bluuebunny/crossref_metadata_2025 huggingface dataset:
A Study on the Kinetics and Structural Changes of Silicon during Ball Milling
Authors: Gauthier Roby , Bennett J. Craig , Scott Benjamin , Obrovac Mark
Published: August 2024

Enhancing our understanding of the ball milling process is important to optimize silicon amorphization, a key factor in improving the performance of lithium-ion battery anodes. To improve this understanding, we quantitatively studied the kinetics of silicon amorphization during ball milling using x-ray diffraction (XRD) and electrochemical methods, among other methods. The percentage of amorphous and crystalline silicon was deduced by fitting the XRD data and electrochemical results. The resulting trend versus ball milling time was then fitted using the Avrami model. The material resulting from ball milling was further studied using scanning and transmission electron microscopy (SEM/TEM). Under extended milling times, we found that a maximum of 86% of the silicon became amorphous. Similarly, the grain size of the crystalline silicon phase could not be reduced below 6 nm. Our observations suggest that amorphization results from defects creation during ball milling. Amorphization then stops when the grain size reaches a limit where defects are no longer formed.

Figure 1
Plasma Jet Mediated Reduction of Metal Salt
Authors: Lockwood Estrin Francis , Hagger Oliver S. J. , Parkes Michael A. , Sener M Emre , Caruana Daren J.
Published: August 2024

We demonstrate electrodeposition where the plasma acts as both an electrolyte and electrode, to deposit metallic conductive coatings. In conventional electroplating metal ions are reduced at a working electrode with an applied electrochemical potential. Here an RF atmospheric pressure plasma jet (APPJ) is able to induce a electrochemical reduction due to the presence of free electrons. The advantage of this method is demonstrated by the ability to deposit conducting metal tracks on delicate surfaces including insulators and polymers. The small size and gaseous nature of the plasma allows deposition in difficult geometries with precise spatial control.

The reduction process occurs within the plasma. As the aerosolized metal salt crystals interact with the plasma, the free electrons reduce the metal and the hydrogen combines with the anion producing a water soluble acid. The metal reduction takes place within the plasma jet, as show by varying the plasma power and determining the amount of zerovalent metal deposited. Even at low powers, <6 W, the plasma was able to fully reduce the silver, however the copper requires plasma powers of 12 W and above in order to be fully reduced. Once reduced the deposited tracks were shown to be conductive with around 20 % and around 5 % of bulk conductivity for silver and copper respectively. A sintering process occurs also within the plasma, leaving a contiguous track of fused particles of zerovalent metal producing the conducting tracks. The technique is demonstrated mainly for copper and silver, however multiple other metals were capable of being deposited. In addition to the conductivity, the track adherence was tested both using a Scotch Tape© pull test and an in-house constructed scratch test. The track was completely unaffected by the tape pull and the stylus type scratch test showed that the films were scratch resistant up to a pressure up to of 420 kg cm-2, with no measurable drop in conductivity.

The APPJ is an accessible, low power, sustainable, precise electroplating device, capable of depositing pure metallic films onto a variety of surfaces. Furthermore, we demonstrate deposition on rough surfaces such as damaged fiberglass, as well as sensitive surfaces including plant tissue and pigskin, with limited damage to the surface.

Figure 1. a) showing the deposition setup including nebuliser, salt solution injection, gas flow and power supply. An optical image of the APPJ during deposition operation is included, as well as Schlieren imagine showing the laminar gas flow. b) A silver Hilbert curve printed onto Kapton 0.05 mm thickness via the plasma deposition technique, in a single step process, with no sample prep or post processing. c) Copper deposited on porcine skin showing conductance as part of a LED circuit.

Figure 1
Electrochemical Plasma-Activated CO2 Reduction at a Plasma-Water Interface
Authors: Simon Julia , Kim Ji-Yong , Winter Lea R
Published: August 2024

The development of technologies and processes to decarbonize chemical and fuel production is key to reducing global anthropogenic greenhouse gas emissions. Electrochemical carbon dioxide reduction enables a sustainable pathway to circularize carbon-based chemical products by upgrading recovered carbon dioxide using renewable energy sources. Electrochemical CO2 reduction has successfully been employed to produce chemicals such as methanol and ethylene, but it has been hindered by dependence on elevated temperature to achieve high yields and limited ability to generate higher order carbon products. Non-thermal carbon dioxide plasma can be generated at ambient temperature and pressure and contains energetically excited oxygen and carbon species. When introduced to an electrocatalyst, these reactive species could more readily participate in reaction pathways with higher activation barriers towards forming higher order carbon species compared to electrochemical reactions involving ground-state reactants. Further, plasma discharges over water in an electrochemical cell generate plasma-activated water, introducing solvated electrons and secondary reactive oxygen species.

In this work, we investigate how the use of plasma-activated carbon dioxide and a plasma-water interface impacts electrochemical product generation. We design a novel non-thermal plasma electrode to discharge carbon dioxide plasma into water in an electrochemical cell with a Cu nanoparticle electrocatalyst. Results suggest the potential for a plasma-water electrochemical system to generate value-added products that are less commonly generated in electrochemical processes at ambient pressure and temperature.
Plasma Electrochemistry in Non-Aqueous Solvents and Application to Organic Synthesis
Authors: Peyres Sean , Wang Jian , Hollyfield Drew , Confer Matthew Phelan , Uner Necip Berker , Bhargava Rohit , Moore Jeffrey S. , Sankaran Mohan
Published: August 2024

Low-temperature, atmospheric-pressure plasmas in contact with liquids have attracted interest for various chemical applications including the synthesis of colloidal nanoparticles, degradation of organic pollutants, and conversion of abundant feedstocks. Compared to other chemical approaches, plasma-liquid electrochemical processes do not require a catalyst material, are electrified, and produce unique reactive species such as solvated electrons, one of the strongest chemical reducing species.

Here, we present a study of plasma-liquid electrochemistry in non-aqueous solvents and apply such a system to organic synthesis. The majority of studies to date of plasma-liquid electrochemistry have focused on water. For some applications, including organic synthesis, non-aqueous solvents are required. However, the compatibility of plasmas with these solvents and the chemistry has not been thoroughly investigated. We focused on methanol and the well-known pinacol coupling reaction.1 Parametric studies were performed on methyl-4-formylbenzoate (MFB) as the substrate. The solvent had important effects including the generation of side products through parasitic radical formation. By adding water, the selectivity to the desired pinacol product could be improved. A reaction-diffusion model and thermodynamic calculations at the composite correlated G3(MP2)B3 molecular orbital theory level to support experimental measurements will also be discussed, as well as the potential application of this approach to other organic reactions.

1J. Wang et al., J. Am. Chem. Soc. 2023, 14, 19, 10470-10474.
(Invited) Self-Discharge of Layered Oxide Cathodes Induced by Carbonate-Mediated Hydrogenation
Authors: Wan Gang
Published: August 2024

Significant efforts have been made to improve the energy and power characteristics of cathodes in Li-ion batteries, while the research into cathode self-discharge has lagged behind. Self-discharge is the voltage drop experienced by all rechargeable batteries while stored in the charged state. The voltage drop becomes more problematic with increased cathode voltage and temperature. The physicochemical nature of internal reactions leading to cathode self-discharge is hardly understood and seldom discussed.

To tackle this challenge, the structure and redox evolution of commercial LiNi0.5Mn0.3Co0.2O2 electrodes and single crystal cathode thin films upon the self-discharge in carbonate-based electrolyte is revealed by surface-sensitive X-ray scattering, spectrometric and electrochemical characterizations in conjunction with thermodynamic analysis. As evidenced by the interfacial toolkits and theoretical calculations, there is an evolution and growth of cathode surface reduction layer in different types of electrolyte after self-discharged from different potentials. Structural and chemical chacterizations as well as the elemental depth profiles within cathode thin film confirms proton-insertion-induced layered cathode hydrogenation. Calculation shows that such process is both thermodynamically and kinetically favorable and is triggered by the interfacial hydrogen atom abstraction of methylene group in carbonate solvent on delithiated cathode surface. A combination of experimental and theoretical studies reveals the carbonate-mediated cathode hydrogenation mechanism accounting for the voltage drop in the self-discharge. This offers additional understanding regarding defect generation and the degradation mechanism in layered cathodes beyond the traditional behaviors of lithium-diffusion-induced self-discharge and rock-salt phase induced cathode degradation. This study offers foundational knowledge of the interfacial degradation of cathode that can be translated to the rational design of improved cathodes and electrolytes, and the self-discharge mechanism studies in other electrochemical ion insertion materials and devices.
Operando Electrochemical Liquid Cell STEM Investigation of the Growth and Evolution of the Mosaic Solid Electrolyte Interphase for Lithium-Ion Batteries
Authors: Walid Dachraoui , Pauer Robin , Battaglia Corsin , Erni Rolf
Published: August 2024

The solid electrolyte interphase (SEI) is a key component of a lithium-ion battery forming during the first few dis-/charge cycles at the interface between the anode and the electrolyte. The SEI passivates the anode-electrolyte interface by inhibiting further electrolyte decomposition extending the battery's cycle life. Insights into SEI growth and evolution in terms of structure and composition remain difficult to access. To unravel the formation of the SEI layer during the first cycles, operando electrochemical liquid cell scanning transmission electron microscopy (ec-LC-STEM) is employed to monitor in real time the nanoscale processes that occur at the anode-electrolyte interface in their native electrolyte environment [1]. The results show that the formation of the SEI layer is not a one-step process, but comprises multiple steps. The growth of the SEI is initiated at low potential during the first charge by decomposition of electrolyte leading to the nucleation of inorganic nanoparticles. Thereafter, the growth continues during subsequent cycles by forming an island-like layer. Eventually, a thick dense layer is formed with a mosaic structure composed of larger inorganic patches embedded in a matrix of organic compounds. While the mosaic model for the structure of the SEI is generally accepted, our observations document for the first time how the complex structure of the SEI is built up during dis-/charge cycling.

[1] W. Dachraoui, R. Pauer, C. Battaglia, R. Erni, ACS Nano 2023, 17, 20434
External Cooling and Degradation Interplay in Lithium-Ion Battery Fast Charging
Authors: Karmakar Avijit , Vishnugopi Bairav Sabarish , Mukherjee Partha P.
Published: August 2024

Fast charging of Li-ion batteries involves key challenges such as lithium plating, mechanical stress formation, high temperature rise, and non-uniform temperature distributions. The advancement of thermal management systems to maintain an optimal cell temperature distribution and minimize degradation is critical to enable fast charging. This work analyzes the various degradation modes, including lithium plating, solid electrolyte interphase growth, and mechanical stresses in large-format Li-ion cells during fast charging, and delineates their dependence on external cooling conditions. Based on the cell design and operating conditions, unique attributes related to the evolution of internal thermal gradients, spatiotemporal lithium plating response, and the formation of mechanical stress hotspots are delineated. Further, optimal external cooling configurations that enable longer life and safety under fast charging conditions are determined. The study provides guidance toward the design of next-generation battery thermal management systems for Li-ion batteries with fast charging capabilities.
Elucidating the Electrochemical Impact of the Calendering Process on Three-Dimensional Designed Electrodes for Lithium-Ion Batteries
Authors: Straßburger Niclas , Zhu Penghui , Pfleging Wilhelm
Published: August 2024

Significant advancements in battery technology are imperative to meet the ambitious demands for electromobility and stand-alone energy storage devices. This stems from the need to achieve operations with high energy and power density, coupled with stringent safety standards and extended lifespans, while reducing production and material costs. The preferred energy storage technology for the coming decade is anticipated to remain lithium-ion battery (LIB) technology. The focus on researching high-energy active materials to optimize this technology is paramount. In addition to optimizing materials, significant performance enhancements can be achieved by using electrodes with high mass loading and a multiscale tailored electrode design that can be scaled up to production level.

The technological challenges of achieving a breakthrough in gaining simultaneously high energy and power density characteristics while maintaining high process and operational reliability with significant cost savings are the subject of current research and development in the field of LIB technology. To tackle this, the study explores the laser-assisted generation of three-dimensional (3D) electrode architectures and assesses its impact on battery performance and future integration into battery production. The advanced electrode design involves micro and sub-micron structures that can be tailored in various ways, leading to notable improvements in battery lifespan, battery safety, and fast charging and high-power operation capabilities compared to batteries with conventional two-dimensional (2D) electrodes. High-power ultrafast laser ablation emerges as a precise method for introducing such structures.

Coordinating the production of 3D electrodes with laser assistance necessitates synchronization with established manufacturing steps in the battery production process. Notably, the calendering of electrodes holds significance due to its substantial influence on the microstructural properties of the electrode material, encompassing porosity, material density, and layer adhesion. The study investigates the impact of laser-induced structuring, encompassing micro-/nano-porosities and microtopography, on electrodes with varying mass loadings ranging from 2mAh/cm² to 6mAh/cm². Electrochemical characteristics such as high-rate capability, fast charging, and cycle lifetime are evaluated accordingly, employing cells with graphite anodes and lithium-nickel-manganese-cobalt oxide cathodes.
Coupled Electrical – Thermal – Electrochemical Model of a Battery Module
Authors: Tewari Deepti , Rajagopalan Kannan Dhevathi Rajan Rajagopalan , Jeevarajan Judith
Published: August 2024

A battery module comprises of several lithium-ion cells connected in series and parallel configuration to obtain the desired voltage, current and power specifications. The overall response of a module can be affected by (i) the electrical topology, (ii) the thermal topology and (iii) the cell-to-cell variations. The distribution of current depends on the series/parallel assembly and variation in interconnect resistance in the module. Operation of a cell is accompanied by an increase in temperature. In a module, the thermal environment seen by a cell is different depending on whether it is an interior cell or a cell at the boundary of module exposed to environment. There is additional thermal cross talk between cells through heat conduction in metallic interconnects. Finally, there can be several reasons for cell-to-cell variation in a module. The cells used for building a module can have variable state of charge and internal resistance at the manufacturing level. As the module is cycled, the ageing of cells in a module can differ due to variation in current, evolution of range of lithiation of electrodes and the temperature of the cell.

In this research work, we develop a coupled electrical, thermal, and electrochemical model to simulate the charge and discharge of a battery module with the overall aim of identifying the cell with largest performance degradation and most likelihood of failure. This physics-based modeling approach comprises of a simplified electrochemical and lumped thermal model of an individual cell. At the module level, the modeling framework is extended to include the electrical and thermal connectivity along with the electrochemical response.
Liquid-Solid Phase Diagrams for Lithium-Ion Battery Electrolytes in the Ternary Space and Beyond
Authors: Self Julian , Bergstrom Helen K.
Published: August 2024

Although practical lithium-ion battery electrolytes generally utilize two or more solvents in addition to the dissolved lithium salt, liquid-solid phase diagrams have, as far as the authors know, only been reported for binary single-solvent electrolytes. This precludes rational design of low freezing point liquid electrolyte mixtures. We herein present a thermodynamic framework to draw out ternary electrolyte liquidus surfaces using the comprising binary liquid-solid equilibria data and limited ternary data measured via calorimetry. LiPF6 in liquid carbonate mixtures are here studied. The introduced thermodynamic framework also allows evaluation of the thermodynamic factor, which appears in the context of transport parameter measurements.
(Invited) Understanding Electrochemical Reaction Mechanisms of Sulfur in All-Solid-State Batteries through Operando and Theoretical Studies
Authors: Zhu Hongli , Cao Daxian
Published: August 2024

All-solid-state lithium-sulfur batteries (ASLSBs) have been considered a promising next-generation energy storage technology due to their remarkable safety and high energy density. In ASLSBs, the electrochemical pathways are intrinsically different from conventional Li-S batteries using liquid electrolytes. However, the mechanism still lacks clear identification and deep understanding. Herein, for the first time, we investigated the chemistries and explored the electrochemical reaction mechanism in ASLSBs through coupling operando Raman spectroscopy and ex-situ X-ray absorption spectroscopy. We proved that no long-chain lithium polysulfides (Li2Sn, 4≤n≤8) were formed during the redox reactions, but a short-chain polysulfide (Li2S2) intermediate phase formation was identified in the conversion between active material S8 and reduction product Li2S. This evidence explains the electrochemical behavior differences of Li-S batteries when using liquid and solid electrolytes. Moreover, there are partial S8 and Li2S2 remaining at the cathode even at fully lithiation stage, suggesting the sluggish reaction kinetics in the ASLSBs. This study revealed the generation of Li2S2 intermediates in ASLSBs, inspiring future research to further improve the performance of ASLSBs through completing the conversions and promoting reaction kinetics in ASLSBs.
(Invited) Using a Chemo-Mechanical Model to Investigate Electrolyte Infiltration and Surface Reconstruction within Cracked Cathode Material
Authors: Allen Jeffery M. , Weddle Peter J , Smith Kandler , Usseglio-Viretta Francois L. E. , Finegan Donal P.
Published: August 2024

One of the main goals in modeling lithium-ion batteries is to improve/predict longevity and resilience of new chemistries. To that end, this talk investigates the formation of stress-induced fracture within polycrystalline cathode particles and the impact on capacity loss. The model captures anisotropic Li diffusion within a single polycrystalline particle comprised of hundreds to thousands of randomly oriented grains. Fracture is primarily due to non-ideal grain interactions with slight dependence on high-rate charge demands. Essentially, when neighboring grains are misaligned, they expand a different rates relative to one another leading to high stresses and ultimately the formation of intraparticle cracks. A previous study showed that small particle with large or single grain geometry tend to crack less and retain the most capacity.

Cracks within the cathode particle that have access to the surface can potentially fill with electrolyte. When this happens, the cracks can be considered new active surface area where the lithium intercalation reaction can occur. Under sufficient conditions, this could lead to better performance because the grains of the cracked particle start to operate more like a network of single-grain particles. However, the newly open surface area is also subject to side reactions and surface reconstruction resulting in diminished transport properties and potentially trapped lithium. The goal of this talk is to investigate this balance between improved lithium transport pathways caused by lithium infiltration and the reduced diffusion due to surface reconstruction.
Strategies and Perspectives on Enhancing Energy Density in Lithium-Ion Batteries
Authors: Ahn Juhyeon , Doeff Marca M. , Chen Guoying
Published: August 2024

The rapidly growing demand for clean energy transportation and storage systems emphasizes the need for the development of large-scale lithium-ion batteries. Achieving this goal requires a comprehensive approach that considers not only technical aspects but also social, environmental, and economic perspectives. Specifically, the next-generation batteries should exhibit high energy and power densities, long-term cycle stability, and the efficient utilization of low-cost, abundant raw materials. The cathode material is the key determinant of these requirements. This presentation will introduce progress and strategies for enhancing cathode materials and their corresponding cell performances. These strategies include goals to enable reversible redox reaction processes through elemental and compositional choices, as well as crystal structural variations ranging from order to disorder. Furthermore, we combine these with advanced characterization techniques to understand the correlation between material properties and electrochemical behavior at multiple length and depth scales. The discussion also delves into a deeper understanding of the fundamental mechanisms of performance, coupled with advancements in new materials. Overall, the presentation aims to provide valuable insights into the strategy for developing the next generation of lithium-ion batteries.
Electrodeposited Ni-Fe-TiO2 Alloy Composites for the Hydrogen Evolution Reaction
Authors: Annadurai Sreenivasan , Podlaha Elizabeth J
Published: August 2024

Hydrogen is a carbon-free alternative energy source that is environmentally friendly, has high energy density, and is a promising fuel for future generations. Water splitting is an efficient way to produce hydrogen, requiring a catalyst with a small overpotential and Tafel slope, and good stability. However, only 4 % of global hydrogen is produced by water electrolysis due to high cost and lack of inexpensive replacements of the active platinum electrocatalyst.1 However, replacing these noble metal electrocatalysts with those comprised of lower, earth-abundant elements remains challenging as these materials impart a higher overpotential and thus require higher energy. Guided by the recognised enhancements of TiO2 particles in Co-Mo alloys for HER, earth-abundant, low-cost Ni and Fe metals are examined as composite electrocatalysts Ni-Fe-TiO2 towards HER.2

Nano-scale TiO2 particles were embedded into Ni-Fe alloys by using galvanic and pulse-reverse electrodeposition, onto rotating cylinder electrodes. Pulse-reverse electrodeposition considerably increased the concentration of the particles incorporated into the alloy. The composition and morphology were characterized by X-ray fluorescence (XRF) spectroscopy and scanning electron microscopy (SEM), respectively. The addition of particles to the electrolyte affected both the deposit composition and morphology. The alloy composites were then used as electrocatalysts in 1 M KOH to characterize HER via linear sweep voltammetry on the resulting hydroxide surface. The surface area was examined in a ferri/ferrocyanide electrolyte. The polarization data in 1 M KOH shows a significant reduction in the HER overpotential when TiO2 particles are present in the Ni-Fe deposit. The surface analysis of Ni-Fe and Ni-Fe-TiO2 confirmed that the improvement in HER activity is not due to surface roughness but an intrinsic one. The stability of the electrocatalysts under an electrolysis for HER was examined at -10 mA/cm2 for 24 hr and the working electrode potential remained stable over time; Tafel polarization curves after electrolysis were similar to those prior to electrolysis.

References

Le, P. A., Trung, V. D., Nguyen, P. L., Phung, T. V. B., Natsuki, J., & Natsuki, T. RSC advances,
13(40), 28262-28287 (2023).

C. Wang, H. K. Bilan, and E. J. Podlaha. J. Electrochem. Soc. 166 F661 (2019). C. Wang and E. J. Podlaha, J. Electrochem. Soc. 167, 132502 (1~4) (2020).
Engineering Controls for Scaling CO2 Electrolyzers
Authors: Prajapati Aditya , Goldman Maxwell , Krall Eric , Clemens Auston L. , Marufu Michell , Chu An , Gutierrez Laura , Duoss Eric B , Baker Sarah , Hahn Christopher
Published: August 2024

The electrochemical CO2 reduction (CO2R) to ethylene on copper-based catalysts has garnered significant attention for its potential in sustainable industrial practices. While substantial progress has been achieved in the development of small-scale electrolyzers with geometric areas ranging from 1 to 5 cm2, the imperative to address larger scales for industrial decarbonization necessitates a shift in focus. There are inherent critical risks when scaling a nascent technology like CO2 electrolysis. There can be emergent phenomena observed only at larger scales, that can prevent it from reaching commercialization, such as change in local CO2 concentration, defects in the porous transport layer, and temperature gradients The optimized conditions for operating a 5 cm2 electrolyzer may not work well with a 25 cm2 electrolyzer leading to failures. Therefore, there is a need to develop a systematic way to test for these phenomena to address these challenges to successfully operate a CO2R electrolyzer at an industrially relevant scale. In this work, we highlight the performance of a Cu-based catalyst designed for the selective reduction of CO2 to ethylene across varying scales, ranging from 5 to 100 cm2. This investigation shows the changes in the electrolyzer performance at different scales. Our findings highlight the critical importance of implementing engineering controls to overcome challenges associated with the scaling of electrolyzers. Specifically, we explore the impact of anolyte flow rate, gasket compression, and electrochemical pulsing techniques on maintaining the desired selectivity of the electrocatalyst across different scales. By systematically adjusting these parameters, we demonstrate the ability to mitigate non-linear effects and uphold the efficiency of CO2 reduction to ethylene, even on larger electrode surfaces.

This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Modelling Anodic H2O2 Accumulation in Alkaline Water Electrolysis with Experimental Validation
Authors: Phadke Sohan , de Jong Wiebren , Haverkort Johannes Wilhelmus
Published: August 2024

Hydrogen peroxide (H2O2) is a high value commodity chemical used as a green oxidant in industries such as paper milling and textile bleaching, and is currently produced by the anthraquinone oxidation process. The anodic co-production of H2O2 during alkaline water electrolysis has gained interest as a sustainable alternative for anthraquinone oxidation. However, electrochemical H2O2 production is often studied with idealized laboratory setups to determine the H2O2 formation kinetics. In this work, we perform the reaction using a flow cell with separately recirculating anolyte and catholyte. We then fit the H2O2 accumulation data to an analytical model that we derive based on mole balances that accounts for anodic generation, anodic oxidation, and bulk disproportionation of H2O2, as well as anolyte reservoir volume and anode chamber volume. We performed experiments to derive values for maximum H2O2 production at 300 mA cm-2, with values of 0.540 mmol s-1 for anodic generation of H2O2 (FEH2O2 = 58%) and 0.416 min-1 for anodic oxidation of H2O2, with a bulk disproportionation rate constant of 1.85 × 10−3 min-1. We successfully applied our model to two sources in literature to derive values for their systems as well. In all cases, the contribution of anodic oxidation of H2O2 was found to be the larger loss mechanism in comparison to bulk disproportionation.

Figure 1
The 2-Propanol Fuel Cell: Direct CO2-Free Electrification with a Liquid Hydrogen Carrier
Authors: Brodt Matthew , Rajendran Menon Rohit , Hübner Christoph , Thiele Simon
Published: August 2024

Molecular hydrogen is a gas at ambient conditions and requires compression or cryogenic liquefaction for storage and transport, leading to significant losses in efficiency. Therefore, liquid hydrogen carriers are desirable as they are storable without losses. One such fuel that has shown promise recently is 2-propanol (isopropanol), which is converted with high selectivity to acetone in a fuel cell.[1],[2],[3] Power densities over 200 mW/cm2 have been reported for direct isopropanol fuel cells (DIFCs), which rivals the best direct methanol fuel cells (DMFCs), and unlike methanol, isopropanol is non-toxic and it is not fully oxidized to CO2.
[4]

The literature has demonstrated many advantages of DIFCs, yet significant challenges remain.[5] Continuous operation at high current densities can be limited due to anodic catalyst layer network effects: slow removal of acetone from active sites and out of the catalyst layer. Additionally, perfluorinated sulfonic acid (PFSA) ionomers are not fully chemically compatible with 2-propanol and acetone. Operation at higher temperatures with a vaporized 2-propanol feed partially mitigates both of these disadvantages, yet the high energy cost of vaporization reduces the overall efficiency of the system. Future research should focus on stable, high-power operation with a liquid 2-propanol feed.

This contribution chronicles the progress that has been made and discusses the current state-of-the-art and outlook of direct electrification with DIFCs. Recent advances in liquid-fed DIFCs are presented, including design of membrane-electrode-assemblies and operation strategies in full cells. Finally, the concept of using the 2-propanol/acetone couple as an electrochemical liquid organic hydrogen carrier is briefly introduced: a reversible hydrogenation and dehydrogenation cycle for storing and releasing molecular hydrogen on demand.

References

[1] D. Cao, S. H. Bergens, J. Power Sources
2003, 124, 12–17.

[2] Z. Qi, A. Kaufman, J. Power Sources
2003, 118, 54–60.

[3] M. L. Perry, Z. Yang, J. Electrochem.
Soc.
2019, 166, F3268-F3276.

[4] P. Hauenstein, D. Seeberger, P. Wasserscheid, S. Thiele, Electrochemistry Communications
2020, 118, 106786.

[5] M. Brodt, K. Müller, J. Kerres, I. Katsounaros, K. Mayrhofer, P. Preuster, P. Wasserscheid, S. Thiele, Energy Technol.
2021, 9, 2100164.
OREATE as a High Yield and Purity Electrochemical Process for Transition and Rare Earth Metal Recovery
Authors: Sansinena Jose-Maria , Braley Sarah E. , Dangel Gabrielle R. , Sykes Kiana S. , Currier Robert P.
Published: August 2024

Developing a process that can consistently convert transition and rare earth metal oxides to chemically pure metals in near quantitative yield will have significant impact in many levels, from fundamental science to national security-related applications. Traditional separation methods of lanthanides and actinides from aqueous media have been based on liquid-liquid extractions that have proven to be quite efficient, though they are expensive and require complex engineering. Likewise, separation by pyro-chemistry provides a good recovery performance but requires the use of high temperatures that adds technological difficulties to the process. An alternative method that has grown interest in the last few years is the utilization of the difference in the metals’ reduction potentials from ionic state to metallic state. However, this electrochemical approach requires more negative reduction potentials than hydrogen evolution, which requires a very challenging control of their electrolytic deposition onto solid cathodes.

In recent years, our team at LANL has been working on the development of OREATE (Oxide Reduction by Electrochemical Amalgamation and Thermal Extraction). OREATE is a holistic electrochemical approach that involves an initial step wherein the metal oxide is dissolved and chlorinated into an acidic medium. The dissolved metal cation is then electrochemically amalgamated via reduction using a mercury pool cathode. Finally, mercury's high vapor pressure allows an easy thermal extraction process to obtain the metal. From the conceptual perspective and preliminary results, the OREATE process appears easier and simpler than traditional separation methods and is suitable for small- and large-scale preparation of high purity metals.

The results obtained using Cerium (Ce) as a surrogate metal demonstrated near quantitative yield of the electrochemical amalgamation (yield > 99%), almost complete mercury recovery during the thermal extraction (Hg recovery > 99.5%), and high purity of the Ce metal product (purity > 99%). Moreover, a variety of system parameters such as the pH of the buffered solution, concentration of cerium, reduction potential, and temperature were explored to evaluate the effect that the scaling up of the OREATE process may have on reaction rate, current efficiency, process yield, and temperature management.
(Digital Presentation) Integrated Membrane Electrode Assembly in Proton Exchange Membrane Fuel Cells
Authors: 董 行 , Jiang Jia , Chen Qi , Ji Zhaoqi
Published: August 2024

Proton exchange membrane fuel cells (PEMFCs), an electrical device with high energy conversion efficiency and zero-carbon emission, has attracted more attention. The membrane electrode assembly (MEA) is the core component of PEMFCs, mainly including proton exchange membrane (PEM), catalyst layer (CL), microporous layer (MPL) and carbon fiber gas diffusion layer (GDL), which has different structures and significantly affects its power density and durability [1].

Generally, MEA is fabricated by catalyst coated electrodes (CCE) and catalyst coated membrane (CCM) methods, which often results in a huge interface resistance between electrode and membrane, the weak adhesion and poor proton and electron transfer, limiting the electrochemical surface area (ECSA) and the power density of PEMFCs [2].

To solve this problem, many approaches have been adopted, such as improving sintering temperature for MEA, incorporating a guided cracked layer between cathode and membrane, double-layered catalyst and direct deposition method. Zhao et al prepared an integrated membrane electrode assembly structure to reduce the contact resistance between proton exchange membrane and catalyst layer, which significantly improves the efficiency and stability of water electrolysis [4]. At the same time, Klingele and Breitwieser developed a direct deposition of proton exchange membrane technology to improve high performance and long-term stability of PEMFCs. However, these methods are complex and almost impossible to industrialize [5].

In this study, integrated membrane electrode assembly (I-MEA) was prepared by combining casting and doctor blade method techniques. The results show that the casting method is more suitable for fabricating I-MEALT in low-temperature proton exchange membrane fuel cells. The power density of the I-MEALT cell is increased by 18% compared with that of the conventional MEALT (Fig. 1). The doctor blade method is more suitable for preparing I-MEAHT in high-temperature proton exchange membrane fuel cells. The maximum power density of I-MEAHT is increased by about 57% compared with that of the conventional MEAHT. The electrochemical impedance shows that this is mainly attributed to the reduced interface resistance between the electrode and the membrane, which facilitates the proton transfer.

References

[1] L. Zhao, J.B. Zhu, Y. Zheng, M.L. Xiao, R. Gao, Z. Zhang, G.B. Wen, H.Z. Dou, Y.P. Deng, A.P. Yu, Z.B. Wang, Z.W. Chen. Adv. Energy Mater. 12 (2021) 2102665.

[2] K. Jiao, J. Xuan, Q. Du, Z.M. Ba, B. Xie, B.W. Wang, Y. Zhao, L.H. Fan, H.Z. Wang, Z.J. Hou, S. Huo, N.P. Brandon, Y. Yin, M.D. Guiver. Nature 595 (2021) 361-369.

[3] X.D. Wang, W.B. Guan, R. Yu, W. Liu, W.L. Pei, X.D. Zhou. Int. J. Hydrog. Energy. 41 (2016) 22337-22343.

[4] L. Zeng, T.S. Zhao. Nano Energy 11 (2015) 110-118.

[5] M. Klingele, M. Breitwieser, R. Zengerle, S. Thiele. J. Mater. Chem. A. 3 (2015) 11239.

Figure 1
(Invited) Low Cost in Situ Electrosynthesis and Cycling of Quinone Negolytes in a Commercial Flow Battery Stack
Authors: Beh Eugene S. , Bahari Meisam , Symons Peter , Aziz Michael J.
Published: August 2024

Aqueous organic redox flow batteries (RFBs) potentially offer greatly lower capital cost relative to vanadium RFBs or even lithium-ion batteries, as they use no critical materials and are instead derived from very inexpensive precursors. To date, the success of organic RFBs as a whole has been hampered by two factors. The first is the high cost of scaling up a new chemistry, as every synthetic step adds cost and complexity and creates waste that must be disposed of. The second is fast degradation of the reactants and has been largely mitigated through various strategies that have recently been reported. The recent results mean that low-cost compounds that may intrinsically have a fast degradation rate, now merit consideration since their fade rate can be lowered significantly.

We report the development of an in situ electrosynthesis process, from the lab scale to the ton scale, that creates the organic RFB negolyte from the starting reactants using commercial RFB stacks that have been repurposed as chemical reactors. The yield and purity are even higher than the equivalent chemical process and no further purification or downstream processing is required; the entire process is self-contained and produces zero waste which greatly simplifies scaleup, permitting, and implementation. Moreover, the as-produced material can be immediately cycled as a drop-in replacement for vanadium in RFBs with minimal modification of existing vanadium RFB designs.

This unique in situ strategy enables rapid scaling of a new chemistry in a way that supports local manufacture, which is of strategic importance to many governments. Further cost reductions are envisioned if it can be implemented at the customer site -- inside a completed flow battery system -- rather than at a centralized facility.

When combined with previous results on reversing the degradation of quinone RFB reactants, the electrosynthetic pathway to producing organic RFB negolytes is the final missing piece of the puzzle in the commercialization of an affordable, practical, and viable organic RFB chemistry.
(Invited) Commercialization of CO2 Electrolysis
Authors: Ma Sichao , Cooper Jason
Published: August 2024

The atmospheric accumulation of greenhouse gasses such as carbon dioxide (CO2) is the primary cause of global climate irregularities. Over three trillion tons of greenhouse gasses have been emitted since the start of the industrial revolution, and natural disasters such as heatwaves, wildfires, and hurricanes have only increased in regularity. Decarbonization has become an important strategic priority for nations and industries worldwide. Numerous technologies have been developed to capture and store carbon dioxide from the atmosphere. However, most of these approaches do not address the ubiquitous demand for fossil fuel derivatives and their associated petroleum-based infrastructure, nor are these approaches capable of extracting value from the captured CO2.

Our company, Twelve, is developing a highly efficient and scalable electrochemical reactor that converts CO2 into valuable building blocks for chemicals and fuels such as carbon monoxide (CO). The resulting CO can be blended with green hydrogen from water electrolyzers to form syngas, enabling an ultra-low carbon pathway to sustainable aviation fuel (SAF) via the Fischer-Tropsch process. Twelve has previously produced SAF for the Air Force, where we demonstrated the first ever SAF pathway based on CO2 electrolysis. Beyond SAF, Twelve has completed commercial projects for chemicals and materials made from CO2 with global brands that include Procter & Gamble and Mercedes Benz. At scale, this technology can enable a closed loop ecosystem wherein CO2, water, and electricity are converted into manufacturing inputs that are currently derived from fossil fuels. We are presently translating the performance of our lab-scale prototypes to the industrial scale, focusing on SAF as our beachhead market.

In this talk, Twelve’s CO2 electrolysis technology will be used as a model to describe the commercialization challenges and market opportunities of industrial CO2 electrolysis. Key performance metrics and areas of active collaborative research between Twelve and academic institutions will be discussed. Finally, commercial demonstrations of our technology in the automobile, aviation, consumer chemicals, and apparel industries, as well as our company’s long-term vision and goals will be presented.
Design and Implementation of Iron-Based Electrochemical System for Simultaneous Carbon Capture and Hydrogen Gas Recovery
Authors: Taqieddin Amir , Sarrouf Stephanie , Ehsan Muhammad Fahad , Buesseler Ken , Alshawabkeh Akram N
Published: August 2024

The catastrophic results of climate change and energy crisis, such as the rise in wildfires, floods, and ecosystem disruptions highlight the critical need of urgent and innovative global-scale solutions for carbon dioxide (CO2) removal (CDR). Ocean-based CDR methods, leveraging the ocean's capacity as a large sink to sequester up to 30% of emissions, offer a great promise. Yet, implementing and testing marine CO2 removal (mCDR) techniques such as ocean iron fertilization (OIF) or ocean alkalinity enhancement (OAE) face significant challenges. To overcome these challenges, a novel self-operating electrochemical technology is designed and presented in this work. The proposed technology, namely electrochemical OIF (EOIF), does not only combine OIF and OAE, but also recovers hydrogen gas (H2) from seawater, offering a promising solution for achieving quantifiable and transparent large-scale mCDR. The EOIF design s focused on employing Fe/Fe-producing anodes to eliminate the production of acids at the anode in traditional electrochemical OAE systems and replace it with Fe release, where the cathode can be made from naturally abundant cost-effective materials, such as carbon. The obtained results show that the EOIF system can be implemented to increase both the concentration of ferrous iron (Fe+2) by 0-0.5 mg/L, and the seawater pH by 8% (i.e., 25% decrease in the hydrogen ions concentration). It also offers the flexibility to optimize the release of iron (Fe+2/Fe+3) by adjusting the magnitude of the electric current in the systems, as well as by optimizing the electrode material and geometry. In certain ocean regions, enhanced iron concentrations stimulate the naturally occurring biological carbon pump (BCP), leading to increased phytoplankton growth, CO2 uptake, and subsequent export of carbon to the deep ocean. Simultaneously, the system increases seawater alkalinity and the buffer capacity, enhancing CO2 solubility and storage in the shallow ocean through the solubility pump. The techno-economic assessment shows that the combined advantages of the EOIF system can lower the mCDR cost by more than 95% compared to the traditional methods. The obtained measurements demonstrate the scalability of EOIF and its ability to operate using solar energy at a lower cost. Overall, the proposed EOIF technology offers a practical, effective, and sustainable solution for addressing climate change and energy recovery on a large-scale.
Atomic-Scale Investigation of Electromigration Behavior in Cu-to-Cu Joints at High Current Density
Authors: Huang Hua-Jing , Chiu Wei-Lan , Chang Hsiang-Hung , Chen Chih , Wu Wen-Wei
Published: August 2024

Three-dimensional integrated circuit (3D IC) packaging offers significant advantages, such as enhanced computational efficiency through greater integration and shorter interconnection distances. The effective interconnection of layers, particularly through redistribution layer (RDL) technology, is crucial for the successful operation of 3D ICs. While copper remains the preferred material for interconnections, often in conjunction with through-silicon via (TSV) technology for chip-to-chip links, the shrinking dimensions of components present challenges. In particular, the reduction in size may lead to elevated current densities in individual joints, giving rise to issues like electromigration (EM) and potential failure. EM-induced atomic migration may lead to the formation of voids in the interconnection. The accumulation of voids to a critical point may result in an open circuit in the joints, significantly impacting the conductor's reliability. This work delves into the micro-scale aspects of these challenges, complementing previous macroscopic investigations. We aim to elucidate the behavioral mechanisms through atomic-scale observations, employing an in-situ high-resolution transmission electron microscope (in-situ HRTEM) to observe atomic-scale images of EM. The insights gained from this work not only contribute to the academic understanding of industry challenges but hold potential applications in real-world manufacturing processes.

Fig. 1. (a) Schematic diagram of TEM sample preparation. (b) Cross-sectional HRTEM image of copper bonding. (c, d) TEM images showing voids expansion at bonding interface.

Figure 1