bluuebunny/crossref_metadata_2025_split huggingface dataset:
Real-Time Reservoir Balancing and Leak-Free Nonaqueous Cell Design for Flow Batteries
Authors: Smith Kirk P , Howey David Alastair , Ascencio Pedro , Monroe Charles W. 
Published: February 2020

Benchtop-scale testing of redox flow batteries presents numerous operational challenges related to electrolyte imbalance, leakage, and chemical compatibility. Electrolyte imbalance creates a capacity-limiting reservoir and necessitates manual or automatic transfer of electrolyte between reservoirs to rebalance. Leakage of electrolyte in the cell, often at tubing connections or interfaces between the graphite plates, gaskets, and membrane, also reduces capacity and experimental repeatability. The testing of increasingly common nonaqueous electrolytes requires not only strict wetted material compatibility across a range of solvents but also greater resistance to leaks – the lower surface tensions of many organic solvents (vs. water) makes them more prone to leakage.
The above issues are more easily dealt with in large-scale, permanent installations that do not have the benchtop-scale requirements of manual assembly/disassembly, modularity, and configurational simplicity. Additionally, benchtop flow batteries often use peristaltic pumps, a type of positive displacement pump which create large pressure and flowrate pulsations compared to the continuous output of centrifugal pumps commonly used in large scale systems. The use of individual peristaltic pumps for each side of the flow battery can create an electrolyte imbalance when an asymmetric pressure drop occurs across the cell, causing a Darcy flow of electrolyte through the membrane separator. Other aspects of the flow battery can exacerbate this imbalance, such as using porous separators which are more permissive to electrolyte crossover, or more viscous electrolytes which create higher pressure differentials in the hydraulic circuit at a given flowrate.
A new pump control strategy for flow batteries is designed and implemented which controls the speed and flowrate of the pumps in real time in response to the reservoir levels, as shown in Figure 1. This control scheme maintains balanced electrolyte reservoirs by minimizing the average differential pressure across the membrane. Minimal pressure drops are achieved by effectively matching the pressures in each half-cell of the battery by adjusting each pump’s speed and flowrate independently, so that both pumps are operating at the same pressure on their respective fluid mechanical system curves. Additionally, a more leak-resistant cell gasket design shown in Figure 2 is developed, while maintaining chemical compatibility for nonaqueous systems. These two developments are employed in a long-term cycling experiment using a nonaqueous disproportionation electrolyte.

Figure 1
Investigating Anionic Chemistry of Na-Metal Halide Batteries for Large Scale Energy Storage Applications
Authors: Zhan Xiaowen , Lu Xiaochuan , Bonnett Jeff F , Canfield Nathan L , Chang Hee Jung , Sepulveda Jonathan , Sprenkle Vincent , Li Guosheng 
Published: February 2020

Battery technologies continue gaining interests for large scale energy storage applications, because it is becoming more critical to couple renewable resources to the grid and yet to maintain the grid reliability and sustainability. In particular, sodium (Na) based battery technologies are suitable for this application due to its potential low materials cost from using earth abundant Na as the charge carrier and the prolonged cycle life. Among various Na based batteries, Na-sulfur (Na-S) and Na-metal halide (Na-MH, Na-NiCl2 or ZEBRA) have been extensively studied and deployed for practical applications. Although Na-S and Na-NiCl2 batteries share some common features such as molten sodium and beta-alumina solid electrolyte, Na-NiCl2 batteries can provide several advantages over Na-S batteries, including superior battery safety, high open-circuit voltage, lower operating temperature, and ease of assembly in the discharged state without using metallic sodium in the anode.
In here, we extend our studies of cathode materials to other nickel (Ni) halide compounds beside NiCl2, which has been extensively investigated in the past. It is found that using different types of halide anions can alter the anion diffusion process and the overall charge transfer reaction. We will present detailed electrochemical characterizations, battery testing, and spectroscopic characterizations to reveal the anionic chemistry of Na-MH batteries, which is important to further improve battery performances at lower operating temperatures.
Ni/Ni-Cr-P and Ni/Ni-Mo-Cr-P Electrodeposited Coatings As Bipolar Plate in Polymer Electrolyte Membrane Fuel Cell Environment
Authors: Chanda Uttam Kumar , Pati Soobhankar 
Published: February 2020

Polymer electrolyte membrane (PEM) fuel cells are expected to play a major role in transporting humans and goods. However, one of major bottlenecks is the high materials and manufacturing cost. One way to lower the cost to a great extent is by replacing conventional graphitic bipolar plates with metallic bipolar plates (BPPs), as they costs around 30% of the total cost of stack1. That said, metallic BPPs have durability issues. Over time, they corrode and show higher interfacial contact resistance (ICR). In this work we attempt to engineer the surface of metallic BPPs, so that they perform for longer duration without degrading. To keep the process economical and commercially attractive, a bilayer coating of Ni followed by Ni-Cr-P alloy is pulsed electrodeposited on AISI 1020 low carbon steel. The electrodeposition process is optimized varying the process parameters, such as electrolyte composition, temperature and deposition current.
Field emission scanning electron microscopy and energy dispersive x-ray spectroscopy are used to study the surface morphology and compositional analysis of coating, respectively. Variation in microstructure and composition the Ni/Ni-Cr-P coating is observed with change in process parameter such as pH and temperature. Corrosion studies were carried out on Ni/Ni-Cr-P coated samples using potentiodynamic technique in accelerated (0.5 M H2SO4 + 2 ppm HF) solution at 80ºC. Ni/Ni-Cr-P coated samples with higher Cr content exhibited better corrosion resistance behaviour in both cathodic (air-purging) as well as anodic (H2-purging) environment compared to the bare substrate. Long term durability of Ni/Ni-Cr-P coated samples and AISI 1020 low carbon steel samples were studied using potentiostatic polarization technique. Both coated and bare samples are placed in the accelerated electrolyte solution. Ni/Ni-Cr-P coated samples showed better durability with less change in current density, while bare samples completely disintegrate and precipitate into the solution within 2–3 hours in potentiostatic mode in both the environments. Ni/Ni-Cr-P coated sample show lower interfacial contact resistance (ICR) value than that of bare AISI 1020 steel samples.
For better corrosion resistance and improvement in surface electrical property, Mo was included in the coating composition2. Ni/Ni-Mo-Cr-P coated samples show improved corrosion resistance than Ni/Ni-Cr-P coated samples and AISI 1020 low carbon steel bare samples in both anodic and cathodic PEM fuel cell environment.

Reference:

R. Taherian, J. Power Sources, 265, 370–390 (2014) http://dx.doi.org/10.1016/j.jpowsour.2014.04.081.

H. Rashtchi et al., Fuel Cells, 16, 784–800 (2016) http://dx.doi.org/10.1002/fuce.201600062
Development of Large-Scale Proton-Conducting Fuel Cells for Next Generation SOFC
Authors: Wee Seokeun , Lee Sewook , Park Sangho , Shin Dongwook 
Published: February 2020

Solid oxide fuel cells (SOFCs) are known to exhibit an exceptional energy conversion efficiency over 80 % of the various fuel cell types and have environmentally friendly systems with fuel flexibility. Unfortunately, the SOFC based on yttria-stabilized zirconia (YSZ) electrolytes has a major obstacle to commercialization due to its high cost and low durability at high operating temperature range (800~1000 oC). To overcome this issue, many researchers have made efforts in studying materials with performance comparable to conventional SOFCs at intermediate temperature range (500~700 oC). Among these efforts, to use a proton conductive material with a perovskite structure (ABO3) is regarded as an attractive solution. A lot of previous literatures have already proved the potential of proton-conducting oxide fuel cells (PCFCs) as a next generation of SOFCs. However, most of the results are based on laboratory-scale, so the reliability and feasibility have not been confirmed yet. In the attempt of entering the market with the PCFCs, several issues that must be faced are related to large-scale production. Firstly, when it comes to large-scale cell, the difference in the thermal expansion coefficient (TEC) between the electrode and the electrolyte dominantly affects the overall mechanical property of cells. So, the shrinkage rate after sintering should be elaborately controlled to inhibit several problems such as cracking, lifting and warping. Secondly, the low sinterability of BaCeO3 based proton conductors requires a high sintering temperature, which is more serious problem particularly in large-scale cells. That is, the possibility of Ba evaporation during the heat treatment increase, involving in formation of a secondary phase, which eventually causes performance deterioration. To our knowledge, few literatures are reported on this topic, large-scale PCFCs fabrication.
In this work, we attempt to establish large-scale anode-supported PCFCs with BaCe0.6Zr0.2Y0.1Yb0.1 produced by citric-nitrate synthesis method. The electrostatic slurry spray deposition (ESSD) technology was used for each layer fabrication of large-scale cells. An anode functional layer (AFL) was adopted to adjust the TEC and shrinkage rate between the anode and the electrolyte. The quantitative shrinkage rates depending on temperature were analyzed by Dilatometer (Linseis Co.). A scanning electron microscope (SEM, JEOL Co.) was used for microstructural analysis. To examine Ba evaporation and interlayer diffusion, energy dispersive X-Ray spectroscopy (EDX) was used, and the phase development of the synthesized BCZYYb was analyzed by X-ray diffractometer (XRD, Rigaku Co.). The I-V curves and impedance spectra of the single cell were measured in the range of 500 ℃~700 ℃ with humidified hydrogen (~3 % water vapor). Finally, a short-term stability test (100 hours) was performed to confirm the electrochemical durability.
Elucidating the Electrode/Electrolyte Interface of Anionic Exchange Membrane Electrolyzers
Authors: Kendrick Ian , Mukerjee Sanjeev , Weber Adam Z. , Gerhardt Michael R. , Doan Huong 
Published: February 2020

Anion exchange membrane electrolyzers (AEMEs) have the potential to dramatically decrease the cost of hydrogen production by enabling the use of non-platinum group metal (non-PGM) catalysts. While optimum performance is achieved using hydroxide electrolyte solution, corrosion issues require corrosion resistant system components. Recently, it has been demonstrated that using a carbonate solution as an electrolyte feed for the OER electrode has the potential of significantly lowering the overvoltage. Using carbonate in an AEM interface is however counterintuitive from the point of view of its lowering ionic conductivity, electrode poisoning and mass transport.
Initial results from a multiphase, multiphysics computational model of the electrode/electrolyte interface reveal advantages and disadvantages of using a carbonate feed. In terms of the former, the presence of carbonate results in a 1000x increase of the active surface area relative to water. However, the hydroxide flux at the anode causes an accumulation of carbonate ions at the anode resulting in a localized pH shift and Nerstian voltage loss. In addition, carbonate adsorption at the exchange site of the ionomer membrane restricts the use of a carbonate solution to solely the anode.
The computational model developed in the course of this research will be used to further characterize the AEME electrode/electrolyte interface. Observations gleaned from the model will be reconciled with performance data obtained from an AEME using non-PGM using various electrolyte feeds across each electrode.
Effect of Varying Co Content in PtCo Nanoparticles on the Performance of PEM Fuel Cells
Authors: Yarlagadda Venkata , Padgett Elliot , Moylan Thomas E , Gu Wenbin , Kukreja Ratandeep , Cai Yun , Thompson Levi T , Muller David A. , Kongkanand Anusorn 
Published: February 2020

PtCo alloy catalysts are leading cathode candidates for PEMFC because of their relatively high activity and durability. Although it is known that during fuel cell operation the dissolution of Co results in loss of oxygen reduction reaction activity and that the migration of Co2+ into the membrane can have a negative impact on fuel cell high-current-density performance, the detailed mechanisms are unclear. Thus there are opportunities for PtCo alloy optimization to minimize these losses.
Here, we focused on dealloyed PtCo catalysts with varying degrees of acid leaching in an attempt to vary the Pt-rich shell content while maintaining the Pt-to-Co core composition. While the specific activity of the catalyst decreased with reducing Co content, as expected, the high current fuel cell performance improved. Post-mortem analyses were done to quantify the amount of Co2+ in the membrane. Mathematical modelling was used to help interpret the voltage losses at high current density. We also employed newly developed nanobeam electron diffraction techniques to measure local crystal structure across the PtCo core-shell nanoparticles at subnanometer resolution. This allows us to correlate lattice strain relaxation and defect sites to the apparent catalyst kinetic activity.
This work was partially supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy under grant DE-EE0007271.
(Invited) Tailoring Metal Nanostructures for Energy-Efficient Electroreduction of CO2 and O2
Authors: Wang Chao 
Published: February 2020

Electrocatalysts play a vital role in the development of renewable energy technologies based on electrical-chemical energy conversions, such as fuel cells, electrolyzers, photoelectrochemical solar cells and metal-air batteries. Many metallic nanostructures have emerged as promising candidates for such electrocatalytic applications, but the performances are yet to be improved to meet the technical and cost-effectiveness standards for practical implementations. On the other hand, it traditionally relies on the model-catalyst studies of well-defined extended surfaces for mechanistic understanding of electrocatalysis, but discrepancies in catalytic performance and knowledge gaps are also realized to be present between the extended surfaces and nanomaterials. The latter is probably not only due to the intrinsically different bulk and surface structures of materials at these two extremes of size, but also caused by the challenges in probing the active sites and reaction pathways on nanostructured materials.
This presentation aims to discuss two examples of our efforts on tailoring metallic nanostructures for electrocatalytic applications: i)
highly dense Cu nanowires for the electroreduction of CO2 and CO, and ii) Co/Pt core/shell nanoparticles as sustainable electrocatalysts for the oxygen reduction reaction (ORR). These nanostructures are characterized by combining electron-based microscopic imaging, diffraction and elemental mapping, while the surface structures are probed by using surface-specific adsorption/desorption of small molecules (e.g., COad and OHad). The gained structural information is correlated to the measured catalytic activity, durability and/or selectivity, based on which computational simulations are further performed to understand the established structure-property relationships, depict the active sites and reveal the catalytic enhancement mechanisms. Our work highlights the great potential of tailoring nanostructured materials to improve the energy conversion and chemical transformation efficiencies of electrochemical systems.
Na2so4-Polyacrylamide Neutral pH Polymer Electrolytes for Electrochemical Capacitors
Authors: Virya Alvin , Abella Justin , Grindal Andrew , Lian Keryn 
Published: February 2020

Polymer electrolytes are the key enablers for solid-state electrical double layer capacitors (EDLCs) that are thin, light-weight, and flexible. Neutral pH electrolytes are particularly interesting due to their wide operating voltage window for higher energy density and non-corrosive properties for enhanced safety [1-2]. To date, polymer electrolytes comprised of Li2SO4 and polyacrylamide (PAM) have exhibited promising results [3]. However, their ionic conductivity and industrial applications are still limited by the lower mobility of Li+ ions [4] and high cost of lithium salts. Among various sulfate salts, Na2SO4 is a promising candidate as ion conductors for its higher cation mobility, relatively high solubility in water, and low cost from its earth-abundance.
In this work, our objectives are to (a) develop a high-performance, low cost neutral pH polymer electrolyte using Na2SO4 and PAM, (b) understand the origin of the ionic conductivity and material properties of Na2SO4-PAM electrolytes, and (c) demonstrate its application in solid EDLC devices. Metallic cells were constructed to study the ionic conductivity, whereas cells with commercial activated carbon electrodes were fabricated to demonstrate the viability in solid EDLCs.
The ionic conductivities of the polymer electrolytes with different Na2SO4:PAM ratios were tracked over 30 days period in 45 %RH storage environment (Fig. 1). The optimized electrolyte with salt-to-polymer molar ratio of 10,000:1 demonstrated a high ionic conductivity >30 mS cm-1, considerably higher than previously developed neutral pH electrolytes. With activated carbon electrodes, the polymer electrolytes enabled a stable operating 1.8 V voltage window with good cycling performance >10,000x.
References:
[1] Q. Abbas et al., “Strategies to Improve the Performance of Carbon/Carbon Capacitors in Salt Aqueous Electrolytes,” J. Electrochem. Soc., 162, 2015
[2] D.P. Dubal, et al., “Towards flexible solid-state supercapacitors for smart and wearable electronics,” Chem. Soc. Rev., 47, 2018
[3] A. Virya and K. Lian, “Li2SO4-polyacrylamide polymer electrolytes for 2.0 V solid symmetric supercapacitors,” Electrochem. Comm., 81, 2017
[4] R.W. Impey, P.A. Madden, and I.R. McDonald, “Hydration and mobility of ions in solution,” J. Phys. Chem., 87, 1983
Figure caption: Ionic conductivity of Na2SO4-PAM with varying salt content over a 30-days period

Figure 1
Platinum-Iridium Modified Gold Nanoparticles Catalysts for Electrooxidation of Ethanol in Alkaline Media
Authors: Liang Zhixiu , Song Liang , Deng Shiqing , Zhu Yimei , Stavitski Eli , Adzic Radoslav R. , Chen Jingyi , Wang Jia X. 
Published: February 2020

Ethanol is one of the most promising alternative fuels for fuel cells (FC). It is a renewable resource which can be produced on a large scale from biomass originating from agriculture, forestry and urban residues. The energy density of ethanol is as high as 8.01 kWh/kg, which is comparable to that of gasoline. Ethanol is easy to store, transfer and refuel owing to its non-toxicity and high boiling point in comparison with methanol and ammonia. [1] However, the sluggish kinetics and low energy efficiency for ethanol oxidation reaction (EOR) hinder the application of direct ethanol fuel cells (DEFCs). To address this issue, great effort has been made focusing on catalysts discovery as well as reaction mechanism understanding. [2]
Here we report a systematic study on Pt-Ir modified Au/C electrocatalysts for efficient ethanol oxidation in alkaline media. In-situ electrochemical Infrared reflection absorption spectra (EC-IRRAS) reveals a high selectivity toward full oxidization to carbonate at low potentials, resulting in a high energy conversion efficiency. EC-IRRAS also indicate that the C-C bond splits upon ethanol interaction with the surface of PtIrAu/C ternary catalyst. More detailed discussion on this topic will be presented at the meeting.
Acknowledgements
This manuscript has been authored by employees of Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. The publisher by accepting the manuscript for publication acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.
[1] Liang An, Tianshou Zhao, Yinshi Li, Carbon-neutral sustainable energy technology: direct ethanol fuel cells. Renewable and Sustainable Energy Reviews 2015, 50: 1462- 1468
[2] Alexey Serov, Iryna V. Zenyuk, Christopher G Arges, Marian Chatenet. Hot topics in alkaline exchange membrane fuel cells. Journal of Power Sources 2018, 375: 149- 157
Direct Electro-Oxidation of Dimethyl Ether on Pt-Cu Nanoparticles
Authors: Elbaz Lior 
Published: February 2020

As the use of portable devices such as mobile phones, laptops and tablets grows rapidly, efficient portable energy technologies are becoming more necessary than ever. In the past years, fuel cells made a great advancement in the field of power sources technology, and are currently referred to as the most promising alternative energy technology. The most popular type of fuel cells today is the polymer electrolyte membrane fuel cell (PEMFC), fueled with hydrogen. Although it offers very high power density, the lack of fueling infrastructure necessary for the handling of hydrogen is currently one of its biggest commercial impediments. In order to overcome this hurdle with portable devices, direct methanol fuel cells (DMFC) were proposed as an alternative. This is mainly due to the methanol’s high energy density and ease of handling. DMFC’s were studied thoroughly over the past decades, and the technology encountered some barriers such as slow anode kinetics, methanol crossover from the anode to the cathode and issues concerning methanol’s toxicity.
Dimethyl ether (DME) is an ether gas under ambient conditions that could be liquefied under low pressure, traditionally used for aerosol propulsion and as an alternative fuel for diesel combustion engines. It was also recently suggested as an alternative fuel for low-temperature fuel cells. This is mainly due to its higher energy density when compared to methanol, 8.2 vs. 6.1 kWh kg-1. There are no C-C bonds to break in the reaction and its theoretical open cell voltage (OCV) is relatively close to DMFC, 1.18 V compared to 1.21 V at 25°C. In addition, DME has a lower dipole moment than methanol and therefore, the fuel crossover in a fuel cell is expected to be much lower than methanol’s, decreasing the mixed potential impact on the cathode.
In this work, new catalyst for the direct electro-oxidation of dimethyl ether (DME) was synthesized and studied using an array of techniques. One of the most prominent catalysts for this reaction, platinum copper alloy (PtCu), was synthesized in an easy and low cost approach. Structural characterizations such as X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM) and elemental analysis revealed that the synthesized PtCu nanoparticles (3 nm on average), formed homogeneous alloy without aggregation of metallic platinum or copper. The catalyst’s activity towards electro-oxidation of DME was tested using rotating disk electrode (RDE) and in membrane-electrode assembly in a full cell. The catalyst performance was found to be promising. Direct DME fuel cell (DDMEFC) studied in this work has relatively high energy density as well as low “cross-over” tendency due to a low dipole moment and thus shows great potential as fuel for low power fuel cells. The electrocatalysis of the DME oxidation reaction (DOR) was compared between synthesized PtCu and commercial PtRu/C and exhibited an enhanced performance with the newly synthesized catalyst.