bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical Ion Separations By Recyclable Electrode Cell
Authors: Lado Julio J. , Fombona-Pascual Alba , Pérez-Antolín Daniel , Garcia - Quismondo Enrique , Palma Jesus , Ventosa Edgar
Published: February 2024

Electrochemical separations using Faradaic electrodes are able to exceed the ion adsorption values as well as selectivity when compared to capacitive electrodes, which is due to the bulk reactions for the former vs. surface confined for the latter. However, the cyclability of battery/faradaic electrodes is constrained to hundreds or a few thousands of cycles. This work proposes an electrochemical ion pumping design with the unique feature of using injectable electrodes to overcome the ciclability issue and easily control the areal capacity. The idea consists on using injectable electrodes with the intention of recycling the active material once the end-of-life of the device is reached due to active material degradation. In this fashion, the active material is replaced in a straightforward deinjecting-injecting process allowing direct reuse of the inactive components of the device, thus contributing to reducing the replacement cost. This device is called Ion Pumping Injectable Cell (IPIC).

Moreover, the IPIC system is a tremendously versatile technology due to the simple and easy methodology employed to replace the electrodes. In this fashion, the system was tested using different types of lithium intercalation materials (LFP and LMO), different ion capturing such as potassium (Prussian Blue Analogs, PBA´s), sodium (NMO) or more conventional activated carbon electrodes (capacitive non-selective electrode). In addition to this feature, it is important to remark that the IPIC could be used in a symmetric (e.g. LFP-LFP) or asymmetric configuration (e.g. LFP-LMO). The main difference is that the asymmetric system has the ability of storing energy while capturing ions and deliver that energy in the subsequent step. This is so due to the different electrode potential. The selectivity toward specific ions is achieved by using a chemical ion-selective separator such as an ion exchange membrane (LFP-LFP or LFP-LMO systems), or by using ion selective intercalation materials such as LFP and PBA´s without the need of selective membranes.

In this work, the benefits of the injectable electrode cell architecture will be examined, the performance of different cell configurations will be discussed and the electrochemical ion separation mechanism will be analyzed for different applications.

Acknowledgements

: J.J. Lado and Alba Fombona-Pascual acknowledge Comunidad de Madrid for the fellowship (2020-T1/AMB-19799).
(Invited) Electrochemistry Combined in Situ Neutron Reflectometry: A Powerful Tool for a More Sustainable Environment
Authors: Wang Hanyu , Candeago Riccardo , Doucet Mathieu , Browning Jim , Su Xiao
Published: February 2024

Neutrons, having extraordinary characteristics that include penetrating power, sensitivity to lighter elements (such as hydrogen and carbon), and magnetic moment, make neutron reflectometry an ideal candidate for examining surface and interfacial structures of thin films in a non-destructive and non-invasive fashion. Liquids Reflectometer (LR) at the Spallation Neutron Source at Oak Ridge National Laboratory measures specular and off specular neutron reflectivity in a horizontal sample geometry, and tracks changes of layer thickness, scattering length density, and roughness as a function of depth. The exceptional sample environment at LR offers the capability to conduct in situ electrochemistry to probe the morphological and structural changes of solid/liquid interfaces during operation as a function of chemical and electrochemical gradients over time. Furthermore, the time-resolved mode at LR can be carried out continuously over a reduced Q range and binned into 60-second intervals. The improved time resolution of the neutron reflectivity (NR) measurement can help elucidate the kinetic behavior of surface/interfaces under dynamic conditions and provide a unique perspective to the equilibrium study. In this talk, I will give a brief introduction on neutron reflectometry, the LR, and a variety of sample environments at the LR. I will focus on the electrochemical applications coupled with in situ NR measurement. In the end, I will provide a specific example of applications in electrochemically modulated separation for water remediation by using neutron reflectometry. With the rapid growth of human population, it is highly desirable to minimize energy and materials input in selective separations for a more sustainable environment. The study is critical for creating new, more selective separation systems through rationally design of the structure and operating conditions.
(Invited) Microwave Dielectric Relaxation Spectroscopy: A Technique to Inform Ion Transport in Hydrated Polymer Membranes
Authors: Geise Geoffrey M.
Published: February 2024

Providing sustainable supplies of purified water and energy is a critical global challenge for the future, and polymer membranes will play a key role in addressing these clear and pressing global needs for water and energy. Polymer membrane-based processes dominate the desalination market because they are more energy efficient than thermal desalination processes, and polymer membranes are crucial components in several rapidly developing power generation and energy storage applications that rely on membranes to control, selectively, rates of ion transport. Much remains unknown about the influence of polymer structure on basic intrinsic transport properties, and these relationships are important for designing next generation polymer membrane materials.

Key to controlling ion transport in membranes for water purification and energy applications is engineering interactions between ions and the solvated polymer matrix. Microwave dielectric relaxation spectroscopy is a tool that enables study of hydrated polymer membranes because water molecule dipoles can be probed in the microwave frequency region. This technique can provide unique insight into hydrated polymer dielectric permittivity (or dielectric constant) properties, which are critical in emerging thermodynamic modeling of ion transport in hydrated polymers. This presentation discusses the use of microwave dielectric relaxation spectroscopy to uncover structure property relationships in hydrated polymers and, more broadly, presents an overview of research aimed at further understanding fundamental structure/property relationships that govern small molecule transport in polymeric materials considered for desalination and electric potential field-driven membrane applications that can help address global needs for clean water and energy.
(Invited) Layered Double Hydroxides with Enhanced Interlayer Space for Electrochemical Energy Storage and Deionization
Authors: Wang Yang , Pan Qianfeng , Qiao Yixuan , Peng Song
Published: February 2024

Layered double hydroxides (LDHs) have been extensively studied as promising functional nanomaterials owing to their excellent electrochemical activity and tunable chemical composition. In this work, we presented a series of investigations on enhanced interlayer space of LDHs for electrochemical energy and deionization.

Firstly, using acetate anions (Ac-) as an intercalating element, NiCo-LDH nanosheets arraying on Ni Foam with different amounts of Ac- anions intercalation or volumes of hydrothermal solution were prepared by a simple hydrothermal method. The optimized amount of Ac- anions expanded the interlayer space of LDH nanosheets from 0.8 to 0.94 nm. An ultrahigh specific capacity of 1200 C g-1 at 1 A g-1 (690 C g-1 without Ac- anions), outstanding rate capability of 72.5% at 30 A g-1 and cycle stability of 79.90% after 4500 cycles, which were mainly attributed to the higher interlayer spacing of Ac- anions intercalation.

Moreover, CoAl-LDH nanosheets intercalated by sodium dodecyl sulfate (SDS) with an enhanced interlayer spacing from 0.76 to 1.33 nm are synthesized and used as an anode of electrosorption. The enlarged interlayer spacing provides an enhanced ion diffusion channel and improves the utilization of the interlayer electroactive sites, while heat treatment transferring LDHs to layered metal oxides offers additional active oxidation reaction sites to facilitate the electro-sorption rate, contributing to the high salt adsorption capacity (31.78 mg g-1) and average salt adsorption rate (3.75 mg g-1 min-1) at 1.2 V in 500 mg L-1 NaCl solution. In addition, the excellent long-term cycling stability (92.9%) after 40 cycles proves the strong electronic interaction between SDS and the host layer, which is validated by density functional theory calculations later on.

In addition, ionic surfactants like SDS and cetyl trimethyl ammonium bromide (CTAB) can be used to modify the morphology of LDH. The original LDH shows microspheres formed by nanorods, and LDH-CTAB is similar, yet more tangled, while LDH-SDS is like micro flowers consisting of interwoven nanosheets. LDH-SDS achieved better electrochemical performance (1003.6 C g-1 at 1 A g-1 and 73.84% after 3500 cycles) than LDHs-CTAB (430.54 C g-1, 57.3%), and both higher than the original LDH (278.5 C g-1, 54.3%), while the electrocatalytic performance like Tafel slope follows an opposite trend owing to the difficulty of bubbles detachment from the nanosheets or nanorods, clearly showing the importance of morphology regulation in the synthesis of nanomaterials.
A Comprehensive Study on the Ion-Selective Behavior of MnOx for Electrochemical Deionization
Authors: Tu Yi Heng , Hu Chi-Chang
Published: February 2024

Manganese oxide is an effective active material in several electrochemical systems including batteries, supercapacitors, and electrochemical deionization (ECDI). This work conducts a comprehensive study on the ion-selective behavior of MnOx to fulfill the emptiness in the energy and environmental science field. Furthermore, it broadens the promising application of MnOx in the ion-selective ECDI system. With the support of a microfluidic cell and the electrochemical quartz crystal microbalance (EQCM) analysis, we proposed a time-dependent multi-mechanism ion-selective behavior with the following guidelines. (1) Hydrated radius is the most critical factor for ions with the same valence, and MnOx tends to capture cations with a small hydrated radius. (2) The importance of charge density rises when comparing cations with different valences, and MnOx prefers to capture divalent cations with a large hydrated radius but a strong electrostatic attraction. In addition, ion-swapping may occur where divalent cations replace monovalent cations in this circumstance. (3) NH4
+ triggers MnOx dissolution, leading to performance and stability decay. The clear EQCM evidence has directly verified the proposed mechanisms. Moreover, the EQCM data provide a novel but simple method to judge ion selectivity preference. The overall ion selectivity sequence is Ca2+ > Mg2+ > K+ > NH4
+ > Na+ > Li+ with the highest βCa//Li and βCa//Na values around 3 at the deionization time = 10 min.
A Two-Dimensional Transport Model of Bipolar Membrane Electrodialysis for the Electro-Regeneration of Carbon Capture Solvents
Authors: Ledingham Jack , Campbell Alasdair , Sedransk Campbell Kyra
Published: February 2024

Bipolar membrane electrodialysis (BPMED) is a promising technology that uses an electric field to split water into H+ and OH- ions. A repeating stack of cation selective, anion selective, and bipolar membranes are placed between two electrodes, creating a repeating pattern of acid, base, and diluting flow chambers. A major application of BPMED is the electrochemical solvent regeneration of capture solutions used in CO2 point source (PS) or direct air capture (DAC). Protons generated using BPMED can be used to shift the acid-base equilibria back to CO2, providing a more sustainable alternative to traditional thermal regeneration methods when integrated with renewable electricity sources. This method combines electrosynthesis and separation, producing a pure stream of CO2 for sequestration and a concentrated base stream.

Despite its potential, current limitations to BPMED implementation for this application stem from a large power consumption and high membrane costs. In addition, gas bubbles in solution can cause high electrical resistances, and experimental studies of this phenomenon are challenging due to the small scale on which it occurs. To address these challenges, we present a two-dimensional model of BPMED for CO2 capture solvent recovery. This model depicts a single repeating cell triplet and was constructed using COMSOL Multiphysics version 6.1. The Navier-Stokes equations were implemented to compute a convection field, and the ionic species concentration was found by solving the Nernst-Planck equation. A source term in the concentration partial differential equations was implemented to account for ionic speciation and water splitting reactions, captured through kinetic rate expressions.

Experimental validation was conducted on a PC Cell BED 1-4 recirculating batch system with a stack of seven cell pairs of PC acid 60 (anion selective), PC SK (cation selective), and PC Bip (bipolar) membranes. Good agreement between the model and experimental results across a range of conditions and variables demonstrates accuracy and robustness. The calculated pH and concentration profiles revealed that the majority of the speciation reaction takes place inside, or directly adjacent to, the bipolar membrane, including bubble nucleation. Bubbles form inside membrane pores and displace the electrolyte, greatly increasing the electrical resistance of the membrane, particularly when membrane porosity is low. However, the reaction plane location where bubbles are generated can be manipulated by increasing the channel width or reducing the applied voltage.

Future research will focus on expanding to multiphase CFD simulations to investigate the effect on flow. Our two-dimensional model provides valuable insights into the complex and multifaceted nature of BPMED, offering a powerful tool for investigating small-scale processes and advancing the use of BPMED for CO2 capture solvent recovery.

Figure 1
Pulse Electrodeposition in the Presence of Corrosion Reactions during the Off-Time
Authors: Roy Sudipta , Green Todd
Published: February 2024

Pulse electrodeposition of metals and alloys offers one route to enhance or tune material properties. However, an often-neglected period during pulse plating is the off-time, which may also influence deposit properties. Traditionally it is considered a relatively unimportant, allowing, for example, relaxation of concentration gradients, desorption of additives, recrystallization and discharge of the double later capacitance. Over the past few decades, however, studies have shown that it is possible to have ‘internal current’ processes occurring in the off-time which can strongly influence the deposit properties and composition. For example, in the pulse electrodeposition of binary alloys from aqueous solutions, displacement (corrosion) reactions have been observed in the off-time that can significantly alter the alloy composition. This has also been observed in many aqueous and molten salt systems, and appears a very general phenomenon. More recently we have observed corrosion arising from a comproportionation reactions during the pulse plating of copper from a deep eutectic solvent (DES) and noted some of their effect on deposit properties.

The main purpose of this paper is to examine some of the similarities and differences in off-time corrosion caused by displacement and comproportionation processes during pulse electrodeposition. As is shown in the figure, corrosion may occur due to the presence of oxygen, or due the presence of a noble material leading to displacement reactions, as well as the presence of a stable species of differing valency in solution leading to comproportionation reactions. These differing mechanisms can produce different effects on the deposit. We will discuss how these different mechanisms can be understood and the influence on the deposit and their characteristics.

Figure 1
Effect of Pulsed Currents on Oxygen and Carbon Contents of Trivalent Chromium Based Deposits
Authors: Rodriguez Julymar , Lallemand Severine , Gigandet Marie-Pierre , Marcelet Martin , Legrand Benjamin , Tardelli Joffrey , Hihn Jean-Yves
Published: February 2024

Hexavalent chromium salts have been identified as toxic for both humans and the environment by Health authorities, which led the authorities to take measures such as the implementation of strict rules, such as the REACH regulation. While some applications may be substituted by other processes, the thick hard chromium plating used for its functional properties in friction and wear lacks of alternatives. Among them, trivalent chromium salts have been extensively studied [1], but this kind of electrolytes presents typical difficulties, leading to more fragile coatings with through-cracks, and a typical increase of hardness up to very high values after annealing. This change in the chromium coating behavior is often attributed to a significant increase in carbon and oxygen contents [2].

If temperature as well as current density have shown a great influence on both carbon and oxygen, their effects are reversed, with for example a decrease in oxygen content with temperature (due to a high solubility of hydroxides) accompanied by an increase in carbon content that leads to amorphous deposits. It is however very difficult to reduce both carbon and oxygen. The present work is built on a parallel study carried-out in the IRT M2P project CRONOS 2024, which discover the possibilities to limit the pH increase at the interface by inserting long-time toff during electrodeposition [3].

Various parameters (ton times, toff times, peak current density) have been scanned for chromium deposition on a copper tip (to make the oxygen and carbon analysis easier). It has been showed that a possible control of oxygen and carbon is possible, leading to very low values and changes in deposits properties (hardness, behavior after annealing, roughness ...). The best sequence was studied for various temperatures, and the combination of parameters extensively described.

Finally, 15CDV6 steel samples were coated and fully characterized.

[1] P. Benaben, « An Overview of Hard Chromium Plating Using Trivalent Chromium Solutions », Plating and Surface Finishing, p. 8, 2011.

[2] A. Baral et R. Engelken, « Modeling, Optimization, and Comparative Analysis of Trivalent Chromium Electrodeposition from Aqueous Glycine and Formic Acid Baths », J. Electrochem. Soc., vol. 152, no 7, p. C504, 2005, doi: 10.1149/1.1933688.

[3] M. Marcelet et al., « Influence of Pulse-Current Parameters on pH Measured By Local Method », Meet. Abstr., vol. MA2019-02, no 21, p. 1046, sept. 2019, doi: 10.1149/MA2019-02/21/1046.
Electrodeposition of Metals and Their Alloys in Ionic Liquids Using Pulse Plating
Authors: Ispas Adriana , Endrikat Anna , Bund Andreas
Published: February 2024

Pulse plating is often used to improve the morphology of deposits. One can thus electrodeposit films with finer grains and lower roughness, more compact layers by pulse plating than by direct current methods. In some cases, the throwing power and/or the adhesion of the deposits to the substrates can also be improved.

Pulse plating is widely used in industry for aqueous electrolytes, but it is not largely employed in ionic liquids (ILs). Tuning the parameters for pulse plating, such as the frequency and the duty cycle can be challenging due to the very different properties of ILs compared to most molecular solvents. Besides the pulse parameters, the effect of temperature can be rather strong, as ILs have a relatively high viscosity and thus lower conductivity. An increase in temperature will facilitate the mass transport. Further physical-chemical properties of ILs play also an important role in pulse plating applications, e. g. their double layer structure.

This paper will describe results from authors' lab on the electrodeposition of alloys in ILs. The feasibility of electrodepositing of binary alloys of Ta, Ti and Nb was investigated by varying the pulse parameters besides the types of metal salts (chloride or bromide) and ILs and temperature. Better layers in terms of morphology and purity were obtained by pulse plating techniques compared to direct current deposition.

To the best of the authors' knowledge pure titanium cannot be electrodeposited from ILs, but 9-15 wt% could be co-deposited with tantalum in 1-butyl-1-methylpyrrolidinium bis(tri-fluoromethylsulfonyl)amide.

Challenges remain with the optimization of the pulse parameters to tune the composition of the alloys and to minimize the incorporations of impurities.
The Potential of Dynamic Electrochemistry for Post-Processing of 3D-Printed Metal Parts
Authors: Hansal Selma , Hansal Wolfgang , Weiß Susanna
Published: February 2024

Creativity has no limits with 3D-printing of metals allowing the realisation of new geometries that cannot be provided by any other production method. Nevertheless it is a long way from an innovative idea to a 3D-printing based production process. The 3D-printed metal parts leave the printer with a significant amount of support structures fixed to the part, adhering metal powder and a surface roughness that is much too high for the technical application. While mechanical post treatment methods are mostly work, time and cost intensive they also cannot provide a proper finishing on sterically hindered parts and inner surfaces.

Here chemically-electrochemically based methods, such as the Hirtisation® process, enable an integrated production process using the freedom in design of 3D-printing and additionally give an valid option for complete process automatisation that is required for standardisation and qualification of industrial serial production.

While classical electro-polishing is failing to adress most of the issues resulting from the printing process, the use of dynamic electrochemistry, in terms of using current or potential pulses to finish the surface of the metal parts, provides a powerful toolbox for this application.

This presentation will show the possibilities of dydnamic electrochemistry in terms of applying short current or potential pulses on 3D printed parts and will discuss the use of current pulses on different industrial relevant studies. A key factor for the success of such methods is a knowledge-based electrochemical tailoring of the actual current conditions at the metal surface and a deep understanding and adjustment of the material surface chemistry. Only by such an understanding of the different steps in the production chain and adjustment of these steps to each other, a constant and reproducible quality of the final products can be realised.
Characterization and Performance Evaluation of Geranium Leaves Activated Carbon for Energy Storage Applications
Authors: . Akshay , Srikanth Vadali Venkata Satya Siva
Published: February 2024

Supercapacitors have emerged as a promising energy storage technology due to their high power density and fast charging times. One of the critical components of supercapacitors is the electrode material, which can significantly impact their performance. This study investigates the potential of geranium leaves-derived activated carbon as an electrode material for supercapacitor applications. Geranium leaves were pyrolyzed at an optimized temperature and activated with a chemical activating agent to obtain activated carbon. The synthesized material was characterized using techniques such as scanning electron microscopy, X-ray diffraction, and Fourier transforms infrared spectroscopy to determine its morphology, crystallinity, and surface functional groups. The electrochemical properties of the activated carbon were evaluated using cyclic voltammetry, galvanostatic charge-discharge cycling, and electrochemical impedance spectroscopy. Our results show that the geranium leaves derived activated carbon exhibit excellent electrochemical properties such as a high specific capacitance and good cyclic stability. The enhanced electrochemical performance can be attributed to the mesoporous structure of the activated carbon, which provides a large surface area and facilitates efficient electrolyte ion diffusion. In conclusion, our study demonstrates that geranium leaves derived activated carbon can be a promising electrode material for supercapacitor applications. The use of natural resources like geranium leaves for the synthesis of activated carbon not only offers a sustainable and cost-effective approach but also reduces the environmental impact associated with the disposal of organic waste materials.
Electrochemical Reduction of HMF: Study of Alkyl Ammonium Bromides as Electrode-Electrolyte Modifier
Authors: Peirow Asfia Mohammad , Nikolaienko Pavlo , Parada Villarroel Walter Agustin Agustin , Mayrhofer Karl J. J.
Published: February 2024

5-hydroxymethyl furfural (HMF) electrochemical conversion is a promising method for producing polymer and fuel precursors such as 2,5- Bis(hydroxymethyl)furan (BHMF), and 5,5-bis(hydroxymethyl)hydrofuroin (BHH) [1]. Research on this topic has mainly focused on electrode material selection and synthesis [2], whereas our focus has been on electrode-electrolyte interface modification. Thus, we developed a method to study electrochemical reduction of HMF on silver and glassy carbon [3] using different Alkyl Ammonium Bromide Salts (single and double charged) as an electrode-electrolyte interface modifier. Modifiers not only affect the side hydrogen evolution reaction but also accessibility to reduction centers and selectivity towards target products. In the presence of a variety of reagents, electrochemical real-time mass spectrometry (EC-RTMS) [4] was used to analyze the relative product distributions impacted by the potential of both electrode materials. More quantitative results were obtained from performing steady-state potentiostatic electrolysis of HMF in a flow reactor coupled with a gas chromatograph (GC) and high-performance liquid chromatography (HPLC) to support the results from EC-RTMS. Our research illustrates the impact of different AAB salts on the product distribution in the reduction pathway of HMF towards value added products.

References:

Kloth, R., et al., Electroreductive 5‐Hydroxymethylfurfural Dimerization on Carbon Electrodes. ChemSusChem, 2021. 14(23): p. 5245-5253.

Sanghez de Luna, G., et al., AgCu Bimetallic Electrocatalysts for the Reduction of Biomass-Derived Compounds. ACS Applied Materials & Interfaces, 2021. 13(20): p. 23675-23688.

Chadderdon, X.H., et al., Paired electrocatalytic hydrogenation and oxidation of 5-(hydroxymethyl) furfural for efficient production of biomass-derived monomers. Green Chemistry, 2019. 21(22): p. 6210-6219.

Khanipour, P., et al., Electrochemical Real‐Time Mass Spectrometry (EC‐RTMS): Monitoring Electrochemical Reaction Products in Real Time. Angewandte Chemie, 2019. 131(22): p. 7351-7355.
Characterization of Potential Dependent Fouling of Cu Electrodes during Electrochemical Hydrogenation and Hydrogenolysis of Furfural in Acid
Authors: May Andrew S. , Biddinger Elizabeth J.
Published: February 2024

Furfural (FF) is a platform molecule derived from biomass, that can be electrochemically reduced to produce furfuryl alcohol (FA), a furanic polymer intermediate, and 2-methylfuran (MF), a fuel candidate. On Cu in acidic media, it has been shown that FA and MF are produced via parallel reactions as opposed to a series reaction. Our previous work investigated the reactions for FA and MF production electrochemically with FF concentrations between 10 and 120 mM, showing positive order with respect to FF at low concentrations and zero order rates with respect to FF at higher concentrations. This finding suggesting non-competitive Langmuir-Hinshelwood mechanisms at concentrations of FF between 10 and 120 mM in pH 0 and 1 acidic solutions. At 200 mM concentrations of FF, we have identified fouling on the Cu surface. At moderate potentials, the fouling takes the form of a polymer material, whereas at more negative reduction potentials the fouling takes the form of graphitic coking. Understanding how fouling occurs on Cu electrodes is important in achieving progress towards mitigating or reducing the impact of fouling through reactor setup and catalysts design.

In this work, conditions that promote fouling were selected so that the fouling of Cu electrodes could be studied. The conditions were chronoamperometry at -560 or -700 mV RHE, 200 mM FF, 0.5M H2SO4, 20:80 vol% acetonitrile:water, for three hours durations. The Cu electrodes were reused for 3 experiments to further promote fouling and study the impact on the electrochemical performance. We showed that after reuse at -560 mV RHE, a polymeric material formed on the Cu electrode, while when reused at -700 mV RHE the electrode was instead covered in a coke like material. FTIR spectroscopy showed that the polymer formed at -560 mV resembled poly(furfuryl alcohol) while the coking substance showed broad absorbance, expected of coke like materials. To better understand the coke material formed at -700 mV, Raman spectroscopy was used. The material resembled graphitic disorganized carbon, with a D/G band intensity ratio of 0.652.
Carbon-Based Electrode Materials for Electrocatalytic Transformations
Authors: Schröder Christian , Nolan Hugo , Brunet Cabré Marc , Pota Filippo , Mc Evoy Niall , McKelvey Kim , Colavita Paula E.
Published: February 2024

Industrial processes for the synthesis of chemicals and fuels utilise selective hydrogenation reactions. The need for high temperatures and high pressure of H2 makes these reactions energy intensive and only viable on a large scale, requiring expensive transport of materials. Electrocatalytic hydrogenation (ECH) could potentially bypass these limitations, running at ambient conditions and generating the adsorbed hydrogen in-situ. The interest in new electrocatalyst materials increased in recent years, as ECH offers a synthetic route for fuels and value-added chemicals with a reduced carbon footprint. The development of new low-cost catalyst materials will be paramount for the integration of ECH into economic activities.

In this work we focus on heteroatom-modified carbon based electrode materials for the ECH. Carbon materials possess a list of beneficial properties for electrochemical applications: they are widely available, environmentally benign, stable at cathodic potentials and can be tailored towards specific applications. One way of tailoring is to dope the carbon with heteroatoms like nitrogen.

Nitrogen-doped carbon thin films have been synthesised using sputter deposition followed by an annealing process, to control graphitisation and nitrogen distribution of the carbon material. These model electrodes were investigated by themselves and as supports for thin nanoparticle films of MoS2 in the ECH and the hydrogen evolution reaction (HER), as the Volmer step of the HER is needed in the ECH. This allowed us to understand the influence of nitrogen moieties on reduction rates in the absence of morphological effects. The results suggest possible strategies for developing electrocatalysts for the ECH based on functional carbons.

[1] Orella, M.J.; Román-Leshkov, Y.; Brushett, F.R., Emerging opportunities for electrochemical processing to enable sustainable chemical manufacturing. Current Opinion in Chemical Engineering
2018, 20, 159–167.

[2] Behan, J. A.; Stamatin, S. N.; Hoque, M. K.; Ciapetti, G.; Zen, F.; Esteban-Tejeda, L.; Colavita, P. E., Combined Optoelectronic and Electrochemical Study of Nitrogenated Carbon Electrodes. The Journal of Physical Chemistry C
2017,
121 (12), 6596-6604.

[3] Nolan, H.; Schröder, C.; Brunet-Cabré, M.; Pota, F.; McEvoy, N.; McKelvey, K.; Perova, T. S.; Colavita, P. E., MoS2/carbon heterostructured catalysts for the hydrogen evolution reaction: N-doping modulation of substrate effects in acid and alkaline electrolytes. Carbon
2023, 202, 70-80.
Selective Anodic Conversion of Technically Relevant Lignin
Authors: Waldvogel Siegfried R
Published: February 2024

The electrochemical conversion of less exploited biogenic side streams provides an attractive approach to valuable intermediates. Electrosynthesis represents a future technology, which is characterized by its outstanding sustainability.[1] The translation of electrosynthesis is strong dependent on the subsequent downstream processing and has to be implemented into the electrolytic screening on an early stage.[2]

A new strategy is presented to electrochemically convert lignins by ex-cell and in-cell approaches providing selectively access to monomeric species such as vanillin, 5-iodovanillin, vanillic acid and dimethoxybenzoquinone.[3-6] The key is the timely separation of oxidation and liberation event.

References:

[1] D. Pollok, S. R. Waldvogel, Chem. Sci.
2020, 11, 12375–12592.

[2] J. Seidler, J. Strugatchi, T. Gärtner, S. R. Waldvogel, MRS Energy Sustain.
2020, 7, E42.

[3] M. Zirbes, T. Graßl, R. Neuber, S. R. Waldvogel, Angew. Chem. Int. Ed.
2023, e202219217.

[4] J. Klein, S.R. Waldvogel, ChemSusChem
2023, e202202300

[5] J. Klein, R. Kupec, M. Stöckl, S. R. Waldvogel, Adv. Sustainable Syst.
2022, 2200431

[6] J. Klein, K. Alt, S. R. Waldvogel, Adv.
Sustainable Syst.
2021, 6, 2100391.
A Comprehensive Review of Aging Models in Lithium-Ion Batteries
Authors: Madani Seyed Saeed
Published: February 2024

Lithium-ion batteries degrade over time with usage, and it's improbable that the effects of aging-related deterioration can be entirely eradicated. The processes responsible for the aging of these batteries are intricate and varied, closely linked to a range of interacting factors such as battery types, chemical reactions, and operational circumstances. Elements like charge level, charging and discharging speed, cycles, and temperature have a direct impact on degradation, underscoring the significance of operational conditions and stressors. The challenge of battery aging presents a substantial area of research, influencing the energy and power capacity of batteries as time progresses. This piece presents a comprehensive examination of various methods for simulating battery aging and investigations carried out on this subject, with a specific emphasis on indicators employed to gauge the well-being of batteries. The objective of this review is to succinctly outline the outcomes of prediction techniques for the aging of lithium-ion batteries in diverse applications. Given the extensive array of studies focused on battery aging, a wealth of knowledge is available in this domain, and consequently, this article offers an overview of these varied approaches.
An Adaptive Extended Kalman Filter for Model-Based Fault Diagnosis and State of Charge Estimation of Lithium-Ion Batteries
Authors: Madani Seyed Saeed
Published: February 2024

Precisely gauging the state of charge (SOC) of a lithium-ion battery poses a considerable obstacle due to the battery's intricate electrochemical properties, which are highly dynamic and nonlinear. The effectiveness of the control strategy employed in electric vehicles heavily hinges on the precise estimation of the battery's SOC. Among the crucial elements, the accurate assessment of SOC for power lithium-ion batteries stands out. Ensuring the durability and reliability of battery management systems in electric vehicles to predict SOC is a multifaceted endeavor. Given the inherently nonlinear degradation pattern of batteries, achieving precise forecasting of SOC while minimizing degradation proves to be a demanding task. The accurate determination of battery SOC holds significant significance for both battery electric vehicles and hybrid electric vehicles. Lithium-ion batteries have gained extensive usage in various facets of daily life due to their positive environmental and resource-related attributes. The precise determination of SOC is pivotal in ensuring proper battery operation. Nonetheless, the challenges of SOC estimation under low temperatures have received limited attention. To tackle this issue, this study introduces an adaptive extended Kalman Filter for model-based fault diagnosis and SOC estimation of lithium-ion batteries.
Electrochemical Conversion of High Pressure CO2
Authors: Lu Xu
Published: February 2024

The electrochemical reduction of carbon dioxide (CO2R) via an electrochemical process is a strategic approach aimed at completing the carbon cycle for chemical production. Traditionally, this field has predominantly focused on conducting electrolysis on CO2 under standard atmospheric pressure. However, in industrial applications, CO2 is typically pressurized during its capture, transportation, and storage, often existing in a dissolved state. Our research has unveiled a significant discovery: subjecting aqueous CO2 to a pressure of 50 bar alters the CO2R pathways, favoring the formation of formate. This phenomenon is consistently observed across commonly used CO2R catalysts. Through the development of effective techniques for operating under high pressures, including a measurable Raman spectroscopy approach during the ongoing reaction, we have established a connection between the increased preference for formate and the heightened coverage of CO2 on the cathode surface. This collaboration between theoretical models and experimental data strongly supports this mechanism and has led us to enhance the cathode surface of a copper electrode with a proton-resistant layer. This innovation amplifies the selective impact caused by pressure. Furthermore, our research has unveiled the potential to transform gas-phase high-pressure CO2 into ethylene (C2H4) through CO2R. We conducted density functional theory calculations to identify a range of copper alloys that promote C-C dimerization under high pressure, which represents the rate-limiting step for C2H4 production. The theoretical predictions were validated through a combination of electrochemical measurements and operando observations, guiding us in designing a copper-based catalyst for efficient and active conversion of CO2 to C2H4.
Electrochemical Analysis and Quantification of Anodic Oxidation on Activated Carbon Cloth Electrodes through Cyclic Voltammetry
Authors: Ehinger Clara , Callen Lily , Alejandre Airelle , Valentino Lauren
Published: February 2024

Capacitive Deionization (CDI) has applications ranging from water purification to biofuels processing. For CDI to be a viable scalable technology, electrode stability is critical. In extended experiments the activated carbon cloth (ACC), used for the electrode, has been previously observed to degrade as a result of surface oxidation reactions. Carbon cloth oxidation can reduce the surface area and alter the pore structure, in turn reducing the adsorption capacity. While the behavior of oxidation is known, a reliable method of quantifying the extent of degradation is lacking. To quantify it, cyclic voltammetry was explored to measure the capacitance of pristine and oxidized carbon cloth samples. A three-electrode electrochemical cell was used to quantify capacitance of activated carbon cloth in 1M NaCl solution. The specific capacitance of carbon cloth that underwent anodic oxidation was lower than cathodic and pristine carbon cloth. Further tests analyzed the change in the severity of the anodic degradation on whether the initial CDI separations were performed on organic or inorganic ions. Scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) was utilized to verify and quantify surface oxidation. Cyclic voltammetry is demonstrated as a simple and reliable method for analyzing and quantifying anodic oxidation on activated carbon cloth electrodes in CDI stacks.
(Keynote) ALD Challenges and Opportunities in Light of Future Trends in Si-Based Nanoelectronics
Authors: Swerts Johan
Published: February 2024

To enable CMOS transistor density scaling following Moore’s Law, device architectures transitioned in the past decade from the historical 2D planar transistor to FINFET. The next innovation touted for the 3nm node is a 3D stacked gate-all-around architecture in combination with a backside power delivery network. For further scaling, stacking nmos and pmos, the so-called complementary-FET (CFET) design, is envisaged to happen in 2030. The shrinking device dimensions of the interconnects require also new metallization schemes to tackle the RC challenge, such as Cu replacements materials in a direct metal etch integration scheme. Beyond the CFET era, one envisages the introduction of 2D-grown channel materials that will pave the way for further scaling. A broad variety of complementary deposition techniques will be needed to enable the above-mentioned novelties; among them ALD that will play a crucial role.

A similar trend towards stacking functional cells can be observed in various memories, such as the emerging memories that aim to bridge the gap between DRAM and NAND, thereby enabling fast data storage and retreival for real-time processing in connected devices at low cost. These memories are based on phase change, filamentary, magnetic, or ferroelectric mechanisms and often use multi-element materials. They have been extensively explored in 2D capacitor or transistor based devices, but for further density scaling 3D device designs are needed where a conformal deposition technique such as ALD is required. Cell scaling challenges also hold for the traditional DRAM which lead to exploring 3DDRAM integration routes. One viable pathway for scaling implies the replacement of the typical Si-channel based transistor by a deposited semiconductor oxide channel. Ultimate 3DDRAM implementation would require a conformal deposition of that channel.

In this presentation, we will discuss the opportunities and challenges of ALD in a 3D-evolving device landscape where new materials will play a key role.
Understanding Growth Mechanism of Atomic Layer Deposition of Tisiox for Spacer in Double Patterning Process
Authors: Lee Sanghun , Seo Seunggi , Noh Wonate , Oh Il-Kwon , Kim Hyungjun
Published: February 2024

The aggressive scaling down of patterning technology in semiconductor industry is challenging owing to the limitation of current extreme ultraviolet EUV lithography technique, thus applying self-aligned double patterning (SADP) is essential. In this regard, TiSiOx may be a promising spacer material for SADP, which is beneficial to tolerate high aspect ratio structure triggered by shrinkage in patterning size. However, atomic layer deposition (ALD) of quaternary materials is usually faced to unexpected growth characteristics leading to undesired film qualities, while precise control of thickness and film properties is vital to achieve SADP. This work provide understanding of how growth characteristics of ALD TiSiOx are deviated according to process temperature. At 100 °C, hygroscopic TiSiOx surface which is originated by the presence of Ti-O-Si bond is exposed to H2O by-product leading to enhanced growth rate of TiSiOx compared to ideal case. If the process temperature is increased to 200 °C, opposite behavior is observed since hygroscopic TiSiOx surface characteristic is no more dominant to growth rate of ALD TiSiOx due to dehydroxylation. Theses nonconventional growth characteristics dramatically influence on hydroxyl concentration in TiSiOx films resulting in different spacer qualities such as dry etch rate and elastic modulus. These correlative results suggest that the process conditions should be modulated to suppress hydroxyls incorporation into growing TiSiOx surface during ALD to obtain a high-quality TiSiOx thin films for SADP.
New Materials for Memory Applications by Atomic Layer Deposition
Authors: Illiberi Andrea , Leonhardt Alessandra , Surman Matthew , Lukose Leo , Ramachandra Ranjith , Mootheri Vivek koladi , Popovici Mihaela , Givens Michael
Published: February 2024

The architectures of integrated logic and memory devices have shifted from 2D to 3D layouts, enabling a continued scaling of device densities. Atomic layer deposition (ALD) allows the conformal deposition of thin films with sub-nm thickness control on high aspect ratio 3D structures. ALD has become the technique of choice for the synthesis of an increasing number of materials in advanced logic and memory devices. In the first part of this presentation, we briefly review some of the key ALD processes which enable the fabrication of state-of-the-art 3D-NAND and 2D-DRAM. Next, we present the ALD of emerging ferroelectric HfZrO developed at ASM in industrial scale ALD reactors. HfO2 has been established as the preferred gate oxide material for logic devices for almost two decades. The recent discovery of ferroelectricity in HfO2 has opened new applications for HfO2-based materials as active memory elements in DRAM and 3D-NAND. We show that ALD La:HfZrO can achieve high polarization field (2Pr > 60 uC/cm2) and high endurance (> 107 cycle) by applying interface engineering schemes and optimizing deposition processes and film composition (i.e. Hf/Zr ratio, dopant concentration).
In-Situ Reflectance Absorption Infra-Red Spectroscopy (RAIRS) Study on ALD of HfO2 on TiN and Pt Electrodes
Authors: Kim Jiyoung , Kim Jin-Hyun , Lee Minjong , Le Dan , Hong YeEun , Song Siun , Kim Si Joon , Choi Rino
Published: February 2024

Ferroelectricity in hafnia fluoride analogues has been widely investigated for nonvolatile memory applications. Although ALD of HfO2 technology is enough mature for CMOS technology, hafnia-based ferroelectrics still suffer from major reliability issues such as relaxation, imprint, fatigue, and breakdown.1 These reliability characteristics are thought to be related to the interface conditions between the ferroelectric film and the electrode. Thus, many reports suggested routes to enhance reliability and ferroelectric characteristics by modifying the interface states of the metal-ferroelectric-metal (MFM) capacitors. Unfortunately, only few reports disclose direct observation on evolution of interface formation and its mechanism. Recently, it is reported that scaling down the ferroelectric hafnia-based films to a few nm range dramatically improves the MFM capacitors’ reliability where the series capacitance and surface effect dominate, making it crucial to understand the interface properties carefully.2

In this presentation, we perform In-situ characterization using reflectance absorption infrared spectroscopy (RAIRS) to monitor the surface reaction and interface formation while HfOx ALD using TDMA-Hf with various oxidation reactants, such as H2O, O3, and anhydrous H2O2. TiN and Pt bottom electrodes are investigated at 250 °C. The RAIRS results show that the initial exposure of the oxidant generates the most amount of oxidation on the TiN surface by showing Ti-O and TiN-O peaks which were not observed for the Pt substrate. Moreover, the Ti-O and TiN-O peak area increase versus the dosing time of oxidant was minimum for H2O, and O3 showed continuous peak increase even after 12 s exposure. Interestingly, for the H2O2 case, there was almost no peak increase in the Ti-O bond region like H2O, but the TiN-O and TiO-O peaks appeared after the first 3 s and saturated after 6 s exposure. Also, not only on the TiN substrate, the peak for O-O stretching was observed for the Pt substrate as well, indicating that the H2O2 generates self-limiting peroxide bonds on the surface with a minimum interface formation. This suppressed interface formation with superior film properties using H2O2 might be the reason behind the robust reliability of the H2O2-based HZO capacitor. We are going to report reliability characteristics in conjunction with interface evolution.

Acknowledements: We thank to YEST and KEIT for supporting the project through ISTD Program (No.20010806). This work is also supported by GRC-LMD program (task#3001.001) through SRC. The BRUTE hydrogen peroxide was provided by RASIRC. Ozone generator for TMEIC

References

1 J. Mohan et al., ACS AELM, 4, 4 (2022).

2 K. Toprasertpong et al., ACS AMI, 14 (2022).