers to control the formation of nitrogen doped reduced graphene oxide and multi-walled carbon nanotube hybrid fibers. Consequently, the all-carbon hybrid fibers have tunable geometries, while maintaining good electrical conductivity, high ion-accessible surface area and mechanical strength; this allows us to address two important issues in micro-supercapacitor research. First, we found a clear correlation between the geometry of the hybrid fibers and their capacitive energy storage properties. Thinner fibers (30 mm in diameter) have higher specific volumetric capacitance (281 F cm-
3), superior rate capability, and better length dependent performance. In contrast, larger-diameter hybrid fibers (236 mm in diameter) can achieve much higher specific length capacitance (42 mF cm-1). Second, we realized the first built-to-order concept for micro-supercapacitors by using all-carbon hybrid fibers with diversified geometry as electrodes. The device energy can cover two orders of magnitude, from <0.1 μW h to nearly 10 μW h, and the device power can be tuned in four orders of magnitude, from 0.2 μW to 2000 μW. Furthermore, multiple mechanically flexible fiber-based micro-supercapacitors can be integrated into complex energy storage units with wider operation voltage windows, demonstrating broad application potentials in flexible devices.

Figure 1
Nanocarbon Current Collectors for Aqueous Batteries
Authors: Hayden John , Lin Chuan-Fu , Luo Wei , Rubloff Gary W , Hu Liangbing 
Published: February 2020

Carbon materials are a promising alternative to metal current collectors that are currently used in aqueous batteries, because of their light weight, high electrical conductivity, and promising corrosion resistance. In this report, we investigate the corrosion resistance of multiple flexible and robust nanocarbon current collectors (NCCCs) for aqueous battery applications.
We have fabricated a number of polymer-nanocarbon composite materials to serve the purpose, including activated carbon cloth (ACC) with carbon nanotubes (CNTs) and cellulose nanofibers combined with CNTs (CNT/CNF), both of which exhibit high conductivity and mechanical strength.
We evaluated durability of these composites under potentiostatic stress in conditions mimicking those of lead-acid and nickel metal hydride (NiMH) batteries in an attempt to expose the carbon current collectors to the most severe conditions they would experience in an aqueous battery. Cyclic voltammetry and Fourier transform infrared spectroscopy (FTIR) were used to characterize the oxidation of the NCCCs after holding them at stressing potentials for long periods of time. Stress-strain and four-point probe measurements were also taken before and after holding potential to evaluate changes in mechanical strength and DC conductivity of the NCCCs.
The CNT/CNF show improved electrochemical stability in acidic conditions compared to ACC while maintaining reasonable mechanical and electrical properties, and thus they are promising as alternative current collectors in an acidic aqueous battery such as lead-acid. We are also exploring other variations of nanocarbon-based current collectors and the use of atomic layer deposition to further develop NCCC technology options.
DFT Simulation of the Oxygen Reduction Reaction on Graphene Catalyst Edges
Authors: Ly Quang , Goddard William A , Yu Ted H. 
Published: February 2020

We utilized density functional theory (DFT), to calculate energy barriers for various reaction steps leading to the 4e- water formation and the 2e-formation on graphene catalysts. We examined the Eley-Rideal reactions for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells, determining the energy pathways for associative electrocatalytic mechanism generated by stepwise addition of hydrogen.
Our binding energy calculations show why ORR occurs only on the graphene edges because the O2 and OOH intermediates do not bind on the basal plane surface. We predict an onset potential for ORR to produce 2e- products on armchair graphene edges to be 0.65 V, which compares very well to the experimental onset potential of 0.68 eV1. We find that the onset potential for ORR to produce 4e- products on armchair graphene is also 0.65 V. In comparison, we find that the zigzag graphene edges formed bonds to the ORR intermediates that were too strong, requiring an onset potential of 0.14 V to produce 4e- ORR products. This result shows that the preferred site for ORR is the armchair edge.
These PBE calculations were carried out to determine energy barriers as a function of applied potential2 using the a new CANDLE method to simulate the effect of water solvation3. We found the rate determining step (RDS) to form the 2e- product is OO + H -> OOH, with an electronic energy barrier of 0.78 eV at a potential of 0.65 V. We found that the RDS to form the 4e-product is the reaction, O + H -> OH, with a barrier of 1.35 eV at a potential of 0.65 V. Figure 1 shows the compares the ORR mechanism for the 2e- and 4e- reaction. Figure 2 shows the calculated Tafel Plot of the preferred 2e- reaction using the Butler-Volmer equation using current densities calculated from potential dependent barriers.
References:
1. S. Malkhandi, P. Trinh, A. K. Manohar, K. C. Jayachandrababu, A. Kindler, G. K. Prakash and S. R. Narayanan, J Electrochem Soc 160(9), F943-F952 (2013).
2. H. Xiao, T. Cheng, W. A. Goddard and R. Sundararaman, J Am Chem Soc 138(2), 483-486 (2016).
3. R. Sundararaman and W. A. Goddard, J Chem Phys 142(6), 064107 (2015).

Figure 1
Electrochemical Properties of PDTT and PETDP As Cathode Materials for Rechargeable Lithium Battery
Authors: Shadike Zulipiya , Bak Seong-Min , Wang Xue-Long , Lee Hung-Sui , Yang Xiao-Qing 
Published: February 2020

Recently, Organodisulfide compounds have attracted extensive research interests as cathode materials due to the advantages of higher theoretical capacity, environmental friendness, lightweight and abundant resources for high specific energy lithium secondary batteries. The key moiety of high specific capacity in organodisulfide compounds is the reversible two-electron redox reaction of the disulfide bond (S-S). However, the exiting problem of organodisulfide compounds as electrodes materials in LIBs is the large capacity fading caused by the high solubility of polysulfides in liquid electrolytes. An Important strategy to solve this problem is to polymerize the small molecules into insoluble polymeric chains in order to improve the cyclic stability of the electrodes.
Based on this strategy, the electrochemical performance and energy storage mechanism of Poly [1, 2-dithiole-3-thion-4(5)-thio] (PDTT) and Poly [2-(1, 2-ethylenediamino)-1, 6, 6a, Δ4-trithia-1, 6-diaza-pentalen-5-yl] (PETDP) were designed, synthesized, and investigated. As shown in figure 1, based on the two-electron reaction, PDTT can provide theoretical capacity of 326 mAh g-1, and the theoretical capacity of PETDP is calculated to be as high as 371 mAh g-1 based on the three-electron reaction. Electrochemical performances of PDTT and PETDP were evaluated by cyclic voltammogram and galvanostatic discharge/charge measurements. CV results indicated that PDTT electrode has two pairs of redox peaks at 2.09/2.38 and 2.29/2.63 V. PETDP cathode also presents two pairs of well-defined redox peaks at 2.11/2.26 and 2.37/2.42 V, respectively. Cyclic performance of PDTT and PETDP was compared using two type of electrolytes, the ether based (1M LiTFSI in DME/DOL) and carbonate based (1M LiPF6 in EC/DMC) electrolytes. Results show that both of them deliver best cyclic stability in ether based electrolyte. In addition, the discharge and charge profiles of PDTT electrode are consistent with its CV curves and having specific capacity of 321 mAh g-1 at a current density of 0.1 C (1C=33 mA g-1), this value is as high as 98.4% of the theoretical capacity. Even at 0.5C rate, high initial capacity of 318 mAh g-1 (97.5% of theoretical value) was obtained, confirming the almost fully utilization of active materials. When cycled over 50 cycles, PDTT electrodes can still deliver high capacities of 291 mAh g-1with capacity retentions of 90.6%, showing a high potential to be used as organodisulfide cathode materials for high capacity Li-S batteries.More details about the charge storage mechanism studies using synchrotron based X-ray absorption spectroscopy will also be presented at the meeting.
Acknowledgement
The work at Brookhaven National Lab. was supported by the U.S. Department of Energy, the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies (BMR and VTO Battery500 projects) under Contract Number DE-AC02-98CH10886.

Figure 1
Novel Obstructed Flow Field Designs for Improved Perfomance in Vanadium Redox Flow Batteries
Authors: Akuzum Bilen , Robinson Nick , Agar Ertan , Kumbur E. Caglan 
Published: February 2020

One of the major challenges that limits the widespread commercialization of vanadium redox flow batteries (VRFBs) is their relatively low power density, which often results in higher cost [1]. In recent years, significant effort has been put on understanding the effect of flow field design on the power density performance of VRFBs [2-3]. Flow fields play a crucial role in effective delivery and removal of active species from the electrode surface and hence they can significantly alter the power output of the VRFBs. Due to inherent similarities between fuel cells and redox flow batteries, flow field designs for VRFBs have been limited to previously studied conventional flow designs such as parallel, serpentine, and interdigitated. Though significant effort has been placed on analyzing which design performs better and how certain parameters can result in higher performance; investigation of novel flow designs outside the fuel cell research has remained much unexplored.
Although conventionally utilized flow field designs have very different flow paths for delivery of the electrolyte in two dimensions; the channel depth seems to remain constant for the flow field studies reported so far. Considering the porous electrodes lie in parallel with the channel floors in most of the VRFB cell fixtures, it is believed that alterations of the channel depth throughout the length of the flow channels can help facilitate better transport of active species to the electrodes. Motivated by this, various forms of channel obstructions and ramped flow field designs have been investigated to understand the effect of channel depth and delivery of electrolytes on the power density of the VRFBs. Results have shown significant improvements in power density (up to 90%) with the addition of alterations to the channel depth with minor (10%) or no change in pumping losses. These findings suggests that engineering of the flow field designs in all three dimensions can help further improve the power density of VRFBs.

References

[1] Agar, E., Dennison, C.R, Knehr, K.W., Kumbur, E. C., J. Power Sources, 2013, 225, 89-94.
[2] Kumar, S., Jayanti, S., J. Power Sources, 2016, 307, 782-787.
[3] Dennison, C.R., Agar, E., Akuzum, B., Kumbur, E.C., 2016, J. Electrochem. Soc., 163, A5163-A5169.
(Keynote) Organic Coatings for Corrosion Protection: Self-Healing at the Delaminated Interface
Authors: Rohwerder Michael 
Published: February 2020

Recently significant progress has been made in developing self-healing coating systems capable of healing even macroscopic defect sites (see e.g. [1-3]). The corrosion triggered release and transport of sufficient amounts of inhibitors and/or self-healing agents to the defect site is enabled by the delamination of the coating. This allows fast spreading of the trigger signal, such as change of pH or potential, into the coating and also fast transport of the released active agents along the delaminated interface. However, when corrosion in the defect site is successfully inhibited it is important that also at the delaminated interface corrosion is inhibited and adhesion between metal and the organic coating is re-established again. Our knowledge of how to do this is still limited. Recent progress on this topic will be presented and discussed.
[1] D. Crespy, K. Landfester, J. Fickert, and M. Rohwerder, Self-Healing Materials 273 (2016) 219-245.
[2] T.H. Tran , A. Vimalanandan , G.Genchev , J. Fickert , K. Landfester , D. Crespy , M.Rohwerder, Advanced Materials 27(25) (2015) 3825-3830.
[3] A. Vimalanandan, L.P. Lv, T.H. Tran, K. Landfester, D. Crespy, M. Rohwerder, Advanced Materials 25(48) (2013) 6980-6984.
Corrosion Sensors to Monitor the Degradation of Hot-Dip Galvanised Steel and Painted Steel during Accelerated Corrosion Tests
Authors: Thierry Dominique , Ledan Frederic , Diler Erwan , Le Bozec Nathalie 
Published: February 2020

Hot-dip galvanised steel and electrogalvanised steel are widely used in the automotive and construction industry. The corrosion testing of these metallic coatings includes exposure at natural weathering sites and exposure in cyclic corrosion tests in the laboratory. The corrosion rate is then evaluated using mass loss measurements and visual observations such as time to red rust. In this work we have developed a new sensor based on electrrical resistance measurements and applied it on galvanised steel. This new device allow in-situ and real time measurements of the corrosion rate of galvanised steel. Exemple of utilisation of the sensor in cyclic corrosion tests will be given. The new device offer the possibility to better undertand the different phases of cyclic corrosion testing with the ultimate goal to develop more relevant testing procedure. This provides new possibilities to study the atmospheric corrosion of metallic coated steel in various environments. Exemple of use in the case of painted steel will also be given.
Corrosion Behavior of Carbon Steel Under Environment Simulated inside of Concrete Containing Chloride Ion
Authors: Katayama Hideki , Doi Kotaro , Yamada Maya , Hoshi Yoshinao , Shitanda Isao , Itagaki Masayuki 
Published: February 2020

Many infrastructures such as expressways and buildings were constructed in Japan between the 1950s and the 1970s. There is greatly influence of airborne sea salt on corrosion in Japan surrounded by the sea, and reinforcement corrosion is accelerated by rainfall, dew condensation and water absorption of airborne sea salt. Therefore, many of these infrastructures are in a condition requiring repair or renewal in the present. In this study, electrochemical measurements of carbon steel were conducted in an aqueous solution simulated the inside of concrete, in order to investigate corrosion behavior of reinforcing bars in concrete. In addition, the influence of surface condition of the reinforcing bars before corrosion on their corrosion resistance was examined by the corrosion monitoring using an electrochemical impedance method.
Carbon steel and 0.1% Ca(OH)2 solution were used as the sample for the reinforcing bar in concrete and as the test solution simulating the internal environment of the concrete, respectively. The corrosion resistance of passive film in concrete was investigated by anodic polarization measurement and electrochemical impedance measurement. The passive film region was observed regardless of concentration of chloride ion in the test solution. The current density in the test solution containing 0M and 0.01M of chloride ion did not abruptly increase in the passive state region and local corrosion such as pitting corrosion did not occur on the steel surface. A sharp rise in current density was observed in the test solution containing 0.1M or more of chloride ion.
The anodic polarization curves of carbon steel with passive film formed by immersion in the test solution was measured, in order to investigate the influence of the film formation period on the properties of passive film. A passive region was observed in the anodic polarization curves of all samples. The passive current density decreased with an increase of immersion time, indicating that the corrosion resistance of the passive film improved as the immersion time increased. Furthermore, the electrochemical impedance measurements of carbon steel passivated in the test solution were carried out. The impedance characteristic can be represented by a typical Randles type equivalent circuit, and the diameter of the semicircle corresponds to the film resistance. The film resistance increased in proportion to the immersion time in the test solution. This result is consistent with the result of the anodic polarization measurement.
Dielectric Property of Concrete Investigated By EIS
Authors: Hasegawa Chiaki , Okamoto Tatsuki , Tokieda Hiroyuki , Hoshi Yoshinao , Shitanda Isao , Itagaki Masayuki , Kato Yoshitaka 
Published: February 2020

Electrochemical impedance spectroscopy (EIS) is effective tool to investigate degradation of concrete and corrosion of reinforcing steel bar. The impedance spectrum of concrete reinforced by steel bar shows many capacitive loops on the Nyquist plane. McCarter et al. [1] reported that capacitive loop in the high frequency range originated form the dielectric property of concrete absorbing water. According to the paper by McCarter et al. [1], the EIS allows the information concerning the amount of water and pore structure in concrete. We measured impedance spectra of concrete sandwiched between two stainless steel electrodes, and found that the capacitance is very large when the concrete absorbed much water. We observed the variation of capacitance during the drying process of concrete, and proposed a complicated pore structure in concrete.
Reference:
[1] W. J. McCarter and S. Garvin, J. Phys. D: Appl. Phys., 22 (1989) 1773-1776.