bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Approach to Synthesis of Porous Si Anode for Li-Ion Batteries Via Organic-Solvent Assisted Etching
Authors: Jin Dahee , Kim Ju-Myung , Yi Ran , Zhang Ji-Guang 
Published: December 2024

Silicon (Si) has been regarded as a promising anode for Li-ion batteries due to its high theoretical capacity (4200 mAh/g) compared to graphite anode (372 mAh/g). However, it undergoes significant volume changes (~ 300%) during lithiation and delithiation, leading to particle pulverization and continuous electrolyte decomposition on Si surface, which hinders its practical application. The porous silicon obtained by wet etching method using hydrogen fluoride (HF) can accommodate the volume changes and improve the overall performance of silicon anodes. However, HF etching is highly corrosive, leading to the generation of excess heat and bubbling, lower yields, and difficult to scale-up. Furthermore, the water in etchant oxidizes the newly exposed Si, generating more SiOx, which also cause over-etching of Si and worsen electrochemical performance.
Herein, we report an organic-solvent assistant etching process for Si anode. In this process, selected organic solvent were mixed with the HF etchant. When micron sized Si/SiOx powder was added to the solution, the organic solvent in the mixed solution will preferentially be absorbed on the surface of Si/SiOx powder and form a shield which can enable controlled etching of silicon oxide (SiOx) and prevent direct contact between water and newly etched Si surface. This method leads to controllable etching of Si and avoids bubbling/overheating, results in a higher Si yield. The maximum temperature during the etching process is less than ~30°C. The various process parameters, including etchant composition, stirring speed, and time have been optimized to maximize the yield and electrochemical performance of the Si anode. A Si-based anode with organic-solvent assisted etching process has demonstrated improved cycling performance in a Si||Li(Ni0.6Co0.2Mn0.2)O2 (NMC622) full cell. It also leads to low swelling in both particle and electrode levels required for the next generation of high-energy LIBs. Similar organic-solvent assisted etching process can also be used in safe-etching of a broad range of materials.
(Invited) Unveiling Olivine Cathodes for High-Energy-Density Lithium-Ion Batteries: Engineering from the Atomic Level to the Electrode Scale
Authors: Hwang Wonchan , Kim Jaehwan , Park Jungjin 
Published: December 2024

The pursuit of high energy density has spurred significant interest in layered cathodes such as lithium nickel cobalt manganese oxide (NCM) or lithium nickel cobalt aluminium oxide (NCA), renowned for their excellent energy storage capabilities. However, Ni- and Co-based layered cathodes face significant thermal instability, resulting in thermal runaway in the case of short circuits, high temperature exposure, and so forth. Recently, lithium iron phosphate (LFP) has emerged as an alternative due to its enhanced structural and thermal stability, despite the absence of expensive metals such as Co and Ni. However, LFP encounters significant challenges, notably its inherently low redox potential and capacity (energy density), which undermines its competitiveness in electric device applications such as electric vehicles (EVs) and energy storage systems (ESSs). Boosting energy density can now be accomplished through the engineering of active materials and electrode configurations. It has been noticed that new strategies, such as increasing the working voltage through fine-tuning of active materials and/or using thick electrodes to augment the ratio of active materials per unit area, can make a breakthrough for elevating energy density within the existing battery volume dimension. However, transitioning to thick electrodes poses challenges related to electron and ionic conductivity, as well as the structural stability of the electrode.
Herein, I will present integrating strategies for enhancing the high-energy density of olivine cathodes. This includes atomic modifications such as substitutional doping with manganese to achieve a high redox voltage, and particle/electrode engineering techniques like optimizing tap and press density. In addition, I will briefly show key technologies involving conducting agents and binders used to construct thick electrodes for olivine cathodes through eco-friendly processes. A comprehensive understanding will provide insights into how to conduct research on olivine-based cathodes and contribute to the impacts of secondary batteries in both academia and industry.
Engineering Surface Oxidation States in Co-Free, High-Ni Core/Shell Cathode Precursors: Impact on Physicochemical Properties and Lithium-Ion Battery Performance
Authors: Shim Jinha , Bang Jin Ho 
Published: December 2024

This work explores the core/shell structure (Ni-rich core, Mn-rich shell) as a promising approach to improve interfacial stability in high-nickel cathode materials. This structure reduces surface reactivity without sacrificing capacity. Traditionally, co-precipitation is used to synthesize these materials. Here, we investigate the impact of manganese (Mn) oxidation state during drying on the physicochemical and electrochemical properties. We focus on how this state depends on the sintering temperature. Our findings reveal that the presence of oxidized Mn in the precursor lattice can mitigate further transition metal (TM) oxidation at lower sintering temperatures. This also induces oxygen vacancies on the particle surface. However, this leads to poor electrochemical performance due to two factors: the magnetic frustration effect and the “cross-talk effect” caused by TM dissolution and deposition on the graphite anode. In contrast, higher sintering temperatures promote complete Mn oxidation in the precursors. This kinetically suppresses Mn diffusion, preserving the core/shell structure and minimizing surface defects. This approach also demonstrably suppresses the cross-talk effect.
This study highlights the profound influence of surface Mn oxidation state in core/shell high-nickel cathode material precursors. The oxidation state impacts surface properties, intrinsic characteristics, and reaction kinetics during heat treatment. Consequently, this research emphasizes the critical role of precursor surface chemistry and offers valuable insights for developing strategies to enhance cathode material interface stability.
Keywords: Ni-rich cathode / Core-Shell structure / Precursor surface oxidation / Transition metal dissolution / Magnetic Frustration
Improving the Electrochemical Performance of Sb-Modified Ni-rich NCM Cathode Materials for Lithium-Ion Batteries
Authors: Kim Hyun-Soo , Sim Seong-Joo , Jin Bong-Soo 
Published: December 2024

Ni-rich layered LiNixCoyMn(1-x-y)O2 (Ni-rich NCM) (x≥0.8) cathode materials have recently attracted much attention for high energy density lithium ion batteries(LIBs) owing to their high reversible capacity (>200 mAh g-1), relatively high operating voltage (3.6 V vs Li/Li+) and low cost. However, the cycle life and safety become more serious with increasing Ni contents. It can be caused by various problems such as phase transitions during charge-discharge, surface side reaction and the reaction of Ni4+ and oxygen release resulting in destroy the crystal structure.
To overcome these problems, various strategies have been researched such as doping, coating, core-shell, concentration-gradient structure and single-crystal. Among these methods, doping method is a beneficial way to enhance the structural stability of the materials to prevent deterioration of the crystal structure. The dopants improve the Li+ transport and suppress the cation mixing by preventing the migration of Ni2+ to the Li layer and inhibit oxygen release by strengthening TM-O bond.
Various elements (such as Al, Ti, Zr, Mg, Fe, F, etc.) has been modified by substituting the transition metal sites. Antimony can be an attractive candidate as a dopant material because of similar ionic radius and bond strength compared with Ni ions. It indicates that Sb can be substituted for Ni sites.
In this work, Sb-modified Li[Ni0.91Co0.06Mn0.03]O2 (denoted as Sb-NCM) was synthesized by solid-state method to improve the structure stability resulting in cyclic stability during charge-discharge. The Sb-NCM exhibited improved cycling retention and rate capability compared to the pristine NCM. The effect of Sb-NCM on the structural characteristic, morphology and electrochemical properties was investigated. The results indicate that the doped Sb performs an important role for enhanced electrochemical performance.
Dry Battery Electrode Manufacturing for Graphite Anodes: Implications on Electrochemical Properties and Cell Manufacturing
Authors: Huber Korbinian , Scheidle Christian , Wichmann Moritz 
Published: December 2024

Dry Coating of Lithium-Ion Battery electrodes is widely considered as a gamechanger technology to reduce the cost, energy demand and footprint of battery Gigafactories. By now, industrialization has primarily focused on the negative electrode using graphite and as active material, notably by Tesla.[1] Yet, the full scope of the implications and advancements brought by a dry coating process for graphite anodes on cell properties and downstream manufacturing processes remains unexplored.
Current dry coating technologies necessitate using a fibrillizable PTFE binder. While PTFE is very stable towards oxidation when used as a binder in Lithium-Ion Battery cathodes, a reduction of the fluoropolymer in battery anodes at low potentials < 1 V vs. Li/Li+ is reported.[2] We discuss the decomposition reaction of PTFE in graphite anodes during the formation process and the resulting irreversible consumption of Li. Our interest focuses on the decomposition mechanism of PTFE, examining the nature of the decomposition products through XPS analysis. We assess whether the reduction is quantitative and if the decomposition persists beyond the initial lithiation of graphite into subsequent cycles. We contemplate strategies to reduce the irreversible capacity loss and show that reducing the PTFE binder content while maintaining the mechanical integrity of the electrode is a promising approach to enhance the coulombic efficiency during formation.
Beyond the electrochemical implications, differences in microstructural properties and the processing conditions during electrode manufacturing between a wet and a dry coated graphite anode offer opportunities for adaptions in the downstream process of Lithium-Ion Battery manufacturing. We demonstrate that the electrolyte filling time of cylindrical cells in a 4695-format is strongly influenced by the coating method and the arising differences in pore size distribution and electrode tortuosity. Also, we show that a vacuum drying of the anodes might not be needed if the electrode is dry coated instead of using water as the solvent for a slurry-based coating.
[1] https://www.youtube.com/watch?v=8WPPBhqeekw
[2] Y. Suh, J. K. Koo, H. Im, Y.-J. Kim, Chemical Engineering Journal
2023, 476, 146299.
Developments in Nanostructuring for Enhanced Solar Water Splitting: Investigating Morphology Effects on Photoelectrode Performance
Authors: Jeong Hye Won , Park Hyunwoong , Janaky Csaba 
Published: December 2024

The importance of developing efficient technologies for converting solar energy into chemical energy has drawn attention, particularly through solar water splitting using photocatalytic materials. It highlighted the complexity of factors affecting the performance of photoelectrodes in this process, including bandgap energy, carrier density, morphology, defects, and surface properties. Among them, nanostructuring in photoelectrodes offers the potential for improved efficiency due to their large specific surface area and accelerated charge transfer. Despite more than a decade of dedicated research into the impact of nanoscale morphology on the photoelectrochemical (PEC) performance of semiconductor materials, the literature still contains notable disparities and debates. This study aimed to provide clarifying comparisons of the effect of the shape and dimensions of particles in a photoelectrode. It explores various synthetic methods to control morphology, using titanium dioxide (TiO2) as a model material for testing. Surface analysis via XRD, Raman spectroscopy, XPS, etc. demonstrated that the chemical nature of the nanostructures is practically identical, and only morphology offers a difference in PEC performance. A comparison of morphology effects of PEC activities in sulfite and water oxidation gave insight into the dependence on particle morphology.
This research was supported by the National Research Foundation of Korea (NRF-2022R1I1A1A01053034 and RS-2023-00254645).
(Invited) Semi-Monolithic Integration of Dissimilar Material Classes into Efficient Water Splitting Devices
Authors: Gaillard Nicolas 
Published: December 2024

Materials compatibility is an important issue in multi-junction (MJ) device integration, which has stifled innovation in photoelectrochemistry (PEC) for decades. Essentially, the deposition process of each layer must not damage the previously deposited layers and interfaces in any way. For example, with state-of-the-art chalcopyrite technology, it is impossible to fabricate high-efficiency monolithic MJ devices by directly depositing a wide-bandgap cell on top of a narrow-bandgap CIGSe device, because the required temperatures for high quality films (Tprocess = 500oC) destroy the underlying CdS/CIGSe heterojunction. As a result, the power conversion efficiency (PCE) of monolithically integrated chalcopyrite solid-state tandems has not exceeded 4.3%. The limitation of monolithic integration goes far beyond the chalcopyrite class, as it inherently restricts materials selection to a sub-set of compatible systems while limiting the adoption of emerging promising candidates. An integration scheme in which material classes can be combined, regardless of their nature, while preserving their intrinsic performance could revolutionize manufacturing technologies that rely on material stacking and lead to combinations of different material classes previously not considered for PEC water splitting.
In this communication, we report on our recent efforts to develop a novel and scalable integration scheme to combine promising material classes, regardless of their thermal, physical, or chemical compatibility, into low-cost MJ PEC devices. Such a scheme, pioneered by HNEI and known as semi-monolithic integration, relies on 2D layer-assisted exfoliation and room temperature bonding techniques to transfer fully processed cells from their original substrates onto new handles. With this integration scheme, sub-cells of different bandgaps can be successively transferred onto a new host substrate to create a fully functional MJ structure. By design, semi-monolithic integration allows to circumvent all material incompatibilities, enabling new MJ architectures otherwise not possible with conventional monolithic integration.
(Invited) In Situ X-Ray Spectroscopy for Clean Energy: Insights into Reactive Intermediates
Authors: Pushkar Yulia 
Published: December 2024

Transition from fossil fuels requires increased use of solar energy and electrification of chemical industries. To store the excess green electricity from wind and solar generation, batteries and electrolyzers are needed. Green hydrogen can also be produced via artificial photosynthesis where water is split by energy input of sunlight. Hydrogen can be later used in fuel cells. All these applications require new, electrochemically active materials and catalysts. To boost applications in energy storage and conversion, materials with exotic redox states are often desirable. X-ray spectroscopy is an excellent tool for in situ analysis of such energy storage and conversion systems in situ under working conditions.
In presentation I will discuss characterization of exotic Mn1+ proposed to play a role in the function of sodium-based Prussian blue analogues (PBA) batteries, a highly sought-out technology for industrial energy storage. Here, we report the detailed electronic structure characterization of uncharged and charged sodium-based manganese hexacyanomanganate anodes via Mn K-edge X-ray absorption spectroscopy (XAS), Kβ nonresonant X-ray emission (XES), and resonant inelastic X-ray scattering (RIXS).
For electrochemical and photoelectrochemical water oxidation high oxidation states of IrV, RuV and FeV are needed to activate water and form O-O bond. These species were generated in situ under catalytic conditions and characterized by hard X-ray XAS. Active catalyst such as [Ru(H3-Tpy)(Qc)Cl] was assembled into MIL-142 metal organic framework to produce device prototype for artificial photosynthesis. It delivered high photocurrent in the photo-electrocatalytic water splitting at pH=1 and unassisted photocatalytic H2 evolution under visible light with Pt as the co-catalyst. The high activity of this new system enables hydrogen gas capture from an easy-to-manufacture, scaled-up prototype utilizing MOF deposited on FTO glass as a photoanode.
In Situ Probing Electrified Interfacial Molecular Anion Structures at Atomically Flat Gold Electrode
Authors: Mohseni Armaki Seyedamirhossein , Ahmadi Majid , Mol Arjan , Taheri Peyman 
Published: December 2024

Electrochemical interfaces—buried between electrodes and electrolytes—are notoriously difficult to probe, and enormous efforts, both experimentally and computationally, have been devoted to this endeavour. Although some progress has been made, the microscopic structures of electrochemical interfaces remain elusive and a great challenge in physical sciences.[1]

Answering this question is not only of fundamental interest but also of technological importance in a broad range of research areas in science and technology, to name a few, energy storage in supercapacitors, electrocatalysis of relevance to energy and environmental applications, self-assembly of colloidal particles, ion transport across biological membranes, and mineralization processes in earth science. Despite its significance, molecular-level understanding of Electrified Double Layer (EDL) is largely missing, owing to its complexity and small scale making it difficult to probe. Because of the advent of advanced experimental (e.g., synchrotron-based techniques and Raman spectroscopy) and computational methods [e.g., ab intio molecular dynamics (AIMD)], it is not until recently that the microscopic structures of EDL have started to be unveiled. [2,3]

In this study, we employ in-situ Shell Isolated Nanoparticle Enhance Raman spectroscopy (SHINERS) to investigate the structures of electric double layers at electrochemical interfaces. Specifically, we focus on understanding the arrangement and surface interaction of anions on electrified gold single-crystal electrode surfaces under varying bias potentials. We discuss how these ions orient themselves and interact with the electrode surface, and how these interactions influence local permittivity and ion-surface attraction, ultimately impacting the structure and behavior of the EDL and electrochemical processes.
[1] Le et al., Sci. Adv. 2020; 6
[2] Li et al.,Nature Materials, 2020; 18
[3] Wang et al., ,Nature, 2021;600
High Local CO Concentration Generated By Delicate Control of Au Nanoparticles from Au-Cu2o Tandem Catalyst Boosts Electrochemical CO2 Conversion into Value-Added C2+ Products
Authors: Wang Suneon , Oh Jihun 
Published: December 2024

The electrochemical reduction of carbon dioxide (CO2RR) holds promise for carbon capture and utilization (CCU), aiming to produce carbon-neutral fuels and valuable chemical intermediates. Copper (Cu) is recognized as the primary metallic catalyst facilitating C-C coupling reactions to yield multi-carbon compounds.
Many researchers have been developing Cu catalysts, such as oxide-derived Cu (OD-Cu), and tandem catalysts to increase the kinetics of C-C coupling. The investigation of tandem catalysts, especially those derived from oxides of copper (OD-Cu), has been conducted to improve selectivity towards multi-carbon compounds like ethylene and ethanol.
Nonetheless, the effect of the loading structure of the CO-producing catalyst within the tandem catalyst on CO2RR performance has not been fully explored. In this study, we synthesized Au nanoparticles with different sizes and loading densities on Cu2O through the galvanic replacement reaction and examined their influence on CO2RR properties.
Tandem catalysts containing smaller Au nanoparticles demonstrated heightened activity in the electrochemical CO2RR, leading to an anodic shift in potential. Additionally, tandem catalysts with smaller Au nanoparticles exhibited improved Faradaic efficiencies (FEs) and partial current densities (PCDs) for C2+ compounds. The tandem catalysts with larger Au nanoparticles also showed better CO2RR performance than the original OD-Cu; however, it was found that CO2RR results of the tandem catalysts with a small size of Au nanoparticles were superior to those with large size of Au nanoparticles.
Interestingly, the FEs and PCDs of n-propanol, a C3 product, increased as the coverage of Au nanoparticles increased. This behavior contrasts with the case of ethylene and ethanol. The maximum Faradaic efficiencies (FEs) of these C2 products from tandem catalysts did not exceed those from OD-Cu.
The effectiveness of the tandem effect relies on the localized concentration of CO, heightened by the CO-producing catalyst situated on the confined OD-Cu surface. The improvement of the selectivity towards the C3 product may come from the interface between the Au nanoparticles and OD-Cu, where the C1-C2 coupling reaction is favorable.
We utilized a Nickel single-atom catalyst (Ni-SAC) to create a high local concentration of CO within the catalyst layer. Despite this, we did not observe any tandem effect. This suggests that the proximity between CO active sites and C2+ active sites plays a crucial role in triggering the CO spillover effect. Our results shed light on a strategy for constructing efficient tandem structures in CO2RR.