bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring the Potential of Cadmium Selenide Nanowires-Based Chalcogenide Devices for Photoelectrochemical Hydrogen Production
Authors: Vijay Shiljashree , Cheng Wei , Jawahar Hussaini Syed Mubeen
Published: December 2024

Hydrogen, as a clean fuel and vital industrial chemical, plays a pivotal role in our sustainable energy future, particularly in applications such as the fertilizer and steel industry. To meet the growing demand for renewable hydrogen production, our work focuses on the potential of photoelectrochemical (PEC) water splitting technology. The commercialization of PEC hydrogen production hinges on significant advancements in three key areas: (a) improving solar-to-hydrogen (STH) conversion efficiency, (b) reducing manufacturing costs, and (c) enhancing device durability. Technoeconomic analysis highlights high efficiency as a critical metric, but current triple-junction III-V devices, despite achieving >20% STH, suffer from low durability and high costs. Conversely, single junction oxide materials offer stability and low cost but limited STH performance. Recently, dual-junction tandem PEC devices, configured with a buried photovoltaic-electrocatalyst (PV-EC) architecture, have emerged as promising solutions. This approach integrates semiconducting PV materials beneath an electrocatalyst layer with or without a protective encapsulant, improving overall efficiency and stability. The selection of an appropriate dual-junction PEC device centers on achieving a high voltage (VOC > 1.6 V) with substantial current density (JSC > 10 mA/cm²), minimizing additional power losses due to catalysts and membranes. Within this context, cadmium-based chalcogenides, especially cadmium selenide (CdSe) nanowires and cadmium telluride (CdTe) nanowires, hold promise as top and bottom cell candidates. Although Cd-chalcogenides have made significant strides in the PV industry, their application in PEC hydrogen production remains underdeveloped, particularly concerning their integration with electrocatalysts for stable and efficient solar hydrogen production. This talk will address how we mitigate this gap by developing novel device architectures for fault-tolerant CdSe-based PEC devices, demonstrating their manufacturability at various scales i.e. from lab scale to wafer-scale, and finally, the talk will cover the application of electrodeposited cadmium selenide nanowires and investigating their performance in solar water splitting when interfaced with suitable catalysts within the buried PV-EC architecture.
Electrodeposition for the Guided Synthesis and Screening of Binary Alloy Thin Films
Authors: Pepas Jakub , Ma Yifan , Zhang Guangxing , Kang Minju , Carsley John , Chen Hailong
Published: December 2024

Alloy coatings can enhance the mechanical and electrochemical properties of engineering materials such as surface hardness, wear resistance, catalytic performance, and corrosion resistance. The development and testing of alloy films requires extensive time and experimentation due to the non-monotonic variation of many properties with alloy composition and the large experimental space of compositions, which increases rapidly with the number of components in the alloy. The development time of alloy thin films can be reduced by analyzing many compositions in a single experiment. However, many current thin film deposition-based gradient synthesis techniques are expensive, produce a limited experimental range of compositions, and may not vary the composition of each component independently. Electrodeposition is an attractive technique for thin film deposition due to its low cost, high scalability, and sensitivity to the geometry of the deposition environment, but conventional co-electrodeposition of multiple metals from a single electrolyte bath suffers from limited compositional control and experimental range. We report an electrodeposition-based method that produces a wide range of compositions on a single sample with good compositional control. To demonstrate, we coated samples of polished Cu with NiCo alloys with gradient local composition. The composition, phase, morphology, and performance of the NiCo thin films are investigated using a range of high-resolution techniques including x-ray fluorescence spectroscopy, synchrotron X-ray diffraction, SEM, and nanoindentation.
Fabrications of Au–Pt Bimetallic Heterostructure Electrodes By Ligand-Exchange Assisted Layer-By-Layer Self-Assembly for Hydrogen Evolution Reaction
Authors: Lee Sujin , Jang Youn Jeong , Yeom Bongjun
Published: December 2024

Platinum (Pt) is a widely utilized electrocatalyst for hydrogen evolution reaction (HER) for water splitting, since the Pt–H bond strength is optimal for hydrogen adsorption and desorption for HER. In order to improve its catalytic activity and stability, previous research reported various types of preparation methods for Pt-containing bimetallic catalysts with noble metals (Ru, Pd, Ag, and Au) or transition metals (Cr, Mn, Fe, Co, Ni, Cu, and Zn) with exhibitions of electronic and bifunctional effects. Among such examples, Au–Pt bimetallic electrocatalysts indicated several advantages, such as d-band shift of active element of Pt lowering binding strength of protons, shifting Pt oxidation potential for improved stability, and increased electron transfer. These catalysts were synthesized by seeded growth, galvanostatic deposition, surface dealloying, and electrodeposition methods. Nevertheless, a facile and effortless synthesis approach must be established to realize large-scale production of multicomponent catalysts.

In this study, ligand-exchange assisted layer-by-layer (LbL) self-assembly method was utilized to prepare Au–Pt nanocomposite films for HER electrocatalyst. The ligand-exchange assisted LbL self-assembly technique was used to fabricate metallic nanoparticle (NP) thin films to reduce the amount of insulating organic components, and improves electrical conductivity through metal fusion between metal NPs. Tetraoctylammonium bromide (TOA-Br) ligands on the surface of Au and Pt nanoparticles (NPs) are alternately deposited onto Ti electrodes paired with diethylenetriamine (DETA), a short alkyl amine. This process is accompanied by the removal of the pre-attached bulky surface ligands of TOA-Br. The resulting Au and Pt NP LbL nanocomposite films are characterized by uniform thin-film depositions with a metal-level electrical conductivity (8.7 × 104 S cm-1), which is similar to the bulk metal conductivity. The Au–Pt NP nanocomposite films exhibited 80 mV at a current density of 10 mA cm-2 of HER overpotential under an acidic condition of 0.5 M H2SO4, which corresponds to one-third of that of the control sample of only Pt NP LbL film. The Au–Pt LbL film indicates competitive overpotential (less than 100 mV) despite the ultra-small amount of Pt contents (0.73 wt%), which is suggestive of enhanced catalytic activity. Higher activity could be ascribed to the synergistic effect of bimetallic heterostructure films with the d-band shift, superb electrical conductivity, rapid charge transfer, and increased electrochemical surface area. The suggested synthesis approach is expected to be effective for the fabrications of various electocatalystic thin films for various energy conversion devices.
Regulating Zinc Electrodeposition on the Anode By Controlling Crystal Growth
Authors: Zhang Duhan
Published: December 2024

Ensuring the reversible electrodeposition of metals at liquid-solid interfaces is crucial for the long cycle life of rechargeable batteries that employ metals as anodes. While extensive research has focused on the electrochemical transformations influencing reversibility, the fundamental hurdles related to maintaining morphological control when an intrinsically crystalline solid metal phase emerges from an electrolyte solution have received less attention. However, these challenges present significant opportunities for advancement.

Here, we propose a method to stabilize crystal growth and reshape the initial growth and orientation of crystalline metal electrodeposits. This approach leverages polymer-salt complexes (PEG-Zn2+-aX−) (where a = 1,2,3) spontaneously formed in aqueous electrolytes containing zinc (Zn2+) and halide (X−) ions to regulate electro-crystallization of zinc. Specifically, we demonstrate that when X = Iodine (I), these complexes facilitate the electrodeposition of zinc in a hexagonal closest packed morphology, with the (002) plane preferentially oriented parallel to the electrode surface. This precise control over zinc electrodeposition morphology on planar substrates leads to exceptional anode reversibility and unprecedented cycle life. We validate the practical benefits of this approach through studies on Zn-I2 full battery cells, implemented in both coin cell and single-flow battery cell configurations.
Interface Control of Electrodeposited CZTSSe Thin Film Solar Cells for Perovskite Tandems
Authors: Hwang Sun Kyung , Park So Jeong , Park Ik Jae , Kim Jin Young
Published: December 2024

In spite of the high potential economic feasibility of the tandem solar cells consisting of the halide perovskite and the kesterite Cu2ZnSn(S,Se)4 (CZTSSe), they have rarely been demonstrated due to the difficulty in implementing solution-processed perovskite top cell on the rough surface of the bottom cells. Here, we firstly demonstrate an efficient monolithic 2-terminal perovskite/CZTSSe tandem solar cell by significantly reducing the surface roughness of the electrochemically deposited CZTSSe bottom cell. The surface roughness (Rrms) of the CZTSSe thin film could be reduced from 424 nm to 86 nm by using the potentiostatic mode rather than using the conventional galvanostatic mode, which can be further reduced to 22 nm after the subsequent ion-milling process. The perovskite top cell with a bandgap of 1.65 eV could be prepared using a solution process on the flattened CZTSSe bottom cell, resulting in the efficient perovskite/CZTSSe tandem solar cells. After the current matching between two subcells involving the thickness control of the perovskite layer, the best performing tandem device exhibited a high conversion efficiency of 17.5% without the hysteresis effect.
(Invited) Hard X-Ray Core Shell Spectroscopy Studies of Battery Materials
Authors: Balasubramanian Mahalingam
Published: December 2024

Understanding the charge compensation mechanisms during electrochemical cycling of battery materials is of both fundamental and applied interest. X-ray Absorption Fine Structure (XAFS), an element specific probe of the projected, unoccupied density of states as well as the local and medium-range structure around the probed photoabsorbing atom, has been a workhorse technique that sheds light on the atomic and electronic structure of the metal ions. However, the rising edge at the metal K-edge — the energy of which is used in assigning oxidation state — also depends on other factors such as the nature of the ligand, covalency, coordination number, and metal spin-state. We have recently show that by coupling XAFS with Resonant X-ray Emission Spectroscopy (RXES), questions concerning metal oxidation state and site symmetry can be addressed, even in highly covalent systems [1]. In this talk, we will highlight the application of these hard X-ray spectroscopy methods to understand fundamental structure-function relationships of materials and systems relevant to lithium-ion batteries. The first topic of the talk will address the redox mechanisms and migration tendencies in an earth-abundant Li1.3Mn0.5Fe0.2O 2 cathode material (see figure below). In the second topic, we will examine the evolution of the electronic structure of nickel and dopant ions (cobalt) in a nickel-rich material.

[1] Redox Mechanisms and Migration Tendencies in Earth-Abundant 0.7Li2MnO3·0.3LiFeO2 Cathodes: Coupling Spin-Resolved X-ray Absorption Near Edge and X-ray Absorption Fine Structure Spectroscopies, C.Y. Kwok, S. Mallick, C. J. Pollock, A. Gutierrez, M. Dixit, J. R. Croy, and M. Balasubramanian, Chemistry of Materials 2024
36 (1), 300-312

Figure 1
(Invited) Are There Still Gold Nuggets on the Sandy Beach? Efforts to Further Reducing the Cost of Li-Ion Batteries through the Discovery of Low-Cost New Cathodes
Authors: Liu Zhantao , Zhao Simin , Tang Yuanzhi , Zhu Ting , Chen Hailong
Published: December 2024

The cost of lithium-ion batteries (LIBs) has undergone a remarkable reduction, decreasing by approximately an order of magnitude over the past 15 years, from around $1000/kWh to approximately $130/kWh today, following an exponential curve. However, achieving further cost reductions to around $20/kWh within the next 10-15 years is extremely challenging. Despite significant efforts over the past decade or so to decrease the use of expensive Co in LIBs, such as transitioning from NMC111 to NMC811 or NMC9055, semi-expensive Ni is still heavily used, and the manufacturing cost associated with the high-temperature synthesis of layered oxides remains largely unchanged. The manufacturing expense is also a factor in the high cost of LiFePO4, which only comprises abundant elements but requires expensive carbothermal synthesis and carbon coating.

There appears to be a long quiet period in the discovery of new intercalation-type cathodes following the successful development of LiCoO2 (1979), LiMn2O4 (1984), LiFePO4 (1997), and the NMC family (1990s). To date, no cathode material for rechargeable LIBs beyond those listed above has been commercialized on a large scale. Here we present the recent discovery of a novel, low-cost intercalation cathode that demonstrates very good performances in an all-solid-state configuration and shows significant potential for commercialization. When paired with a competitive solid electrolyte, this cathode material displays two flat voltage plateaus averaging at 3.65 V, an impressive initial capacity of 159 mAh/g, a high energy density of 580 Wh/kg, and stable cycling. Characterizations via neutron diffraction and X-ray absorption spectroscopy reveal that the Li+ storage mechanism is associated with a topotactic intercalation-deintercalation reaction associated to a Fe2+/Fe3+ redox couple during cycling. Most importantly, this cathode material costs only 2% of LiFePO4 and 1% of LiCoO2, holding tremendous promise for commercial applications, particularly in large-scale energy storage such as grid storage.
Exploring the Chemical Space of O2-Type Lithium-Rich Layered Cathodes
Authors: Eum Donggun
Published: December 2024

Despite the high-energy density of lithium- and manganese-rich layered oxides (LRLOs) provided through the high-voltage anionic redox chemistry, critical issues such as capacity fading and voltage decay have limited their real-world applications. As an elegant solution, O2-type LRLOs were recently reported to mitigate these voltage issues via reversible transition-metal (TM) migration during the successive charging and discharging; however, these materials still suffer from capacity degradation during long-term cycling. Repetitive mechanical stress and failure has also been proposed as the origin of the capacity fading even in LRLOs. Nevertheless, in-depth studies on the mechanical behavior in LRLOs, particularly with respect to the extent of high-voltage oxygen redox, remain elusive. Herein, a series of O2-type LRLOs were designed and synthesized to investigate the evolution of the bulk structures as a function of varying oxygen-redox capabilities and to examine their effects on persistent electrochemical degradation. We demonstrate that the generation of bulk microcracks in the particles is strongly coupled with repeated lattice evolution and structural distortions during the high-voltage oxygen redox. These internal cracks lead to the formation of an electrochemically inactive phase near the cracks, which is followed by capacity fading as extended cycling occurs. These findings clarify how the oxygen redox in LRLOs is highly correlated to the mechanical degradation (and consequently capacity fading) and provide a general design principle towards genuine high-energy cathode materials.
(Invited) Advancing and Manufacturing Materials for Next Generation Li-Ion Batteries
Authors: Yushin Gleb
Published: December 2024

As conventional intercalation-type Li-ion battery electrode materials approach their theoretical limits, substantial gains in battery energy density only come as a trade-off in safety or performance. Supply chain limitations additionally constrain the use of many conventional materials. This talk will discuss how novel, industry-relevant active and inactive materials may significantly improve performance, reduce the cost of Li-ion batteries, overcome existing and expected supply chain challenges and pave the way for renewable energy technologies. For example, Sila's innovative drop-in-replacement nanocomposite silicon anode powder offers 6 times higher gravimetric capacity than graphite, permits both fast charging and over 20% more energy density today over state-of-the-art lithium-ion, and enables radical product innovation - all without compromising performance. This material has been shipping in millions of devices for three years and is scaling up for massive electric vehicle (EV) use by mid-decade. With Sila’s industrialized and scaled scientific innovation, wearables, portable electronics, and EV manufacturers can create breakthrough products today that will minimize our environmental impact tomorrow. This talk will provide multiple examples of flexible ceramic separators and other technologies that may become instrumental for the transition to a clean and energy-sustainable economy.
(Invited) Generation and Evolution of Materials in the Anode Solid Electrolyte Interphase (SEI) of Lithium Ion Batteries
Authors: Lucht Brett L.
Published: December 2024

A solid electrolyte interphase (SEI) is generated on the anode of lithium ion batteries during the first few charging cycles. The SEI provides a passivation layer on the anode surface which inhibits further electrolyte decomposition and affords the long calendar life required for many applications. However, despite thorough investigation of the SEI for the last few decades, the SEI remains poorly understood. Over the last several years additional investigations of the structure of the initial SEI formed on graphite electrodes along with changes which occur to the SEI upon additional cycling have been conducted. The investigations provide significant new insight into the structure and evolution of the anode SEI. The characterization of SEI components via ex-situ surface analysis of cycled electrodes has been complemented by investigations utilizing the one-electron reducing agent, lithium naphthalanide, to independently prepare and investigate the reduction products which constitute the SEI. The initial reduction products of ethylene carbonate (EC) are lithium ethylene dicarbonate (LEDC) and ethylene. However, the instability of LEDC generates an intricate mixture of compounds which greatly complicates the composition of the SEI. The reduction products and their subsequent decomposition products have been thoroughly investigated via a combination of NMR, XPS, IR-ATR, TGA, GCMS, and OEMS. Mechanisms for the generation of the complicated mixture of products are presented along with the differences in the SEI structure and function in the presence of electrolyte additives and the effect of crossover reactions related to electrolyte oxidation on the cathode will be discussed.
Improving Zn Anode Stability in Zn Ion Battery by Controlling Electrochemical Zn Growth with Organic Additives
Authors: Lim Hana , Oh Jiwoo , Kim Myung Jun
Published: December 2024

Lithium-ion batteries (LIBs) are indispensable for storing electrical energy in portable electronics and electric vehicles, thanks to their high energy density, light weight, and excellent reversibility and cyclability. Despite their successful integration into various electronic devices, their application in Energy Storage Systems (ESS) with substantial capacities is hindered by safety concerns. This is because increasing the energy storage capacity inevitably leads to a higher volume of flammable organic solvents. Therefore, significant research efforts have been directed towards aqueous batteries to develop safer alternatives, including representative Zn-ion batteries (ZIBs). Compared to conventional LIBs, ZIBs offer cost-effectiveness, high safety, and environmental friendliness. However, the practical application of aqueous Zn ion batteries (AZIBs) is hindered by several issues, particularly concerning Zn dendrite growth, corrosion, and the hydrogen evolution reaction (HER) on the Zn anode side, which critically reduce the cyclability of ZIBs. To mitigate these challenges, several solutions have been proposed, including the modification of the Zn ion hydration structure, the use of water-in-salt electrolytes, and the addition of additives to modulate the properties of the Zn surface. This presentation will introduce organic additives aimed at controlling the electrochemical Zn growth to enhance the cyclability of the Zn anode. These organic additives influence both the kinetics of the Zn deposition/dissolution processes and the properties of Zn deposits. We will discuss the effect of organic additives on Zn growth and the cyclability of Zn||Zn symmetric cells based on the molecular structure and adsorption behavior of the additives. By considering all results, we will determine which functional group is critical for controlling Zn growth and suggest the optimal organic additive for AZIBs.
(Invited) Epitaxial Electrodeposition of Metals for Interconnects Beyond Cu
Authors: Barmak Katayun
Published: December 2024

Cu has been the metal of choice for interconnects in silicon microprocessors since the mid-1990s. The continuous scaling of these interconnects in CMOS technology has not only produced a challenge with respect to power consumption and computing performance, but also with respect to reliability. As the critical dimensions of interconnects are scaled towards, and then below the electron mean free path (EMFP) of Cu (39 nm at room temperature), the resistivity is found to increase. This increase, termed the resistivity size-effect, results in resistance scaling beyond Ohm’s law dimensional scaling and leads to even larger power consumption and further limits improvements in computing performance. The resistivity rise with decreasing dimension is a result of electron scattering at grain boundaries and surfaces (vs. phonons). Given that electron scattering from grain boundaries is the major contributor to the resistivity rise in nanoscale interconnects, there has been increasing interest in producing and evaluating epitaxial, single-crystal conductors absent of grain boundaries. In this presentation, epitaxial electrodeposition of Co, Ru and Cu at room-temperature is reviewed. The choice of seed layer for electrodeposition, the role of symmetry of the seed layer and the epitaxial orientation relationship of the electrodeposited film and the seed layer are discussed. In addition, the impact of underpotential deposition on film nucleation and growth morphology is examined. The effects of electrolyte, ion concentration and pH are also addressed. Potential pathways for implementation of epitaxial electrodeposition in back-end-of-line processing will be discussed.
Electropolishing to Surface Finish of Hastelloy X Manufactured By Laser Powder Bed Fusion
Authors: Jo Hyunbin , Park Serim , Kim Jisu , Kim Hyunsik , Kim Donghyun , Lee Junghoon
Published: December 2024

Laser Powder Bed Fusion (LPBF) is a metal additive manufacturing technology (AM) that uses high power laser to melt powder layer by layer to create mechanical parts. LPBF several advantages, including short manufacturing time, freedom to design complex geometries and user-friendly customization. It is widely used in the manufacture of high-value parts in aerospace, automotive and biomedical industries. Due to the nature of the layer-by-layer process, partially melted powder is attached to the as-built part surface during LPBF, resulting in a significant increase in surface roughness. Furthermore, initial surface roughness of final part is different with locations since quantity of powder adhesion varies depending on building angle. Increase of surface roughness due to attached metal powder can cause out of dimensional tolerance that designed. Such dimensional inaccuracy can lead to failure or breakage of the mechanical parts. Therefore, surface post-treatment is essential to reduce surface roughness with minimizing dimensional change. Conventional mechanical and chemical treatments for surface finishing have limitations such as limited tooling range and surface damage due to the use of strong acids and long-time of processing. Electropolishing, based on electrochemical reactions, is suitable for improving the roughness of LPBF manufactured parts with complex geometries. Thickness reduction can be predicted by controlling the applied voltage and processing time. Also, surfaces in contact with the electrolyte is polished without geometric restrictions. Studies have been reported that analyze the change in surface roughness after electropolishing to improve the roughness of alloys manufactured with LPBF. However, for application to real parts, it is necessary to conduct basic research to optimize the electropolishing conditions to obtain satisfactory surface roughness with minimal thickness reduction by considering the effect of dimensional changes during electropolishing. In this study, we electropolished Hastelloy X fabricated by LPBF. Four types of electrolytes were selected for electropolishing. We measured surface roughness and thickness reduction with respect to applied voltage and processing time. With such results, optimized condition to reduce the surface roughness with minimal thickness changes are discussed. Then, these conditions were applied to LPBF specimen with different building angles. Surface roughness and weight changes were measured to compare polishing efficiency to each electrolyte.
Technical Economic Assessment of Carbon Dioxide Reduction to Ethylene Using an Integrated System Approach
Authors: Blazer Jr. Scott , Marchetti Barbara , Zhou Xiao-Dong , Wang Yudong
Published: December 2024

Carbon dioxide emissions are one of the most prevailing issues that has to be dealt with its main role in global climate change. In order to curtail this issue there are two forms of options to deal with CO2 emissions currently and that is CCU (Carbon Capture and Utilization) and CCS(Carbon Capture and Sequestration). CCS operations focus on mitigation through storing the CO2 underground in reservoirs, but this comes with inherent cost which makes it costly especially at an industrial scale. CCU operations although offer not only CO2 mitigation but also a marketable product which can then mitigate the cost of operating the conversion process. These CCU operations can work in a variety of ways, but we will focus on the electrochemical pathway which has shown promise as a low carbon emission and low cost pathway when coupled with green electricity. Through this pathway important petrochemicals can be made such as ethylene through use of an AEM. Currently this procedure has been to be prohibitively expensive due in part to a variety of factors from stability, efficiency, Membrane Electrode Assembly (MEA) design, and even the current price of electricity. In response to this research has been done in order to lower the cost of the MEA, increase its stability, and design a system that maximize production without requiring external ingredients. That is the purpose of the integrated system designed here it allows for the production of ethylene with only the use of water, CO2 from industrial sources, and Air in order to operate. From this the AEM can then produce ethylene at an industrial scale with only ingredients available on site. The next step is to figure out the required operational parameters for this proposed system in order to achieve current market prices to compete with current petrochemical methods. This is done through the modeling of the reactor system consisting of three reactors while optimizing the reactor design, the operational current density, the ASR (Area Specific Resistance), Faradaic Efficiency, and the price of electricity in order to find the absolute minimums in order to meet the current price (~$1200/metric ton). This is then used to complete an economic assessment in order to find the price of the produced product as a function of the parameters listed above. This will be key in figuring out the key areas of research in order to make this technology a practical industrial process instead of just persisting as a lab scale processes which is the main importance in completing Techno Economic Assessments (TEA).
Numerical Strategy to Optimize Barrel Electroplating : Discrete Element Method and Electrochemical Modeling
Authors: Fedi Baptiste , Marchais Kevin , Schoenleber Jonathan , Boucher Aurélien
Published: December 2024

Electroplating barrel processes are widely used, particularly for corrosion protection of small components like screws, or gold plating applied to micro components. Achieving uniform coating for all parts is essential, requiring the identification of optimal parameters such as applied current, barrel rotation speed, or charge rate. The main goal is to maximize anode exposure times and reduce the risks of shocks or part sticking, which can result in heterogenous thickness distribution and aesthetic defects. Traditionally, the definition of optimal process parameters is on empirical approaches, with inherent limitations. This conference aims to present how complementary simulation methods can enhance the identification of optimal processing conditions, focusing on two key aspects.

The first aspect involves modeling the electrochemical kinetics of the process to understand the current distribution due to the geometry part itself and predict thickness distribution or alloy composition in the case of an alloy.

The second aspect explores the use of granular simulation with the Discrete Element Method (DEM), leveraging the computational power of GPU technology. Although DEM is known for its high computational cost, advancements in GPU computing have made it feasible to distribute computations across multiple cores, enabling faster simulations with larger particle counts. This is particularly beneficial for simulating barrel finishing processes, where complex shapes such as screws or bolts need to be accurately represented. By simulating the movement and interactions of these particles within the barrel, it can be possible to explore mixing dynamics and optimize charge rates to improve treatment uniformity.

To validate the numerical models developed using these simulation methods, reduced-scale experimental tests are conducted. A 3D printed transparent drum is used to facilitate tracking of particle movement and interactions during the treatment process. This experimental validation provides crucial insights into the accuracy and reliability of the numerical models, ensuring that the simulated results align with experimental observations.

We will also discuss numerical aspects and challenge in order to link DEM mixing results with electrochemical modeling.

The results of this study enable reduction of quality defects with mixing and charge rates during electrolytic barrel treatment. The combination of electrochemical modeling and granular simulation allows for a better understanding of the link between process parameters and coating properties (thickness, composition...).

In conclusion, the integration of advanced simulation methods offer potential numerical help to increase efficiency and reduce non-quality of barrel electroplating processes.
Optimization of Oxygen Reduction Activity Via Transition Metal-Oxide Based Composite Electrodes in Acidic Medium
Authors: Park Hyeonji , Han Kyeongwon , Kim Hyungjin , Song Jeongeun , Ko Yuri , Jeon Yukwon
Published: December 2024

Global warming has occurred due to the usage of fossil fuels and greenhouse gas emissions. Therefore, a change in the energy paradigm can overcome the problems of global warming and air pollution and provide new energy to humanity continuously. Fuel cells are an eco-friendly system that utilizes the electricity generated during the process of producing water from hydrogen fuel. In general, 20 wt% Pt/C is used as the commercial catalyst for polymer electrolyte fuel cells (PEFCs), but challenges remain to solve such as cost and durability. In PEFCs, oxygen reduction reaction (ORR) is an important key as a rate-determining step (RDS) to react the overall reaction. Therefore, it is necessary to develop efficient materials (electrode, membrane, cell, etc.) for improving RDS. Recently, transition metal oxide (TMO) composite electrodes have gained interest in the electrochemical fields. Especially, nickel, cobalt, iron-based oxides are promising materials as non-noble metal electrocatalysts due to their high electric conductivity and various oxidation state.

The purpose in this research is to improve ORR performance by controlling active sites and electric conductivity using low amount of noble metals on transition metal doped oxides for the use at the electrode. We have developed composite oxide electrodes with noble-transition metal alloy using solid-state methods. Small amount of noble metal can be alloyed with transition metal to form appropriate oxygen binding energy for oxygen adsorption and desorption, which can improve ORR activity. To check the catalytic activity, cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were analyzed using a rotating disk electrode, and it was found that the noble metal-transition metal alloy oxide composite electrode was effective in enhancing the ORR kinetics. Additionally, the strong interaction between the alloy nanoparticles and oxide support surface enhances chemical stability when used in harsh environments such as acidic media. Furthermore, based on the previous ORR data, we fabricated membrane electrode assembly (MEA) using developed catalysts and confirmed their potential for PEFCs applications.
Eco-Friendly and Cost-Effective Electrochemical Synthesis of High-Purity Lithium Hydroxide Monohydrate
Authors: Kim Hyun-Jong , LIM Hana , Park Sung Cheol , Oh SeKwon , Lee Ho-Nyun , Son Seong Ho
Published: December 2024

In recent years, lithium compounds have been seen as energy materials of great commercial value as the global energy industry develops. The use of lithium-ion batteries (LIBs) in electric vehicles (EVs) is driving the global demand for lithium resources. While many studies have shown that EVs have environmental benefits over internal combustion engine vehicles, the impact of battery production is still uncertain. We need to dramatically reduce greenhouse gas (GHG) emission from the LIBs manufacturing process and raw battery material production.

Typically, lithium compounds have been produced from hard rock minerals or continental brines. The former consumes large amounts of sulfuric acid and is more energy-intensive and expensive than the latter. When extracting lithium from conventional brine, we first produce technical-grade lithium carbonate (Li2CO3), which can then react with calcium hydroxide to produce battery-grade lithium hydroxide (LiOH·H2O). In the LCA study, the GHG emissions of producing Li2CO3 from brine were found to be between 2.7 and 3.1 tonne CO2e/tonne Li2CO3, while the GHG emissions of producing LiOH were more than twice as high, between 6.9 and 7.3 tonne CO2e/tonne LiOH·H2O. Therefore, there is a need to further reduce greenhouse gas emissions from the LiOH manufacturing process.

In this study, we developed an eco-friendly and cost-effective process for producing high purity LiOH·H2O from Li2CO3 solution using a membrane-based water electrolysis reaction. This process significantly reduces the energy consumption of the LiOH manufacturing process. We investigated the impact of various operational variables on process efficiency, including solution concentration, current-voltage, and flow rate. The mechanism of LiOH synthesis, the role of membrane, and greenhouse gas emissions will be discussed.
(Invited) Admittance Analysis to Evaluate Carbon Steel Corrosion Covered with Rust Layer in Electrochemical Impedance Spectroscopy
Authors: Hoshi Yoshinao , Akimoto Yusaku
Published: December 2024

An electrochemical impedance spectroscopy (EIS) has been used for the corrosion evaluations of steel materials because it allows the time constants observed in the impedance spectrum to be discriminated1. The impedance response of steels covered with rust layer was reported to investigate the conditions of rust layer. Kihira et al.2 applied EIS to investigate the properties of rust film formed on the weathering steel. They proposed the diagnosis method for the rust stability test based on the ion transmission resistance and the thickness of rust layer. Nishikata et al.3 employed EIS for the monitoring of corrosion rate of steels in atmospheric corrosion. Nishimura et al.4 examined the formation of rust film on the carbon steel under wet and dry corrosion tests by EIS. Itagaki et al.5 applied EIS to investigate the electrochemical properties of rust film membrane of low-alloy steels. Katayama et al. 6 reported the effect of rainfall on atmospheric corrosion of carbon steel by impedance monitoring. These results indicated that the corrosion rate of steels was strongly related to the quality of rust film formed on steel. The determination method of the corrosion rate of steel materials covered with rust layer is required for the safety management in the steel structures.

In the present study, we investigated the impedance characteristics of carbon steel covered with rust layer and evaluated their corrosion rate from the admittance spectra. The atmospheric exposure test was conducted to form the rust layer on the carbon steel for several years. We will introduce the impedance spectra of carbon steels covered with rust layer and the relationship between the impedance of samples and the exposure time. We will discuss the determination method of polarization resistance from the admittance spectra of samples to estimate the corrosion rate of samples.

References

M. E. Orazem, B. Tribollet, Electrochemical Impedance Spectroscopy, Wiley (2008).

H. Kihira, S. Ito and T. Murata, Corrosion, 45, 347 (1989).

A. Nishikata, Y. Yamashita, H. Katayama, T. Tsuru, A. Usami, K. Tanabe and H. Mabuchi, Corros. Sci., 37, 2059 (1995).

T. Nishimura, H. Katayama, K. Noda, T. Kodama, Zairyo-to-Kankyo, 49, 45 (2000).

M. Itagaki, R. Nozue, K. Watanabe, H. Katayama, K. Noda, Corros. Sci., 46, 1301 (2004).

H. Katayama, K. Kiyoizumi, I. Shitanda, M. Itagaki, Y. Tsutsumi and Y. Murase, Tetsu-to-Hagané, 107, 1004 (2021).
Designing Sustainable Electrocatalysts for Electrolysis By Structural Modifications of Multi-Metal Oxides
Authors: Ramezanipour Farshid , Karki Surendra B.
Published: December 2024

Innovations in materials are essential to advances in electrolysis reactions. In particular, the development of sustainable electrocatalysts based on earth-abundant elements can pave the way for significant progress in this field. We have designed several series of highly active electrocatalysts based on multi-metal oxides, comprising earth-abundant metals, specifically materials with perovskite-type structures. Importantly, we have shown that targeted modification of structural properties can be used as a tool for tuning the electrocatalytic performance. To showcase the systematic improvement in the activity of these electrocatalysts, we have demonstrated their activity toward both anodic and cathodic half-reactions of water electrolysis. These studies have shown that a gradual increase in structural order can lead to a systematic enhancement of electrocatalytic properties, as evident from low overpotentials, enhanced kinetics of the electrolysis reaction, and high stability of electrocatalysts. In addition, we have investigated the role of oxygen-vacancies in the new multi-metal oxide electrocatalysts, indicating that the concentration and arrangement of vacancies has a major impact on electrocatalytic properties. Importantly, these catalysts are highly stable and retain their activity and structural integrity over many hours of electrochemical operation, as shown by chronopotentiometry, as well as X-ray diffraction and X-ray photoelectron spectroscopy before and after the electrolysis process. The ability to tune the electrocatalytic activity by controlling the structural properties of earth-abundant catalysts can lead to significant advances in the efficiency and sustainability of electrolysis reactions.
Hydrophilic Separator Stables CO2-to-C2H4 Conversion at Low Cell Voltage with Non-Noble Metal Anode
Authors: Pham Huy , Dinh Cao Thang
Published: December 2024

Electrochemical carbon dioxide (CO2) reduction (ECR) is a promising approach for enabling the conversion of greenhouse gas CO2 into valuable products with electricity from renewable sources to achieve net-zero CO2 emission. ECR simultaneously reduces carbon emissions and dependence on fossil-based fuels and chemicals. Membrane electrode assemblies (MEAs), which often comprise an anion exchange membrane (AEM) and a precious iridium oxide (IrOx)-based anode, have been extensively studied in the last few years. However, challenges such as salt precipitation on cathodic gas diffusion electrodes (GDEs), high cell voltage and the need to use noble metal anodes have hindered ECR's practical applications. Herein, we introduce a new design of MEA cells using a low-cost hydrophilic film separator and a Nickel (Ni) foam instead of AEM and IrOx, respectively. Hydrophilic separator material with high water permeability lowers the full-cell voltage and eliminates the salt accumulation on the GDE in both alkaline and neutral-pH conditions. Using copper-sputtered polytetrafluoroethylene (Cu/PTFE) as cathodes, we demonstrated a stable conversion of CO2 to ethylene (C2H4) at current densities over 100 mA/cm2. In neutral-pH anolyte, the average C2H4 FE was sustained at around 50% for more than 200 hours with a cell voltage of 3.1 V at the current density of 110 mA/cm2. Under alkaline conditions, this system showed 500 hours of stability of CO2-to-C2H4 conversion: the C2H4 FE was maintained above 60% with the cell voltage of only 2.2 V at 110 mA/cm2 current density. Our research provides a solution for achieving stable ECR operation at a relatively high current density using Earth-abundant materials. This work opens opportunities for energy-efficient and stable CO2 conversion without needing expensive and rare elements, which are crucial for practical applications.
Impact of Cross-Linker Length on the Characteristics of Anion Exchange Membrane Water Electrolyzer
Authors: Akter Mahamuda , Park Yeri , Park Jong-Hyeok , Park Jin Soo
Published: December 2024

Water electrolysis, utilizing renewable energy to split water into oxygen and hydrogen, stands out as a promising avenue for generating and storing clean energy from sustainable sources. This study focuses on creating pore-filling anion exchange membranes (PFAEMs) employing an electrolyte monomer incorporating a quaternary ammonium group. Various cross-linker groups of different chain lengths were introduced, while porous polyethylene substrates were treated with surfactants to transition from hydrophobic to hydrophilic. Evaluation of the anion exchange membrane conductivity was conducted in both in-plane and through-plane configurations at room temperature and 60 ℃. Additionally, comprehensive characterizations of the anion exchange membranes encompassing water uptake, swelling ratio, mechanical strength, contact angle, FTIR, SAXs, WAXs, DSC, and TGA analyses were carried out. Consequently, the PFAEM demonstrated notably high ion conductivity with minimal areal swelling ratio and exceptional chemical stability in a KOH solution for 500 hours. As a crucial component of AEMWE, the catalyst layer was prepared using catalyst inks, namely XB-7 ionomer-based and Nafion ionomer-based inks for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) catalyst layers, to assess impedance and I-V polarization curves.

Acknowledgment

This research was supported in part by the New and Renewable Energy of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20213030040520) and by 2021 Green Convergence Professional Manpower Training Program of the Korea Environmental Industry and Technology Institute funded by the Ministry of Environment.
Investigating Star-Shaped Crosslinkers in Pore-Filling Anion Exchange Membranes
Authors: Lee Minyoung , Jeong Dahye , Park Yeri , Akter Mahamuda , Park Jong-Hyeok , Park Jin Soo
Published: December 2024

Anion exchange membranes utilized in anion-conducting electrochemical cells offer distinct advantages over proton exchange membranes. However, the efficiency and durability of these electrochemical cells, in comparison to proton exchange membrane-based ones, heavily hinge on the electrochemical and chemical properties of the anion exchange membranes. Therefore, the development of ionomers with high anion-conducting capabilities is pivotal for achieving superior conversion rates. This study concentrates on fabricating anion exchange membranes with enhanced hydroxide ion conductivity and chemical stability by augmenting the number of crosslinking sites. The membranes were synthesized employing a pore-filling technique on a porous polyethylene substrate. Subsequently, they underwent characterization based on ion conductivity, areal resistance, contact angle, ion exchange capacity, water uptake, swelling ratio, and mechanical strength. Furthermore, their chemical stability was evaluated.

Acknowledgment

This research was supported in part by the Korea Institute of Science and Technology (No. 2E33281) and by 2021 Green Convergence Professional Manpower Training Program of the Korea Environmental Industry and Technology Institute funded by the Ministry of Environment.
Enhancing Properties of Anion Exchange Membranes for Water Electrolysis
Authors: Park Yeri , Lee Minyoung , Jeong Dahye , Akter Mahamuda , Park Jong-Hyeok , Park Jin Soo
Published: December 2024

Water electrolysis, a pivotal technology for producing hydrogen from water decomposition, stands as a crucial approach for generating green hydrogen devoid of carbon dioxide or other pollutants. Among various water electrolysis techniques, Anion Exchange Membrane Water Electrolysis (AEMWE) relies on an anion exchange membrane (AEM). However, AEMs face challenges such as low ionic conductivity and physical stability. To overcome these limitations, an AEM was developed by saturating a porous PE substrate with an electrolyte solution containing an anion-conducting monomer, a cross-linker, and a photo-initiator, followed by UV irradiation for polymerization. The quantity of electrolyte significantly influences the membrane's ionic conductivity, while the number of vinyl groups in the crosslinking agent directly impacts its binding capacity with the electrolyte. Thus, this study employed the same electrolyte while varying the number of vinyl groups in the crosslinker as a variable. The ionic conductivity, ion exchange capacity, contact angle, water uptake, swelling ratio, and transport number of each membrane with two different compositions were measured. Subsequently, the performance and durability in AEMWE were assessed to determine the most suitable composition for this technology.

Acknowledgment

This research was supported in part by the New and Renewable Energy of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20213030040520) and by 2021 Green Convergence Professional Manpower Training Program of the Korea Environmental Industry and Technology Institute funded by the Ministry of Environment.