bluuebunny/crossref_metadata_2025 huggingface dataset:
A Systematical Ab Initio Study of Diffusivity and Ionic Conductivity of Ln2NiO4+
δ (Ln=La, Nd, Pr) Reversible Solid Oxide Cells (r-SOCs)
Authors: Yang Songge , Lee Yueh-Lin , Liu Guangchen , Zhong Yu
Published: September 2023

The Ln2NiO4+δ (Ln=La, Nd, Pr) reversible solid oxide cells (r-SOCs) exhibit a relatively high oxygen diffusivity and surface reaction activity, compatible thermal expansion coefficient with solid electrolyte, and oxygen over-stoichiometry enabling the transportation of oxygen ions. The atomistic simulation technique provides detailed information concerning the diffusion mechanisms of the materials. In the present study, we systematically investigated the vacancy formation energy, thermal expansion, diffusivity, and ionic conductivity of the Ln2NiO4
+
δ (δ=0.125) compound through the ab initio approach. Especially considering the change of the oxygen transport properties caused by the thermal expansion effect, a combination of quasi-harmonic approximation (QHA) and a linear regression model is used to study and reproduce the temperature-dependent properties of the Ln2NiO4
+
δ.
(Digital Presentation) Hydrothermal Electrodeposition of Molybdenum Sulfide Toward Electrochemical CO2 Reduction Catalysts
Authors: Yamaguchi Akira
Published: September 2023

The search and development of efficient carbon dioxide (CO2) reduction reaction electrocatalysts is a hot topic in this era of global warming. Among material candidates for sustainable and cost−effective applications, metal sulfides have attracted attention as promising nature-inspired materials due to multiple adsorption sites which are enhanced by the covalent character of sulfur.

Molybdenum sulfides (MoS2) is one of the trandition metal dichalcogenides (TMDs) and possesses three kinds of struture; namely, metastable octahedral structure with high electronic conductivity (1T), stable triangular prism structure with low electronic conductivity (2H) and insulating rhombohedral structure (3R). Among them, 1T phase has been widely applied as catalysts for various reactions such as electrochemical nitrogen reduction reaction and electro/photochemical hydrogen evolution reaction. Since the structure of MoS2 largely affect its catalytic and other material property, synthetic process to control their bulk and even local structure should be explored to expand their availability as functional materials. Especially, our previous work (J. Phys. Chem.C, 126, 2772, 2022) demonstrated that metal-sufur bonding length is one of the key parameter to control carbon monoxide production selectivity from electrochemical CO2 reduction.

Here in this work, hydrothermal electrodeposition was applied to MoS2 synthesis to control their local structure. Recently, our group developed hydrothermal electrochemical flow reactor which enables the electrochemistry under hydrothermal condition with separate control of temperature and pressure. Using this reactor, hydrothermal electrodeposition of manganese oxides (MnO2) was conducted and samples exhibited higher electrochemical oxygen evolution activity than ones prepared with conventional methods. Also, the characterization results of electrodeposited MnO2 under hydrothermal condition showed the possiblity that morphology and lattice spacing can be controled by changing deposition temperature and pressure, respectively. Thus, we predicted our hydrothermal electrodeposition technique is useful to control the local structure of materials.

The hydrothermal electrodeposition of MoS2 were conducted under various temperature and pressure conditions and those samples were characterized with X-ray diffraction (XRD). Also, the effect of the deposition temperature and pressure on sample local structure was examined with Pair Disribution Function analysis of XRD and Extended X-ray Absorption Fine Structure analysis using synchrotron radiation. The electrochemical CO2 reduction experiments using hydrothermally depositted MoS2 samples revealed that the product selectivity for CO2 reduction was changed with deposition pressure. Thus, we confirmed that our hydrothermal electrochemical deposition can be applicable to the synthesis of metal sulfide-based CO2 reduction electrocatalysts, whose local structures are tuned.
Modeling the Coulombic Efficiency of the Aqueous Iron Electrode
Authors: Thomas-Alyea Karen
Published: September 2023

The aqueous iron electrode is attractive for large-scale energy storage because of its long life and low materials cost. The redox potential of the Fe ↔ Fe2+ reaction is approximately 50 mV negative of that of the hydrogen evolution reaction. Hydrogen evolution therefore causes self discharge of the iron electrode during rest and competes with the iron reaction during charge. Here we model the effect of electrode design and cell operation on the coulombic efficiency of charging the iron electrode at modest charging rates (<C/20). Kinetic parameters (exchange current density and transfer coefficients) for the iron dissolution-precipitation reaction and for the hydrogen evolution reaction are estimated from experimental measurements of electrode overpotential and hydrogen generation rate. The volume change from Fe(OH)2 to Fe metal results in a significant increase in porosity during charge and results in change in electrochemically active surface area. The porous-electrode model includes transport in the electrolyte, Butler-Volmer kinetics, and change in volume and surface area.

The model provides a theoretical explanation for experimental observations that coulombic efficiency decreases with decreasing charge rate, and that coulombic efficiency is lower in thicker electrodes. We then use the model to explore the impact for large-format cells of electrode size and design on coulombic efficiency.
Synthesis-Driven Computational Discovery of Organic Redoxmers for Non-Aqueous Redox Flow Batteries
Authors: Jain Akash , Shkrob Ilya A. , Assary Rajeev S.
Published: September 2023

Organic non-aqueous redox flow batteries (RFBs) are promising grid-scale energy storage systems for storing intermittent renewable energy in molecules. For practical applications, low-cost and stable redox active molecules (redoxmers) that display a large redox potential window and long electrochemical cycling stability are required to deliver a high-energy-density RFB with a long battery cycle life. To accelerate the discovery of redoxmer molecules, previous studies have utilized machine learning (ML) methods along with first-principles simulations. Although many ML-suggested molecules show promising electrochemical properties, they are generally difficult to synthesize because of their highly complex structure. To address this challenge, in this work, we propose a new synthesis-driven computational approach to discovering less-complex molecules with a large redox potential window that can deliver high-energy-density RFBs. Specifically, we devised an algorithm to generate an engineered molecular search space and applied a Bayesian optimization-based active learning algorithm to discover promising molecules from a large molecular search space while using a limited number of expensive density functional theory (DFT) calculations. To increase the energy density of RFBs, we focus on maximizing the redox potential window of redoxmer molecules (or cell voltage) by minimizing the reduction potential of anolyte molecules. Precisely, we studied the 2,1,3 Benzothiadiazole (BTZ) molecule, a promising anolyte (redoxmer) candidate for RFBs, and with our synthesis-driven approach discovered new BTZ-based molecules that show 15-43% smaller reduction potential than the BTZ and in principle can deliver organic RFBs with a cell voltage ≈ 3 V.
Densification, Precipitation, and Dissolution of Vanadium Electrolyte for Vanadium Redox Flow Battery Systems
Authors: Nguyen Trung Van , Li Yuanchao , Perry Mike L.
Published: September 2023

The all-vanadium redox flow battery system (VRFB) is the most mature RFB technology since it uses a single active species, which does not degrade. Rebalancing electrolytes to maintain maximum energy capacity in an RFB system that uses a single active species, or symmetrical electrolytes, is simple and enables the use of relatively low-selectivity separators, which have higher ionic conductivities.1 Conversely, finite-lifetime RFB chemistries, especially asymmetric chemistries, result in significant negative impacts on the levelized cost of storage (LCOS).2 Currently, the vanadium electrolyte used in a MWh-scale VRFB system is typically shipped to the installation site in liquid form in multiple totes and the VRFB-system tanks are filled onsite. A new approach explored in this study is to densify and precipitate the electrolyte in a solid form, which can then be quickly dissolved to its intended concentration onsite by the addition of de-ionized water.3 This approach can enable multiple benefits. First, shipping the electrolyte in solid form provides more stability and higher density during shipping, which significantly reduces shipping costs. Second, the solid electrolyte can be shipped in the actual containers that will be used onsite, which thus simplifies the required onsite work. This presentation will discuss a method used to densify the vanadium electrolyte, as well as nucleation and precipitation processes that generate the solid electrolyte form, which will quickly dissolve when deionized water is added onsite. The nucleation and precipitation process leverages recent work on the solid-liquid high-energy storage density method for RFB systems.4

References

M. L. Perry, J. D. Saraidaridis, and R. Darling, “Crossover Mitigation Strategies for Redox-Flow Batteries,” Current Opinion in Electrochemistry, 21 (2020). 10.1016/j.coelec.2020.03.024

K. E. Rodby, M. L. Perry, and F. R. Brushett, “Assessing Capacity Loss Remediation Methods for Asymmetric Redox Flow Battery Chemistries Using Levelized Cost of Storage,” J. Power Sources, 506 (2021). 10.1016/j.jpowsour.2021.230085

M. L. Perry, Provisional U.S. Patent Application 63/312,999 filed on Feb. 2, 2022.

Yuanchao Li and Trung Van Nguyen, “A Solid/Liquid High-Energy-Density Storage Concept for Redox Flow Batteries and Its Demonstration in an H2-V System,” J.
Electrochem. Soc.,
169 (2022). 10.1149/1945-7111/ac97c6
Proton Activity and Pathway in Aqueous Organic Redox Flow Batteries
Authors: Wang Wei
Published: September 2023

Aqueous soluble organic (ASO) redox-active materials have recently shown great promise as alternatives to transition metal ions employed as energy-bearing active materials in redox flow batteries for large-scale energy storage because of their structural tunability, cost-effectiveness, availability, and safety features. However, development so far has been limited to a small palette of organics that are aqueous soluble. This presentation will use fluorenone as an example to showcase how a natively redox-inactive molecule can be tuned to possess two-electron redox reversibility through hydrogenation and dehydrogenation. The modified fluorenone molecules demonstrated high energy density and recorded stable cycling. Furthermore, research has shown the kinetics of the redox reactions; thus, the system rate capabilities can be improved by incorporating suitable hydrogen acceptors that regulate the proton pathway for a faster redox reaction.

Reference: Feng et al., Science 372, 836–840 (2021), Feng et al., submitted, 2022
Compositionally Unbalanced Symmetric Cell Cycling As a Method for Quantifying Crossover Rates in Redox Flow Cells
Authors: Neyhouse Bertrand J. , Darling Robert M. , Saraidaridis James D , Brushett Fikile R.
Published: September 2023

Redox flow batteries (RFBs) are a promising grid-scale energy storage platform, but broad deployment is stymied by technical and economic constraints.1 Within this context, the membrane serves a central role in determining battery performance, selectively facilitating the conduction of supporting salts to mitigate resistive losses while preventing the undesired crossover of active species.2 Tradeoffs between these two facets—namely, conductivity and permeability—requires a thorough understanding of how transport proceeds under the dynamic conditions observed in practical embodiments (e.g., varying compositions, alternating polarity). To this end, a wide range of experimental tools exists for characterizing membrane properties under controlled environments, but few methods directly assess crossover and resistive losses in conventional redox flow cells.3

In this presentation, we introduce a facile method for quantifying crossover rates in flow cells—compositionally unbalanced symmetric cell cycling (CUSCC). Using a previously developed zero-dimensional modeling framework,4 we first examine fundamental processes that give rise to a characteristic “capacity gain” profile. We then validate the technique experimentally using FeCl2 / FeCl3 and Nafion as a representative system, confirming theoretical predictions and establishing the efficacy of CUSCC for characterizing crossover. Finally, we apply the model to estimate transport parameters from experimental capacity gain profiles, yielding results that are consistent with conventional ex situ measurements. Overall, CUSCC is a robust method for quantifying crossover rates with standard flow cell hardware, potentially expanding the experimental toolkit for RFB development.

Acknowledgments

This work was supported as part of the Joint Center for Energy Storage Research, an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, contract number DE-AC02-06CH11357. B.J.N gratefully acknowledges the NSF Graduate Research Fellowship Program under Grant Number 2141064. Any opinion, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF.

References

M. L. Perry and A. Z. Weber, J. Electrochem. Soc., 163, A5064–A5067 (2016).

J. Yuan, Z.-Z. Pan, Y. Jin, Q. Qiu, C. Zhang, Y. Zhao, and Y. Li, Journal of Power Sources, 500, 229983 (2021).

Y. A. Gandomi, D. S. Aaron, J. R. Houser, M. C. Daugherty, J. T. Clement, A. M. Pezeshki, T. Y. Ertugrul, D. P. Moseley, and M. M. Mench, J. Electrochem. Soc., 165, A970 (2018).

B. J. Neyhouse, J. Lee, and F. R. Brushett, J. Electrochem. Soc., 169, 090503 (2022).
Understanding Capacity Fade in Organic Redox-Flow Batteries by Combining Spectroscopy with Statistical Inference Techniques
Authors: Modak Sanat Vibhas , Shen Wanggang , Herrera Dylan , Goldsmith Bryan R. , Huan Xun , Kwabi David G.
Published: September 2023

Aqueous-soluble organic and organometallic redox-active molecules show considerable promise as redox-flow battery (RFB) reactants because their costs at scale are projected to be low. However, most aqueous organic RFB undergo rapid degradation resulting in high rates of capacity fade. Considerable research has been devoted towards discovering chemically stable charge carriers for RFBs. However, the decomposition mechanisms of underperforming chemistries during flow cell cycling are often poorly understood, and in some instances, competing or incompatible hypotheses about the relationship between reactant decay and capacity fade have often been proposed.

In this talk, we will demonstrate that combining spectroscopic and statistical inference techniques can be used to shed light on relationship between RFB reactant degradation and capacity fade. Specifically, we employ in operando ultraviolet-visible spectrophotometry along with Bayesian inference, Bayesian model selection, and multivariate curve regression in order to quantify the relative probabilities of different decay mechanisms given the data at hand, and to estimate rate constants for specific reactions within the most probable decay scheme. In principle, rate constants thus obtained can be fed into a zero-dimensional electrochemical flow cell model, recently developed by our group, that can simulate capacity fade given a reactant decay mechanism, associated rates, and the cycling protocol. This work has the potential to shed light on the relationship between capacity fade and reactant decay in various organic RFB chemistries, and to enable prediction of the lifetimes of commercial-scale RFBs.
Sodium Metal Hybrid Redox Flow Batteries Containing Sulfide and Thiophosphate Catholytes
Authors: Self Ethan , Lehmann Michelle , Yang Guang
Published: September 2023

Energy storage systems which meet the requirement for long-duration energy storage (LDES) are critical to enable widespread adoption of intermittent renewables (e.g., solar and wind) on the electric grid. DOE’s Long Duration Storage Shot has set an ambitious goal of reducing energy storage costs ≥90% by 2030. To address this challenge, the proposed work is aimed at developing low-cost, high-energy redox flow batteries (RFBs) based on earth-abundant active materials.

Prior work on room temperature Na2Sx catholytes demonstrated outstanding reversibility and cycling stability in batch and flow cell configurations (e.g., reversible capacities ~200 mAh/gS with negligible fade over 250 cycles and several months of continuous testing). While precipitation of low-order polysulfides (x≤4) during discharge doesn’t negatively impact the performance of lab-scale prototypes, these ionically/electronically insulating species will present major challenges for system scaleup (e.g., inhibited charge transfer due to current collector passivation). As such, the practical cycling window of Na2Sx is restricted to soluble species (5≤x≤8) with a sulfur utilization of 125 mAh/gS.

To improve the viability of room temperature Na/Na2Sx RFBs, our team recently discovered that the addition of P2S5 greatly increases the solubility of low-order sodium polysulfides through formation of previously unknown Na-P-S solvated complexes. This general class of sodium thiophosphates has tremendous, untapped potential for next-generation nonaqueous catholytes and can potentially enable reversible Na capacities exceeding 1,000 mAh/g. This presentation will describe ongoing efforts aimed at: (i) assessing key properties (electrochemical reversibility, solubility, chemical stability) of sodium thiophosphates in nonaqueous electrolytes, (ii) benchmarking the performance of lab-scale RFB prototypes containing Na-P-S catholytes and ceramic membranes, and (iii) quantifying voltage losses on electrodes polarized far from equilibrium using 3 electrode AC impedance measurements.

Acknowledgements

This research was conducted at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) and is sponsored by the U.S. Department of Energy through the Energy Storage Program in the Office of Electricity.
(Invited) High-Rate and High-Efficiency Molten Salt Li-O2 and Na-O2 Batteries Enabled by Nitrate Redox
Authors: Leverick Graham , Zhu Yunguang , Shao-Horn Yang
Published: September 2023

The decarbonization of the electrical grid requires advancements in affordable, long-term energy storage to address the intermittency of energy sources like solar and wind, while the continued decarbonization of the transportation sector necessitates advancements in energy dense storage devices such as batteries, with low cost and made from abundant materials. Alkali metal-oxygen batteries can provide greater specific energy than Li-ion batteries and can potentially lower cost by reducing reliance on late transition metals like nickel and cobalt. In this talk, we share our recent work on molten-salt Li-O2
1 and Na-O2
2 batteries operating at 150-170 °C which can deliver high areal energy (33 mWh/cm2
geo) and power densities (19 mW/cm2
geo), with high energy efficiency (~90% at 5 mA/cm2
geo). We show that nitrate redox plays a critical role in these batteries, where the apparent four-electron oxygen reduction to form Li2O in Li-O2 batteries is facilitated by the electrochemical reduction of nitrate to nitrite, and subsequent chemical oxidation of nitrite to nitrate by molecular oxygen. In Na-O2 batteries, on the other hand, Na2O is further oxidized by O2 to Na2O2 to give an apparent two-electron oxygen reduction rection. We demonstrate the role of transition metal oxide catalysts for reducing the overpotential of nitrate redox in the positive electrode, as well as strategies for enhancing the power density and specific energy of these molten-salt metal-oxygen batteries.

References

(1) Zhu, Y. G.; Leverick, G.; Giordano, L.; Feng, S.; Zhang, Y.; Yu, Y.; Tatara, R.; Lunger, J. R.; Shao-Horn, Y. Nitrate-Mediated Four-Electron Oxygen Reduction on Metal Oxides for Lithium-Oxygen Batteries. Joule
2022, 6 (8), 1887–1903.

(2) Zhu, Y. G.; Leverick, G.; Accogli, A.; Gordiz, K.; Zhang, Y.; Shao-Horn, Y. A High-Rate and High-Eﬃciency Molten-Salt Sodium–Oxygen Battery. Energy Env. Sci
2022, 15, 4636–4646.
Cation Modified Highly Soluble Active Materials for Redox Flow Batteries
Authors: Pahari Shyam K , Gokoglan Tugba Ceren , Bolibok Jennifer Nina , Cappillino Patrick J. , Agar Ertan
Published: September 2023

Renewables such as solar and wind energy are making increased penetration into modern electrical grids.1 However, the reliability of such grids is challenged by the intermittent nature of renewable sources and variable atmospheric conditions, posing a major roadblock in transition toward carbon-neutral energy sources. Grid level energy storage has long been seen as a solution to the intermittency problem.2 Among various storage technologies, redox flow batteries (RFBs) stand out, due to their ability to accommodate various needs of renewable-powered grids.3 RFBs based on non-aqueous chemistry (NRFBs) have a potential to greatly increase the energy density, however, a major setback in NRFB implementation arises from instability and low solubility of active materials.4,5

Herein, we present a strategy to design a flow battery utilizing anionic active materials which exhibit high solubility and high stability. To this end, we utilized a highly stable bio-inspired complex, vanadium-bis-hydroxyiminodiacetate (VBH) as a catholyte and anthraquinone-sulfonate (AQS) as an anolyte scaffold. Cycling performance of a flow battery based on VBH/AQS active materials was investigated in a full cell and a detailed chemical and electrochemical analysis of electrolytes before and after cycling was performed. Post-cycling analysis of electrolyte revealed that the active materials are highly stable even under deep charge-discharge cycling. However, lack of suitable membrane resulted in modest capacity fade. To overcome the crossover issue, a full cell comprising compositionally symmetric electrolytes, made by mixing anolyte and catholyte, was performed and various performance metrics of such cell were evaluated.

References:

(1) International Energy Agency. Global Energy Review 2021; Paris https://www.iea.org/reports/global-energy-review-2021, License: CC BY 4.0.

(2) Albertus, P.; Manser, J. S.; Litzelman, S. Long-Duration Electricity Storage Applications, Economics, and Technologies. Joule
2020, 4 (1), 21–32. https://doi.org/10.1016/j.joule.2019.11.009.

(3) Dunn, B.; Kamath, H.; Tarascon, J.-M. Electrical Energy Storage for the Grid: A Battery of Choices. Science
2011, 334 (6058), 928–935. https://doi.org/10.1126/science.1212741.

(4) Pahari, S. K.; Gokoglan, T. C.; Visayas, B. R. B.; Woehl, J.; Golen, J. A.; Howland, R.; Mayes, M. L.; Agar, E.; Cappillino, P. J. Designing High Energy Density Flow Batteries by Tuning Active-Material Thermodynamics. RSC Advances
2021, 11 (10), 5432–5443. https://doi.org/10.1039/D0RA10913D.

(5) Sánchez-Díez, E.; Ventosa, E.; Guarnieri, M.; Trovò, A.; Flox, C.; Marcilla, R.; Soavi, F.; Mazur, P.; Aranzabe, E.; Ferret, R. Redox Flow Batteries: Status and Perspective towards Sustainable Stationary Energy Storage. Journal of Power Sources
2021, 481, 228804. https://doi.org/10.1016/j.jpowsour.2020.228804.

Figure 1
(Invited) Understanding Fluid Structure and Properties of Eutectic and Microemulsion Electrolytes for Energy Storage
Authors: Savinell Robert F. , Gurkan Burcu E
Published: September 2023

The increase of adding intermittent renewable energy sources like solar and wind to the electricity grid requires a commensurate need for large scale energy storage. Flow batteries are the most likely storage technology to meet this need because of its ability to decouple power load from energy storage capacity, and its promise for longer-term storage capacity. Flow battery electrolytes are mostly based on aqueous systems with limited voltage window for energy storage redox couples, with some systems based on organic solvents that are volatile and often toxic. The BEES (Breakthrough Electrolytes for Energy Storage) EFRC (a DOE Emerging Frontier Research Center), in its first four years (2018 to 2022), studied two classes of electrolytes, more specifically reported here is work on deep eutectic solvents (DESs) and microemul
sions (µEs). While each class of liquid presents a unique aspect that can be leveraged for energy storage, collectively they represent novel electrolytes that are structured at the molecular (DESs) to meso-scale (µEs) level. The motivation to explore DES for electrolytes is the potential for high energy density, safety, and sustainability.1 The motivation to explore µEs for electrolytes is the ability to decouple power and energy density through composition.2 A fundamental understanding of the physical, transport, and electrochemical properties of model systems representative of each class of electrolytes in relation to their bulk and interfacial structure was achieved through collaborative experimental and theoretical studies within BEES. This presentation will describe our motivation and approach, and give examples of a few research highlight from BEES. Detailed results of BEES in developing standards and identifying the key structure-property relations and mechanisms, as well as intrinsic limitations and prospects are reported in BEES affiliated peer-reviewed publications.3

Acknowledgment: This work was funded by Breakthrough Electrolytes for Energy Storage (BEES) - an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0019409.

1 Ghahremani, Savinell, Gurkan, J Electrochem Soc, 2022, 169, 3

2 Barth, Imel, Nelms, Goenaga, Zawodzinski, Front Chem, 2022, 10, 831200

3 In Google Scholar search the DOE award number: DE-SC0019409
Single-Flow Batteries Leveraging Multiphase Electrolytes
Authors: Suss Matthew , Rewatkar Prakash , Asarthen Mohamed , Gloukhovski Robert , Kuperman Sofi , Gat Amir
Published: September 2023

The share of electricity generated from renewable sources is growing rapidly, and thus grid-scale battery storage is becoming more prevalent. Aqueous redox flow batteries have the potential to provide safe and scalable energy storage, but the high cost of storage, particularly the membrane and balance of plant costs, has inhibited commercialization. The recently developed single-flow battery leveraging a multiphase electrolyte promises a low-cost system [1], as it is membraneless and uses only one tank and flow loop, but suffers from low Coulombic efficiency [1]. To unlock the potential of such a system, the interplay between interphase mass transport, multiphase flow phenomena, and battery performance must be unraveled. Here, we will compare our previously developed theoretical battery model derived from a boundary layer analysis [2,3] to results from a dedicated experimental program [4]. This led to several key findings, including that our battery operates in a regime characterized by a high Stanton number, and that our analytical solutions led to excellent predictions in various operational regimes when using the interphase mass transport coefficient as a single-valued fitting parameter [4]. In other regimes, such as at low electrolyte velocity, results indicate that gravity acting on the denser polybromide phase played a significant role, and progress towards incorporating gravitational effects into models will be discussed [4].

Figure 1: Schematic of a discharging single-flow battery leveraging a multiphase flow electrolyte. The flow consists of a continuous, bromine-poor aqueous phase and dispersed, bromine-rich polybromide phase. Bromine in the polybromide phase is largely electrochemically inactive, thus such an electrolyte enables membraneless operation by limiting the crossover of bromine to the zinc anode.

References:

[1] Amit, L., Naar, D., Gloukhovski, R., la O', G.J. and Suss, M.E., 2021. “A Single-Flow Battery with Multiphase Flow”. ChemSusChem, 14(4), pp.1068-1073.

[2] Ronen, R., Gat, A.D., Bazant, M.Z. and Suss, M.E., 2021. “Single-flow multiphase flow batteries: Theory”. Electrochimica Acta, 389, p.138554.

[3] Kuperman, S., Ronen, R., Matia, Y., Zigelman, A., Suss, M.E. and Gat, A.D., 2022. “Modelling the fluid mechanics in single-flow batteries with an adjacent channel for improved reactant transport”. Flow, 2, E11.

[4] Ronen, R., Gloukhovski, R. and Suss, M.E., 2022. “Single-flow multiphase flow batteries: Experiments”. Journal of Power Sources, 540, p.231567.

Figure 1
Improved Formulation and Optimization of Sodium Polysulfide/Bromine Electrolytes for Redox Flow Battery
Authors: Khan Safyan Akram , Mansha Muhammad , Ali Shahid , Ahmad Aziz , Khan Majad , Tahir Muhammad Nawaz , Qamar Mohammad
Published: September 2023

Sodium polysulfide/bromine RFBs are one the most promising electrolyte couples for scale-up technology. Sodium polysulfide/bromine RFB utilizes aqueous sodium polysulfide and sodium bromide solution as anolyte and catholyte, respectively, separated by a sodium ion exchange membrane.

Polysulfide electrolyte of different concentrations ranging from S:Na ratio of 0.5 that is without the addition of elemental sulfur, up to saturation limit having S:Na ratio of 2.4 with the addition of elemental sulfur are prepared.

Studies of electrolyte composition have been essential to establishing the optimum conditions for practical use. These involve various parameters such as sulfide concentration, the ratio of dissolved sulfur to sulfide, speciation, pH, and the effect of temperature on battery stability and lifetime. Different experimental methodologies were used to investigate the speciation in these concentrated solutions. A titration method was developed to find the concentration of HS- and OH- species in any sodium sulfide and polysulfide solution. Sulfide and polysulfide chemistry is presented in more detail by comparing the UV-ATR spectra. It was found that polysulfide electrolyte shows very complex system containing species such as HS-, OH-, H+ and Sn
2- where n = 2-5 and sulphur oxoanions.

Furthermore, we have established that controlled speciation of polysulfide solution can substantially impact on the electrochemistry in these electrolytes. Controlling the pH, concentrations of HS- and OH- ions in polysulfide electrolytes is extremely important to overcome many challenges of the polysulfide/bromine RFB system.

Therefore, we have developed an improved polysulfide electrolytes with high charge densities but more soluble species in the presence of excessive HS- species. Charging and discharging data on our improved and well optimized polysulfide electrolyte will be presented.
Scale-up of Interdigitated Design from Small Cell to Large Cell for Aqueous Redox Flow Batteries
Authors: Zeng Chao , Kim Soowhan , Fu Yucheng , Chen Yunxiang , Bao Jie , Xu Zhijie
Published: September 2023

Redox flow batteries present attributes for large-scale energy storage. Interdigitated flow configuration is a promising structure due to its higher power density and lower pressure loss. The screening for new electrolyte is usually first tested on small cell (<10 cm2) due to its easy operation and less electrolyte consumption. To test the electrolyte functionality in practical application condition, large-scale (i.e., 780 cm2) testing is required conventionally in laboratory or industry. The twice testing is due to the fact that the testing results in small cell are different from that for large-scale interdigitated cell. In order to reduce the testing cycles and quickly estimate the application of new electrolytes, scale-up of interdigitated design from small cell to large cell is investigated in this work.

Numerical simulation on different scales of interdigitated cells (10cm2, 78cm2, 130cm2, 780cm2) is conducted to assess the polarization. The local velocity distribution and redox-active species concentration are extracted to show their dominance on the cell performance. It is shown that with similar velocity and concentration distribution, cell with different scales present similar limiting current density and power density, regardless of active area. It implies that the results in small cells can be directly scaled up for large cells without further testing. It provides an avenue for quick estimation of new electrolyte in application condition.

Experimental testing is conducted on vanadium redox flow battery for different scale of interdigitated cell. The experimental results will demonstrate this scale-up from small-scale to middle-scale interdigitated cell.
Role of Acetonitrile Additive in Enhanced Performances of Aqueous Zn Anodes
Authors: Ilic Stefan , Counihan Michael , Lavan Sydney Nicole , Connell Justin G. , Tepavcevic Sanja
Published: September 2023

Zinc-ion batteries have been proposed as promising candidates to address ever-growing demands for energy storage and limited resources available for the currently used lithium-battery systems. Despite their promise, the apparent advantages of aqueous zinc-ion batteries (low cost and high energy density) are still overshadowed by uncontrolled water interactions at the zinc metal-electrolyte interface, such as the hydrogen evolution reaction and electrode corrosion. A number of different strategies – e.g., water-in-salt, addition of chelating agents and/or co-solvents – have been proposed to overcome the aforementioned interfacial problems. Among them, the addition of acetonitrile to aqueous ZnSO4-based electrolytes has shown great promise, with reports of improved Coulombic efficiencies and increased cycle life. However, the actual role of this additive remains unclear. In this work, we determine the mechanistic principles behind the participation of acetonitrile in enhancing the performance of aqueous Zn batteries. For this purpose, we utilized a combination of X-ray absorption and Raman spectroscopies, cyclic voltammetry, and galvanostatic coin cell cycling. Our results indicate that the addition of acetonitrile perturbs the interfacial solvation structure, rather than the bulk. Specifically, acetonitrile does not penetrate the first solvation shell of the Zn2+ ion, but does modify interfacial solvation behavior, likely by physisorption to the electrode surface. The Coulombic efficiency of half cells was found to depend on electrode material, employed current density and capacity, and only moderately on acetonitrile concentration. Overall, this works points strongly to the need for systematic evaluation of battery performance in co-solvent systems, and provides a new framework for future efforts to optimize ion transport and performance in zinc-ion batteries.

_______________________

The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan. http://energy.gov/downloads/doe-public-access-plan
(Invited) Submillimeter Bundled Microtubular Flow Battery Cells with Ultrahigh Volumetric Power Density
Authors: Liu Nian
Published: September 2023

Flow batteries are a promising energy storage solution. However, the footprint and capital cost need further reduction for flow batteries to be commercially viable. The flow cell, where electron exchange takes place, is a central component of flow batteries. Improving the volumetric power density of the flow cell (W/Lcell) can reduce the size and cost of flow batteries. While significant progress has been made on flow battery redox, electrode, and membrane materials to improve energy density and durability, conventional flow batteries based on the planar cell configuration exhibit a large cell size with multiple bulky accessories such as flow distributors, resulting in low volumetric power density. In this talk, I will introduce a submillimeter bundled microtubular (SBMT) flow battery cell configuration that significantly improves volumetric power density by reducing the membrane-to-membrane distance by almost 100 times and eliminating the bulky flow distributors completely. Using zinc–iodide chemistry as a demonstration, our SBMT cell shows peak charge and discharge power densities of 1,322 W/Lcell and 306.1 W/Lcell, respectively, compared with average charge and discharge power densities of <60 W/Lcell and 45 W/Lcell, respectively, of conventional planar flow battery cells. The battery cycled for more than 220 h corresponding to >2,500 cycles at off-peak conditions. Furthermore, the SBMT cell is compatible with zinc–bromide, quinone–bromide, and all-vanadium chemistries. The SBMT flow cell represents a device-level innovation to enhance the volumetric power of flow batteries and potentially reduce the size and cost of the cells and the entire flow battery.

(also see our publication: https://doi.org/10.1073/pnas.2213528120)
Nitrogen-Functionalized Metal Carbide-Modified Graphite Felt As a High Performance Electrocatalyst for an All-Vanadium Redox Flow Battery
Authors: Bayeh Anteneh Wodaje Wodaje , Kabtamu Daniel Manaye , Wang Chen-Hao
Published: September 2023

To improve the electrochemical performance of graphite felt (GF) electrodes in vanadium redox flow batteries (VRFBs), we synthesize nitrogen-doped tungsten carbide nanowires (N-WC NWs), which are grown on the surface of GF through the two-step approach. When applied to VRFBs, the prepared electrode exhibits an apparent electrocatalytic effect toward the VO2+/VO2
+ and V3+/V2+ redox reaction compared with pristine GF. The presence of negatively charged density on nitrogen promotes the absorption of vanadium ions. The nanowire structure exposes more active sites for the redox reaction of vanadium ions. The prepared N-WC NWs-GF electrode displays the best electrochemical performance with energy and voltage efficiencies of 74.8% and 78.9%, respectively, which is much higher than those of 59.8% and 63.2% obtained from the pristine GF at 100 mA cm−2. The N-WC NWs-GF exhibited durability and stability in an acidic electrolyte during long-term operation for 100 cycles at the higher current density of 100 mA cm−2.
(Digital Presentation) Sizing and Economic Assessment of an Electrochemical Rebalancing Process for Vanadium Flow Batteries
Authors: Poli Nicola , Trovo Andrea , Guarnieri Massimo
Published: September 2023

In all-vanadium flow batteries, electrolyte oxidation from atmospheric oxygen and/or hydrogen evolution due to operations at extreme states of charge may occur. After events like these, an electrolyte imbalance affecting the battery capacity appears that cannot be recovered by a simple mixing operation and a more complex rebalancing process must be undertaken. Among the different rebalancing processes which have been proposed in the literature, this work consider the electrochemical method that uses a specific electrolysis reactor to reduce V(V) in the positive electrolyte to the level of V(II) in the negative electrolyte, so as to equate the states of charge in the two tanks. In order to adjust the balancing mechanism to the system, the rated power of the reactor performing this process should be optimized to the VFB rated energy, imbalance level (namely, the process periodicity) and the rebalancing process duration. In turn, the rated power defines the size and thus the cost of the reactor, namely area and number of cells, given their current density and internal area specific resistance. This work presents a model that assembles these parameters and their interplay, allowing to investigate how the process and the reactor can be optimized. Such model also provides an economical evaluation of the investment and operational expenditures of the rebalancing process, thus providing design criteria for the minimization of these cost figures. For the sake of example, numerical calculations are performed referring to a 500-kWh VFB, that is a quite common rating for VFBs, and they indicate that a cost reduction of almost 70% is achieved if 10-hour processes are run four times per year instead of once a year. At this rebalancing frequency, the 500 kWh VFB needs a 9-kW reactor costing around €15.000.

References

[1] E. Rodby, T.J. Carney, Y.A. Gandomi, J.L. Barton, R.M. Darling, F.R. Brushett, Assessing the levelized cost of vanadium redox flow batteries with capacity fade and rebalancing, J. Power Sources 460 (2020), 2227958.

[2] Rudolph, U. Schröder, I.M. Bayanov, On-line controlled state of charge rebalancing in vanadium redox flow battery, J. Electroanal. Chem. 703 (2013) 29-37.

[3] Li, L. Liu, Y. Zhao, J. Xi, Z. Wu, X. Qiu, The indefinite cycle life via a method of mixing and online electrolysis for vanadium redox flow batteries, J. Power Sources 438 (2019) 226990.

[4] Poli, M. Schaffer, A. Trovò, J. Noack, M. Guarnieri, P. Fischer, Novel electrolyte rebalancing method for vanadium redox flow batteries, Chem. Eng. J. 405 (2021), 126583.

[5] Noack, N. Roznyatovsakaya, K. Pinkwart, J. Tübke, Vanadium proton exchange membrane water electrolyser, J. Power Sources 340 (2017) 144-151.

Figure 1
Methanol Sensing Behavior Analysis of Pt-Sn/C Based Micro DMFC
Authors: Soundrapandian Muthuraja
Published: September 2023

A MEMS-based micro DMFC structure of 1cm2, fabricated using 3D printing technology. Pt-Sn/C is offering good power density which was identified as the novel catalyst in DMFC. The synthesized nanoparticles of Pt-Sn/C was characterized and the MEA of the same was fabricated with Nafion membrane was and the cathode catalyst of pure Pt. Physically attached MEA with the DMFC cell was tested for the methanol of different concentrations and different operating temperature of the cell. The polarization curves were plotted for the redox reaction. The performance of the cell was increased with the increment of the temperature. At the same time, the considerable amount of current was observed while the cell was operated at low temperature The produced current was amplified and the sensor’s minimal detection ability of methanol was tested and results are presented.
Rational Design and Synthesis of Novel Catalyst Support for PEMFCs
Authors: Chen Kate , Li Kui , Wang Chengyu , Zeng Yachao , Wang Xiaojing , Wu Gang , Spendelow Jacob S.
Published: September 2023

Catalysts based on metal-organic frameworks (MOFs) are promising candidates to enable fuel cells with higher performance and durability. Our recently developed PtCo catalyst on porous carbon support produced by pyrolysis of Ce-doped-ZIF (PtCo/Ce-ZIF) shows record-high outstanding performance and durability in fuel cell testing. The cell was operated under the conditions prescribed by the Million Mile Fuel Cell Truck Consortium (M2FCT) consortium (250 kPa, 85% relative humidity (RH), 90 C cell temperature, and 15% oxygen). At application-relevant operating voltages of 0.7 V and higher, the PtCo/Ce-ZIF exhibited higher performance than the commercial catalyst. The PtCo/Ce-ZIF catalyst at 0.7 V achieved a life beginning-of-life (BOL) performance level of 1.38 A/cm2; even more importantly, it showed substantially higher durability. The PtCo/Ce-ZIF catalyst provided a current density of 1.25 A/cm2 at 0.7 V after 90K accelerated stress test (AST) cycles, exceeding the M2FCT target of >1.07 A/cm2. The PtCo/Ce-ZIF also showed higher mass activity and greatly improved retention of mass activity of 0.77 A/mgPt vs. 0.54 A/mgPt, at BOL and ending of life (EOL), respectively, ~34 % mass activity loss after 90K AST cycles, exceeding the DOE target of <40% loss after 30K AST cycles. This study demonstrates that MOF-based catalysts are the leading candidates to enable fuel cell commercialization and deployment in support of the global effort to reduce greenhouse gas emissions.
Atomically Dispersed Single Mn Site-Rich Carbon for PtCo Intermetallic Catalysts with Promoted Performance and Durability for Heavy-Duty Fuel Cells
Authors: Zeng Yachao , Yu Haoran , Macauley Natalia , Cullen David A. , Myers Deborah J. , Wu Gang
Published: September 2023

Promoting the activity and durability of the Pt-based catalysts with a reduced platinum group metal (PGM) loading holds significance to the deployment of proton-exchange membrane fuel cells (PEMFCs) in the transportation market. In this work, synergistic catalysts, which integrate ultrafine Pt-based nanoparticles with ORR-active single atom catalysts (SACs), were studied to meet the activity and stability milestones for Pt-based catalysts. The synergistic effect between different SACs and ultrafine Pt nanoparticles were firstly elucidated via DFT calculations. It indicates that MnSA-NC catalyst with high surface area and abundant single atoms sites can improve the activity and stability of Pt catalyst via a strong electronic interaction. Ultrafine Pt and L12 Pt3Co intermetallic nanoparticles were uniformly anchored in the MnSA-NC via a facile strategy. The structures of the Pt@MnSA-NC and Pt3Co@MnSA-NC were comprehensively studied by multiple transmission microscopy and X-ray absorption spectroscopy. It reveals that ultrafine Pt and L12 Pt3Co intermetallic nanoparticles are anchored amongst the atomically dispersed MnNx sites. The Pt@MnSA-NC catalyst achieved a mass activity (MA) of 0.698 A mgPt
−1 (@0.9ViR-free) and maintained 86 % of its initial performance after 30,000 cycles of accelerated stress test (AST, 0.6 and 0.95 V), exceeding the DOE target for 2025. By intercalating Co into the Pt nanoparticles, the L12 Pt3Co@MnSA-NC catalyst achieved significantly improved activity, achieving a MA of 0.905 A mgPt
−1 and 1.631 A cm−2 (@0.7 V, H2-air fuel cell) at 150 kPaabs with 0.10 mgPt cm−2 in the cathode. The loss in the performance at 0.7 V is only 27.2 %, manifesting its high intrinsic stability. Furthermore, the performance of L12 Pt3Co@MnSA-NC catalyst (20 wt.% Pt) was studied under the heavy-duty vehicle (HDV) conditions with a higher Pt loading (0.20 mgPt cm−2) and higher backpressure (250 kPaabs). Encouragingly, the current densities at 0.67 and 0.7 V are 2.12 and 1.80 A cm−2, respectively. After 30,000 cycles of AST, the loss in MA is only 17.4 %, 87.0 % of performance were retained at 0.67 and 0.7 V. The compelling performance holds a great potential to meet the DOE target set for HDVs (>1.07 A cm−2 at 0.7 V after 250,000 hours equivalent operations). The synergistic effect revealed in this work shed light on the design of highly efficient catalysts for PEMFCs.