bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling Bicarbonate Kinetics on Silver Catalysts for CO2 Electrolysis
Authors: Ehlinger Victoria Marie , Lee Dong Un (Daniel) , Lin Tiras Y , Govindarajan Nitish , Varley Joel , Duoss Eric B , Baker Sarah , Jaramillo Thomas F. , Hahn Christopher 
Published: August 2024

Low-temperature CO2 electrolyzers transform captured CO2 into more useful chemicals, such as syngas (CO and H2) for systems with silver or gold catalysts and ethylene and other C2+ products for systems with copper catalysts. At low overpotentials, bicarbonate ions act as proton donors and have been shown to have enhanced activity1, leading to nonlinear Tafel slopes for the hydrogen evolution reaction (HER). We have developed a 1D planar electrode model for CO2 electrolysis, similar to the model developed by Gupta et al.,2 including a thin ionomer layer on top of a silver catalyst layer surface. The model includes buffer chemistry and ion transport in the boundary layer as well as the ionomer thin-film layer. Tafel parameters are fit for both bicarbonate and water as proton donors for HER using the model results to account for mass transport in the boundary layer. A comparison against a bare silver electrode shows that the Donnan potential across the ionomer/electrolyte interface has a significant effect on the ion concentrations at the catalyst layer surface, leading to enhanced HER from bicarbonate at low overpotentials. These results are then compared against Butler-Volmer parameters that are derived from a full microkinetic model. The Tafel kinetic parameters were then used in a 1D full-cell membrane electrode assembly (MEA) model, and we found good agreement with experimental data, illustrating that the ionomer in contact with the catalyst layer surface impacts the underlying kinetics both in planar electrodes and industrially-relevant MEA systems.
References

D. M. Koshy et al., J. Am. Chem. Soc., 143, 14712–14725 (2021) https://doi.org/10.1021/jacs.1c06212.

N. Gupta, M. Gattrell, and B. MacDougall, J. Appl. Electrochem., 36, 161–172 (2006).

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and was partially supported by a Cooperative Research and Development Agreement (CRADA) between Lawrence Livermore National Laboratory, Stanford University, and TotalEnergies American Services, Inc. (affiliate of TotalEnergies SE) under Agreement No. TC02307 and Laboratory Directed Research and Development (LDRD) funding under project 22-SI-006.
LLNL-ABS-857478

Figure 1
Catalytic Activities of Ir-Based Pyrochlore-Type Oxides Doped with Divalent Cations for Oxygen Evolution Reaction
Authors: Miyazaki Kohei , Tanaka Kenji , Miyahara Yuto , Lee Changhee , Abe Takeshi 
Published: August 2024

Alternative energy sources to fossil fuels are essential for a sustainable society, and hydrogen energy is expected to be a solution to environmental and energy problems. Currently, proton exchange membrane water electrolyzers are becoming widely used for the electrochemical production of hydrogen due to their advantages such as high efficiency. However, the highly acidic conditions and the large overpotentials of oxygen evolution reaction (OER) at the anode are problems, and the development of catalysts that are stable and highly active in acidic aqueous solutions is important for further popularization.
Ir-based oxides with pyrochlore structure (A2B2O7) are known to exhibit high catalytic activities in acidic aqueous solutions. Recently, it has been reported that the improved catalytic activities of Pr2Ir2O7 by Zn doping, which controlled the composition of A-site elements in the pyrochlore structure [1]. In this study, we synthesized Pr2-x
MgxIr2O7 (x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5), in which a part of trivalent cation Pr3+ was replaced by divalent cation Mg2+ and improved the OER catalytic activity in acidic aqueous solutions.
Pr2-x
MgxIr2O7 was synthesized by the hydrothermal method. The catalyst was mixed with a conductivity aid carbon (Vulcan XC-72) and a cationic conductive ionomer (Nafion) at a weight ratio of 5:1:1 and dispersed in 2-propanol to form a catalyst ink. The catalytic activity was evaluated by cyclic voltammetry (CV) using a glassy carbon rotating disk electrode (RDE) as a working electrode, a reversible hydrogen electrode (RHE) as a reference electrode, and a platinum wire as a counter electrode. The electrolyte was a 0.1 mol dm-3 HClO4 solution saturated with oxygen, and the CV scanning range was 1.1 to 1.7 V with respect to the RHE, scanning speed was 20 mV s-1, and the RDE rotation speed was 1200 rpm. The stability of the catalyst in acidic aqueous solutions was evaluated by chronopotentiometry (CP) using the same cell.
X-ray diffraction and energy-dispersive X-ray analysis measurements of the synthesized materials confirmed that the desired compounds were obtained, and CV measurements showed that the OER activity of Pr2-x
MgxIr2O7 increased in the first 20 cycles for all compositions, and then stabilized over several tens of cycles. The cycle change was similar to that of Pr2Ir2O7, suggesting that the surface rearrangement proceeds in acidic aqueous solutions [2]. Linear sweep voltammogram (LSV) and OER activity normalized by Brunauer-Emmett-Teller (BET) specific surface area were measured at the 20th cycle, and the catalytic activity stabilized at a high value. The OER activity was enhanced by Mg substitution in the catalysts of Pr2-x
Mg
x
Ir2O7.
References

L. Zhu, C. Ma, Z. Wang, X. Gong, L. Cao, and J. Yang, Appl. Surf. Sci., 31, 151840 (2022).

C. Shang, C. Cao, D. Yu, Y. Yan, Y. Lin, H. Li, T. Zheng, X. Yan, W. Yu, S. Zhou, and J. Zeng, Adv. Mater., 31, 1805104 (2018).
Gas Diffusion Electrode Operation for High Current Density Electroreduction of Carbon Dioxide to Formate
Authors: Bashir Shahid M. , Gyenge Elod L. 
Published: August 2024

In the context of clean energy and green chemical production, the two-phase flow electrochemical carbon dioxide reduction reaction (CO2RR) to formate has gained considerable interest, and efforts are being made to scale up the process[1]. With respect to electrode design, unlike in the simpler single-phase system, which is limited by the solubility of CO2 in the electrolyte and by the mass transport of the dissolved CO2 gas from the bulk of the electrolyte to the cathode surface[2], mixed gas/liquid flow in the trickle bed reactor[3] or segregated flow in the gas diffusion electrode (GDE)[4] reactor provide more efficient gas delivery at the catalyst/electrolyte interface. This enhanced the overall mass transfer coefficient and enabled higher reaction rates per unit geometric area of the electrodes, providing that the electrocatalyst layer's intrinsic activity and selectivity are established. Due to the limitation in retaining the effective electroactive bed thickness in the trickle bed reactor[3], GDEs are preferred for high current density operations (typically above 100 mA cm-2). Despite the continuous gas transport mechanism, the reported performance in the GDE-based system lies around 200 mA cm-2, with occasional reports above 200 mA cm-2 but on a tiny electrode area (typically 1 cm2 or below)[5]. The flooding of the GDE porous structure is believed to be the prime cause that limits electrode durability at high current density. Here, we present the optimization of the two-phase flow dynamics and the GDE (with 20 cm2 geometric area) operating conditions to enable high current density operation up to 500 mA cm-2 using a tin-based catalyst layer and scalable reactor design. The performance was compared with other catalytic materials that were intrinsically active for CO2RR to formate.

References

[1] M.F. Philips, G.M.Gruter, M.T.M. Koper and K.J.P. Schouten, ACS Sustainable Chem. Eng., 2020, 8(41), 15430-15444.
[2] N. Gupta, M. Gattrell and B. Macdougall, J. Appl. Electrochem., 2006, 36(2), 161-172.
[3] I. Hodgson and C. Oloman, Chem. Eng. Sci., 1999. 54(23): p. 5777-5786.
[4] S. Hernandez-Aldave and E. Andreoli, Catalysts, 2020, 10(6), 713
[5] S. Sen, S. M. Brown, M. Leonard and F.R. Brushett, J. Appl. Electrochem.,2019, 49, 917–928
Effect of Mechanical Compression on Ionic Conductivity of PEO-LiTFSI Solid Polymer Electrolytes
Authors: Jadhav Aryan , Cao Dang Khoa Minh , Baltazar Jericko Jay , Oh Dahyun , Lee Sang-Joon John 
Published: August 2024

In the field of energy storage materials, the development of robust solid polymer electrolytes for lithium-ion batteries necessitates an understanding of ionic conductivity when subjected to mechanical stress. Accurate determination of ionic conductivity requires knowing the electrolyte thickness, which is subject to volumetric changes during charging and discharging of solid-state batteries. However, compressive stress reduces the thickness of the electrolyte by an indeterminate amount.
This work presents experimental measurements of ionic conductivity as a function of compressive stress, using poly(ethylene oxide) and with bis(trifluoromethane) sulfonimide (PEO-LiTFSI). In this study, we not only measure the stress-strain response of the electrolytes directly, but also monitor the extent of compression during electrochemical impedance spectroscopy (EIS). Compression was applied up to 50% strain for three consecutive cycles, and the typical thickness for the fabricated electrolytes was ~50 µm. EIS testing was performed by using an impedance analyzer, with the electrolyte placed between stainless steel blocking electrodes. Bulk resistance was determined by equivalent circuit modeling of impedance between 100 Hz and 2 MHz. Ionic conductivity κ was calculated from bulk resistance Rb
, electrolyte thickness h, and cross-sectional area A, according to the equation κ = h/(Rb·A).
In order to measure both stress and deformation simultaneously, a custom positioning stage was engineered to apply prescribed compression. The apparatus has an in-line load cell for force measurements and a laser triangulation sensor for position tracking with submicron resolution. We found that the bulk resistance at room temperature decreases exponentially, with magnitude reduced by approximately five-fold when subjected to compressive stress up to 10 MPa. Beyond ~7 MPa, bulk resistance values were no longer dependent on the amount of applied compression.
In addition to mechanical measurements, changes in crystalline and amorphous regions were correlated to the magnitude of compressive stress and the measured ionic conductivity of the electrolyte. For optical imaging with simultaneous EIS measurements, glass slides coated with an indium tin oxide (ITO) film were used instead of stainless steel disks. The extent of crystallinity was visualized by optical microscopy of spherulites through a viewing window when compressed between rigid plates.
Figure 1. Apparatus (left) and representative ionic conductivity vs. compressive stress (right) data for a PEO-LiTFSI polymer electrolyte.

Figure 1
Influence of Mechanical Degradation in Polycrystalline NMC Particles on the Electrochemical Performance of Lithium-Ion Batteries
Authors: Nagda Vinit , Kulachenko Artem , Ekström Henrik 
Published: August 2024

Lithium-ion batteries (LIBs) have gained widespread popularity for energy storage systems owing to their high coulombic efficiency and energy density. Within the cathode electrode materials of LIBs, the structural integrity of secondary particles, composed of randomly oriented single-crystal primary active particles, is crucial for sustained performance. The fracture of these particles can occur due to both mechanical stress and chemical interactions within the solid. Modeling LIBs presents a multiphysics challenge as it involves addressing the electro-chemo-mechanical phenomena and their interactions across various length scales. During electrochemical cycling, volume changes in active particles induce mechanical stresses, while the mechanical state of the battery influences the diffusion of lithium.
This study proposes a numerical modeling framework to investigate the degradation of active material particles and its impact on electrochemical performance. The model integrates mechanical and electrochemical processes, solving nonlinear equations related to surface charge transfer, lithium diffusion, and mechanical stresses. By incorporating phase field damage, the model tracks crack evolution and mechanical failure of active particles. The coupled equations are solved within a finite element framework using COMSOL Multiphysics.
Notably, the model offers numerical insights into intergranular and transgranular fracture within secondary active material particles. The infiltration of liquid electrolyte into cracks is identified as a positive effect, reducing electrochemical overpotential by increasing electrochemically active surface area from particle cracking. However, prolonged cycling with particle cracking poses a notable threat to battery performance and capacity. This comprehensive numerical modeling approach provides valuable insights into the intricate interplay of mechanical and electrochemical factors governing LIB performance and degradation.
A Multiscale Computational Modeling Framework to Quantify Microstructural Effects on Nucleation of Li Metal on Carbon Scaffold Architectures
Authors: Wang Bo , Li Sichi , Cross Nicholas R. , Freyman Megan C. , Xiao Yiran , Zhu Cheng , Bucci Giovanna , Heo Tae Wook , Wood Marissa 
Published: August 2024

Carbon materials with scaffold architecture have been shown to mitigate the non-uniform Li plating/stripping issues during cycling, which is critical for achieving significantly enhanced energy densities and improved safety of Li metal batteries. However, optimal design of the architecture and microstructure of the carbon materials requires fundamental understanding of the Li metal nucleation behavior at different length scales. In this poster, we present a multiscale computational modeling framework to quantify the microstructural effects of carbon materials on the tendency of Li metal nucleation during plating by integrating atomic-scale simulation, mesoscale microstructure-based homogenization, continuum-scale electrochemistry modeling, and classical nucleation theory. We modeled the architecture of the carbon scaffold and the electrochemistry of Li transport across the electrode and electrolyte by finite element simulation to determine boundary conditions for our mesoscale models. We then generated different porous microstructures of various carbon materials by stochastic and physics-based simulations informed from experiments and performed multiphysics-based simulations at mesoscale to identify the electro-chemo-mechanical hotspots which are sensitive to the microstructure morphology. We calculated the energy barriers for Li to form clusters on graphene surfaces as a function of local Li concentrations and electric fields by ab initio molecular dynamics simulations. The synergistic deployment of different models across scales allows us to theoretically estimate the Li metal nucleation tendency based on a modified classical nucleation theory for different microstructures under various electroplating conditions. Comparison of the theoretical predictions and experimental results will be briefly discussed. The insights obtained from this multiscale framework offer new understanding and strategies for the design of carbon scaffold architectures to mitigate the non-uniformity of Li plating and issues in Li metal anode deployment in solid-state batteries.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and 22-ERD-043.
Electrochemical-Mechanical Coupling Experiments on Solid-State Battery Materials and Interfaces
Authors: Albertus Paul , Larson Karl , Bhargava Bhuvsmita , Carmona Eric A , Crofton Lane , Stewart David Murdock , Talin Albert Alec 
Published: August 2024

The interaction of mechanical and electrochemical effects in the areas of thermodynamics, kinetics, and transport are known, but accurately measuring those couplings can be complicated by the difficulty of getting a uniform stress at a solid-solid interface where surface roughness, voids and inclusion result in inhomogeneous contacts.1 This is a particular challenge for solid-state batteries where both the active material and electrolyte are in the solid phase. In addition, cycling of metal anodes (e.g., Na and Li) results in processes such as dendrite and void formation in which electrochemical and mechanical can be amplified.2 This talk will focus on two improvements to typical experiments in which electrochemical-mechanical coupling strongly influences results: (1) The use of a solid-state reference electrode for solid Na / solid electrolyte interfacial studies, and (2) the use of a nanoindentation platform to assess electrochemical-mechanical coupling behaviors in thin-film solid-state materials.
For topic (1), we will discuss our use of a solid Na metal reference electrode to inform the cycling of Na metal against a Na-β″-Al2O3 solid electrolyte using cycling protocols of commercial relevance (e.g., 5 mAh/cm2, <5 MPa external pressure).2 Our work identifies the current density at which stripping shifts from stable to unstable, and shows that large (100s of mV) of interfacial overpotential can persist for hours in some stripping test protocols, which, according to models indicates that >80% of the initial electrochemical active interfacial area has been lost. We will also present recent results on how the applied pressure affects the interfacial behavior of Na metal / Na-β″-Al2O3 interfaces, as well as the role of applied pressure and the cycling protocol for an interface that starts as only current collector / Na-β″-Al2O3.
For topic (2), we will present on our electrochemical-mechanical coupling studies of thin-film (i.e., <1 um thick) V2O5 samples on an Ohara Li+-conducting glass ceramic disc. This platform allows us to simultaneously control electrochemical behavior (e.g., Li insertion and removal, current) and the applied force, to study thermodynamic and kinetic electrochemical-mechanical couplings. This platform enables the application of a uniform stress on the thin-film V2O5 sample.
1. Joule 7, 652–674, April 19, 2023.
2. ACS Appl. Mater. Interfaces 2023, 15, 42, 49213–49222
Revealing the Link between Morphological Heterogeneity and Reaction Behavior of Cathode in Solid-State Batteries
Authors: Park Se Hwan , Juarez Yescaz Carlos , Zahiri Beniamin , Luo Yuting , Braun Paul V. , Vishnugopi Bairav Sabarish , Naik Kaustubh Girish , Mukherjee Partha P. , Greer Julia R. , Wang Yingjin , Xiao Xianghui , Hatzell Kelsey 
Published: August 2024

Structural heterogeneity within solid-state electrodes can have a significant impact on material utilization and reaction rates. This reaction heterogeneity is greater in solid state systems in comparison to conventional liquid electrolytes because it requires exquisite solid-solid contact between the active energy storage materials and the solid ion conducting phase (e.g. solid electrolyte) [1]. Electrode reaction behaviors encompass electrochemical lithiation and delithiation dynamics and chemo-mechanical processes such as volume change and fracture [2]. Understanding the connection between structural heterogeneity and reaction behavior is crucial for understanding degradation mechanisms and optimizing solid state battery architectures. Herein, we examine the implications of reaction heterogeneity in an additive-free, crystallographically textured electroplated lithium cobalt oxide (LCO) cathode [3]. The electroplated dense cathode alleviates the need for any solid electrolyte material in the cathode. A diverse set of synchrotron-based operando and ex situ experiments are combined with modeling to uncover the relationship between structural heterogeneity and reaction behavior. Operando energy dispersive X-ray diffraction and ex situ 3D XANES are used to identify reaction heterogeneity and X-ray nanotomography is used to probe nano-scale structural heterogeneity. Nanoindentation is utilized to determine the mechanical properties of LCO. To validate the results, we combine these experimental results with transport and mechanics modeling. Through this comprehensive characterization approach, we confirm that the reaction behavior of cathode in our model is mainly determined by the morphological heterogeneity rather than the Li diffusion within the electrode. Structural heterogeneity causes localized high stress and leads to fracture, which in turn limit the full utilization of the cathode.

Reference

[1] Jung, S.H., Kim, U.H., Kim, J.H., Jun, S., Yoon, C.S., Jung, Y.S. and Sun, Y.K., 2020. Ni‐rich layered cathode materials with electrochemo‐mechanically compliant microstructures for all‐solid‐state Li batteries. Advanced Energy Materials, 10(6), p.1903360.
[2] Liu, X., Zheng, B., Zhao, J., Zhao, W., Liang, Z., Su, Y., Xie, C., Zhou, K., Xiang, Y., Zhu, J. and Wang, H., 2021. Electrochemo‐mechanical effects on structural integrity of Ni‐rich cathodes with different microstructures in all solid‐state batteries. Advanced Energy Materials, 11(8), p.2003583.
[3] Zahiri, B., Patra, A., Kiggins, C., Yong, A.X.B., Ertekin, E., Cook, J.B. and Braun, P.V., 2021. Revealing the role of the cathode–electrolyte interface on solid-state batteries. Nature Materials, 20(10), pp.1392-1400.

Figure 1