bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Digital Presentation) On the Nature of Surfactant Adsorption on Metals: Adsorption of Hexylamine on Platinum
Authors: Ostapenko Gennady I. , Kalashnikova Nina A. 
Published: July 2022

The kinetics of the Fe2+ and Fe3+ oxidation-reduction reaction on a platinum electrode in 1 M HClO4 was investigated by the EIS method in the presence of hexylamine as a surfactant. With surfactant adsorption, the effective area of the solution-electrode interface decreases. A proportional increase in charge transfer resistance takes place. This resistance values obtained at various hexylamine concentrations. The surface coverage θ(R) for the solution-platinum interface have been calculated.
The hexylamine adsorption at the solution-air interface was investigated by the maximum bubble pressure method. The surface tension γ at various hexylamine concentrations are obtained. The surface coverage θ(γ) for the solution-air interface has been calculated. The area occupied by the hexylamine molecule at the interface and the adsorption layer thickness are estimated.
It is shown that adsorption process is described by the Dhar-Flory-Huggins isotherm at both interfaces. The slope tg α of the θ(R) and θ(γ) dependence on the hexylamine concentration is close to the theoretical unit in the Dhar-Flory-Huggins coordinates. The main parameters of the hexylamine adsorption (adsorption constant Kad, free adsorption energy ΔGad) were calculated for both interfaces (see Table).

Solution-platinum interface

Solution-air interface

tg α

0.94±0.09

0.98±0.18

K
ad / L mol-1

10.0±4.0

15.8±0.3

ΔG
ad / kJ mol-1

–(14.8 ± 5.0)

–(16.7±0.3)

In the general case, the surfactant adsorption on a metal electrode can be due to the interaction of surfactant molecules with the metal or the hydrophobic effect of the surfactant displacement molecules onto the solution surface by polar water molecules. For the solution-air interface, the hydrophobic effect is the main reason for surfactant adsorption at this interface. The values of the main adsorption characteristics on both interfaces are close. Probably, the hydrophobic effect is also the predominant reason for the hexylamine adsorption on platinum. This assumption requires additional studies of the surfactant adsorption on other metals.
Impedance-Based Li-Ion Battery Forecasting amid Uneven Usage
Authors: Jones Penelope , Stimming Ulrich , Lee Alpha 
Published: July 2022

Accurate forecasting of Li-ion battery performance is important for easing consumer concerns about the safety and reliability of electric vehicles. Most research on battery health prognostics focuses on the R&D setting where cells are subjected to the same usage patterns, yet in practice there is great variability in use across cells and cycles, making forecasting much more challenging.
In my talk, I will show that a combination of battery `biomarkers’ derived from electrochemical impedance signals with probabilistic machine learning enables us to accurately forecast future battery performance amid uneven usage, even when cell history is completely unknown. More broadly, our results bring into question the concept of a scalar State of Health, and instead suggest that battery state is better quantified by a multidimensional vector. I will discuss how this insight lays the foundations for novel algorithms for battery prognostics and control. I will further outline our application of such algorithms in optimal protocol design for intelligent battery charging, and low-data inference via transfer learning across cell chemistries and usage patterns.
“Water-in-Salt” and Nasicon Electrolyte-Based Na-CO2 Battery
Authors: Im Eunmi , Kang Seok Ju , Moon Geon Dae 
Published: July 2022

Aprotic electrolytes are much less feasible for producing cost-effective Na metal-based CO2 batteries due to high cost and flammability. As an alternative electrolyte, super-concentrated electrolytes, referred to as “water-in-salt (WiS) electrolytes”, have been received attention due to their wide electrochemical stability window, cost-effectiveness, and non-flammability. However, the highly reactive Na metal prevents the direct use of WiS electrolytes because the unsolvated water molecules would react with the Na Metal.
In this study, we demonstrated the ability of a WiS and NASICON electrolyte-based Na-CO2 battery for utilizing CO2 gas and serving as an energy storage cell. The NASICON separator allowed us to fabricate a hybrid Na-CO2 battery comprising Na metal as the anode material and WiS as the cathode electrolyte without damage of Na metal. Additionally, linear sweep voltammetry (LSV) with corresponding differential electrochemical mass spectroscopy (DEMS) measurements rendered the direct observation of H2 evolution retardation with increasing WiS concentration. Furthermore, we introduced a nano-sized Ru catalyst onto the current collector using Joule heating method for reducing the overpotential gap. Consequently, the Na-CO2 batteries with Ru@carbon current collector reduced the overpotential gap and exhibit a cycling endurance of over 75 cycles.

Figure 1
Constructing Favorable Microstructures in Solid-State Organic Cathodes Via Mechanical Property Manipulation
Authors: Chen Zhaoyang , Ai Qing , Lou Jun , Hadjiev Viktor G , Liang Yanliang , Yao Yan 
Published: July 2022

Organic electrode materials, due to their low environment footprint and high material-level specific capacities, have become competitive alternatives to inorganic materials for solid-state batteries (SSB) in recent years. Additionally, the soft nature of organic compounds ensures consistent and intimate contact with solid sulfide electrolytes during cycling, which is beneficial for battery longevity. However, the low-modulus organic materials and high-modulus sulfide electrolytes, upon mixing and compression, would form unfavorable composite microstructure where sulfide particles are encapsulated by organics and cannot form an efficient ion conduction path. This mismatch in mechanical property prevents a high fraction of organic compounds to be used in a solid-state cathode, limiting the energy density of organic solid-state batteries.
Here we report the formation of favorable microstructures of organic cathodes by “softening” the sulfide electrolytes. Solvent treatment of the sulfide electrolyte Li6PS5Cl more than halves its modulus from 28.6 ± 8.5 GPa to 16.0 ± 1.6 GPa. Thermal gravimetric analysis, Raman spectroscopy, and X-ray diffraction were used to elucidate the evolution of the sulfide electrolyte during the softening and recovering process. The organic cathode formed by mixing organic materials with this softened electrolyte shows a favorable microstructure where the electrolyte forms a percolated domain. As a result, the utilization of an organic material, pyrene-4,5,9,10-tetraone (PTO), is increased by 133.6% and 90.8% compared with cells with a re-hardened and the pristine Li6PS5Cl, respectively. The mass fraction of PTO can be improved from 20 to 40wt% while maintaining high utilization (85.7%). Our exploration of softened electrolyte builds the correlation among structure, mechanical property, microstructure engineering and battery performance, and the strategy is applicable to other active materials with low modulus.
High-Capacity Cathodes for All-Solid-State Thin-Film Batteries
Authors: Hu Fei , Li Zhuo , West William , Tenhaeff Wyatt 
Published: July 2022

Lithium-ion batteries (LIBs) are critically important rechargeable energy storage devices, finding widespread application in consumer electronics and electric vehicles. However, safety issues associated with their flammability impede their development for many applications. As a fully solid-state device, the thin film battery (TFB) is a compelling candidate for advanced microscale applications, including wearable devices, smart ID cards, and microelectromechanical systems (MEMS). A typical TFB design consists of solid thin films of crystalline cathode, amorphous LiPON electrolyte, Li metal anode and current collectors supported on a rigid substrate. Polycrystalline cathodes are often employed, such as LiCoO2, Li2Mn2O4, LiNiO2, V2O5, etc., because they provide high specific capacity and good reversibility. However, these cathodes require thermal treatment to generate the crystalline microstructure for optimal electrochemical performance, demanding substrates that are stable to several hundreds of degrees Celsius. The industry is interested in lower-cost, flexible all-solid-state thin-film batteries that can be readily integrated into a wide range of applications, including wearable devices. Thus, there is strong demand for thin film cathodes that can be processed at low temperatures.
Herein, we report a new amorphous inorganic thin-film cathode material, which is a solid state composite of Li2RuO3 and LiCoO2. (LRCO). Without any post-deposition annealing steps, as-deposited LRCO thin films possess a high discharge capacity of over 110 µAh cm-2 µm-1 at 0.3 C and capacity retention over 92% after 150 cycles owing to both cationic and anionic (oxygen oxidation) redox processes, which is competitive with conventional polycrystalline thin-film cathodes. The surface of LRCO cathode is smooth and isotropic, leading to uniform Li ion transport and thereby reducing the possibility of short-circuiting. More importantly, the entire preparation process is conducted at room temperature, enabling wider substrate options for TFBs, such as Kapton® films, polyethylene terephthalate (PET) films, or even paper sheets. Using PET plastic sheets to support LRCO TFBs; a specific capacity of 101 µAh cm-2 µm-1 at 0.3 C and capacity retention of 97.5% after 120 cycles was achieved, even when the substrate was mechanically bent (flexed).
Using High Energy X-Ray White Beam Tomography to Quantify the Location and Morphology of ZnO Discharge Products in Alkaline Batteries
Authors: Guida Dominick P. , Gallaway Joshua W. 
Published: July 2022

In alkaline Zn anodes, the active material is discharged to both aqueous zincate ions and solid ZnO. The mobility of zincate in the electrolyte allows considerable transport of the discharge products, which can form directly on the Zn active material or far from it, effectively relocating material long distances inside the cell. Additionally, ZnO can exist in more than one form, namely type I and type II, which differ in their density and passivating character.1 This leads to complex compositions of discharged primary Zn anodes and can cause cell failure due to redistribution of Zn in rechargeable cells. Models of Zn anodes are typically designed for continuous discharge,2 yet real-world use conditions usually involve intermittent discharge. Therefore, the ability of these models to predict ZnO morphology and distribution for cells used in real-world applications is questionable.
It has been previously reported that when alkaline AA cells are discharged, ZnO forms passivating shells around undischarged Zn cores. At high discharge rates, this passivation of Zn increases in severity and hinders cell performance. Additionally, higher discharge rates increase the non-uniformity of ZnO distribution within the anode, preferentially precipitating ZnO near the separator which impedes hydroxide transport from the cathode to the inner portion of the anode.3 In this work, we analyze cylindrical cells discharged using intermittent profiles that approximate real battery use. We then compare the ZnO distribution to that found after continuous discharge.
Synchrotron X-ray tomography was used to obtain in situ volumetric reconstructions at a spatial resolution of 3 microns. To observe the spatial distribution and morphology of ZnO formation in partially discharged Zn anodes, multiple AAA cells were discharged using distinct protocols. When using a continuous discharge, the reconstructions verified previous findings that core-shell structure is the primary morphology of ZnO and is non-uniformly distributed towards the separator.3 However, a radically different morphology and spatial distribution of ZnO was observed when using an intermittent discharge protocol. Specifically, when providing an 8 hour rest after each hour of discharge, ZnO forms isolated clumps distributed throughout the anode. Using this intermittent discharge protocol avoids passivating active material and potentially enables a higher Zn utilization by minimizing isolation of active material.
References
[1] I. Arise et al 2013 J. Electrochem. Soc. 160 D66
[2] E. J. Podlaha and H. Y. Cheh 1994 J. Electrochem. Soc. 141 15
[3] Quinn C. Horn and Yang Shao-Horn 2003 J. Electrochem. Soc. 150 A652
Numerical Investigation of Supporting Electrolyte Using in a Vanadium Redox Flow Battery
Authors: Alphonse Phil-Jacques , Tas Mert , Elden Gülşah 
Published: July 2022

The vanadium redox flow battery (VRFB) store chemical energy and generate electricity by redox reactions between vanadium ions dissolved in electrolytes. The main components of VRFB are positive and negative porous electrodes, membrane, current collectors, electrolyte, and pumps. The electrolyte is composed of vanadium species and supporting electrolytes. The supporting electrolyte has two main functions: 1) to increase the electrolyte's ionic conductivity, and 2) to deliver hydrogen ions to the positive electrode reaction. The supporting electrolytes are many kinds of an acid such as sulfuric acid, hydrochloric acid, methane sulfonic acid, etc. Some study has been done to improve the performance of VRFB a mixed electrolyte supporting. Zhang et al. proved that the stabilities of vanadium ions in sulfuric acid solution could be improved marginally by adding some additives as stabilizing agents 1. Sha et al studied the effect of organic additives on positive electrolyte for vanadium redox battery They found that the energy efficiency for the electrolyte with D-sorbitol was higher than that electrolyte without additives 2. Chang et al investigated coulter dispersant IIIA additive into the positive electrolyte 3. The obtained result showed that the coulter dispersant IIIA increased the stability of the positive electrolyte in VRFB.
According to the authors' knowledge, there is no a numeric study that comparing, the supporting electrolyte used in a VRFB. The aim of this study is to perform comparatively a numerical analyze of the supporting electrolyte of H2SO4 and HCl in the negative and positive electrodes. To achieve these objectives a two-dimensional model is developed with COMSOL Multiphysics under some assumptions and boundary conditions. The electrolyte potential is deeply investigated through the state of charge (SOC).
The simulation result shows that the difference in the electrolyte potential between the supporting electrolyte of H2SO4 and HCl, the supporting electrolyte of H2SO4 possesses a higher potential compared to the HCl. This phenomenon is strongly related to the number of hydrogen protons delivered by the supporting electrolyte of H2SO4 which is more compared to that of HCl 4.

Acknowledgement

The authors would like to thank the Scientific Research Projects Unit of Erciyes University for funding under the contract no: FDK-2019-9340.

Reference

1. J. Zhang et al., J. Appl. Electrochem., 41, 1215–1221 (2011).
2. S. Li et al., Electrochim. Acta, 56, 5483–5487 (2011).
3. F. Chang, C. Hu, X. Liu, L. Liu, and J. Zhang, Electrochim. Acta, 60, 334–338 (2012).
4. H. Yan et al., Membranes (Basel)., 10, 1–15 (2020).

Figure 1
(Keynote) Spectroscopic and Theoretical Studies of HOR/HER Electrochemical Interfaces
Authors: Shao Minhua , Zhu Shangqian , Qin Xueping 
Published: July 2022

Hydrogen fuel cells and water splitting electrolyzers are clean electrochemical devices toward the sustainable utilization of H2 as an energy carrier to replace traditional fossil fuels, in which hydrogen oxidation and evolution (HOR/HER) are two key reactions. Regardless of the apparent simplicity of these two reactions that involve *H as the only surface intermediates, the reaction mechanisms are still under intensive debate.
It has been well reported that the HOR/HER kinetics in alkaline media is about two orders of magnitude slower than that in acid environment on Pt-group metals, while the reasons are not fully revealed. In this work, power surface-enhanced infrared absorption spectroscopy (SEIRAS) is utilized to directly monitoring the structures of HOR/HER electrochemical interfaces in a wide pH range. Through the changes of vibrational wavenumbers of Pt-H and O-H stretching, we find both the weakened *H and H2O binding strength on Pt as the solution pH increases, which are important contributions to the lowered reaction kinetics. Through constructing density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulation models that contain various interfacial parameters, HER activation energy barriers as a function of pH are further elaborated.
In addition, Ru adatoms have been found to significantly accelerate HER/HOR kinetics on Pt in alkaline media. However, the promotion mechanism is unclear. Through directly monitoring the vibrational features of Pt-H and Ru-H on Ru-modified Pt thin films, we find that the HER/HOR kinetics is proportional to the Ru coverage, which unambiguously demonstrates Ru overlayer as the true active sites, instead of an auxiliary to Pt through the oxophilicity or alloying effects as proposed previously. DFT calculations illustrate that the strain and electronic effects of the Pt substrate lead to the more suitable binding energies of *H and *OH on the Ru overlayer, which lower the activation barrier of the rate-determining Volmer step.
The authors acknowledge the support from Hong Kong Research Grant Council (16308420, 16310419, C6011-20G, and HKUST PDFS2021-6S08), Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (SMSEGL20SC01), and Hong Kong Innovation and Technology Commission (ITC-CNERC14EG03).
(Keynote) Effect of the Surface Charge on the Oxygen and Hydrogen Peroxide Reduction Reactions
Authors: Herrero Enrique , Feliu Juan , Briega Valentin 
Published: July 2022

The electrochemical behavior of hydrogen peroxide, which is a possible intermediate of the oxygen reduction reaction (ORR), has been investigated on platinum single crystal electrodes containing terraces with (111) symmetry separated by monoatomic steps with either (110) or (100) symmetry in different pH solutions [1]. On these electrodes, a decrease, in absolute value, of the reduction current at low potentials is observed. The potential at which the decrease is observed, can be correlated with the potential of maximum entropy (pme) of the double layer formation on the terraces. In addition, it is possible to relate the peak appearing at potentials below 0.3 V (RHE) to the local pme in the steps.
By performing experiments at different pH values, up to pH ≈ 5, it is observed that the inhibition potential on the terraces shifts 59 mV per pH unit towards more positive potentials, in line with what was observed for the pme in laser-induced temperature jump experiments. For the possible explanation of this phenomenon, it must be taken into account that OH adsorption may influence this trend when the pme values are close to the potentials corresponding to OH adsorption. From results obtained in alkaline medium, it is clear that the surface charge plays an important role in this inhibition of the limiting diffusion current.
Finally, the comparison of the results obtained under similar conditions for the hydrogen peroxide and oxygen reduction reactions suggests that the formation of hydrogen peroxide as an ORR intermediate is less favored with increasing pH. As a consequence, there must be a bifurcation in the ORR mechanism prior to peroxide formation. These results agree with previous results [2], which indicate that ORR involves different steps in which several bifurcation points may exist. Depending on the experimental conditions, the reaction may follow a different reaction pathway [3].

References.

(1) Briega-Martos, V.; Herrero, E.; Feliu, J.M. Electrochimica Acta
2020
, 334, 135452.
(2) Gomez-Marin, A.M.; Feliu, J.M. ChemSusChem
2013, 6, 172-176.
(3) Briega-Martos, V.; Herrero, E.; Feliu, J.M. Chinese J. Catal.
2020, 41, 732-738.
(Invited) Correlation between the Porosimetric Features, Morphology, “Ex-Situ” and “in-Situ” electrochemical Performance of Hierarchical “Core-Shell” Carbon Nitride Pt-Alloy ORR Electrocatalysts
Authors: Negro Enrico , Vezzu Keti , Lorandi Francesca , Pagot Gioele , Zuliani Giacomo , Bang Yannick , Kulesza Pawel J. , Rutkowska Iwona A. , Di Noto Vito 
Published: July 2022

The widespread commercialization of proton-exchange membrane fuel cells (PEMFCs) is still bottlenecked by the high loading of platinum-group elements (PGMs), typically platinum, in the cathodic electrocatalytic layer. One strategy to overcome the sluggish kinetics of the oxygen reduction reaction (ORR) taking place at the PEMFC cathode is to increase the mass activity of Pt by implementing Pt-alloy electrocatalysts (ECs) [1]. This strategy allows to decrease the overall Pt loading in the membrane electrode assembly (MEA), the crucial functional component at the heart of the PEMFC.
This contribution discusses “core-shell” hierarchical ECs (H-ECs) consisting of: (i) a hierarchical “core” comprising a blend of nanostructured carbons, that are covered by (ii) a carbon nitride (CN) “shell” wherein Pt-alloy active sites are stabilized by C- and N- ligands in “coordination nests” [2]. The active sites are based on Pt together with Ni and Cu as “co-catalysts” to enhance the ORR kinetics [3]. The bulk of the support of the H-ECs is minimized to promote mass transport phenomena.
The morphology of the H-ECs is probed by ultra-high resolution scanning electron microscopy (UHR-SEM) and transmission electron microscopy (TEM), and is discussed in relation to the synthetic parameters and chemical composition. In a second step, nitrogen physisorption techniques are used to evaluate the porosimetric features of the H-ECs, including the specific surface area and the size distribution of the pores. The porosimetric and morphological features are correlated with the electrochemical performance of the H-ECs as measured: (i) “ex-situ”, via cyclic voltammetry with the thin-film rotating ring-disk electrode method (CV-TF-RRDE); and (ii) in single PEMFC under operating conditions as a function of the partial pressure of oxygen in the cathodic feed. A new framework is finally proposed to rationalize and quantify the porosity-morphology-performance correlation for the H-ECs.

References

[1] Y. Sun, S. Polani, F. Luo, S. Ott, P. Strasser, F. Dionigi. Nature Commun. 12, 5984 (2021).
[2] V. Di Noto, E. Negro, K. Vezzù, F. Bertasi, G. Nawn. Electrochem. Soc. Interface, 24, Summer 2015, 59-64 (2015).
[3] V. Di Noto, E. Negro, A. Bach Delpeuch, F. Bertasi, G. Pagot, K. Vezzù, Patent application PCT/EP2017/084801 (2017).

Acknowledgements

The described research has received funding from: (a) the European Union's Horizon 2020 research and innovation programme under grant agreement 881603; (b) the project "Advanced Low-Platinum hierarchical Electrocatalysts for low-T fuel cells" funded by EIT Raw Materials; and (c) the project "Hierarchical electrocatalysts with a low platinum loading for low-temperature fuel cells e HELPER" funded by the University of Padova.