bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drivers of Membrane Fouling in the Non-Aqueous Vanadium Acetylacetonate Redox Flow Battery
Authors: Rungta Rohit , Monroe Charles W. 
Published: August 2024

Due to their unique advantages in terms of long cycle life and modular design, redox flow batteries (RFBs) are being developed to load-level and peak shave energy from intermittent sources such as wind and sunlight. RFBs have yet to meet the stringent cost requirements needed to achieve broad market penetration, however. The second largest cost associated with state-of-the art RFBs after the electrolyte itself is the ion-exchange membrane, which accounts for 30% of the total cell cost [1]. Porous separators provide a pathway to substantially decrease the cost of RFBs, but long-term performance has been difficult to assess due to the coupling of electrolyte degradation, self-discharge, and membrane fouling. This study applies an adaptive observer model to estimate crossover from the open-circuit voltage relaxation of RFB cells, providing detailed information that can be used to decouple membrane fouling from electrolyte degradation by side reactions.
For this study the nonaqueous V(acac)3 (vanadium acetylacetonate) electrolyte chemistry [2] is used. Because the RFB cell reaction is based on an electrochemical disproportionation of the neutral V(acac)3 complex, crossover of the active species in this system only results in reversible self-discharge.
A novel set of 'canary cell' experiments unequivocally point to membrane fouling as the predominant factor that drives permanent cell degradation. An adaptive observer [3] is used to monitor the crossover rate, which is a proxy for membrane porosity, during self-discharge experiments where the cell is fully charged and the voltage is monitored during an open-circuit relaxation. Figure 1 shows that the porous Daramic separator starts off with ideal Fickian behavior because crossover is a linear function of the state of charge. Over time, however, the cell deviates, with active-species crossover becoming non-Fickian as the membrane fouls. The mass transfer coefficient (determined by the slope of the curve) decreases with exposure to current. It is hypothesized that pore clogging is responsible for this decreasing mass transfer coefficient, and in turn the diminution of cell performance. Deconvoluting membrane and electrolyte processes is a crucial step to determine the stability and long-term viability of RFB electrolyte systems.

References

[1] J. Noack, L. Wietschel, N. Roznyatovskaya, K. Pinkwart, and J. Tübke, "Techno-Economic Modeling and Analysis of Redox Flow Battery Systems", Energies, 9 (8), Aug. 2016.
[2] Q. Liu, A. E. S. Sleightholme, A. A. Shinkle, Y. Li, and L. T. Thompson, "Non-aqueous vanadium acetylacetonate electrolyte for redox flow batteries", Electrochem. Commun., 11 (12), Dec. 2009.
[3] P. Ascencio, K. Smith, C. W. Monroe, and D. Howey, "Adaptive Observer for Charge-State and Crossover Estimation in Disproportionation Redox Flow Batteries undergoing Self-Discharge", American Control Conference (ACC), Jul. 2019.

Figure 1
Importance of Controlling Cycling Conditions to Improve the Lifetime of Anthraquinone-Based Negolytes with a Potentially Low Cost of Manufacture
Authors: Vallem Veenasri , Hamedi Amir Sina , Beh Eugene S. , Bahari Meisam 
Published: August 2024

Organic redox flow batteries (RFB) in general and anthraquinones in specific have shown a great promise for developing cost-effective alternatives to vanadium RFBs. Two main hurdles, however, have been the fast fade rate and a high estimated cost of manufacture (COM) that have slowed down the scale up of organic RFBs. In this study, 1,8-dihydroxy-2,7-dicarboxymethyl-9,10-anthraquinone (1,8-DCDHAQ), 1,5-dihydroxy-2,6-dicarboxymethyl-9,10-anthraquinone (1,5-DCDHAQ) and 1,3,5,7-tetrahydroxyanthraquinone (THAQ) have been explored. These negolytes are expected to have a reasonably low COM due to their simple synthesis route. Additionally, these electroactive species have a low fade rate. Nevertheless, the fade rates are not adequately low for scaleup and commercialization purposes. Therefore, the effect of various factors including the electrolyte flow rate, cutoff voltages, SOC limits, and OH- concentration on the cycling performance have been explored in order to further reduce the fade rate.
Our experimental analysis suggests that: (1) the electrolyte flow rate and the extent of mixing in the electrolyte reservoir may lead to inaccurate capacity utilizations and fade rates, (2) increasing the OH- concentration significantly lowers the fade rate and the effect continues even at concentrations higher than 1.0 M, (3) choosing an unnecessarily low discharge cutoff voltage has a detrimental effect on the fade rate of anthraquinones, (4) SOC limit is a very important tool that significantly lowers the fade rate. Through controlling these cycling conditions, the lifetime can be improved by at least a factor of 10. Under properly chosen conditions, the fade rate of 1,5-DCDHAQ and THAQ remains < 0.001%/day (< 0.4%/year). To further verify the effect of the operating conditions, cyclic voltammetry and HPLC techniques were used to identify and/or characterize the side products in the electrolyte. COM of 1,5-DCDHAQ and THAQ at scale are estimated to be 27.99 and 47.44 $/kAh (or 24.13 and 37.95 $/kWh), respectively. 1,8-DCDHAQ and 1,5-DCDHAQ are expected to have a similar COM.
Due to the expected low COM for the abovementioned anthraquinones and their very low fade rate under optimum cycling conditions explored in this study, these molecules now present a distinctive prospect for developing and commercializing an affordable and long lifetime organic RFB chemistry.
Cu/F Dual-Doping on the Ni–Mn Based Layered Oxide As Cathode Material for Sodium-Ion Batteries
Authors: Chen Hsiang Jung , Chen Han-Yi 
Published: August 2024

As demands for energy storage are ever-increasing, sodium ion batteries (SIB) have been widely conducted for superior electrochemical performance and reduction in cost compared to lithium ion batteries (LIBs), one of the most commonly used energy storage devices nowadays. Among all the parts in batteries, cathode materials play a crucial role with regard to performance. Here, layered transition metal oxides (LTMOs) (NaxTMO2, TM = Cu, Mn, Fe, Ti, Co, Cr, Ni, etc.) have kept catching researchers’ eyes due to their mature developments in commercial LIBs over decades.
P2-type Ni/Mn-based LTMOs (such as Na0.67Ni0.33Mn0.67O2, NNMO) exhibit high theoretical specific capacity (~173 mAh g−
1) with environmentally friendly and cheap elements. However, they show limited stability upon charging over 4.2 V, directly restricting their energy density and lowering operating voltage. Besides, disadvantages such as poor rate performance and air/moisture sensitivity are remaining improvements for commercialization. Hence, our study mainly focuses on improvements for shortages of NNMO by applying a facile cation-and-anion co-doping strategy. Via transition metal Cu ion doping, the cycling stability of NNMO can be improved without sacrificing too much capacity, and the air stability can also be improved. In addition, F doping to replace oxygen can further enhance the structural stability and increase the rate performance by modifying interlayer spacing of the layered structure. A facile sol-gel method with heat treatment is used to synthesize cation-and-anion co-doped NNMO. The material characterization shows successful synthesis after cation and anion doping. In addition, the long cycle test shows that capacity retention increases from ~50% to ~90% over 100 cycles after Cu doping. The specific discharge capacity also increases from ~110 mAh/g to ~130 mAh/g at 0.1C with a slight increase in cycle retention from ~75% to ~77% after F doping. Also, the capacity at 20C could be maintained at ~50 mAh/g, around 45% of the initial capacity at 0.1C. The detailed charge storage mechanism will be studied by applying operando X-ray absorption spectroscopy and ex-situ X-ray photoelectron spectroscopy. As for the moisture sensitivity part, the XRD spectra indicate that no noticeable structural changes or impurity formation occurred after air exposure for one month, showing good air stability. Furthermore, operando XRD is conducted to confirm structural reversibility during charging and discharging.
In summary, by applying a simple Cu/F co-doping strategy, Na0.67Ni0.13Cu0.20Mn0.67O2-xFx exhibits sufficient cycle stability for over 100 cycles as well as excellent rate capability even at a high current density of 20C, which proves itself a promising candidate as high-performance cathode material in SIBs. In addition, the cheap and environmentally friendly elemental usage (Ni, Mn and Cu) and air-stability enhancement also increase possibility of this material for large-scale energy storage application in industry.
Modeling of Lithium-Flow Batteries with Aqueous Electrolyte
Authors: Law Destiny , Andrei Petru , Liu Shengyi , Goss Roger 
Published: August 2024

Flow batteries with aqueous electrolyte at the cathode are safe, low-cost and ecofriendly energy storage systems. When the aqueous cathode is coupled with a Li-metal anode with organic electrolyte, these batteries have extremely high energy densities (over 4,000 Wh/Kg), which makes them attractive not only for grid applications (where flow batteries are often used) but also in maritime applications such long endurance surface vessel systems and wave gliders [1-4]. In this presentation, we derive the mathematical model for lithium-flow batteries and use this model to predict the performance of the batteries under different discharge conditions, cathode microstructures, water flow velocities, etc. The results are then compared to experimental data already available in the literature. The mathematical model is based on coupling the flow equations (Navier-Stokes) with electrochemical equations for reaction rates and using average microscopic models for the cathode. For instance, Fig. 1 shows the voltage of a flow battery as a function of time for different water velocities in a flow battery simulated by solving the above model. For low water velocities, the water is not able to provide enough oxygen in the cathode and the voltage of the battery collapses after a few seconds. However, as long as the water velocity is above approx. 1.2 cm/s, the battery will have enough oxygen to operate continuously; in this case, the higher the flow of the water, the higher the voltage of the battery in the stationary state will be because of lower overpotential losses. In these simulations, the anode contained Li-metal. The cathode had a length of 1 cm (measured in the direction of water flow) and a thickness of 100 μm. The cell was discharged at a small rate of 0.01 mA/cm2. The incoming water had an oxygen concentration of 5 mg/l (which is equal to the oxygen concentration in seawater) and was pumped through the cathode at different velocities. A detailed derivation of the mathematical model and more simulation results and predictions will be presented at the meeting.

References:

[1] R. E. Davis and J. T. Sherman, “Evaluating a Lithium-Seawater Battery on Gliders,” J. Atmospheric Ocean. Technol., vol. 34, no. 5, pp. 1175–1182, May 2017, doi: 10.1175/JTECH-D-16-0151.1.
[2] X. J. Chen, A. Shellikeri, Q. Wu, J. P. Zheng, M. Hendrickson, and E. J. Plichta, “A High-Rate Rechargeable Li-Air Flow Battery,” J. Electrochem. Soc., vol. 160, no. 10, pp. A1619–A1623, Jan. 2013, doi: 10.1149/2.012310jes.
[3] J. P. Zheng, P. Andrei, M. Hendrickson, and E. J. Plichta, “The Theoretical Energy Densities of Dual-Electrolytes Rechargeable Li-Air and Li-Air Flow Batteries,” J. Electrochem. Soc., vol. 158, no. 1, pp. A43–A46, 2011, doi: 10.1149/1.3515330.
[4] B. Horstmann, T. Danner, and W. G. Bessler, “Precipitation in Aqueous Lithium–Oxygen Batteries: a Model-Based Analysis,” Energy Environ. Sci., vol. 6, no. 4, pp. 1299–1314, 2013, doi: 10.1039/C3EE24299D.

Figure 1
Advancing Low-Cost Iron Redox Flow Batteries for Grid Storage
Authors: Jayathilake Buddhinie Srimali , Ivanovskaya Anna N. , Overland Alexandra E. L. , Chandrasekaran Swetha , Clemens Auston L. 
Published: August 2024

Iron-based redox flow batteries are promising and low-cost energy storage technologies for grid level showing the potential to meet DOE’s cost targets LCOS, $0.05/kWh due to its natural abundancy and eco friendliness. Iron deposition process has a parasitic hydrogen evaluation reaction (HER) controlling the storage capacity and efficiency. HER reaction imbalances the electrolyte composition and causes durability issues. Our present study shows how the performance of the iron flow battery can be increased by introducing advanced 3D electrodes and engineered electrolytes.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Funding was provided by Lawrence Livermore National Laboratory Directed Research and Development (LDRD) Grant 22-DR-014. IM release number: LLNL-ABS-858432
Development of Next Generation Membranes for PEM Water Electrolysis in AGC
Authors: Hayabe Shintaro , Salem William , Sawada Toshiaki 
Published: August 2024

AGC’s FORBLUETM product family has over 70 years of experience in ion-exchange membranes (IEMs). S-SERIES, a FORBLUETM member, is a per-fluorinated sulfonic acid polymer (PFSA) membrane utilized in various electrochemical devices and industrial electrolysis. AGC’s IEM technology had a lot of experience in the chlor-alkali application and was further developed for the PEM water electrolysis industry.
AGC R&D has developed S-SERIES membranes with a smaller thickness, improved reinforcement, and high ion exchange capacity (IEC) that enhanced not only an electrochemical performance but also dimensional stability.
A membrane electrode assembly (MEA) was fabricated using a developed membrane with high IEC polymer (IEC 1.25 meq/g). As a result, IV characterization of a single cell with 25 cm2 electrode area at 80°C showed a significant voltage reduction compared to a commercial membrane in the PEM water electrolysis market. In addition, H2 crossover during the electrolysis was evaluated in a single cell with a 25 cm2 electrode area at 80°C and ambient pressure, and the H2 concentration in O2 at the anode side was compared at a current density of 1.0 A/cm2. The developed membrane showed 0.3 vol% H2 crossover, whereas the commercial membrane showed 0.5 vol%.
Furthermore, next-generation membranes with gas recombination catalysts (GRC) and radical scavengers leading to lower gas crossover and higher chemical stability are under development. Recently, high-pressure electrolyzers have been getting more attention and the increase of H2 crossover is a concern against the lower explosive limit (LEL) for hydrogen in oxygen. In general, PFSA membranes are considered to have high chemical durability, however, F ion release is observed, that indicate that this PFSA polymer is attacked by OH radicals generated in the PEM water electrolysis system. AGC has been investigating the application of GRC and radical scavengers to the newly developed membranes. It was evaluated in a single cell with 25 cm2 electrode area at 80°C and 2.0 A/cm2. As a result, the H2 crossover and F ions release rate (FRR) were reduced compared to the membrane without both additives. The data will be presented on these improved performances.
A Paper-Based Microfluidic Methanol Fuel Cell Catalyzed By Ni-Co@LTA Electrocatalyst for Micro-Nano Power Systems
Authors: Baruah Sarmistha , Kumar Akshai , Peela Nageswara Rao 
Published: August 2024

Sustainable energy generation has recently gained popularity due to the rising energy demand and environmental concerns caused by conventional non-renewable energy sources. In the context of portable electronics, and microsystems all would require fully integrated, dependable power generation. In this regard, paper-based microfluidic fuel cells (PMFC), have drawn significant attention. By utilizing the inherent properties of paper substrate and microfluidic reactant streams, this fuel cell device takes away the requirement of any membranes or external pumps that are necessary for conventional FCs. In co-laminar flow, where PMFCs work, a unique diffusive mixing area serves as a pseudo-membrane by preventing the convective mixing of two reactants. The reactants flow by capillary action with the aid of an absorbent pad. While the ions transport across the channel through the mixing zone. This not only makes the pumping of fluids into paper-based systems simpler, but also provides numerous other benefits such as cost-effectiveness, simplicity in manufacturing, ease of disposal, and portability over traditional FCs. In this work, we synthesized a Ni-Co catalyst encapsulated within zeolite 4A (also known as LTA) via a hydrothermal synthesis route. The resulting catalyst exhibited better catalytic activity of 12.1 mA cm-2 at 1.12 V vs Ag/AgCl and retained remarkable stability (~77%) even after 1000 cycles CV test in 0.1 M KOH + 1 M methanol. By utilizing this catalyst as anode and Pt/AC (5 wt%) as cathode, we demonstrate a Y-shaped membraneless PMFC using Whatman filter paper grade 41 as paper substrate. It has been shown that the device can deliver power densities in the range of 2 - 10 mW cm-2 (Fuel: methanol, Oxidant: KMnO4), and can retain power output for at least 30 min. Additionally, the power of the cell can easily be raised by connecting two or more cells in series, making these PMFCs suitable for micro/nano power generation systems.
Keywords: Fuel cell, Microfluidic, Paper substrate, Co-laminar flow, Zeolite 4A.
Multi-Substituted Phosphonated and Sulfonated Polymer Materials: Characterization and Blends with Basic Polymers
Authors: Stigler Theresa , Byun Jiwon , Thiele Simon , Kerres Jochen Alfred 
Published: August 2024

The growing demand for energy, limited resources, and climate warming call for alternative sustainable energy production. A promising candidate is the proton-exchange membrane fuel cell (PEMFC) using a proton conducting polymer as an electrolyte membrane. The most common proton-exchange membranes are based on sulfonated polymers, such as Nafion®. Since their proton conduction is driven by hydronium ions (H3O+) and hence require water, the operating temperature is limited to 100°C. Unlike in sulfonated polymer materials, the proton conduction in materials with phosphonic acid groups occurs via a hopping process and does not require water.1 This study introduces a highly substituted phosphonated and sulfonated polymer based on poly(pentafluorostyrene), which makes the material adaptable in anhydrous and hydrous operating conditions since the phosphonic acid and sulfonic acid units can conduct cooperatively. The phosphonic acid group is introduced via the nucleophilic aromatic substitution Michaelis-Arbuzov reaction. The Para-Fluoro-Thiol reaction was used to introduce sulfonic acid groups into the polymer backbone. In the past, both reaction steps were well investigated.2,3 The highly substituted polymer material was blended with a basic polymer to circumvent water solubility and investigated according to its proton conductivity, thermal stability, and mechanical properties.
(1) Kumar, A. J. Mater. Chem.
A
2020, 8 (43), 22632–22636. DOI: 10.1039/d0ta07732a.
(2) Atanasov, V.; Oleynikov, A.; Xia, J.; Lyonnard, S.; Kerres, J. Journal of Power Sources
2017, 343, 364–372. DOI: 10.1016/j.jpowsour.2017.01.085.
(3) Delaittre, G.; Barner, L. Polym. Chem.
2018, 9 (20), 2679–2684. DOI: 10.1039/c8py00287h.
Colloidal Nafion in Liquid Media: Insight from SANS Analysis and Molecular Dynamics Simulations
Authors: Klein Jeffrey Michael , Welch Cinthia , Ponnurangam Sathish , Tarokh Atefeh , Karan Kunal , Hawley Marilyn , Sokolova Anna , Yim Sung-Dae , Hjelm Rex , Kim Yu Seung 
Published: August 2024

Colloidal Nafion™ morphology in liquid media plays a critical role in determining the electrode performance of fuel cells and electrolyzers. In this presentation, we demonstrate that commonly reported, cylindrical morphologies of Nafion in liquid media are not ubiquitous among Nafion dispersions and assuming such may provide inaccurate information.1 Here we compare colloidal Nafion™ morphology in N-methyl-pyrrolidone (NMP) and water using small angle neutron scattering (SANS) and all atomistic molecular dynamics simulations (MD).2 Our SANS analyses using model-dependent and model-independent techniques combined with MD simulations demonstrated highly gel-like particles best describe Nafion particles in NMP, which is in stark contrast to the commonly assumed cylindrical morphology. In high dielectric constant dispersants such as water, the cylindrical morphology is a feasible choice to describe the scattering data, however, the particle radius is much lower than previous report (R = 10 Å). MD simulations support the SANS analysis and show that the sulfonic acid groups are fully dissociated and strongly solvated on the outer wall of the particle suggesting that the structure is driven by hydrophobic interactions.
References

Aldebert, B. Dreyfus, G. Gebel, N. Nakamura, M. Pineri, F. Volino, Macromolecules, 19, 2651-2653 (1986).

Jeffrey M. Klein, Cynthia Welch, Sathish Ponnurangam, Atefeh Tarokh, Kunal Karan, Marilyn E. Hawley, Anna Sokolova, Sung-Dae Yim, Rex P. Hjelm, Yu Seung Kim,
ACS Macro Letters, 12, 1648-1653 (2023).
Raman Microscopic Investigation of Organic Solvent Concentration Profiles in Proton Exchange Membranes and Their Permeability
Authors: Götz Carina , Komma Miriam , Dworschak Dominik , Thiele Simon , Boehm Thomas 
Published: August 2024

Direct alcohol fuel cells (DAFCs) suffer from severe problems related to the employed polymer electrolyte membranes, such as fuel crossover, resulting in low faradaic efficiency and performance of the fuel cell.1,2,3 We introduce a 3D-printed diffusion cell setup, which is capable of determining the interaction of membranes and organic solvents via confocal Raman microscopy.4 Thus, the suitability of proton exchange membranes (PEMs) for usage in DAFCs can be evaluated. In this setup, the membrane is clamped between two flow channels, similar to the flow field plates of a fuel cell. The donor channel is filled with an organic solvent-water mixture, and the receptor channel is filled with water. Depth scans through the membrane and the two flow channels provide concentration profiles of the organic solvent within the membrane, which are used to calculate membrane properties such as permeability and sorption coefficient (see Fig. 1).
In this study, the membrane-solvent interactions between standard unreinforced and composite PEMs and various organic solvent solutions, such as 2-propanol, acetone, and ethanol, are investigated. All membranes analyzed show a preference for organic solvent absorption from 1 M solutions, with sorption coefficients ranging from 2.5 to 3.0. In addition to the absorption, the organic solvents permeate through the membrane. The corresponding permeabilities range from 10-5 to 10-4 cm² s-1. However, the permeabilities of the membranes for different solvents do not scale with their sorption coefficients, in contrast to the membrane swelling.
This diffusion cell setup is an accessible and fast pre-screening method, which can enhance the development and evaluation of new ion exchange membranes for use in DAFCs and related applications.
References:

H. R. Corti, E. R. Gonzalez, Direct Alcohol Fuel Cells, Springer Netherlands, Dordrecht 2014.

S. Deabate, R. Fatnassi, P. Sistat, P. Huguet, J. Power Sources
2008, 176, 39.

P. Scharfer, Zum Stofftransport in Brennstoffzellenmembranen, Karlsruhe 2009.

C. Götz, M. Komma, D. Dworschak, S. Thiele, T. Böhm, Adv. Mater. Interfaces
2023.

Figure 1