bluuebunny/crossref_metadata_2025 huggingface dataset:
Utilization of Waste Melamine Formaldehyde Resin As an Enhancer in g-C3N4 Photocatalyst and Photoelectrochemical Applications
Authors: Kang Myung Jong
Published: December 2024

Melamine Formaldehyde resin (MF), one of the thermoset plastic frequently used for cook wares, adhesive, insulator and coatings because of its thermostability, mechanical strength, electronic insulation and ease of manufacture. However, because of above properties of MF resin, it is hard to recycle after used, which causes serious environmental contamination. To overcome this drawback of after-used MF resin, we introduce a method on utilizing after-used MF resin for an enhancer of g-C3N4 photocatalyst, inspired by pristine methodologies to synthesize g-C3N4 photocatalyst.

The pristine g-C3N4 photocatalyst is synthesized by heat polymerization of urea, dicyandiamide(DCDA) and melamine and it utilize widely as a photocatalytst because it has a suitable band gap for visible light absorption, high chemical stability, and high thermal stability. However, high electron-hole recombination rate of g-C3N4 photocatalyst regarded as the reason decreases photocatalytic activity of g-C3N4 photocatalyst.

Therefore, in this study, after-used MF resin as an enhancer during g-C3N4 photocatalyst syntehsis process, to improve photocatalytic activity of g-C3N4. The pure g-C3N4 photocatalyst was synthesized by heat polyemrization of urea and MF resin added g-C3N4 photocatalyst (MR X, X is the amount of added MF resin) was synthesized by adding certain amount of MF resin during g-C3N4 synthesis process. Comparing photocatalytic activity between pure g-C3N4 and MR photocatalyst was carried out by Methyl Orange (MO) degradation under 1 sun illumination. Finally, pure g-C3N4 and MR photocatalyst was fabricated as an photoelectrode and their oxygen evolution reaction(OER) activity was analyzed by electrochemical analysis techniques.
(Invited) Operando visualization of Li Metal Anodes: From Liquid to Solid Electrolytes
Authors: Dasgupta Neil P.
Published: December 2024

In recent years, there has been an explosion of research into Li metal anodes for high-energy-density batteries. However, despite tremendous progress in the field, the reversible plating and stripping of Li has been hindered by the complex interplay between electrode morphology, surface chemistry, and mechanics. This has led to many empirical observations of improved performance, but our ability to rationally design solutions to solve the challenges of reversibility remain limited by our fundamental understanding of the complex electrodeposition and dissolution processes involved [1]. Moreover, the emergence of solid-state batteries has created new opportunities to enable Li metal anodes, but the unique chemo-mechanical coupling at solid-solid interfaces also brings new challenges for Li metal anodes.

To address these challenges, in situ/operando analyses are of paramount importance to the community. However, given the dynamic nature of Li plating and stripping, challenges arise with respect to tradeoffs in spatial and temporal resolution. To address these challenges, we have recently integrated our optical visualization cells with a digital microscope capable of focus variation microscopy. This enables 3-D visualization of the electrode morphology with high temporal resolution, allowing for video capture of Li plating and stripping [2].

In this talk, I will discuss the application of operando 3-D microscopy for visualization of Li metal anodes using both liquid and solid-state electrolytes. In the case of Li metal anodes, we observe significant anisotropy in the geometric shape of individual pits during stripping [2]. The nucleation density and anisotropy are shown to be strongly influenced by the surface microstructure and underlying crystallographic texture of the Li metal surface. As a results, pits can exhibit strong faceting, which influences the nature of nucleation at pit edges in subsequent cycles [3].

The dynamic morphological evolution of Li metal anodes for solid-state batteries will also be demonstrated using 3-D microscopy. This enables visualization of nucleation and growth in anode-free architectures, where the Li metal anode is formed in situ at a solid electrolyte/current collector interface [4]. The similarities and differences between liquid and solid systems will be discussed in the context of electro-chemo-mechanical coupling, pointing towards new opportunities to enable reversible plating and stripping.

References

[1] A. J. Sanchez, N. P. Dasgupta, J. Am. Chem. Soc.
146, 4282 (2024).

[2] A. J. Sanchez, E. Kazyak, Y. Chen, J. Lasso, N. P. Dasgupta, J. Mater Chem. A.
9, 21013 (2021).

[3] A. J. Sanchez, E. Kazyak, Y. Chen, K.-H. Chen, E. R. Pattison, N. P. Dasgupta,
ACS Energy Lett.
5, 994 (2020).

[4] E. Kazyak, E., M. Wang, K. Lee, K, S. Yadavalli, A. J. Sanchez, M. D. Thouless, J. Sakamoto, N. P. Dasgupta, Matter
5, 3912 (2022).
Computational Design of Electrocatalytic Devices via Continuum Models
Authors: Andreussi Oliviero
Published: December 2024

Continuum models of solvation have played a crucial role in the computational characterization of molecules solvated in neutral or electrolyte solutions. Recent advances in the field have extended the capabilities of this class of methods towards the characterization of solvated interfaces, possibly in the presence of an applied electrochemical potential. When combined with computational thermodynamic approaches, continuum models allow to improve the description of electrochemical environments for chemical processes at heterogenous interfaces. This allows a high-throughput characterization of the stability and catalytic activity of materials for electrochemistry and electrocatalysis applications. Moreover, leveraging experimental databases of solvation free energies for different solvents (both neutral organic solvents and room-temperature ionic liquids), these continuum models have shown to be able to describe solvation effects within chemical accuracy and with minimal and transferable empirical parameters. This unlocks the possibility to systematically screen environment effects, thus providing design strategies to optimize electrocatalytic processes and devices. Following an overview of these recent advances, applications of continuum models to the study of environment effects in electrocatalysis, such as for water splitting and recombination reactions on 2D materials, will be presented.
Lignin-Derived Carbons for Electrocatalytic Oxygen Reduction Reaction in Alkaline Media
Authors: Rzeznicka Izabela Irena , Horino Hideyuki
Published: December 2024

With the Paris agreement, many countries around the world have set ambitious decarbonization goals. Due to high abundance and greenhouse gas emitting index, there is a growing interest toward conversion of lignocellulosic biomass into materials used in the production of electrodes for batteries, fuel cells and supercapacitors. Lignin-derived carbons could substitute fossil fuel-based acetylene black. However, there are many challenges facing production of electrode-grade carbon from lignin. They include, control of inorganic impurities such as SiO2, porosity and conductivity. Lignin source and extraction processes also lead to many undesired impurities and batch to batch variability.

Carbon black alone is known to catalyze the oxygen reduction reaction (ORR), a key catalytic reaction controlling performance of metal-O2 batteries and fuel cells. The ORR can proceed via sequential 2-electron (2e) or a more desirable direct 4-electrons (4e) reduction pathway depending on the chemical identity of the active material.1-2)

In this presentation, we will report on the physio-chemical properties of kraft lignin-derived carbons and their application in formulation of catalytic inks for electrocatalytic applications. In particular, we will discuss the effect of lignin source and pyrolysis parameters on the ORR performance in alkaline media.

Lignin-derived carbons were characterized by powder X-ray diffraction, SEM-EDX, Raman spectroscopy and electrochemical methods. The catalytic activities of the electrodes prepared using lignin-derived carbons were studied by linear swept voltammetry (LSV) and rotating disk electrode (RDE) methods. Fig. 1 shows LSV of commercial acetylene black and pine-wood derived carbon, after three-steps pyrolysis. The ORR onset potential and a half-wave potential is 0.81 and 0.72 V vs. RHE, for the lignin carbon, which is closer to the half-wave potential of the widely-used 40% Pt/C catalyst. The electron transfer number, obtained from the Koutecky-Levich analysis, was 1.5, suggesting 2e reduction process.

References

1) Donghui Guo et al., Active Sites of Nitrogen-doped Carbon Materials for Oxygen Reduction Reaction Clarified using Model Catalysts.Science351,361-365 (2016).

2) R.P. Putra, Y. Samejima, S. Nakabayashi, H. Horino, I.I. Rzeznicka, Copper-based Electrocatalyst Derived from a Copper Chelate Polymer for Oxygen Reduction Reaction in Alkaline Solutions, Catalysis Today, (2020).

Acknowledgements

This work was supported by JST Strategic International Collaborative Research Program (SICORP), Grant Number JPMJSC2302, Japan.

Fig 1. LSV in the ORR region in 1 M KOH for acetylene black and lignin-derived carbon.

Figure 1
(Keynote) Key Intermediates and Cu Active Sites for the Electrocatalytic Reduction of CO2 to Ethylene and Ethanol
Authors: Roldan Cuenya Beatriz , Herzog Antonia
Published: December 2024

Electrocatalytic reduction of CO2 (CO2RR) to multi-carbon products is a promising technology to store intermittent renewable electricity into high added value chemicals and close the carbon cycle. Its industrial scalability requires electrocatalysts to be highly selective to certain products, such as ethylene or ethanol. However, a substantial knowledge gap prevents the design of tailor-made materials, as the properties ruling the catalysts selectivity remain elusive. Here, I will describe how the findings from a combined in-situ surface-enhanced Raman spectroscopy and density functional theory study on electrochemically-roughened Cu foil electrocatalysts can be used to unveil the reaction scheme for CO2RR to C2+ products under potentiostatic conditions. In particular, ethylene generation occurs when *OC-CO(H) dimers form via CO coupling on undercoordinated Cu sites. The ethanol route opens up only in the presence of highly compressed and distorted Cu domains via the crucial intermediate *OCHCH2.

Moreover, although it is known that subjecting copper to short anodic pulses during CO2RR improves both, the activity and the selectivity towards hydrocarbons and alcohols, the nature of the active sites is still unclear. To address this issue, the final state of an electrochemically treated Cu(100) surface was resolved by a combination of spectroscopy, microscopy and diffraction methods applied concurrently. The evolution of the morphology, chemical state and crystal structure of Cu(100) exposed to potential pulses during CO2RR has served to shed light into the nature of the active sites formed under dynamic reaction conditions. In particular, anodic pulses, which enhance the ethylene and ethanol production, favor the formation of (n10) facets. Furthermore, pulsing between specific anodic and cathodic potentials during CO2RR also leads to the stabilization of Cu oxide species that are located either at the surface or directly below ultrathin metallic Cu layers, depending on the nature of the pulse potential. The latter is key for the enhanced C2+ product selectivity obtained during pulsed CO2RR.

Finally, by identifying and tracking the critical intermediates and specific actives sites, our work provides guidelines to selectively decouple different products on rationally designed catalysts.
(Keynote) Design and Electrochemical Study of Bimetallic Nanostructured Catalysts for the Reduction of Carbon Dioxide
Authors: Chen Aicheng
Published: December 2024

There is a growing interest in developing high-performance catalysts for the electrochemical reduction of carbon dioxide (CO2) to address the increasingly serious impacts of global climate change. In this talk, we report on the design of Cu-based and Co-based bimetallic nanomaterials for the electrochemical reduction of CO2. The morphology, composition and structure of the synthesized nanomaterials were characterized with various imaging and spectroscopic techniques, including FE-SEM, TEM, XRD, EDX and XPS. The effects of an applied potential on the electrochemical reduction of CO2 were investigated using various electrochemical methods. The products generated from the CO2 electrochemical reduction were identified by gas chromatography and nuclear magnetic resonance (NMR) spectroscopy. Scanning electrochemical microscopy (SECM) was also employed to monitor the activity of the catalysts and the CO2 reduction products. The kinetics of the CO2 reduction reaction at the nanomaterials was further studied using in situ electrochemical Fourier transform infrared (FTIR) spectroscopy. The critical roles of nanostructured surfaces in the electrochemical reduction of CO2 are discussed.
Application of Molecular Silver Complexes for Efficient Electrochemical CO2 Reduction in Zero-Gap Electrolyzers
Authors: Wiesner Wiebke , Maldonado Arias Jenny Yurley , Siegmund Daniel , Apfel Ulf-Peter
Published: December 2024

Powered by renewable sources the electrochemical conversion of CO2 can be a sustainable opportunity to generate fuels. In the past various molecular complexes have been studied in homogeneous, lab-scale systems for the electrochemical CO2 reduction. Lately the field of incorporating molecular metal complexes in heterogenous electrocatalysis emerged. This approach offers distinct advantages, such as well-defined and easily tunable environments around the active metal centers and enabling a deeper understanding of the structural features necessary for efficient catalysis. Factors like the presence of donor atoms and hydrophobicity play pivotal roles in influencing catalytic activity. Another advantage of using molecular complexes is the possibility of lower metal loadings per square centimeter compared to the usage of i.e. nanoparticles while maintaining the same activity level.[1] In recent years, our group has been focused on the integration and optimization of silver-based complexes in heterogenized systems and gas diffusion electrodes. Herein, we present our progress across two readily synthesized silver-based complexes: the Ag(tetraphenylporphyrin) and Ag(dithiacyclam)[2] complex. Although these complexes exhibited low to moderate performance in homogeneous electrocatalytic CO2 reduction, their integration into gas diffusion electrodes with a carbon black support led to a remarkable increase in faradaic efficiency for CO formation when used in scalable zero-gap electrolyzers. Performing lab scale screenings at current densities of 100 mA/cm2 with catalyst loadings of 0.5 mg/cm2 every complex exhibited a faradaic efficiency for CO formation above 90 %. Remarkably, even at a tenfold reduction in catalytic loading to 0.05 mg/cm2 the complexes’ performance was not decreased significantly. Further, these complexes also showed a high activity towards the formation of CO at elevated current densities of 300 mA/cm2, opening the gate towards electrolysis in application-orientated relevant conditions namely: even higher current densities over 500 mA/cm2, elevated temperatures of 60 °C and long-term measurements up to 100 hours.

[1] Pellumbi, K.; Krisch, D.; Rettenmaier, C.; Awada, H.; Sun, H.; Song, L.; Sanden, S.; Hoof, L.; Messing, L.; junge Puring, K.; Siegmund, D.; Roldán Cuenya, B.; Schöfberger, W.; Apfel, U.-P Cell Reports Physical Science 4
2023, 101746.

[2] Johnson, A.; Iffland, L.; Singh, K.; Apfel, U.-P.; Suntharalingam, K. A Dalton transactions
2021, 50 (17), 5779–5783.

Figure 1
Suppressing Electrolyte Flooding in CO2 Electrolyzers Via Surface-Functionalized Microporous Layers
Authors: Karimian Bahnamiri Fazele , Ren Yi , Ng Li Harris , Lee ChungHyuk
Published: December 2024

The advancement of carbon dioxide (CO2) electrolyzers employing a three-compartment configuration represents a significant stride towards sustainable chemical processes. Central to this approach is the necessity for an effective supply of gaseous reactants and the suppression of competing hydrogen evolution reactions (HER) to ensure efficient and selective chemical production. A key component within this setup is the porous gas diffusion electrode (GDE), mainly responsible for optimizing CO2 diffusion through the gas diffusion layer (GDL) to the catholyte compartment. GDEs, located in between the catholyte chamber and the gas flow field, are indispensable for industrial applications due to their ability to achieve high current densities by ensuring a sufficient supply of CO2 to the reaction sites. However, conventional GDEs with carbon substrates have encountered challenges such as electrolyte flooding, leading to decreased efficiency and hindering practical application. The efficacy of CO2 diffusion is further hindered by pressure imbalances across the GDL, resulting in undesirable crossflow phenomena. Catholyte crossover into the CO2 flow field triggers flooding, adversely affecting electrochemical efficiency, blocking CO2 transport pathways, causing liquid product loss, and damaging the cell. To address these issues, precise surface engineering techniques are necessary to impart hydrophobicity onto microporous layers (MPLs). Chemical grafting mechanisms, affixing functionalized silane group agents onto MPLs, enable robust covalent bonds and minimize surface tension, enhancing resistance to electrolyte flooding and facilitating effective CO2 transport. Here we present a single-step treatment approach under room temperature, offering a more viable approach for optimizing the local microenvironment by suppressing catholyte crossover phenomena. , the impact of silane-treated GDLs on CO2 electrolyzers is analyzed, highlighting their role in flood prevention, enhancing cell durability, and achieving high current densities. This research underscores the pivotal role of surface modification techniques in advancing electrochemical systems tailored for sustainable CO2 conversion processes, thus contributing to a greener and more sustainable future.
Novel Nonlinear Laser Wave-Mixing Spectroscopy Coupled with Capillary Electrophoresis for the Sensitive Detection of Sars-Cov-2 Biomarkers.
Authors: Shatirishvili Nino
Published: December 2024

We present a highly sensitive detection method for the multivalent SARS-CoV-2 nucleocapsid protein, a crucial RNA-binding protein involved in virus assembly and genome packaging. The nucleocapsid protein's structure facilitates the recognition of antiviral drug targets, making it essential for viral RNA production and antiviral drug development. Traditional nucleic acid amplification assays like PCR, gene sequencing, CRISPR, CT-scan, ELISA, LFA, and LAMP are currently used for COVID-19 identification. However, these techniques have limitations such as false results, template quality issues, cost, limited specificity, and sensitivity. To overcome these challenges, we introduce our patented nonlinear laser wave-mixing technique, offering numerous advantages including label-free native detection, enhanced sensitivity, minimal sample requirements, short optical path length, and high spatial resolution. Our approach utilizes four-wave mixing (FWM), a nonlinear optics phenomenon, to generate coherent signals by interacting two or three wavelengths and producing new wavelengths. Phase- matched four-wave mixing is achieved using collinear incommensurate waves, resulting in efficient signal generation within the analyte. The small probe volume, achieved by overlapping two laser beams, makes our technique compatible with microfluidics and capillary-based electrophoresis systems. Furthermore, wave-mixing, being an absorption-based method, enables the detection of small amino acids and proteins using common labeling methods like fluorophores and chromophores. In our study, we successfully detected the SARS-CoV-2 nucleocapsid protein labeled with the Chromeo P540 tag using a 532 nm solid-state laser as the excitation source. Our technique exhibited high sensitivity, with a detection concentration limit of 0.26 nM, corresponding to a mass detection limit of 19.3 zeptomoles. This innovative detection method holds great promise for advancing COVID-19 diagnostics by providing superior sensitivity, compatibility with various labeling techniques, and the ability to detect infected carriers who may not exhibit clinical symptoms.
A Novel Electrochemical Biosensor for Oral Cancer Biomarker Detection
Authors: Nagdeve Sanket Naresh , Suganthan Baviththira , Ramasamy Ramaraja
Published: December 2024

Oral cancer is a prominent public health concern, distinguished by the anomalous proliferation of cells in the oral cavity, especially the lips, tongue, cheeks, and throat. It represents a complex interplay of genetic and environmental factors, with microRNAs (miRNAs) playing pivotal roles in its development and progression. Given its impact and increasing cases worldwide, early detection and treatment are crucial for timely intervention and rapid outcomes. This work presents a biosensing platform for detecting miRNA oral cancer biomarkers in artificial saliva samples using impedimetric detection. The biosensor platform is based on a DNA/graphene bio-nanocomposite, and offers high sensitivity and specificity allowing for identifying target miRNA at low concentrations. This approach showcases a promising tool for non-invasive and early detection of oral cancer, potentially revolutionizing current diagnostic approaches1-2.

Ziober, B.L., et al., Lab‐on‐a‐chip for oral cancer screening and diagnosis. Head & Neck, 2008.

Badwelan, M., et al., Oral Squamous Cell Carcinoma and Concomitant Primary Tumors, What Do We Know? A Review of the Literature. Current Oncology, 2023.
Enhancing the Output Performance of Triboelectric Nanogenerators By Inserting CdS into Dielectric Layer
Authors: Mao Jianbin , Seo Soonmin
Published: December 2024

Triboelectric nanogenerators (TENGs) have emerged as promising devices for harvesting mechanical energy from various environmental sources. In this study, we focus on enhancing the performance of TENGs by inserting nano-sized cadmium sulfide (CdS) into a polydimethylsiloxane (PDMS) material. The synthesis of CdS nanomaterials was achieved through an ultrasonication method, resulting in a significant reduction in particle size compared to commercial CdS. The fabrication process of the TENG involved dispersing CdS nanoparticles into PDMS and depositing the composite thin film onto a polyethylene terephthalate (PET) substrate. Characterization studies using field emission scanning electron microscopy (FE-SEM) and UV-visible spectroscopy confirmed the successful transformation of micron-level CdS into nano-level CdS with improved optical and morphological properties.

The TENG device was assembled employing a two-electrode configuration, comprising copper foils as electrodes and the CdS/PDMS composite thin film as the friction layer. Subsequent electrical measurements were conducted to assess the TENG's performance, encompassing evaluations of open circuit voltage, short circuit current, and charge transfer density. The findings revealed that the integration of CdS nanoparticles into PDMS significantly augmented the TENG's output, manifesting in notable increases in both voltage and current in comparison to PDMS-based TENGs. Moreover, a comparison between TENGs incorporating nano-scale CdS and those utilizing micro-scale CdS exhibited superior performance of the former, attributed to the enhanced charge transfer properties facilitated by the nanoparticles. Specifically, these findings indicate a threefold enhancement in output voltage and a 2.5-fold enhancement in current compared to the initial PDMS-based TENG.

Additionally, a comprehensive study on the impact of external load resistance on the TENG's output energy density demonstrated its potential for practical applications, with the device capable of powering LEDs continuously. Rectification of the TENG's output voltage using a full bridge rectifier showcased efficient conversion of mechanical energy into electrical energy without a significant performance decline. Stability tests conducted over multiple days confirmed the reliability of the TENG based on CdS/PDMS, suggesting its suitability for long-term applications.

In conclusion, the integration of nano-level CdS into PDMS material presents a promising approach to enhance the TENG performance for mechanical energy harvesting. Despite challenges such as CdS agglomeration in the polymer matrix, our findings highlight the potential of CdS-based TENGs for various energy harvesting applications and pave the way for future research in optimizing their performance and stability.
Polydopamine Inspired Silver Nanoflower SERS Substrate for Highly Sensitive Detection of Nivalenol in Food Samples: Unveiling Biocompatibility in Mammalian Cells
Authors: Kitaw Sintayehu Leshe , Birhan Yihenew Simegniew , Ahmed Yohannis Wondwosen , Tsai hsieh-Chih
Published: December 2024

Surface-enhanced Raman spectroscopy (SERS) is a reliable analytical technique for mycotoxins' swift and precise determination. However, thus far, there has been no exploration of SERS for the quantitative detection of nivalenol (NIV). In this study, we engineered polydopamine-coated silver nanoflower (PDA-AgNFs) SERS substrates with potent "hot spots" to enhance Raman signals of NIV. These substrates exhibited exceptional SERS enhancement capabilities in detecting and quantifying the target analyte, demonstrating uniformity (with a relative standard deviation of SERS signals, RSD = 4.1% for substrate-to-substrate test and 3.24% for spot-to-spot test), an enhancement factor of 2.87 × 10^6 for rhodamine 6B (R6G), and detection sensitivity as low as 1 femtomolar (10^-15 M) for R6G probe molecule. Furthermore, we successfully employed the PDA-AgNFs SERS substrates for the first time to detect NIV in corn, horse beans, and mushroom samples. The calibration curve exhibited a satisfactory linear fit based on SERS intensities at different NIV concentrations, with a detection limit (LOD) of 0.22 nM (S/N = 3) for the proposed approach. Intriguingly, the MTT assay experiment demonstrated the biocompatibility of PDA-AgNFs, showing no toxicity against mammalian NIH-3T3 cells. These biocompatible substrates, endowed with intense plasmonic effects and binding sites, showcased remarkable Raman enhancement, offering an efficient, label-free, and rapid SERS-based analysis of NIV in real samples.

Keywords:
Polydopamine-inspired, silver nanoflowers, mycotoxins, nivalenol, biocompatibility.

Figure 1
Flexible Screen-Printed Electrochemical Sensor Based on Cu, Poly 1,5-Diaminonaphthalene and Carbon Black for Nitrate Detection in Real Water Samples
Authors: Benhaiba Saad , Ezzahi Amine , El Rhazi Mama
Published: December 2024

The contamination of groundwater, rivers and lakes by nitrates has become a serious problem. The latter, mainly from agricultural activity, such as the use of chemical fertilizers, harm the aquatic ecosystem and the supply of drinking water. On the other hand, the World Health Organization (WHO) recommends a maximum level of 50mg/L of NO3
- in water, but this threshold is often exceeded, making drinking water unfit for consumption in many regions. In this context, sensitive and reliable detection methods have become a top priority. In this work, we have developed and characterized electrodes based on screen printed modified electrodes (SPEs) by a composite of a Copper film, poly 1,5-Diaminonaphthalene (1,5-DAN) and carbon black. The developed electrochemical sensor is named Cu /Poly 1,5-DAN/CB /SPE. The prepared electrode showed electroactivity towards nitrate ions in a concentration range between 5-100 µM with a detection limit less than 1 µM. The sensor showed very good repeatability and reproducibility and was successfully tested in different water samples.

Figure 1
(Invited) Unlocking Iron Metal As a Cathode for Sustainable Li-Ion Batteries By an Anion Solid-Solution
Authors: Ji Xiulei (David)
Published: December 2024

Li-ion battery (LIB) is the dominant high-energy rechargeable battery; however, its increasing adoption in transportation has dramatically driven up global demand for Ni and Co, which are indispensable for current LIB cathodes. Therefore, it is pivotal to invent alternative high-energy battery chemistries. Beyond Li-ion, other cations have been extensively studied; however, battery chemistry using anion charge storage has received meager attention for energy storage. Can anion-hosting electrode systems deliver more competitive properties than LIBs? This is the question that we intend to answer by investigating the mechanisms and understanding the limiting factors using anions as charge carriers. This talk will introduce our recent results of converting iron powder as a cathode active mass for Li-ion batteries by the anion-defined chemical environment. We found that the solid solution of phosphate and fluoride activates the reactivity of iron to release its large capacity. The electrode comprising iron and lithium salts, denoated as lithium salt composite cathode, delivers a high energy density of up to 940 Wh/kg, stable cycling, and excellent high-rate capability. During initial charging, dissociated from the lithium salts of the composite electrode, Li-ions commute to the counter electrode, rendering LSC a rocking-chair battery electrode, facilitating this new electrode for practical applications. We found that the amorphous solid solution of fluoride and phosphate plays a pivotal role in the electrode. This talk will introduce the operation mechanisms of this new electrode and the remarkable potential of lithium salt cathode materials as a new family of cathode materials for Li-ion batteries and beyond.
Kinetic Analysis of Lithium Titanium Oxide by Applying the Diluted Electrode Method to Various Electrochemical Measurements
Authors: Tsuchida Kamma , Ariyoshi Kingo
Published: December 2024

Elucidating the diffusion phenomenon of Li ions in lithium insertion electrodes used in lithium-ion batteries is important for improving power capability of the batteries. However, it is extremely difficult to identify the rate-determining process of the reaction because there are various mass transport processes in the lithium insertion electrode. In our laboratory, by using a diluted electrode in which part of the active material is replaced with an electrochemically inactive material, the rate-determining step can be controlled by varying the active material content; the rate-determining step is Li-ion diffusion in the electrolyte within electrode pore for the conventional electrode with high active material content versus Li-ion transportation in the solid active material for the diluted electrode with quite low content. Thus, we have succeeded in measuring the inherent electrochemical properties of lithium insertion material via diluted electrode method.

In this study, we applied this diluted electrode method to various electrochemical measurements such as chronopotentiometry, chronoamperometry, and cyclic voltammetry, and analyzed the results in a complementary manner to understand the electrode kinetics of lithium insertion electrodes. In the experiment, lithium titanium oxide (Li[Li1/3Ti5/3]O4; LTO) was used as the active material and aluminum oxide (Al2O3) as the inactive material. The diluted LTO electrode consisted of (LTO+Al2O3):AB:PVdF = 88:6:6.

According to the results on chronopotentiometry (Fig. a), the capacity retention in the oxidation reaction was significantly higher than that in the reduction reaction. This means that the inherent reaction kinetics of LTO is asymmetric between oxidation and reduction. Chronoamperometric results at various applied voltages (Fig. b) also showed that the capacity increased more rapidly in the oxidation reaction than in the reduction reaction at the diluted LTO electrode. In the cyclic voltammograms of the diluted LTO electrode (Fig. c), the oxidation and reduction peaks were symmetrical, suggesting that there was almost no difference in reaction rate between the oxidation and reduction reactions.

In this presentation, we will analyze these measurement results using equations related to diffusion phenomena (Cottrell equation, Sand equation, etc.), and compare the independently obtained kinetic parameters from each measurement, we will discuss the validity of applying these analytical formulas to lithium insertion electrodes.

Figure 1
ホスホニウム系イオン液体中の抽出されたPd(II)錯体の電気化学的および分光学的分析
Authors: Tsuyuki Ryosuke , Matsumiya Masahiko , Sasaki Yuji
Published: December 2024

The phosphonium-based ionic liquids (IL) were applied for Pd(II) extraction in this study. The anion-exchange mechanism of Pd(II) extraction was confirmed by slope analysis with the concentration dependence of the phosphonium cation. On the other hand, the IL-Pd(II) complex was identified by means of UV-Vis-NIR and Raman spectroscopic analyses. According to the spectroscopic analysis, the extracted IL-Pd(II) complex found to be present in IL medium and the [NTf2]- anion is not coordinated at the first coordination sphere. The electrochemical analysis revealed that the extracted Pd(II) can be reduced in one step; Pd(II) + 2e- → Pd(0). The diffusion coefficient of the extracted Pd(II) in phosphonium-based IL was also evaluated by semi-integral analysis. Finally, the potentiostatic electrodeposition of the extracted Pd(II) allowed us to recover the electrodeposits, which were identified as Pd metal through SEM/EDX, XPS, and XRD analyses.
Heterointerfaced Ni-Fe2O3 Nanoparticles Toward Water Oxidation in Alkaline Medium
Authors: Jeong Wooseok , Hong Yun-Kun , Ha Don-Hyung
Published: December 2024

Hydrogen is an attractive energy carrier with high energy density and without harmless burning products, leading to magnificent efforts to build the hydrogen production system. Accordingly, water electrolysis is one of the promising strategies to generate hydrogen without carbon emission, requiring highly active catalysts for oxygen evolution reaction (OER) due to its sluggish reaction kinetics than hydrogen evolution reaction (HER). To reduce overpotential and increase economic feasibility, Ni and Fe based catalysts have extensively studied due to their high OER activity as well as excellent stability in alkaline media. Many studies have controlled the morphological characteristics and electronic structures of Ni-Fe based OER catalysts to enhancing electrocatalytic performances. Particularly, interface formation is considered as one of the most significant aspects to design and obtain the desirable anode material.

In this study, we synthesized colloidal Ni-Fe intermediate nanoparticles (NFI NPs) with various molar ratios between Ni and Fe. Unique physical mixture phase of NFI NPs was identified by the X-ray diffraction (XRD) and transmission electron microscopy energy dispersive spectroscopy (TEM EDS), displaying that their morphological characteristics as well as crystalline phases depending on the composition of Ni and Fe. Through washing processes, the Fe2O3 NPs were mainly aggregated around the metallic Ni NPs, meaning a formation of multiple contacts between Ni metal and Fe2O3 NPs. Subsequent annealing step turned the simple contacts to Ni-Fe2O3 heterointerfaces. Electrochemical performances were examined, revealing significantly lower OER overpotential (199 mV) at 10 mA cm-2 (75:25 sample) than that of the previous Ni-Fe catalysts. Among the products of various Ni and Fe ratio (from 100:0 to 0:100, molar ratio of metal precursors), the 75:25 sample presented the highest OER activity than the other samples. In addition, the 75:25 sample exhibited long-term durability under alkaline OER operation for 5 days, confirmed through chronopotentiometry analysis at 10 mA cm-2. We speculated that this outstanding OER performance of 75:25 sample was due to the electronic structure modulation through Ni-Fe2O3 heterointerfaces. The sample was further investigated through X-ray photoelectron spectroscopy (XPS) to confirm the chemical states of catalyst surface. XPS results confirmed that oxyhydroxides were well formed on the metallic Ni sites than NiO, meaning that the Ni-Fe2O3 was more efficient catalyst than the NiO-Fe2O3. This work revealed that colloidally synthesized 75:25 sample having Ni-Fe2O3 heterointerfaces showed the highest OER performance among the samples we prepared. Furthermore, these results provide the insights to design the OER catalyst possessing heterointerfaces without precious metals.
Mixed Oxy-Sulfide Glassy Solid Electrolyte Material: Understanding Structural Compositions through the Use of Raman Spectroscopy, Infrared Spectroscopy, and X-Ray Diffraction
Authors: Riley Noah , Wakefield Alec , Maier Keaton , Martin Steve W
Published: December 2024

All solid-state sodium-ion batteries (ASSSB) are a very promising technology for the future of energy storage because of their relatively inexpensive materials vs lithium and improved safety over current liquid electrolyte batteries. Glassy solid electrolytes (GSE) are a type of electrolyte that is more resistant to dendrite growth due to their lack of grain boundaries.. Glasses in the series (1 - y)Na2S + y{(1 - z)[(1 - a)SiS2 + aPS5/2] + zNaPO3} with varied sodium to glass-former ratios were studied using Raman, FTIR, and XPS to examine how the structure of the GSE changes as the ratio of sodium to glass former changes. The Raman shift of 472cm-1, attributed to a free sulfur defect, was of specific interest. Sulfur defects have been shown to contribute to side reactions, leading to sodium sulfide formation and glass degradation. Crystallization has also been a setback faced and testing why the sodium to glass former ratio would affect the formation of crystallites. This series is promising to find a composition with as high of a sodium to glass former ratio without sulfur defects and being more resistive to crystallization.
(Invited) Overcoming the Air, Cycle, and Thermal Instability Challenges of High-Nickel Cathodes
Authors: Manthiram Arumugam
Published: December 2024

The push to increase the driving range and lower the cost has prompted to increase the nickel content in layered oxide cathodes for lithium-ion batteries. However, as the nickel content increases, the cathodes encounter air, cycle, and thermal instabilities. These instabilities arise from the high surface reactivity of Ni3+ and Ni4+. The reactivity of Ni3+ with ambient air results in the formation of lithium hydroxide and lithium carbonate on the surface, termed as residual lithium, which not only degrades the cathode performance but also causes clogging during electrode fabrication. The high surface reactivity of Ni4+ with the electrolyte in the charged state results in a reduction of Ni4+ to Ni2+ on the surface, loss of oxygen, formation of resistive rock-salt phases, formation of cracks, loss of active lithium, Ni dissolution and migration to the anode, and consequent capacity fade during extended cycling. The reactivity also leads to thermal instability, gas evolution, and safety concerns. The surface reactivity depends both on the surface characteristics of high-Ni cathodes and the electrolyte.

Doping of the cathode with various ions is generally pursued to overcome these challenges. The doping generally improves air and thermal instabilities, but there is no clear understanding of which dopant does what. This presentation will focus on a systematic investigation of doping LiNiO2 with various dopants, such as Co, Mn, Al, Mg, Ti, Nb etc. to identify the role of each dopant. The effect of dopants on air and thermal stabilities and gas release in the charge state will be presented. The reaction mechanisms involved and the nature of phases formed on cathode surface with various dopants in contact with air will be presented. This will help to design cathodes with appropriate dopants that have specific functions. In addition, a systematic investigation of various electrolyte compositions on the cycle stability and gas release will be presented. Also, the fundamental understanding developed with the use of advanced analytical techniques, such as in-situ XRD, SEM, XPS, and TOF-SIMS will be discussed. It will be demonstrated that the cycle instability and gas release can be overcome to a large extent by developing cathodes with a robust surface structure as well as by employing electrolytes with less reactivity with the cathode surface.
Multifunctional Layer Coated Cu for Anode-Free Lithium Metal Batteries
Authors: Hwang Bing-Joe
Published: December 2024

Anode free lithium metal battery (AFLMB) is one of the alternate choices and new system for high energy density storage system because it has no active anode material initially. In addition, the fabrication of AFLMB is simple, low-cost, safe since Li metal or other active anode material is not directly used as an anode. The energy density of AFLMB will be significantly larger, by more than ~50% relative to conventional LIBs. Since the Li amount is limited and electrolyte decomposition, consuming Li during the SEI formation, the capacity can fade quickly relative to LMB. However, AFLMB is not only provide the highest energy density but the best system to understand the interfacial phenomena [1-3] and the effectiveness of the approaches to improve cell performances of LMBs [4-8]. In this talk, I will present our multifunctional layer coating approaches to improve the cell performance of anode-free lithium metal batteries.

Keywords: Multifunctional Layer Coating; Anode-free; Lithium; Coulombic efficiency; Capacity Retention

References:

A. Weret et al., ACS Energy Letters,

8,
2817 (2023).

M. Hagos et al., Accounts of Chemical Research, 54, 4474 (2021).

J. Huang et al., Nature Communications, 12, 1452 (2021).

T Agnihotri et al., Eng. J., 484, 149608 (2024).

SK Merso et al., Eng. J., doi.org/10.1016/j.cej.2024.149547.

J. Huang et al. , ACS Nano,

17,
13247 (2023).

Nikodimos et al., Energy Storage Materials, 61, 102861 (2023).

T. Wondimkun et al., Energy Storage Materials, 35, 334 (2021)
(Invited) New Class of Halide-Based Na-Ion Conducting Solids and a Critical Role of the Anion Framework
Authors: Ohno Saneyuki , Huang Zheng
Published: December 2024

All-solid-state sodium-ion (Na-ion) batteries are promising candidates for the post-lithium-ion (Li-ion) batteries owing to their improved safety and earth abundance, enabled by less- to non-flammable solid electrolytes (SEs). Extensive research efforts have been devoted to the development and exploration of new and better-performing ion conducting solids for decades, and numerous solid electrolytes, particularly sulfides, and oxides, have been discovered.

Ion-conducting halides are an emerging class of materials for solid electrolytes that may satisfy all requirements with their balanced ionic conductivity (> 1 mS cm–1 at room temperature), oxidation stability (~ 4 V), and room temperature processability. Ion-conducting halides first stepped into the spotlight in 2018 with the report of mechanochemically synthesized Li3YX
6 (X = Cl, Br). Up to date, a wide variety of Li-ion conducting halides have been reported, e.g., Li3
M
3+
X
6 (M
3+ = In, Sc, Ti, Y, Ho, Er, Yb and X = Cl, Br, I), Li2
M
4+
X
6 (M
4+ = Zr, Hf and X = Cl, Br, I), LiM
5+Cl4O (M
5+ = Nb, Ta) and LaCl3-based Li-ion conductor. Many exhibits room-temperature ionic conductivity higher than 1 mS cm–1 and demonstrated stable cycling with the state-of-the-art cathode active materials operating > 4 V.

Despite the success in Li-ion conducting halides, only a few Na-ion conducting halides have been found to date, e.g., Na3
M
3+Cl6 (M
3+ = Y, Er, In), Na2ZrCl6 and NaAlCl4, and their reported room-temperature ionic conductivity are mostly less than 0.1 mS cm–1. With the less polarizing nature of Na ions, Na-ion conducting SEs tend to possess higher ionic conductivity than their Li-analogues, and indeed, higher ionic conductivity is generally reported in Na-ion conducting oxides and sulfides than those in Li-ion conducting counterparts. Inspired by the fact that the known Na-ion conducting halide-based SEs exhibit much inferior ionic conductivity to the Li-analogues, here we explore the new Na-ion conducting halides, NaM
5+Cl6 (M
5+ = Nb, Ta), achieving 0.1 mS cm-1 at 30 °C. This high ionic conductivity is attributed to the beneficial inductive effect and improved migration entropy and is one of the highest among the crystalline monoanionic Na-ion conducting halides.

Figure 1
Interfacial Electrochemistry and Mechanics of Carbon Interlayers for Anode-Free Solid-State Batteries
Authors: Liao Daniel W. , Mulla Muzamil , Kawakami Hiroki , Aotani Koichiro , Thouless M.D. , Dasgupta Neil P.
Published: December 2024

Solid-state batteries provide a promising alternative to Li-ion batteries with improved energy density, safety, and manufacturability. However, anode-free cell configurations still suffer from multiple shortcomings, including 1) nonuniform Li deposition and dissolution, 2) continual formation of a solid-electrolyte interphase (SEI), and 3) limited rate capability. Recent efforts have investigated the integration of a carbon/silver composite interlayer to address the aforementioned challenges [1]; however, complete understanding of the mechanisms of this improved performance is not fully understood. The type of carbon, metal alloy, and lithiation effects of these components have been investigated [2,3], particularly, the electrochemical characteristics, but the mechanical properties of these interlayers have not been thoroughly investigated. Therefore, in this study we explore the interfacial mechanics at an amorphous carbon interlayer and argyrodite solid electrolyte interface on in situ Li metal formation.

The carbon interlayer and solid electrolyte interfacial adhesion were modified to investigate the corresponding influence on Li metal deposition. Peel tests are performed to quantify the interlayer adhesion under various processing conditions. Li metal was observed to preferentially deposit at regions with the lowest energy penalty for nucleation and growth. By intentionally tuning the carbon/solid electrolyte interface, the growth of Li metal can be promoted at different interfaces. Operando video microscopy and post-mortem focused ion-beam/scanning electron microscopy were utilized to confirm the Li deposition behavior. This work demonstrates that Li deposition in the presence of a carbon interlayer can be systematically modified by tuning the interfacial mechanics. The outcomes of this study will further our understanding of the processing conditions and underlying mechanics during in situ Li metal formation to enable high efficacy interlayers in solid-state batteries.

[1] Y.G. Lee, S. Fujiki, C. Jung, N. Suzuki, N. Yashiro, R. Omoda, D. S. Ko, T. Shiratsuchi, T. Sugimoto, S. Ryu, J. H. Ku, T. Watanabe, Y. Park, Y. Aihara, D. Im, I. T. Han, Nature Energy.
5, 299-308 (2020)

[2] D.W. Liao, T.H. Cho, S. Sarna, M.K. Jangid, H. Kawakami, T. Kotaka, K. Aotani, N.P. Dasupta, Journal of Materials Chemistry A, 12, 5990-6003 (2024)

[3] N. Suzuki, N. Yashiro, S. Fujiki, R. Omoda, T. Shiratsuchi, T. Watanabe, Y. Aihara, Advanced Energy and Sustainability Research, 2, 2100066 (2021)