bluuebunny/crossref_metadata_2025 huggingface dataset:
Coupling Supramolecular Assemblies and Megasonic Energy for Improved p-CMP Cleaning of Silicon Carbide
Authors: Miliauskas Mantas M. , Caridi Adam T. , Gentile Ryan J. , Powell Joseph L. , Keleher Jason J.
Published: July 2022

Wide band gap (WBG) materials (i.e. Silicon Carbide (SiC)) are rapidly emerging in the semiconductor arena because of their properties (i.e. high capacitance, thermal stability, and wear resistance), which allow these substrates to be used as insulating wafers and transistors in integrated circuits (IC). During CMP, removable defects (i.e. particles, organic residues, pad debris etc.) and non-removable defects (i.e. scratches or corrosion) are generated on the wafer surface. Industry standards currently utilize aggressive post-CMP processing conditions, which may lead to further defectivity. This research focuses on a comparison between an industry-standard brush cleaning (i.e. contact mode) and an emerging megasonic cleaning approach (i.e non-contact mode). Implementation of supramolecular cleaning chemistries such as micelles, vesicles, and polyelectrolytes will be employed in both modes as an alternative “soft” cleaning process. Initial results indicate a correlation between the structure of the “soft” cleaning additives on overall simulated defect removal. In addition, significant concentration dependency (i.e. above and below the critical micelle concentration (CMC)) emerged as a key driver for the rate of defect removal.
A Co-Axial Microtubular Flow Battery with Ultra-High Volumetric Power
Authors: Wu Yutong , Filippas Alexandros , Liu Nian
Published: July 2022

The increasing application of renewable energy sources has created the need for efficient electric energystorage. Redox flow batteries offer a viable alternative for these applications, having the advantages of long-life cycles and decoupling the power output and the storage capacity. Current RFBs use a planarconfiguration for the reactor. This configuration has been thoroughly studied and it has probably reached itsupper limit with respect to power density. This work presents a scalable hollow-fiber based co-axialmicrotubular flow battery design which proves to be a major leap forward in the power density of RFBs. Thisengineering solution provides significantly higher packing efficiency and membrane surface-to-area-ratio,lowering the capital cost and improving the volumetric power density. The performance of the new device isassessed by measuring the peak charge and discharge power densities, as well as the cycling performancefor both organic and inorganic redox couples.
Co-Exsolution Method Via Seeded Effect for Catalytically Active Anode in Protonic Ceramic Fuel Cells
Authors: Lee Na hyeon , Lee Ki Yun , Kim Yo Han , Jo Seungyeon , Myung Jae-Ha
Published: July 2022

Protonic ceramic fuel cells (PCFCs) have great potential in terms of reducing the operating temperature (400-600oC), because of the low activation energy of proton conduction in oxides compared to oxygen ion conduction. These characteristics provide a pathway to overcome the limitation of conventional SOFC (600-1000oC) such as durability, degradation of catalysts. However, poor catalyst activity at low operating temperatures still remains a problem to be solved. One promising way to improve catalytic activity is in-situ exsolution of various metal nanoparticles. Exsolved nanoparticles not only increase the active catalytic area but also have excellent resistance to thermal agglomeration and carbon coking. Unfortunately, it is difficult to achieve a high population density of metal nanoparticles due to the low exsolution kinetics (diffusion, nucleation) in the anode atmospheres of PCFC. In this study, we designed an A-site deficiency proton-conducting oxide, Ba0.9(Zr0.1Ce0.7Y0.1Yb0.1)0.95M0.05O3-d, as a host material to maximize exsolution behaviors. In addition, a co-exsolution strategy with Cu, which has the highest reducibility among transition metals, was introduced to achieve a high population density of exsolved atoms at low temperatures. A single doped Ni metal in the designed host material exhibited a population density value of 1.13 particles/um2 in reducing atmosphere at 600oC. The single doped Cu metal showed 24.1 particles/um2, but Co-doped with Ni and Cu metal produced the highest particle population of 98.31/um2, which is 87 times greater than a single Ni doping. These results follow the seeded growth mechanism induced by the additional surface energy of pre-exsolved Cu. This suggests a new synergy effect on exsolution phenomena that enhances segregation and nucleation kinetics

Figure 1
Engineering the Heterogeneous Interface of Sulphur Doped Nickel-Manganese Oxide for Efficient Overall Electrochemical Water Splitting
Authors: Madan Chetna , Halder Aditi
Published: July 2022

Electrochemical water splitting is the technique to utilize stochastic renewable sources for a continuous uninterrupted supply of energy through the production of hydrogen fuel. However, the performance of a water electrolyzer is limited due to the instability as well as larger overpotential associated with the current state of the electrocatalysts. Transition metal oxides show remarkable potential for catalyzing water electrolysis. Among transition metal oxides, binary transition metal compounds exhibit the forte to replace the expensive and scarce noble-metal electrocatalysts. The engineering of hetero-interfaces between sulphur doped nickel and manganese oxide nanostructures has been systematically presented in our study. The difference in morphology too affects the catalytic activity of the samples owing to variable electrolyte interaction. The strategic development of these hetero-interfaces wields the electrocatalyst its superior bifunctional activity for catalyzing oxygen evolution reaction at an overpotential as low as 300 mV at 20 mA cm-2 current density and hydrogen evolution reaction at 280 mV at 10 mA cm-2 current density. The catalyst also delivered a stable current density for a long-term durability study without any significant loss in the performance.
Investigation of Temperature-Triggered Collapse of Surface-Bound ELP
Authors: Feeney Stanley , Balog Eva Rose M , Halpern Jeffrey M
Published: July 2022

The reversible Lower Critical Solution Temperature (LCST) response of Elastin-Like Polymers (ELP) has been investigated. It is well known that the coacervation versus solubility of ELPs in solution can be triggered by different factors including ionic strength and temperature. Recently our group studied the electrochemical impedance spectroscopy (EIS) response of ELP-modified surfaces associated with changes in ionic strength, and we observed intermediate states of ELP surface collapse.1

Within this work, we present our progress on monitoring the thermal response of surface-bound ELP. We will examine the localized temperature-triggered collapse for a (VPGIG)40 ELP (with a cysteine near the N terminus) with EIS to better understand the way charge transfer changes within a range of temperature and intermediate states. We studied two surfaces, (1) carboxyphenyl-modified glassy carbon electrode modified with ELP via EDC/NHS bioconjugation chemistry and (2) gold electrode thiol-bonded ELP surfaces. We will report on observed changes in charge transfer resistance from 5 to 40 degrees Celsius.

[1] Morales, M.A., Paiva, W.A., Marvin, L., Balog, E.R.M. and Halpern, J.M., 2019. Electrochemical characterization of the stimuli-response of surface-immobilized elastin-like polymers. Soft matter, 15(47), pp.9640-9646.
(Digital Presentation) Improved Nanocatalysts, Supported IrOx and IrRuOx, for Enhanced Oxygen Evolution Reaction
Authors: Bornet Aline , Berner Etienne , Quinson Jonathan , Schröder Johanna , Arenz Matthias
Published: July 2022

The production of hydrogen via acidic electrochemical water splitting is an important pillar towards more sustainability. The overall water electrolysis is hindered by the slow kinetics of the oxygen evolution reaction (OER). Therefore, the catalyst material for the anode still requires optimization. Hereby, we present two highly active OER catalysts, IrOx and Ir0.4Ru0.6Ox nanoparticles (NPs), prepared by a straightforward, surfactant-free, colloidal synthetic route.1 The metallic NPs are ~1.5 nm in diameter and were deposited on carbon Ketjen Black (CKB) as well as on antimony doped tin oxide (ATO) to investigate the active phase as well as potential influences of the support material. After the colloidal synthesis and supporting, the catalysts were activated, thus undergoing a particle growth of ~1 nm. Their performance was benchmarked in terms of activity and stability using our recently developed electrochemical flow cell called gas diffusion electrode (GDE) setup.2 This novel approach allows closing the experimental gap between the two most common methods, namely the rotating disk electrode (RDE) and the membrane electrode assembly (MEA). Independently from the support, Ir0.4Ru0.6Ox shows a higher activity towards OER than IrOx at three tested temperatures, i.e. 30, 40, 60 °C. The two different support materials were also compared, and it was found that independently from the material, NPs deposited on CKB showed slightly higher activity at low current densities (up to 40 mA mgIr
-1). As expected, accelerated potentiostatic stability test reveals a rapid degradation of the IrOx/CKB, while IrOx/ATO and Ir0.4Ru0.6Ox/ATO exhibit similar stability than commercially available Ir black.

[1] Francesco Bizzotto, Jonathan Quinson, Alessandro Zana, Jacob J. K. Kirkensgaard, Alexandre Dworzak, Mehtap Oezaslan, Matthias Arenz, Catal. Sci. Technol., 2019, 9, 6345-6356.

[2] Johanna Schröder, Vladislav A. Mints, Aline Bornet, Etienne Berner, Mohammad Fathi Tovini, Jonathan Quinson, Gustav K. H. Wiberg, Francesco Bizzotto, Hany A. El-Sayed, Matthias Arenz, JACS Au, 2021, 1, 247-251.

Figure 1
AuCu Nanostructures Active in the Visible Light – Optical and Photoelectrochemical Properties
Authors: Lipinska Wiktoria , Grochowska Katarzyna , Karczewski Jakub , Siuzdak Katarzyna
Published: July 2022

Nowadays, due to global warming and increasing environmental pollution, intensified research on materials for energy harvesting from renewable sources is being carried on. Solar energy is one of the most abundant energy resources that can be converted into electric energy. Here, we demonstate that AuCu bimetallic nanostructures placed on structured titanium foil can be applied in solar driven processes [1, 2].

The electrode material is fabricated via Ti foil anodization process, chemical etching, thin AuCu layer (10 nm) magnetron sputtering and rapid thermal treatment at 600°C in varius atmospheres (air, vacuum, argon, hydrogen). AuCu nanoparticles are obtained only for annealing in air, while in argon and hydrogen porous structures and nanoplates are formed, respectively. UV-vis spectroscopy and X-ray diffraction studies of marterials indicate that the shape of the reflectance spectra differ significantly due to the changes in material morphology as well as its structure. The reflectance band minima are located at 380 nm and 750 nm for electrode material annealed in air and hydrogen, respectivetly. Moreover, sample thermally treated in air exhibits wide absorbance band from 300 to 1000 nm, whereas the one annealed in hydrogen from 500 to 1000 nm. Linear voltammetry measurements in dark and under light illumination were carried out in 0.1M NaOH solution in order to evaluate the photoactivity. The highest photocurrent in visible light is obtained for AuCu electrode annealed in hydrogen (5 times higher than in air), however, under Uv-vis light for electrode processed in air.

All in all, thermal treatment in various atmospheres has a great impact on morphology, optical and photoelectrochemical activity of AuCu structures placed on Ti support material. We believe that presented results provide new opportunities in designing advanced photoactive materials.

Research is financed by National Science Centre (Poland): Grant no. 2019/35/N/ST5/02604.

[1] W. Lipińska, K. Grochowska, J. Ryl, J. Karczewski, K. Siuzdak,
Influence of Annealing Atmosphere on Photoelectrochemical Activity of TiO2 Nanotubes Modified with AuCu Nanoparticles, ACS Applied Materials and Interfaces, 13 (2021) 52967–52977, DOI: 10.1021/acsami.1c16271

[2] W. Lipińska, K. Grochowska, J. Karczewski, J. Ryl, A. Cenian, K. Siuzdak, Thermally tuneable optical and electrochemical properties of Au-Cu nanomosaic formed over the host titanium dimples, Chemical Engineering Journal, 399 (2020) 125673–125685, DOI: 10.1016/j.cej.2020.125673

Figure 1
Development of a Label-Free Immunosensor for Quantitative, Electrical Detection of Target Antigens
Authors: Osman Sommer , Claus Echo LeeAnn , Strait Madison , Anand Robbyn Kimberly
Published: July 2022

Point-of-care immunoassays require rapid, sensitive, and user-friendly operation. The most common example is an at-home pregnancy test, which falls under a class of diagnostics called a lateral flow assay (LFA). However, LFAs present many disadvantages such as poor sensitivity and a difficulty for users to interpret test results accurately. The gold standard immunoassay, ELISA, exhibits excellent limits of detection (LOD) and limits of quantitation (LOQ). However, barriers to the implementation of ELISA must be considered, such as the consumption of large amounts of expensive reagents, the need for trained personnel to perform the assay, and the possibility of false positives or negatives due to improper washing or procedure. A clear demand exists for a label-free immunological sensor with high sensitivity and specificity, requiring only a small amount of sample and with fully automated operation. Previous work in our group has demonstrated the successful label-free detection of nucleic acids in a microfluidic device with an embedded 3D porous electrode by their hybridization to a bed of bioconjugated microbeads. An increase in conductivity, observed by a current-voltage curve, was attributed to the negative charge added to the beads upon hybridization of the target nucleic acids. In this presentation, we demonstrate label-free sensing of antibody targets by an analogous method despite their low net charge under the conditions employed. In this system, biotinylated goat anti-rabbit IgG immobilized on streptavidin-modified beads serves as the capture antibody. The analyte, Rabbit IgG, is introduced into the channel and incubated for 30 min. A current-voltage curve (CVC) is obtained before and after incubation to detect and quantify binding of Rabbit IgG to the bead surface. We evaluated the sensitivity of this method and found that the LOD is approximately 5 nM. Following validation of this method, we examined binding kinetics by obtaining CVCs at several time points during incubation. Next, to improve the LOD in this device, faradaic ion concentration polarization (fICP) was employed to electrokinetically enrich the negatively charged IgG over the bead bed test line. After an enrichment period of 30 min, the antigen was preconcentrated over 100-fold, which resulted in greater sensitivity. Finally, we characterize the impact of ionic strength on the sensor and evaluated its performance in a simulated biofluid, saliva, under several conditions: neat, spiked with Tris, and diluted. Ongoing research in our group will translate this method to biomarkers relevant to viral diagnostics. The authors gratefully acknowledge the Roy J. Carver Charitable Trust for the funding of this project.
(Invited) Electrochemical Pathways Towards Recycling Spent Lithium-Ion Batteries
Authors: Yin Huayi , Zhao Jingjing , Gao Shuaibo
Published: July 2022

The ever-increasing grid-scale energy storage farms and electric vehicles call for more secondary lithium-ion batteries (LIBs). However, the battery resource is limited. Thus, the retired LIB is a potential secondary resource for remaking LIBs. Thus, it is urgent to develop efficient and green methods to recycle spent LIBs. Based on the long-time establishments in high-temperature molten salt and electrochemistry, the author developed electrochemical ways to repurpose spent LIBs, including molten salt electrolysis, cathodic assisted electrolysis, and paired electrolysis approaches. Unlike traditional way using chemicals to break down the chemical bonds, the electrochemical methods use electrons to enable the separation. As such, the electrochemical ways are green if renewable electricity is integrated. Hence, we hope to employ electrochemical technologies and classical thermodynamic principles to develop green recycling methods, aiming to provide fundamental insights into the sustainable battery development and renewable energy utilization.
(Digital Presentation) Develop a Novel Approach to Graphite Recycling in Industrial Level
Authors: Yao Zeyi , Wang Yan
Published: July 2022

Due to their high specific energy density (Wh/kg), high volumetric energy density (Wh/L) and long cycle life, lithium-ion batteries (LIBs) are being widely used in U.S. military and civilian applications. With the rapid growth of demands these years, recycling methods are developed to solve the shortages of supply for rare metal cathode materials, especially Li and Co. However, not being evaluated as high value material, graphite in spent LIBs always gets neglected. Therefore, graphite is burnt or downcycled and consequently generate CO2 gas as an inescapable result. Recent reports show the market demand for energy storage from Li-ion batteries will reach to 400 GWh in 2022, which required nearly 3 million tons of graphite, also it is estimated that 3 billion batteries are thrown away each year by Americans. Considering the raw material making graphite is organic materials from nature with an irreversible process, a vicious circle can’t be broken if graphite doesn’t get recycled. Remarkably, our group has developed a novel closed-loop hydrometallurgical process for recycling end-of-life Li-ion batteries. After developing methods of acid leaching and alkaline sintering, recycled graphite with an ultra-high purity (over 99.9%) is obtained for the first time. Being successfully scaled up to industrial level, it’s proved to be a green and high-efficient method in battery recycling. Further coating and surface treatment means are followed, recovering the capacity and improving the stability of recycled graphite to commercial standard. In summary, our research provides a novel maneuver to fully purify and recover the recycled graphite, which has great potential to be commercialized.
Low-Cost and Sustainable Direct Recycling of Battery Materials
Authors: Chen Zheng
Published: July 2022

The development of next-generation energy storage devices and systems for electric vehicles (EVs) relies on materials with significantly improved performance and lower cost. The increasing amount of lithium-ion battery (LIBs) consumption will result in the resource shortage and price increase of lithium and precious transition metals (Co, Ni etc.) that are critical for making high-performance LIBs. Also, future batteries that mainly use low-cost materials (Na, Fe, Mn) will have limited economic benefits to recycle even though the wastes generated from disposal of used batteries can cause severe environment pollution. In this context, design of low-cost and energy-efficient recycling and regeneration process for spent batteries is attracting growing interest. From a reversible chemistry point of view, this talk will focus on a potential strategy to directly recycle and regenerate spent LIBs using a “non-destructive” approach, which will lead to new electrode materials that can show the same level of performance as the native materials. We will show successful recycling of various battery materials, including cathode (LiMO2, LiMn2O4, and LiFePO4) and anode (graphite) using the direct regeneration approach. Such a strategy combines fundamental understanding and process optimization for remanufacturing of energy materials. Therefore, it can potentially offer a sustainable solution for future energy storage.
(Invited) Effects of the Local Chemical Environment on the Anode and Cathode Processes of CO2 Electrolyzers
Authors: Janaky Csaba
Published: July 2022

Continuous-flow electrolyzers allow CO2 reduction at industrially relevant rates, but long-term operation is still challenging. In this talk, I am going to present some interesting findings on the role of different ions, crossing the anion exchange membrane in zero-gap electrolyzer cells, contributing to unstable operation.

In the first part of my talk, I will show that while precipitate formation in the cathode gas diffusion electrode is detrimental for the long-term stability, the presence of alkali metal cations at the cathode improves performance. To overcome this contradiction, we develop an operando activation and regeneration process, where the cathode of a zero-gap electrolyzer cell is periodically infused with alkali cation-containing solutions. [1] This enables deionized water-fed electrolyzers to operate at a CO2 reduction rate matching that of those using alkaline electrolytes (CO partial current density of 420 ± 50 mA cm−2 for over 200 hours). We deconvolute the complex effects of activation and validate the concept with five different electrolytes and three different commercial membranes. Finally, we demonstrate the scalability of this approach on a multi-cell electrolyzer stack, with a 100 cm2 / cell active area.

In the second part of the presentation, I will discuss the role of anode catalyst in CO2R cells. The urge to substitute Ir is driven by its high- and steeply rising market price as well as its limited stability in alkaline media. Although Ni is a ~ten thousand times cheaper, active, and stable oxygen evolution reaction (OER) catalyst in alkaline media, I will demonstrate that there are factors, which hinder its application in CO2 electrolysis. While Ni is a suitable OER catalyst in short experiments, the cell voltage increases, and the measured total Faradaic efficiency decreases continuously during prolonged electrolysis. This is caused by the local acidic pH at the anode surface, the crossing CO3
2- ions and by the gradual change in the anolyte composition, leading to Ni dissolution. The catalyst loss is only a minor part of the problem; the dissolving metal ions also penetrate into the anion exchange membrane, where precipitate forms due to the high local carbonate ion concentration, inducing cell failure.

Finally, I will present a complex machine learning based approach, through which we aim to find the optimal operating conditions of such CO2 electrolyzer cells.
Multi-Material Additive Manufacturing of Coreless Transformers By Aerosol Jet Printing and Electrochemical Deposition
Authors: Tsui Lok-kun , Sui Yongkun , Pillars Jamin R. , Hartmann Thomas Michael , Dye Joshua , Lavin Judi
Published: July 2022

Coreless transformers are an attractive technology for power electronics due to their light weight and the absence of a brittle magnetic core material.[1] A coreless transformer consists of a primary spiral inductor with few turns and a secondary spiral inductor with many turns stacked together. Aerosol jet printing (AJP) is an additive manufacturing technology which can be used to print metals and polymers with linewidths as narrow as 10 µm. In this work we have used a combined AJP, electroless deposition, and electrodeposition approach to fabricate multi-layer coreless flyback transformers. This combined approach makes accessible both the high-resolution patterning from AJP and the high-density, high-conductivity materials such as Cu and Ni from electrochemical deposition techniques.[2]

We have designed two-layer primary and secondary inductors separated by AJP-deposited UV-curable dielectric layers. Micrographs of the primary and secondary inductors are shown in Figure 1(a) and 1(b) respectively. Electroless deposition of Cu and electrodeposition of Cu and Ni are optimized in order to minimize resistive losses and promote uniform film growth. The typical inductances measured on the 2-layer primary are 0.2 µH and the inductances measured on single layers of the secondary are on the order of 4 µH. Initial testing of the transformer for flyback voltage conversion demonstrated the capability of generating an output to input voltage ratio of >50. Comparisons of the experimentally measured inductance of the primary and secondary inductors as well as the transformer voltage ratio will be compared with simulated models.

SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525. SAND2021-15239 A

References:

[1] S.C. Tang, S.Y. Hui, H.S.-H. Chung. IEEE Transactions on Power Electronics. 15 (2000) 931–941.

[2] L. Tsui, S.C. Kayser, S.A. Strong, J.M. Lavin. ECS J. Solid State Sci. Technol. 10 (2021) 047001.

Figure 1. Additively manufactured coreless transformer showing (a) the two-layer Ag-Cu-Ni primary inductor spiral and (b) the addition of a dielectric separation layer and one secondary inductor layer.

Figure 1
(Invited) Scalable Printing of Flexible/Wearable Energy and Sensor Systems
Authors: Zhang Yanliang
Published: July 2022

Nanoscale materials are attractive and promising building blocks for a broad range of emerging technologies due to their unique and superior properties compared to the bulk form. However, converting nanoscale materials into high-performing functional systems while translating their unique properties from nanoscale to macroscale remain a major challenge due to many scientific and technological obstacles.

This talk will focus on our research on developing versatile and synergistic additive manufacturing and nanomanufacturing methods to manufacture and transform a broad range of emerging functional nanomaterials into innovative and sustainable energy and sensor systems in a highly scalable, controllable and affordable manner. This talk will present our recent research progresses scalable printing and photonic sintering to fabricate flexible thermoelectric generator (f-TEG) for energy harvesting. Our printed p-type and n-type flexible films demonstrate peak thermoelectric figure of merit ZT greater than unity near room temperature, which is among the highest reported ZT values in flexible thermoelectric materials. In addition, this talk will also present a novel hybrid printing method that can integrate functional materials and soft structural materials and fabricate highly stretchable and wearable sensors for a broad range of physical and chemical sensing applications.
Probing the Li Metal Solid Electrolyte Interphase Using a Stable Nitroxide Radical
Authors: Wang Evelyna , Insinna Teresa , Grey Clare P.
Published: July 2022

The solid electrolyte interphase (SEI) on a Li metal anode is important in protecting the Li from further oxidation. Previous work has demonstrated that the SEI formed in a lithium-air battery (LAB) can be tailored depending on the gas species present. Oxygen helps create an oxide-rich SEI and promotes uniform Li metal deposition as opposed to dendritic Li which are formed when only argon is present. In order to compare the protective quality of the SEI formed under O2 or under Ar, we used TEMPO, (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl, as a probe. First, we studied the possible reduction products of TEMPO. We found that TEMPO initially reduces to TEMPO-, then undergoes further reductive degradation such as ring opening or formation of amines. Next, we exposed a Li metal electrode with SEI formed either under O2 or Ar to an electrolyte solution containing TEMPO. We characterized the ability of the SEI to prevent TEMPO reduction using operando Electron Paramagnetic Resonance (EPR) spectroscopy as well as ex situ solid-state and solution Nuclear Magnetic Resonance (NMR) spectroscopy. We show that the concentration of TEMPO in the electrolyte decreases more slowly and fewer TEMPO reduction products are formed when the Li metal has an oxide-rich SEI. This suggests that the oxide-rich SEI is better at protecting the Li metal from oxidation and that TEMPO is a suitable probe for SEI quality.
Cross-Sectional Preparation of Challenging Devices and Their Scale-Bridging Micro- and Nanoanalytical Characterization
Authors: Butz Benjamin , Hepp Marco , Derr Katharina
Published: July 2022

Complex devices like batteries, fuel cells or organic sensors and solar cells are commonly assembled from multiple functional components with different materials properties. To gain a fundamental understanding of the microstructure-property relations of such complex macroscopic structures, their degradation and failure mechanisms by complementary scale-bridging microscopic and spectroscopic techniques, it is desirable to prepare cross sections of entire devices or parts. Most challenging is the generation of electron transparent cross-sectional samples for investigation by (cryo) transmission electron microscopy (TEM); preparing TEM samples of devices consisting of different material classes may be utmost difficult. Therefore, TEM sample preparation is often preceded by the disassembly of a device down to individual components rendering an investigation of relations between the individual components impossible.

(Cryo-)ultramicrotomy as well as plasma-FIB as advanced cross-sectioning techniques for challenging samples may solve those issues. Both are capable to generate ultra-thin, electron transparent cross sections of hundreds of micrometers in size being larger than the typical thickness of modern devices.

In this contribution, we demonstrate the capabilities of modern (cryo-)ultramicrotomy in conjunction with advanced TEM to characterize such sensitive or reactive and thus challenging devices down to the atomic scale. Examples include battery parts, PEM fuel cells and novel flexible all-organic electronics. The achieved thickness of those cross sections is commonly of the order of a few 10 nm, which even allows for atomic-resolution imaging and advanced spectroscopy for microstructure and defect analyses as well as compositional and chemical-bond investigation, respectively.

Hepp et al., Trained Laser-Patterned Carbon as High-Performance Mechanical Sensors, NPJ Flex. Electron. 6 (2022), 3, DOI: 10.1038/s41528-022-00136-0

Beaupain et al., Reaction of Li1.3Al0.3Ti1.7(PO4)3 and LiNi0.6Co0.2Mn0.2O2 in Co-sintered Composite Cathodes for Solid-State Batteries, ACS Appl. Mater. Inter. 13 (2021) 47488-47498, DOI: 10.1021/acsami.1c11750

Li et al., Atomic structure of sensitive battery materials and interfaces revealed by cryo-electron microscopy, Science 358 (2017), 506–510, DOI: 10.1126/science.aam6014

Figure 1
Concentration Field Measurements Near the Anode during Lithium Metal Dissolution in Highly Concentrated Electrolyte
Authors: Kamesui Go , Nishikawa Kei , Matsushima Hisayoshi , Ueda Mikito
Published: July 2022

Introduction

Recently, high concentrated electrolyte (HCE, 3 mol L-1) has been attracting attention as an electrolyte for next-generation batteries. It has been reported that the solvation structure surrounding Li+ in HCE is significantly different compared to the electrolyte with a concentration of about 1 mol L-1 conventionally used in Li-ion batteries. This unique structure gives rise to high decomposition resistance and low vapor pressure. Also, next-generation batteries, such as lithium sulfur batteries, use Li metal as the negative electrode with high theoretical capacity. It is necessary to use HCE as the electrolyte and Li as the electrode to achieve breakthroughs in energy density, and it is important to clarify the deposition and dissolution mechanisms in the vicinity of the electrode in such batteries. However, there are only a few studies from this viewpoint. In this study, mass transfer phenomena associated with electrochemical dissolution reactions were investigated using a sulfolane-based HCE. In addition, the coordination states surrounding Li+ were measured by in situ Raman spectroscopy. In this presentation, the relationship between solvation structure and mass transport was investigated.

Experimental

Li metal with a thickness of 200 μm was used for the anode and cathode. The electrolyte was a mixture of LiTFSA (Lithium bis(trifluoromethanesulfonyl)amide) and SL (Sulfolane) at a molar ratio of 1:2. The electrochemical cell was arranged in a quasi-two-dimensional configuration to minimize the eﬀect of natural convection. Constant currents (1.0, 2.5, and 5.0 mA cm-2) were applied and real-time interferometric measurement was performed near the anode during the electrochemical dissolution reaction. In addition, in-situ Raman spectroscopy was used to observe near the anode to investigate changes in the solvation structure surrounding the Li+ near the electrode.

Results and Discussion

Interferometric measurements near the anodes during the electrochemical dissolution reaction showed that the concentration of the electrolyte near the anodes increased as soon as the electrolysis started. As the reaction progressed, the diffusion layer extended toward the bulk direction while maintaining parallelism with the anode surface. The concentration at the anode surface increased continuously with the electrolysis time, and the LiTFSA/SL molar ratio increased to 0.62 after 225 s. The relationship between mass transfer phenomena and solvation structure will be discussed in this presentation.
(Digital Presentation) Electrochemical Synthesis of Highly Crystalline γ-NiOOH and Its Bifunctional Electrocatalytic Activity Towards Oxygen Evolution and Reduction Reactions in Alkaline Solutions
Authors: Rzeznicka Izabela Irena , Putra Ridwan Pratama , Horino Hideyuki
Published: July 2022

Nickel (oxy)hydroxides are widely used as cathode materials in alkaline rechargeable batteries, including NiOOH-Cd, NiOOH-Zn and Ni-metal hydride batteries. NiOOH is a 2D-layered compound, known to exist in three different polymorphs α, β and γ. Compared with β-NiOOH, γ-NiOOH has a higher theoretical specific capacity and a lower self-discharge rate. However, when using a battery-grade Ni(OH)2, the β-NiOOH is mainly formed, which may transform to γ-NiOOH in the long run. Batteries based on β-NiOOH have poor life cycling and suffer from volume expansion. Therefore, γ-NiOOH is a desirable electrode material which can also be used in the next-generation high-capacity metal-air batteries due to its excellent electrocatalytic activity towards oxygen evolution reaction (OER).

In this presentation, we will report a new synthesis method of γ-NiOOH, in which only γ-phase is formed. The method is based on in-situ electrochemical transformation of a two-dimensional nickel chelate polymer in a carbon matrix in an alkaline electrolyte. γ-NiOOH prepared in this way is highly crystalline and has an excellent catalytic activity towards OER with overpotential of 390 mV at 12 mA/cm2. In addition, it can also catalyze oxygen reduction reaction (ORR), with an onset potential of 0.81 V vs. RHE in 1 M KOH.

Acknowledgements

The authors would like to thank Japan Society for Promotion of Science under the JSPS KAKENHI Grant Number JP 20K05689 for financial supports.
(Invited) The Application of Conducting Polymers for Nanomaterials Based Alloy Anodes in Battery Manufacturing
Authors: Liu Gao
Published: July 2022

Electrically conductive polymers are a class of polymers, which can conduct electricity. Conductive polymers have found niche applications such as anti-statics. The electrochemical energy storage devices, especially lithium-ion rechargeable batteries, has grown significantly in the past two decades. Multifunctional conductive polymers may play a significant role as electrode binders for Silicon (Si) and Tin (Sn) alloy based anode electrode. Si is an attractive candidate for lithium-ion batteries because it delivers 10 times greater theoretical (∼4200 mAh/g) specific capacity than that of a traditional graphite anode (∼370 mAh/g). However, the widespread application of silicon materials has remained a significant challenge because of the large volume change during lithium insertion and extraction processes, disrupting both the Si electrode surface and electrode mechanical integrity. This large volume change causes electrode failure, leading to loss of the electrical contact and drastic capacity fading. Nanosizing the Si and Sn based anode materials provides better performance, but poses significant challenges to manufacturing of the electrode, including particle aggregation, and difficulties in maintaining constant electrical contacts to the nanoparticles, and excessive surface area. Conductive polymer binders can play multiple functions for Si electrode, including improved adhesion and connectivity, lithium ion compensation, better ion and electric conductivity as well as surface and interface modification. Organic and polymer chemistry has provided almost infinity possibilities to modify the polymeric binders to include the desired functionalities. This presentation will discuss the specific molecular design principles and synthetic steps to realize the structures and functionalities of the binders, how these binders interact with different nano Si materials, and the electrochemical performances of the electrodes based on these binders.
(Invited) Plasma-Assisted Synthesis of Advanced Carbon Nanostructures for Batteries and Supercapacitors
Authors: Cvelbar Uros , Santhosh Neelakandan Marath
Published: July 2022

Designing advanced energy materials based on carbon nanostructures that could meet consumer requirements with high performance at low cost and not requiring expensive or precious materials is a green step towards new-gen energy systems. Such systems would be lightweight and could replace rapidly exhausting Li-based batteries. Although several carbon nanomaterials were reported for high performance, the problems with capacity, rate capability, or electrochemical stability still have to be improved for the high performance of these materials. The most promising and widely accepted way to improve the electrochemical properties of electrode materials is their tailoring at the nanoscale. Therefore, in our research, we developed one of the most promising ways to achieve these properties with the plasma-assisted synthesis of various advanced carbon nanostructures. Plasma is also a clean, ecologically benign and safe processing tool to tailor electrode materials at the nanoscale, without any waste residuals. The plasma-assisted processing was aimed at all-in-one packaged electrodes at a low cost for industry requirements. Using different carbon-containing gases, we produced different graphene-like 1D or 2D materials or their hybrids in low-temperature plasmas as a base or in single-step. The hybrid carbon nanostructures doped or with nanoparticles were used directly as electrode materials. However, in some cases, the sequent conversion or modification secondary step was applied to modify electrode materials for high performance. This was done either with doping with N atoms or conversions with sulphur. These electrode materials were then tested for batteries improving Li-storage or designing new multivalent metal-ion batteries and electrochemical supercapacitors. The obtained results were compared to the existing state of the art, and significant improvements in electrochemical performance were achieved. The talk will highlight these achievements with different synthesis processes for various carbon nanostructures and their hybrids and compare their performance as electrodes for improving batteries and supercapacitors.
Nano-FTIR Correlation Nanoscopy for Organic and Inorganic Material Analysis
Authors: Gokus Tobias
Published: July 2022

Significance: Correlation scanning probe techniques to complement nanoscale IR measurements for next generation sample characterization

Scattering-type Scanning Near-field Optical Microscopy (s-SNOM) is a scanning probe approach to optical microscopy and spectroscopy, bypassing the ubiquitous diffraction limit of light to achieve a spatial resolution below 20 nanometers. s-SNOM employs the strong confinement of light at the apex of a sharp metallic atomic force microscopy (AFM) tip to create a nanoscale optical hot-spot. Analyzing the scattered light from the tip enables the extraction of the optical properties of the sample directly below the tip and yields nanoscale resolved images simultaneous to topography [1]. In addition, the technology has been advanced to enable Fourier-Transform Infrared Spectroscopy on the nanoscale (nano-FTIR) [2] using broadband radiation from the visible spectral range to THz frequencies.

Recently, the combined analysis of complex nanoscale material systems by correlating near-field optical data with information obtained by other scanning probe microscopy (SPM)-based measurement methodologies has gained significant interest. For example, the material-characteristic nano-FTIR spectra of a phase-separated polystyrene/low-density polyethylene (PS/LDPE) polymer blend verifies sharp material interfaces by measuring a line profile across a ca. 1 μm sized LDPE island. Near-field reflection/absorption imaging at 1500cm-1 of the ca. 50nm thin film allows to selectively highlight the distribution of PS in the blend and simultaneously map the mechanical properties like adhesion of the different materials [3,4].

Further, we present results that correlate the near-field optical response of semiconducting samples like graphene (2D) or functional SRAM devices (3D) in different frequency ranges (mid-IR & THz) to Kelvin Probe Force Microscopy (KPFM) measurements. Thus, s-SNOM systems represent an ideal platform to gain novel insights into complex material systems by different near-field and AFM-based method.

[1] F. Keilmann, R. Hillenbrand, Phil. Trans. R. Soc. Lond. A 362, 787 (2004).

[2] F. Huth, et al., Nano Lett. 12, 3973 (2012).

[3] B. Pollard, et al., Beilstein J. of Nanotechn. 7, 605 (2016).

[4] I. Amenabar, et al., Nature Commun. 8, 14402 (2017).
Green Approach for Fabrication of Holey Graphene Based Electrode for Supercapacitor Application
Authors: Patole Shashikant
Published: July 2022

Holey graphene, also known as perforated graphene is formed generating in-plane holes in basal planes of graphene based materials. By combining the advantages of holes and graphene, holey graphene based materials have attained significant research interest in energy storage systems due to the high surface and high electrical conductivity. In the present work, the holey graphene nanosheets are synthesized using ‘metal catalyst activation strategy’ using a green chemistry approach. The synthesized holey graphene nanosheets are studied in detail using various comprehensive characterization and electrochemical analysis techniques. The green chemistry based fabricated holey graphene nanosheets are directly used as an electrode material in the supercapacitor application. In the supercapacitive study, the fabricated electrode exhibits an efficient performance (high capacitance, rate capacity and stability) than its pristine form (graphene) due to the formation of highly pores morphology which provides stupendous electroactive sites and resistance free pathways for ionic interaction and transport. The presented results provide a new platform for employing green approach for fabricating holey graphene based materials as an electrode in energy storage systems.

Keywords:
Holey Graphene, Pores, Nanosheets, Green Chemistry, Supercapacitors

References:

[1] Green chemistry based fabrication of holey graphene electrodes for high-performance supercapacitors, Materials Letters, 271, 127793 (2020).

[2] Holey graphene: An emerging versatile material, J. Materials Chemistry A, 8, 918 (2020).
X‐Ray Spectromicroscopy Investigation of Heterogeneous Sodiation in Hard Carbon Nanosheets with Vertically Oriented (002) Planes
Authors: Li Zhi
Published: July 2022

Hard carbon (HC) is a promising anode material for sodium-ion batteries, but the performance remains unsatisfactory and the sodiation mechanism in HC is one of the most debated topics. Here, from self-assembled cellulose nanocrystal sheets with crystallographic texture, unique HC nanosheets with vertically oriented (002) planes are fabricated and used as a model HC to investigate the sodiation mechanisms using synchrotron scanning transmission X-ray microscopy (STXM) coupled with analytical transmission electron microscopy (TEM). The model HC simplifies the 3D sodiation in a typical HC particle into a 2D sodiation, which facilitates the visualization of phase transformation at different states of charge. The results for the first time unveil that the sodiation in HC initiates heterogeneously, with multiple propagation fronts proceeding simultaneously, eventually merging into larger aggregates. The spatial correlation between the preferential adsorption and nucleation sites suggests that the heterogeneous nucleation is driven by the local Na-ion concentration, which is determined by defects or heteroatoms that have strong binding to Na ions. By identifying intercalation as the dominant sodium storage mechanism in the model HC, the findings highlight the importance of engineering the graphene layer orientation and the structural heterogeneity of edge sites to enhance the performances.

Figure 1
(Invited) High Surface Area N-Doped Carbon Fibers with Accessible Reaction Sites for All Solid State Lithium Sulfur Batteries
Authors: Zhu Hongli , Sun Xiao
Published: July 2022

All solid-state lithium-sulfur batteries (ASSLSBs) are believed to deliver extremely higher energy density and remarkable safety than conventional Lithium-Sulfur batteries using liquid electrolytes. However, the low utilization of active material (sulfur) caused by sluggish reaction kinetics greatly hindered the development of ASSLSBs. It is significant to fabricate an advanced electrode where sulfur has efficient electron/ion accessibility. Porous carbon host, which has been widely used in liquid cells, is proposed to address the challenges. However, the conventional porous carbon host used in liquid cells can not be directly used in ASSLSBs, because the nonmobile solid electrolytes can not reach the sulfur confined in the pores buried deeply inside the carbon. An ideal porous carbon host should own a large specific surface area to provide sufficient sites for sulfur, but it is very critical that the pores should only locate at the out surface of the carbon. Till now, though many works reported the application of porous carbon in ASSLSBs, but none of them discussed the structure requirement of porous carbon. Here, for the first time, we discussed the ideal structure of the porous carbon and developed a polyacrylonitrile-derived porous carbon fibers (named PPCF) with a unique core-shell structure where a layer of micropores cover on dense core contributing to a high specific surface area.

Porous carbon fibers were successfully prepared through electrospinning and following carbonization and activation processes. This PPCF owns a unique core-shell structure where a layer of micropores is covered on the dense cores. A high specific surface area of 1519 m2 g-1 was achieved, and the micropores could effectively confine the sulfur avoiding the formation of bulky sulfur. More importantly, the pores mainly distributed on the outer surface which rendered remarkable ion access to sulfur, contributing to high sulfur utilization. The fibrous morphology enabled efficient electron conduction paths through effective percolation. Compared with the vapor grown carbon fibers (VGCF), a common carbon fiber with no surface pores, the cathode using PPCF exhibited improved reaction kinetics with an overpotential reduction by 149 mV. The reduced overpotential explains the faster kinetic and higher utilization of sulfur in S-PPCF-SE. In the dQ/dV measurement, S-PPCF-SE showed strong anodic/cathodic peaks with high intensity of 3156/4367 mAh g-1 V-1 which are significantly higher than 1010/1268 mAh g-1 V-1 in S-VGCF-SE, demonstrating a greatly improved reaction kinetics. The ASSLSBs using PPCF exhibited three times enhanced initial capacity of 1166 mAh g-1 at C/20. After 50 cycles, the capacity gradually decreased to 710 mAh g-1 and was maintained stable after 220 cycles at C/10. A remarkable capacity of 889 mAh g-1 at C/2 was achieved. In comparison, the ASSLSBs using VGCF as carbon additive delivered a low rate capacity of 100 mAh g-1 at C/2.