bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical Stability of BaMg0.33Nb0.67-XFexO3-δ in High Temperature Methane Conversion Environments
Authors: Denoyer Luke H , Benavidez Angelica , Brearley Adrian , Ramaiyan Kannan , Garzon Fernando H. 
Published: September 2023

Doped perovskite metal oxide catalysts of the form ABxC1-xO3-δ are of interest to the catalysis community due to the ability to fine tune the catalytic activity or chemical stability through doping. Doped barium niobate perovskites have shown remarkable stability in CO2 sensing and methane conversion measurements. However, the reason for the chemical stability is not well understood. Doping with transition metal cations for B site cations can lead to exsolution under reducing conditions. Many perovskites used for the oxidative coupling of methane (OCM) or the electrochemical oxidative coupling of methane (E-OCM) either lack long term stability, or catalytic activity within these highly reducing methane environments. Here, we present our results obtained with a highly stable Mg and Fe co-doped barium niobate perovskite BaMg0.33Nb0.67-xFexO3-δ (BMNF) that has shown activity in E-OCM setups over long term (>100 hour) experiments and stability in CO2 environments as a sensor.[1] The crystalline structure and atomic distributions within these synthesized materials analyzed via X-ray powder diffraction (XRD), scanning transmission microscopy (STEM), and X-ray photoelectron spectroscopy (XPS). Along with this, temperature programmed reaction (TPR) under 95% methane and 5% oxygen showed the effectiveness of the catalyst in an OCM setup, as well as the stability of the BMNF perovskite in methane. Through these analyses we posit that iron doping may increase the ionic conductivity of the BMNF material while change in Nb4+/5+ oxidation states prove stability in reducing environments.[2]
(1) Denoyer, L. H.; Benavidez, A.; Garzon, F. H.; Ramaiyan, K. P. Highly Stable Doped Barium Niobate Based Electrocatalysts for Effective Electrochemical Coupling of Methane to Ethylene. Adv. Mater. Interfaces
2022, 9 (27), 2200796. https://doi.org/10.1002/admi.202200796.
(2) Denoyer, L. H.; Benavidez, A.; Garzon, F. H.; Ramaiyan, K. P. Chemical Stability of BaMg0.33Nb0.67-XFexO3-δ in High Temperature Methane Conversion Environments. under communication - ECS Journal of Solid State Science and Technology.
Optimizing the Electrolyte Mixing in Industrial Tanks of Vanadium Redox Flow Batteries
Authors: Prieto-Diaz Pablo Angel , Vera Marcos 
Published: September 2023

Redox flow batteries (RFB) are an emerging technology for large-scale grid energy storage. Different approaches have been adopted to investigate the operation of RFBs, such as experimental testing and mathematical modelling of the electrochemical cells [1]. However, the effect of the flow and mixing in the electrolyte tanks on the performance of RFBs has been largely overlooked and only recently has started to receive some attention [2]. In a recent work, the authors used numerical simulations to show how the fluid dynamics of the electrolytes within small lab-scale tanks can lead to different flow behaviors depending on whether forced or natural convection is dominant. The irregular transient mixing of the electrolyte in the tanks modifies both the cell potential and battery capacity with respect to those predicted under the widely used perfect mixing assumption (i.e., continuous stirred-tank reactor) [3]. However, this first attempt relied on several simplifying assumptions, such as two-dimensional geometries under small-cell (i.e., laminar) flow conditions, and thus provided only a qualitatively understanding of the flow in the tanks.
This work exploits the idea of using CFD simulations to investigate the effect of operating conditions on the electrolyte flow in the tanks and its impact on battery response, focusing on high capacity industrial tanks with high (i.e., turbulent) flow rates and less restrictive simplifying assumptions. Our numerical simulations show how turbulence improves mixing, but also produces quasi-steady flows where a turbulent jet crosses the tank leaving dead electrolyte regions. Different tank solutions are presented aiming to improve the mixing and increase the capacity of the battery, playing both with the tank geometry and the operating conditions. Results on the charging and discharging operations, cell potential and electrolyte mixing index are presented and discussed.

Acknowledgments

This work has been partially funded by FEDER/Ministerio de Ciencia, Innovación y Universidades – Agencia Estatal de Investigación Projects PID2019-106740RB-I00 and RTC-2017-5955-3/AEI/10.13039/501100011033, and by Grant IND2019/AMB-17273 of the Comunidad de Madrid.

References

[1] A. Z. Weber, M. M. Mench, J. P. Meyers, P. N. Ross, J. T. Gostick, Q. Liu, Redox flow batteries: a review, Journal of Applied Electrochemistry 40 (10) (2011) 1137–1164. doi:10.1007/s10800-011-0348-2.
[2] Y. Wang, K. C. Smith, Numerical investigation of convective transport in redox flow battery tanks: Using baffles to increase utilization, Journal of Energy Storage 25 (2019) 100840. doi:10.1016/j.est.2019.100840.
[3] P. A. Prieto-Diaz, A. A. Maurice, M. Vera, Modelling the electrolyte flow in the tanks of vanadium redox flow batteries: A CFD perspective, ECS Meeting Abstracts MA2022-01 (48) (2022) 2009. doi:10.1149/MA2022-01482009mtgabs.
Li Electrodeposition Modeling for Analyzing the Effect of Li+ Redistribution in Li Metal Secondary Batteries
Authors: Kim Suhwan , Lim Minhong , Park Joonam , Jin Dahee , Lee Hongkyung , Lee Yong Min 
Published: September 2023

To meet the high-energy-density requirement of Li secondary batteries for EV applications, Li metal is still being re-examined extensively beyond conventional carbon-based anode active materials. However, unlike intercalation mechanism-based anodes, Li metal anodes (LMAs), suffering from significant surface morphology changes during electroplating and stripping, can accompany several issues such as Li dendrite growth and continuous side reactions, thereby leading to the poor electrochemical performance and cycle stability. Among various reasons of the Li dendrite formation, inhomogeneous and slow Li+ transport to the LMAs are representatively known, accelerating irregular electrodeposition and rapid Li+ depletion on the LMA surface.
In this study, we attempted to simulate Li dendrite growth under practical current conditions by developing a 2D Li electrodeposition model. Based on this model, we analyzed the geometric-electrochemical characteristics of Li metal interface depending on Li+ concentration distribution in the electrolyte and SEI. Furthermore, in order to verify a nanomaterial-based micro-convection effect in the electrolyte for improving mass transfer, the Li+ concentration change nearby the interface was calculated while simulating the Li dendritic growth. Also, real 2D morphologies of the Li dendrites were reconstructed and analyzed together in a similar way. As a result, the micro-convection enables relatively uniform Li+ distribution at the LMA interface and enhances the mass transport in the electrolyte, which can suppress the Li dendrite growth even at 5.0 mA cm-2.
Dendrite Growth Suppression and in-Situ Surface Observation of Lithium Battery Under an Optical Microscope
Authors: Ding Tianyao , Qu Deyang , Zheng Dong , Zhang Xiaoxiao , Qu Huainan , Qiu Dantong , Liu Miao 
Published: September 2023

Dendrite growth is a major obstacle to the commercialization of lithium metal batteries. A dendrite formed on a Li anode can cause thermal run-aways and permanent capacity loss. Despite previous research efforts, the behavior of lithium dendrite growth is elusive since it is related to multiple factors. An in-situ optical techniques is considered as one of the major methods to study the dendrites growth behaviors and morphologies real-time.
A better knowledge of the physico-chemical processes and the side reactions during a battery operation can be gained.
A home-designed in-situ optical cell with a digital optical microscope was used to investigate the behavior of Li deposition on a metallic Li electrode under different electrochemical operation conditions. The impacts of electrolytes, additives and cycling conditions on the dendrite formation were investigated. The changes of the morphology and the shape of the dendrites were investigated correspondingly. Guiding by the in-situ optical observation results, polycyclic aromatic hydrocarbons (PAHs) were introduced as additives to suppress the dendrite growth. It was observed in an in-situ optical experiment, that the freshly formed dendrites can be dissolved and dispersed throughout the surface, eventually a dynamic elastic protection layer was formed. With the liquid electrolyte trapped in the protection layer, the thickness of the layer could be self-adjusted to compensate for the volume change of the Li anode during the battery cycling. Among the eight additives added to the electrolyte, several PAH additives have significant effect on suppressing dendrite growth and greatly enhance the cyclability of the Lithium electrode in a symmetry Li/Li cell.

Tarascon, J.-M., & Armand, M. (2001). Issues and challenges facing rechargeable lithium batteries. Nature, 414(6861), 359–367.

Tripathi, A. M., Su, W.-N., & Hwang, B. J. (2018). In situ analytical techniques for battery interface analysis. Chemical Society Reviews, 47(3), 736–851.

Figure 1
Pre-Treatment of Li-Metal Anode with Hydrohalic-Acid for Stable Cycling of Li-Metal Batteries Under Practical Conditions
Authors: Seo Jiyeon , Lee Jaeho , Lim Minhong , Lee Hongkyung , Kim Gunyoung , Lee Hyuntae 
Published: September 2023

Lithium (Li) metal anodes (LMAs) are considered as an ultimate choice for beyond Li-ion batteries because of their high capacity (3860 mAh g–1) and low working potential (–3.04 V vs. SHE). However, due to extremely high surface reactivity, uncontrollable dendritic plating, and infinite volume expansion, making Li-metal batteries (LMBs) has long encountered fatal challenges. Heterogeneous solid-electrolyte interphase (SEI) can be the main reason for Li dendrite growth, stemming from the electrolyte byproducts and native LMA surface. In this regard, uniform passivation of LMAs and homogenous SEI at the initial stage is necessary which can occur uniform Li+ ion flux. Furthermore, halogenated SEI is considered as promising component for achieving superior mechanical strength, insulating properties and thermodynamic stability.
In this study, we present a simple LMA treatment using hydrohalic acids (HXs, X = F, Cl, Br, and I) to regenerate native passivation layer (NPL) of as-manufactured LMAs and evenly nourish halogenated compounds. The water molecules of aqueous HXs can dissolve the existing inorganic Li-compounds in the NPL, e.g., Li2O, LiOH, and Li2CO3, rendering the chemical reactions of HXs with pure Li, enriching the LiX compounds within the NPL. A comparative study was done to reveal which LiX compounds is beneficial to stabilize the LMA surface and to enhance the cycling stability of LMBs. Furthermore, it is elucidated that the pivotal role of LiX compounds was proved in the interfacial reaction when using localized high concentration electrolyte (LHCE) as an advanced electrolyte in LMBs. Through comparative study, building LiCl-rich SEI at the initial stage effectively reduces the energy barrier of Li nucleation and interfacial resistances, thereby enhancing the cycling performances in LMBs even under practical conditions.
Li Dendrite Formation on the Side of Cu Current Collector during Charging in Misaligned Pouch-Type Lithium-Ion Batteries
Authors: Choi Seungyeop , Kim Nayeon , Jin Dahee , Roh Youngjoon , Lee Yong Min 
Published: September 2023

Not only high-capacity electrode materials but also electrode/cell design greatly governs the electrochemical performance of LIBs. For instance, there are systematic works to unravel the effect of area or capacity ratio between anode and cathode or the electrolyte amount. [1,2,3] Especially, our research group has already reported the effect of electrode misalignment, which can frequently occur during the coin cell assembly, on the electrochemical properties, where Li dendrites formed on the coin cell bottom mainly deteriorated the cell performance. [4] However, considering the commercial cell configurations like pouch-type LIBs, which have insulating polypropylene inner layer, those negative phenomena should be evaluated in misaligned LIB cells.
For this purpose, three pouch-type cells (well-aligned, slightly misaligned, and largely misaligned) using LixNi0.6Co0.2Mn0.2O2 cathode and graphite anode were fabricated in a dry room. Surprisingly, a similar misalignment effect to coin cells was also observed in the pouch-type cell, even though the inner layer of the Al-pouch is insulative. When we disassembled the misaligned cell after precycling, we could observe Li dendrites formed on the side of the Cu current collector (CC) of the anode. That is, the Li ions from the cathode are able to be plated on the metal side of Cu CC of a few micrometer thickness. Thus, even in pouch cells, the electrode misalignment can lead to Li inventory loss. To solve this problem, an insulating coating was applied to the side of the Cu CC, and as a result, the cycle performance of the misaligned cell was improved by suppressing the Li dendrite formation. In addition, the electrochemical characteristics were compared as a function of the lithiation state (SOL, x in LixNi0.6Co0.2Mn0.2O2) using EIS, DC-IR, XRD, etc.
Reference

B. Son, Y. M. Lee et al.,
J. Power Sources
, 243 (2013) 641-647

R. Xue et al.,
J.

Power Sources
, 55 (1995) 111-114

B. R. Long, J. R. Croy et al.,
J.

Electrochem. Soc.
, 163 (2016) A2999

N. Kim, Y. M. Lee et al.,
J.

Electrochem. Soc.
, 169 (2022) 023502
(General Student Poster Award Winner - 2nd Place) Electrochemical Routes for Polymer Upcycling
Authors: Haque Zenifar G. , Ortega Ramos Jessica , Botte Gerardine G 
Published: September 2023

Approximately 380 million tons of plastic are produced annually, and it is projected to rise to nearly 1.1 billion by 2050 [1]. The largest fraction of such waste consists of polyethylene (PE) and polypropylene (PP), which commonly require energy-intensive methods to achieve depolymerization (such as pyrolysis and hydrogenolysis) due to their remarkable thermodynamic stability. Electrochemical methods are a promising alternative for polymer upcycling as they can utilize renewable energy to create an external potential, overcoming the thermodynamic constraints that the C-C bond cleavage endothermicity imposes on low-temperature polymer conversion. They also offer improved chemical process control by manipulating the electrode potential and minimizing the use and storage of hazardous reagents. Electrochemistry provides a broad range of opportunities for establishing green routes to converting plastic into valuable products.
Botte's group is investigating electrochemical approaches to convert polyolefins into valuable products like fuels and fatty acids [2]. Our findings indicate that an electrocatalyst in concert with controlled ionic strength and applied potential enable the selective functionalization of polyolefins and their defragmentation towards target molecules regardless of impurities present in the polymer. In this presentation, we will discuss results of the electrochemical functionalization and deconstruction of low-density polyethylene implementing transition metal electrocatalysts.

Acknowledgments: The authors would like to acknowledge the financial support of the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Upcycling of Polymers Program, under Award DE-SC0022307
[1] J. E. Rorrer, C. Troyano-Valls, G. T. Beckham, and Y. Román-Leshkov, "Hydrogenolysis of Polypropylene and Mixed Polyolefin Plastic Waste over Ru/C to Produce Liquid Alkanes," ACS Sustainable Chemistry & Engineering, vol. 9, no. 35, pp. 11661-11666, 2021/09/06 2021, doi: 10.1021/acssuschemeng.1c03786.
[2] G. G. Botte, "Process for the Electrochemical Up-Cycling of Plastics (US Pending Patent)," U.S. Patent 63040929, 2020.
Multi-Metal Additive Manufacturing with Submicron Resolution by Electrohydrodynamic Redox 3D Printing
Authors: Nydegger Mirco , Reiser Alain , Spolenak Ralph 
Published: September 2023

The ability to design metals with control over the 3D chemistry at a submicron level unlocks unique possibilities for tailoring and programming their properties. Small scale additive manufacturing of metals has recently shown promising results towards the direct synthesis of chemically heterogeneous 3D geometries. However, the fast and reliable deposition of a wide range of device-grade materials as well as the ability the change the chemistry on-the-fly still pose challenges to the field.
Here, we will show how electrohydrodynamic redox (EHD-RP) 3D printing can serve as a toolbox to manufacture multi-metal structures [1]. This technique is based on the dissolution, transfer and re-deposition of metals in solvents using electrochemistry. The on-demand generation of metal ions enables the local modification of the chemical composition in a voxel-by-voxel fashion. The confined electroplating process on the substrates allows feature sizes down to 120 nm, while providing an as-deposited dense microstructure. We’ll focus first on the challenges involved in depositing a large range of metals with EHD-RP [2]. Second, we’ll show how the deposition of metals using different solvents can be combined to manufacture multi-metal structures with a high chemical resolution.
[1] A. Reiser, M. Linden, P. Rohner, A. Marchand, H. Galinski, A. S. Sologubenko, J. M. Wheeler, R. Zenobi, D. Poulikakos, and R. Spolenak. Multi-metal electrohydrodynamic redox 3D printing at the submicron scale. Nat. Commun., 10(1):1-8, 2019.
[2] M. Nydegger, A. Pruška, H. Galinski, R. Zenobi, A. Reiser and R. Spolenak. Additive Manufacturing of Zn with Submicron Resolution and its Conversion into Zn/ZnO core-shell structures. Nanoscale, 2022
Proton Exchange Membrane Fuel Cell Chemical and Mechanical Durability Study of Heteropoly Acid Functionalized Perfluorinated Sulfonic Acid with Expanded Polyteterafluoroethylene Support
Authors: Kim Chuloong (Christoph) , Kuo Mei-Chen , Lindell Matthew , Jiang Ruichun , Gittleman Craig S , Herring Andrew M. 
Published: September 2023

The application of proton exchange membrane fuel cells to heavy-duty vehicles has been a new trend for fuel cell society due to high efficiency, power density, faster refueling, and ability to remove auxiliary power units. However, the critical bottleneck for the commercialization and technology transfer from already-commercialized light-duty fuel cell vehicles is the chemical and mechanical durability of the proton exchange membranes. Chemical degradation is initiated by H2O2 which forms ▪OH radicals during the fuel cell operation. The radicals that are formed during the fuel cell operation can be suppressed by adding a radical decomposing catalyst such as cerium, cerium oxide, manganese, manganese oxide, and heteropoly acids. However, those metal oxides and heteropoly acids lack immobilization. We have previously reported the chemical immobilization of silicotungstic acid (HPA), a heteropoly acid with radical decomposing functionality, using dehydrofluorination. This has resulted in improvements in both the chemical durability and proton conductivity, wherein the HPA serves as a proton conductor.
In this study, we applied the chemical anchoring synthesis method to multiple polymers with different binding monomer group ratios and supported with expanded-polyterafluorethylene (e-PTFE) support. We investigated the optimized HPA ratio to the perfluorinated sulfonic acid membrane and studied the chemical and mechanical durability of the composite membrane. The structure-property relationship of composite membranes was studied using scanning electron microscopy (SEM), small angle x-ray scattering, and dynamic mechanical analysis (DMA). The chemical degradation was tested with open-circuit voltage (OCV) and fluoride release rate (FRR) under the accelerated standard condition (AST).
The Effect of Heteroatom-Doped Graphene Supports on the PtNPs Electrocatalytic Activity for ORR
Authors: Chambers Raegan , Erikson Heiki , Tammeveski Kaido 
Published: September 2023

There has been a global shift in energy production emphasizing the reduction of fossil fuels by the augmentation of more renewable energy. Proton-exchange membrane fuel cells (PEMFC) and anion-exchange membrane fuel cells (AEMFC) can mitigate a need for fossil fuels and provide an alternative route of hydrogen-based energy production. Fuel cells utilize a catalyst at both the cathode and anode to increase the overall kinetics of the redox reactions and enhance the cell performance.1 Current fuel cell technology employs a platinum based catalyst due to its efficiency and robust performance in both alkaline and acidic environments.1,2 The drawbacks associated with Pt-based catalysts are centered around its economic viability and its affinity towards surface poisoning.1

A catalyst using platinum nanoparticles (PtNPs) loaded onto a graphene support can address some of the aforementioned drawbacks.1 To maximize the electrocatalytic activity of the PtNPs – all aspects of the PtNPs catalyst must be optimized, which includes the optimization of the support material. The effect that the different commercially available heteroatom-doped graphene had on the activity of the PtNPs was investigated during this study. The PtNPs were synthesized using the citrate method, which produces ≤ 5 nm size particles. Our study confirmed that the choice of doped graphene support has an effect on the overall activity of PtNPs. The results were confirmed via a comparison with PtNPs supported on Vulcan XC-72R carbon. All Pt catalysts supported on the doped graphene showed an improvement in the oxygen reduction reaction (ORR) half-wave potentials (E
1/2) over PtNPs on Vulcan XC-72R carbon (Fig. 1A); with the nitrogen-doped graphene exhibiting the greatest improvements in the half-wave potential with the E
1/2 value of 0.85 V vs. RHE as compared to the 0.77 V of the Pt/C. A comparison of the Tafel slopes (Fig. 1B) confirmed that the transfer of the first electron was the rate-determining step for all of the Pt catalysts supported on doped graphene as all Tafel slopes were around -120 mV per decade. This has been confirmed in literature with Pt on various carbon supports.2

Figure 1. A) Comparison of RDE polarization curves for oxygen reduction on Pt/NGr (pink), Pt/SGr (green) and Pt/N-PGr (blue) with Pt/C (black) at 1900 rpm in a O2-saturated 0.1 M HClO4 solution (v= 10 mV s−1). B) Mass transfer corrected Tafel plots derived from A

References:

(1) Holton, O. T.; Stevenson, J. W. The Role of Platinum in Proton Exchange Membrane Fuel Cells. Platin. Met. Rev.
2013, 57 (4), 259–271. https://doi.org/10.1595/147106713X671222.
(2) Hussain, S.; Erikson, H.; Kongi, N.; Sarapuu, A.; Solla-Gullón, J.; Maia, G.; Kannan, A. M.; Alonso-Vante, N.; Tammeveski, K. Oxygen Reduction Reaction on Nanostructured Pt-Based Electrocatalysts: A Review. Int. J. Hydrog. Energy
2020, 45 (56), 31775–31797. https://doi.org/10.1016/j.ijhydene.2020.08.215.

Figure 1