bluuebunny/crossref_metadata_2025 huggingface dataset:
A Carbon Nanotube-Based Impedimetric Biosensor for Detection of Micro-RNA
Authors: Asadi Hamid , Ramasamy Ramaraja P.
Published: February 2020

MicroRNAs (miRNAs) have been recently regarded as clinically important biomarkers for early cancer diagnostic. Accumulative evidences have proved that dysregulated expression of miRNAs is closely related with the occurrence, diagnosis and treatment of cancer [1]. Conventional methods of miRNA detection have some limitations like requiring large amount of sample input, expensive instrumentation, and long analysis time. To address these shortcomings as well as providing multiplexing capability, selectivity, and real-time measurement different types of cancer biosensors have been developed. Among them electrochemical biosensors have shown great promise for this application due to their high sensitivity, specificity, cost-effectiveness, and compatibility with the miniaturization [2]. A label-free and ultrasensitive impedimetric biosensor for miRNA detection is reported in this study. We utilized a glassy carbon electrode (GCE) modified with multi-wall carbon nanotube (MWCNT) as a biosensor platform. Incorporation of nanomaterials such as MWCNT offers unique advantages including enhanced electronic properties, higher surface area, and rapid electrode kinetics which leads to higher sensitivities and lower limit of detection [3]. Capture DNA probes were immobilized onto the surface of MWCNT modified electrode using a novel molecular tethering agent. All surface modification, immobilization, and hybridization between probe DNA and the target miRNA were investigated by electrochemical analyses. Besides, different variables such as probe concentration, pH, ionic strength, and hybridization time were investigated and optimized to get the optimal experimental conditions for miRNA detection. The obtained results demonstrated that the proposed biosensor exhibits excellent analytical properties including high sensitivity, low detection limit, selectivity, and reproducibility for miRNA detection.

References

Lan H, Lu H, Wang X, Jin H (2015) MicroRNAs as potential biomarkers in cancer: opportunities and challenges. BioMed research international 2015

Kilic T, Erdem A, Ozsoz M, Carrara S (2018) MicroRNA biosensors: Opportunities and challenges among conventional and commercially available techniques. Biosensors and Bioelectronics 99:525-546

Oliveira T, Morais S (2018) New Generation of Electrochemical Sensors Based on Multi-Walled Carbon Nanotubes. Applied Sciences 8 (10):1925

Figure 1
(Invited) Plasmonic Nanostructures for Early Disease Detection and Precision Cancer Therapeutics
Authors: Curtin Kathrine , Gao Xuefei , Boryczka Jennifer , Zheng Peng , Kasani Sujan , Wu Nianqiang
Published: February 2020

Cancers are one of the leading causes of death in the world taking nearly 9 million lives annually. Because cancers place a burden on society, there is considerable interest in developing biosensors for early diagnosis and new, more effective treatments. At early stages of the disease, early diagnosis is integral for treatment success; however, concentrations of cancer biomarkers are very low, and testing is very extensive. Point-of-care biosensors can overcome these challenges by offering fast, accurate results in healthcare fields compared to low-sensitivity, expensive, and time-consuming laboratory techniques. Because of their unique and highly tunable optical properties, plasmonic nanostructures have been applied for biosensor design and in-vivo therapeutics to improve performance. Plasmonic nanostructures have been integrated into paper-based biosensors for high sensitivity and accurate assessment of cancer biomarkers in whole blood with no sample preparation. Cancers are conventionally treated using chemotherapy and radiation treatment; however, advancements in precision medicine are working to overcome drug resistance and target cancer directly instead of through systemic treatment. A plasmon induced resonant energy transfer (PIRET) nanostructure has been designed for in-vivo dual-Raman imaging and photodynamic therapy of cancer. This design provides means for Raman-guided imaging and surgery and destruction of cancer while maintaining the integrity of healthy tissues.
Aggressive Prostate Cancer Detection with an 8-Protein Biomarker Panel
Authors: Jones Abby L , DhanapalaMudiyanselage Lasangi , Baldo Thaisa , Sharafeldin Mohamed , Krause Colleen E. , Lee Norman , Rusling James F
Published: February 2020

Prostate cancer treatment has risk associated with patients’ being overdiagnosed leading to an overtreatment epidemic. In the United States 1 in 9 males are diagnosed with prostate cancer with approximately 10% of these patients having aggressive forms usually requiring surgery. To diagnose these patients, physicians most often rely on the Prostate Specific Antigen (PSA) blood test and the digital rectal exam. PSA is currently the only biomarker approved for prostate cancer diagnostics, but cannot discern cancer from other prostate conditions, such as Benign Prostatic Hyperplasia (BPH) or Prostatitis. Most importantly, PSA cannot identify the aggressive forms of prostate cancer. These inaccuracies lead to unnecessary treatments including surgery of indolent prostate cancer patients that adversely affect the patients’ quality of life. Measurements of small panels of molecular biomarkers in serum holds tremendous potential for cancer diagnostics and personalized therapy. We are evaluating a new protein panel for prostate cancer including PSA, CD-14, ERG, GOLM-1, PEDF-1, IGF-1, VEGF-D and IGFBP-3 that may be indicative of prostate cancer or cancer progression. We designed a microfluidic immunoarray that features miniaturisation, low sample volume, sensitivity adjustable to the sample characteristics, rapid analysis, and low reagent consumption. A protocol was developed for the simultaneous assay of this 8-protein panel in serum that features online capture and detection with a semi-automated multiple protein immunoarray. A nanostructured sensor array with bound capture antibody in the microfluidic device captures the biomarker proteins from the sample, and a sandwich immunoassay is completed following a concurrent injection of target protein standards or sample, biotinylated secondary antibody and polymerized horseradish peroxidase into the detection chamber. Ultra-low limits of detection (LOD) in the sub fg ml-1 range were achieved for the proteins in the panel. Using this strategy, 8-16 proteins can be detected simultaneously within 30 minutes. Measurements of the biomarker panel tested with prostate cancer patient samples and statistical analyses to assess diagnostic utility will be described.
(Invited) Closed Bipolar Electrochemistry with Multiplex Optical Readout for Rapid Diagnostics of Sepsis Syndrome Biomarkers
Authors: Lopez Arielle , Oh Christiana , Bohn Paul W.
Published: February 2020

The combination of optical readout - fluorescence, localized surface plasmon resonance (LSPR), and absorption spectroscopy - with electrochemistry presents new avenues for the study of redox reactions, with potential for enhanced throughput, sensitivity, and spatial resolution. Here we describe a novel, dual-cell configuration for coupling high sensitivity voltammetric measurements of redox active sepsis syndrome biomarkers in an analytical cell with remote electrochemically-triggered optical reporter reactions in a reporter cell. Coupling is mediated by a mm-scale closed bipolar electrode (CBE) which communicates the local solution potential in the analyte-measuring portion of the device to an opposing reporter reaction in a remote location. Oxidation (reduction) of reversible analytes at the disk working electrode is accompanied by reduction (oxidation) on the bipolar electrode and then monitored by the accompanying oxidation of the reporter to produce a change in optical response. Applications of these optical reporter reactions for point-of-use, multiplex determinations of lactate, pyruvate, and the liver enzymes aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in service of developing a rapid diagnostic for sepsis syndrome will be described.
A Flexible Al//Fe(III) and Aqds-Doped PANI Air Battery with Capacity Self-Restoring Performance
Authors: Cao Huijun , Si Shihui , Xu Xiangbin , Li Jirui
Published: February 2020

The synergism between nitrate and triethanolamine (TEA) in the Al electrode activation was investigated in the NH4Cl electrolyte. Using the Fe(Ⅲ), anthraquinone-2,6-disulfonic acid disodium salt-doped polyaniline (PANI/Fe/AQDS) cathode as the air electrode, Al as counter anode, a gel electrolyte of NH4Cl, TEA and NaNO3, a flexible and ultrathin air battery was prepared. The resulting Al//PANI battery exhibits excellent electrochemical performance, and it has a thickness of approximately 0.5 mm, a discharge plateau of 1.2 V, and a discharge capacity of 50 mAh·cm-
2
and a considerable self-restoring capacity. So the battery has the feasibility to use as a disposable battery.

Figure 1
Tailoring Microstructures and Ionic Conductivities of Li1+XAlxGe2–X(PO4)3 (LAGP) Solid Electrolytes for All-Solid-State Batteries
Authors: Kim Yong-Chan , Park Min-Sik , Jung Kyu-Nam
Published: February 2020

Lithium ion batteries (LIBs) have been successfully utilized as power sources for various electronic devices (e.g. mobile phone, remote controller, lab-top, etc.). Recently, the application of LIBs is extending to emerging markets such as electric vehicles (EVs) and energy storage systems (ESSs) for grid-supporting. Unfortunately, conventional LIBs still suffer from safety issues associated with the use of flammable organic electrolytes. To overcome such limitation of LIBs, many attentions have been devoted to the development of all-solid-state batteries (ASBs) that are employing solid electrolytes with excellent structural and electrochemical stabilities. Li1+xAlxGe2–x(PO4)3 (LAGP) is a kind of potential solid electrolytes with a NASICON structure. It offers relatively high bulk ionic conductivity (~10-4 Scm-1) with a wide electrochemical window and great moisture tolerance.[2] Owing to these advantages, LAGP can be a great option as a practical solid electrolyte for realizing ASBs. However, there are some technical issues to be resolved before commercial use of LAGP solid electrolytes as follow; i) a low ionic conductivity arising from the high boundary resistance and ii) a high synthesis temperature (i.e. energy consumable process).

In this work, the microstructures of LAGP solid electrolyte are tailored by addition of Bi2O3 and B2O3 with a purpose of improving the ionic conductivity and reducing the fabrication temperature. Based on various structural and electrochemical analyses, we investigate the correlation between microstructure and ionic conductivity of LAGP. In practice, Bi2O3 is able to improve the structural integrity of LAGP with turning down of the sintering temperature, leading to the densification of LAGP [1] and, on the other hand, B2O3 facilitates the grain growth of LAGP during synthesis.[3] As a result of co-addition of Bi2O3 and B2O3, the ionic conductivity of LAGP solid electrolyte increases about one order of magnitude higher than pristine LAGP. This work will provide a practical guideline to develop a highly reliable solid electrolytes for ABSs.

(Figure 1 image)

SD Lee and KN Jung, ChemSusChem
10, 2175 (2017)

Masashi Kotobuki, Keigo Hoshina, Yasuhiro Isshiki, Phosphorus Research Bulletin
24, 061 (2010)

Harsharaj S. Jadhav, Ramchandra S. Kalubarme, Seong-Yong Jang, KN Jung, Mo, Dalton Trans.
43, 11723 (2014)

Figure 1
CO2-Derived Manganese-Oxide Carbon Composites As Electrode Materials for Fuel Cells and Supercapacitors
Authors: Park Jae Hyun , Choi Won Yeong , Kim Yeeun , Lee Jae W.
Published: February 2020

Boron-doped porous carbon impregnated with manganese oxide were synthesized from sodium borohydride (NaBH4) and carbon dioxide (CO2) under a moderate experimental condition (1 bar and 500 ℃) by a facile two-step method. The boron-manganese oxide-carbon nanocomposites exhibited enhanced electrochemical properties in both electrocatalysts for oxygen reduction reaction (ORR) and electrode materials for supercapacitors. The composites showed a four electron transfer pathway and had electrocatalytic activity comparable to that of commercial platinum-carbon catalyst. They also provided a high capacitance (150 F g-1 at 1.0 A g-1 and 136 F g-1 at 10.0 A g-1) compared to that of bare boron-doped carbon (58 F g-1 at 1.0 A g-1 and 15 F g-1 at 10.0 A g-1) due to generation of new active sites, increase in specific surface area, and reduction of overall resistance by efficient interaction within the composites.
Advanced Porous Membranes with Slit-like Selective Layer for Flow Battery
Authors: Qiao Lin , Zhang Huamin , Lu Wenjing , Xiao Chuanhai , Fu Qiang , Li Xianfeng , Vankelecom Ivo F.J.
Published: February 2020

An advanced porous membrane containing slit-like selective layer on its top surface is designed and prepared for flow battery application. The structure is realized by regulating the parameters during membrane formation process. The porous membrane exhibits a thick skin layer with narrow slits and sponge-like support layer in the cross-section. The thick and comparatively hydrophobic skin layer hinders the passage of vanadium ions. Meanwhile, the slit structure and comparatively hydrophilic support layer facilitates the transport of protons. The resulting poly(ether sulfone) (PES)/sulfonated poly(ether ether ketone) (SPEEK) porous membrane containing slit-like selective layer achieves an excellent balance between ion selectivity and proton conductivity, resulting in a columbic efficiency of 98.5%, a voltage efficiency of 91.7%, and an energy efficiency of 90.4% at 80 mA cm-2, which is much higher than a vanadium flow battery (VFB) with the commercial Nafion 115. Therefore, this work provides a simple and economical method to develop high-performance, low-cost membranes for VFB applications.

Fig. 1 The principle of the nonsolvent-induced segregation of hydrophilic polymer chains in PES/SPEEK blend membranes.

Figure 1
Additive-Mediated Electrode-Electrolyte Interphase for Long Service-Life, High-Nickel Cathodes for Lithium-Ion Batteries
Authors: Li Jianyu , Manthiram Arumugam
Published: February 2020

With a dramatically increasing demand for electric vehicles (EVs), a driving range of minimum 300 miles is a must to satisfy the market requirement. Such a demand has motivated enormous efforts focused on the development of high-Ni layered oxide cathodes (LiNi1
−xMxO2 with M = Mn and Co and (1 − x) > 0.9). However, degradation of the electrode–electrolyte interphase, which is a major cause for poor cycle life, remains as a critical problem that hinders their widespread application, especially when the voltage exceeds the HOMO (highest occupied molecular orbital, ≈ 4.3 V vs. Li/Li+) of the organic carbonate electrolytes used. Specifically, the parasitic electrolyte decomposition occurs on the charged cathode surface, resulting in the formation of cathode–electrolyte interphase (CEI) with complicated surface chemistry. Moreover, the surface degradation on cathode usually involves active mass dissolution, which is a common phenomenon in various cathodes. Subsequently, the dissolved transition-metal ions reach the anode side through chemical crossover and poison the anode–electrolyte interphase (AEI) on the graphite surface. Thus, understanding the chemical and electrochemical reactions between the electrode and electrolyte, which influences the composition, microstructure, and chemical properties of the formed electrolyte–electrolyte interphases (EEIs), is crucial to establishing high-energy-density Li-ion batteries with long, stable service life. Herein, with an ultrahigh-Ni layered oxide (LiNi0.94Co0.06O2) as a model cathode and lithium bis(oxalate) borate (LiBOB) as a model electrolyte additive, the EEI chemical and physical property changes on both the cathode and anode are elucidated. Moreover, the layered architecture of the CEI and AEI at the nanometer scale is revealed by time-of-flight secondary ion mass spectrometry (TOF-SIMS) and the correlation between CEI and AEI properties is illustrated. On a chemical perspective, the tuned EEIs are configured with B
x
O
y
species and less ethylene carbonate/LiPF6 decomposition products, which endows the CEI with extreme robustness against electrochemical abuse and better Li-ion diffusivity within both the CEI and AEI. Moreover, it reveals that the modification of the surface chemistry on the cathode side would beneficially change the physical stacking behavior of components on the AEI. AEI is reconstructed from a thick “three-layer” architecture (F-enriched exterior layer, O-dominating intermediate layer, and Li-containing interior layer) to a thin “two-layer” architecture (O-enriched exterior layer and Li-dominating interior layer), benefiting from the B
x
O
y
enrichment within the EEI. As a result, superior electrochemical performance is achieved by manipulating the electrode surface chemistry even under a moderately high operating voltage (4.4 V vs Li/Li+), and the capacity retention is greatly increased from 61 to 80% after 500 cycles in a full cell assembled with graphite anode.

Figure 1
Investigation of Solvent Effects on Electrochemical Quartz Crystal Microbalance (eQCM) Studies of Carbon Nanomaterials
Authors: Quinlan Ronald Allen , Carrion Alexandra Rosado , Outlaw Ronald Allen , Premathilake Dilshan
Published: February 2020

The electrochemical quartz crystal microbalance (eQCM) technique provides a direct assessment on the behavior of electroadsorbed ions and a fundamental understanding of charge-storage mechanisms. Though recent efforts have illustrated changes in measurements as a function of electrolyte composition, our work describes the effects of solvent choice on the eQCM measurement itself. Results comparing aqueous, polar aprotic, and polar protic solvents with model substrates will be presented.
Characterization of CaZrO3 Coating Layer Formed on YSZ Plate for SOM Anode in CaCl2-CaF2-CaO Electrolyte
Authors: Kim Wan-Bae , Nersisyan Hayk , Kwon Suk-Cheol , Yoo Bung-Uk , Lee Jong-Hyeon
Published: February 2020

Conventional metal production ways using graphite anode emits pollutants such as CO2 and CO. This can be solved by replacing the graphite anode with the SOM anode, and YSZ is the representative SOM anode material. In this study, it was evaluated the formation behavior and characterization of CaZrO3 layer formed on YSZ anode surface due to in-situ reaction in CaCl2-CaF2-CaO electrolyte during electrolysis.

The experiment was performed in three stages: compacting, sintering and CaZrO3 layer formation reaction. First, the PVA was used as a binder to manufacture YSZ granule powder, green compact was made using uniaxial press. Second, the green compact was sintered in a box furnace. Finally, The CaZrO3 layer formation reaction was performed in a glove box. YSZ plates were analyzed by SEM/EDS and XRD for CaZrO3 layer formation, morphology, component and phase analysis. The yttrium concentration eluted into the electrolyte by CaZrO3 layer formation reaction was analyzed by ICP-OES. In order to evaluate the performance of YSZ including CaZrO3 coating layer as a SOM anode, ion conductivity was measured. In this paper, the stability of SOM anode with CaZrO3 layer will be discussed.
Ultrasonication Assisted Production of Silicon Nanoparticles from Nanowires
Authors: Mohan Susmitha , Alice Francis Aneeta , Koech Philemon K , Ogini Martins E , Deo Makarand , Albin Sacharia
Published: February 2020

With the rapid development of nanoscience and engineering, silicon nanoparticles (SiNPs) have attracted great attention in the fields of medicine, energy, and optoelectronic engineering due to their remarkable physical and chemical properties. SiNPs offer active surface state for functionalization, size-dependent multicolor light emission, stability against photobleaching, and biocompatibility. Most fabrication methods such as chemical vapor deposition or laser pyrolysis require specialized equipment and harsh chemicals for producing SiNPs. Sonochemical synthesis of SiNPs has advantages such as mild reaction environments and fewer reagent requirements. In this work, a simple method to produce SiNPs by combining the chemistry of two-step metal-assisted chemical etching (MACE) using HF/H2O2 and ultrasonication is demonstrated (Fig. 1). MACE is recognized as a unique process for producing silicon nanowires (SiNWs) (Fig. 1a). Arrays of SiNWs were dislodged from the substrate (Fig. 1c), with their original morphology almost intact and were converted into nanoparticles by fragmentizing using ultrasonication. With a yield strength of 2x106 g/cm2, a SiNW of 100nm diameter can be broken from the substrate with a 1.53mg force. Thus, a standard ultrasonicator with 80W power (40kHz) commonly available in the laboratory is sufficient for this process. In order to study the effect of ultrasonication time on the fragmentation of nanowires at a constant power, the samples were sonicated in IPA and the particles were characterized using SEM and spectrometer. The average number of nanowires dislodged from the substrate increased with time and reached its optimum level at approximately one hour of sonication (Fig. 1b). Fragmentation by longer sonication time, beyond 50mins makes the nanowires shorter to form nanoparticles as small as 50nm (Fig. 1d). These particles can be further reduced in size by controlled chemical etching, if required. The possibility of reusing the silicon wafer after each etching and ultrasonication has been investigated by means of gravimetric analysis of SiNWs fabricated on a 4cmx4cm Si substrate. The efficiency of SiNW production was estimated to be 17%. Further studies on the effect of sonication time and power on the efficiency of SiNW production will be reported. The starting wafer could be reused again to minimize cost, which will be a great advantage for mass production of SiNWs and SiNPs.

Figure 1
Study of Channel-Induced Convective Mass Transport in a PEMFC Using Limiting Current Method
Authors: Mojica Felipe , Sarker Mrittunjoy , Rahman MD Azimur , Chuang Po-Ya Abel
Published: February 2020

In a proton exchange membrane fuel cell (PEMFC), oxygen transport is a critical limitation for operating at high current density due to sluggish Oxygen Reduction Reaction (ORR). Total oxygen transport resistance includes losses from channel, diffusion media, and catalyst layer. This study focuses on studying the effect of flowfield design on total oxygen transport resistance with the assist of limiting current diagnostic tool. The limiting current method is an in-situ experimental tool to study dry and wet oxygen transport resistances by varying oxygen concentration. In addition, a commercial finite element simulation software, COMSOL Multiphysics, is employed to elucidate gas flow characteristics in the channel and diffusion media. In this work, we designed and fabricated a novel three-dimensional channel and compared with a baseline straight rectangular channel as shown in Figure 1. The novel 3-D channel has converging-diverging nozzle like design. Therefore, the oxygen gas is being directed in and out of the diffusion media when entering and exiting the throat area, respectively. In addition, the alternating nature of the neighboring channel enables cross flow through the diffusion media. As confirmed by the Comsol simulation, convective gas flux is induced inside the diffusion media rather than pure diffusion mechanism observed in conventional channel design (Figure 1a). All fuel cell tests were done with baseline materials, which consist of wet-proofed Toray-H-060 coated with microporous layer and NR211 membrane electrode assembly from Ion Power. The limiting current results show that the novel 3-D channel design has significant lower total oxygen transport resistance compared to conventional straight channel design under both dry and wet conditions. As a result, 3-D channel design shows much improved fuel cell performance under wet operating condition. Detail experimental and simulation results will be shared at the conference.

Figure 1
Two-Dimensional CoSx/SnSx Chalcogenides Layered Ultrathin Nanosheets for Electrocatalytic Hydrogen Evolution
Authors: Kim Dong-Hyung , Shinde Sambhaji S , Lee Jung-Ho
Published: February 2020

Hydrogen evolution reaction (HER) via water splitting through electrocatalysis using advanced inexpensive materials to replace precious platinum catalysts holds great promise for clean energy technology. Ultrathin two-dimensional nanosheets of layered transition metal chalcogenides are fundamentally and technologically intriguing. Mono- or few- layered chalcogenides obtained either through exfoliation of bulk materials or bottom-up synthesis are depending on their composition, structure, and dimensionality. Herein, we designed an intra-layered CoSx/SnSx catalysts with abundant exposed edges anchored on reduced graphene oxide through facile hydrothermal process. The intra-layers play a crucial role in tuning their intrinsic catalytic properties and long-term stability by creating substantial intrinsic active sites and covalent nature of inter-layer. The CoSx/SnSx catalyst exhibited a large cathodic current, low overpotential of 37 mV at 10 mA cm-2, small Tafel slope of 62 mV dec-1, and long-term stability in acidic environments than those of noble metals. This work shows a grate potential for scalable, low-cost, and highly efficient catalysts for hydrogen evolution, fuel cells.
Characterizing the Performance of Biologically Templated Membrane Electrode Assemblies for Low-Loaded Electrodes in Proton Exchange Membrane (PEM) Electrolyzers
Authors: Kim ChulOong , Pramounmat Nuttanit , Renner Julie N.
Published: February 2020

Hydrogen is one of the world’s most important chemicals. Hydrogen is produced at around 50 billion kg/year, and that number is expected to grow with increasing renewable usage in the future. Hydrogen generation via proton exchange (PEM)-based electrolysis is a promising technology because of its flexibility and deplorability.1 However, since platinum group metal catalysts are a major cost driving factor at large scales, a fundamental understanding the catalyst support interactions and the effect of architecture on PEM electrolysis performance is needed to reduce noble metal catalyst loadings.

This work focuses on investigating biologically templated electrode components. Specifically, we explore bi-functional material-binding proteins to position ionomer on or near catalyst sites and comparing the performance in a lab-scale PEM electrolysis cell. The work compares the performance of a baseline platinum coated cathode electrode to platinum cathodes with biological organization. Protein additives increase the performance of an ultra-low catalyst PEM electrolysis cell. This has implications across many other green, electrochemical technologies useful for the energy sector.

References

Ayers, K. E., Renner, J. N., Danilovic, N., Wang, J. X., Zhang, Y., Maric, R., & Yu, H. (2016). “Pathways to ultra-low platinum group metal catalyst loading in proton exchange membrane electrolyzers”. Catalysis Today, 262, 121-132. doi:http://dx.doi.org/10.1016/j.cattod.2015.10.019
Electrochemically-Controlled Dimerization in Ferrocene Ureidopyrimidone Derivatives. the Effect of Ferrocene Position
Authors: Mikhaylova Veronika , Smith Diane K
Published: February 2020

Ureidopyrimidones (UPy’s) are well-known to dimerize in weakly polar solvents such as CH2Cl2, via the formation of four strong, linear H-bonds. This, coupled with their relative ease of synthesis, has led to their use as a linker in supramolecular polymers and gels. The attraction of such materials is their inherent self-healing properties, whereby a defect can be repaired by using heat or mechanical stress to reversibly break the polymer at the H-bond sites. This increases the fluidity of the material, allowing the defect to fill in. Upon cooling or relief of stress, the H-bonds reform and the defect is repaired. However, while the use of heat or mechanical stress as stimuli are clearly useful, neither is inherently very selective. On-going research in our lab is focused on increasing the versatility of the UPy system by creating electroactive UPy’s in which dimerization strength can be controlled in a more selective manner through oxidation and reduction.

Previously, our group has shown that dimers based on the ferrocene-UPy derivative, 1, break apart upon oxidation of the ferrocene to the ferrocenium form at mM concentrations in CH2Cl2. This could be due both to the creation of electrostatic repulsion and a decrease in H-bond strength due to the reduced H-donor ability of the O and N on the pyrimidone side. In this project, another Fc-UPy has been prepared, 2, in which the ferrocene is attached to the urea side of the molecule. In contrast to 1, oxidation of 2 shows a single reversible ferrocene CV wave in CH2Cl2 at mM concentrations. Under these conditions, 1H NMR indicates that 2 is fully dimerized, thus, it appears that, unlike with 1, oxidation has no significant effect on dimerization of 2. In both cases, oxidation would increase electrostatic repulsion. However, unlike in 1, oxidation of 2 should actually increase H-bond strength by making the urea NH a stronger H-donor. Therefore, it appears that the effect of oxidation on the H-donating or accepting ability is a more crucial factor for dimerization control than electrostatics in these systems.

Figure 1
Design Integrated Microfluidic Chips for Clinical Applications
Authors: Li Bor-Ran
Published: February 2020

A biosensor is generally defined as an analytical device, which converts the biochemical responses into the quantifiable electronic signals. Its extensive utilities in medical diagnosis, toxicity testing, chemical analysis, food industry, and many other areas for quantitative assessments has appeared. Quartz crystal microbalance and field-effect transistor based devices have been demonstrated to possess exceptional characteristics and outstanding performance while conjugated with the advanced nanotechnology. However, both devices still have to face the nonspecific binding issue, which is a headache for researchers on all biosensor platforms. In our research, we have efficaciously reduce 95% nonspecific binding via immobilize the zwitterionic layer on the surface of the chip. Moreover, we integrate microfluidics, nanoparticles, rapid surface modification on several bio-sensing platforms to efficiently pretreat specimens and detect target biomolecules. In addition, a series advanced microfluidic ships are designed for lymphocyte isolation, active sperm sorting, and nanoparticle synthesis.

Figure 1
Modelling of Direct Laser Patterning of Self Assembled Monolayers (SAMs) on Cobalt-Chromium Alloy
Authors: Powell Christianna , Mahapatro Anil
Published: February 2020

The implantation of biomedical devices is often accompanied with complications such as post-operative infections, lack of tissue integration, and biofilm formation. A strategy that will limit these complications by administering a focused multi-therapeutic treatment is needed. The direct laser patterning of self-assembled monolayers (SAMs) onto the implant can be used to modify the surface and provide a platform for multi-therapeutic treatment. Conventionally, surface patterning of SAMs requires a uniform surface, but most bio-implants are irregularly shaped. Laser patterning is able to bypass this problem and modify the surface of an implant of irregular shape with precision. Effective optimization of patterning process is needed to minimize experimental trials and error for the development of laser assisted patterns. In this abstract, we report the development of a model to simulate the direct laser patterning process on Cobalt-Chromium (Co-Cr) Alloy. COMSOL Multiphysics 4.3b was used to create the 3D model. Governing equations associated with heat transfer in solids were used with the heat source being the heat provided by the laser. The model calculated the resulting temperature gradient on the cobalt chromium surface giving an indication of SAM desorption based on the surface temperature of the metal. Temperature profiles as simulated by the model indicated a laser etch diameter of approximately 11µm. Experimental results of direct laser etching of SAMs on cobalt chromium alloy gave a laser etch of 12µm. The close proximity of the predicted and experimental diameter confirms the validation of the developed model.
Imaging Electrochemistry at the Nanoscale By Liquid Cell Transmission Electron Microscopy
Authors: Hietzschold Sebastian , Sepunaru Lior
Published: February 2020

Direct optical visualization of electrochemical processes at the nanoscale is an exciting field of research. It became more and more feasible through the development of enclosed liquid cells for transmission electron microscopes over the past years [1]. The liquid cell itself is built by stacking two silicon chips with electron transparent silicon nitride windows, which are then sealed by a gasket against the surrounding high vacuum in the microscope column. Microfabrication of electrode structures onto the chips opened up the opportunity to control the electric potential and current within the cell in order to perform in-situ potentiometric measurements and impedance spectroscopy. This unique feature enables the correlation of real-time optical imaging at the nanoscale and electrochemistry. So far, most of the experiments have focused on batteries and corrosion studies [2,3]. While there have been numerous reports on the diffusion and agglomeration of nanoparticles [4], the visualization of nanoparticle dynamics coupled to voltammetry in the vicinity of an electrode surface has received less attention. Herein, we investigate the diffusion, deposition and stripping of nanoparticles at an electrode under an applied electric bias. We give insight into how a nanoparticle collision event quantitatively transfers into an electrochemical current signal and disentangle electron beam effects. These results might pave the way towards observation and understanding of reactions catalyzed by nanoparticles in general.

References:

[1] N. de Jonge and F. M. Ross, Electron microscopy of specimens in liquid. Nat. Nanotechnol., 6 (2011), 695-704

[2] B. L. Mehdi, J. Qian, E. Nasybulin et al., Observation and quantification of nanoscale processes in lithium batteries by operando electrochemical (S)TEM. Nano Lett., 15 (2015), 2168-2173

[3] S. W. Chee, S. H. Pratt, K. Hattar et al., Studying localized corrosion using liquid cell transmission electron microscopy. Chem. Commun., 51 (2015), 168-171

[4] H.-G. Liao, K. Niu and H. Zheng, Observation of growth of metal nanoparticles. Chem. Commun., 49 (2013), 11720-11727
Bubble Nucleation-Based Electrochemical Sensor for Detection of per- and Polyfluoroalkyl Substances (PFAS) in Water
Authors: Luo LONG , Ranaweera Ruchiranga
Published: February 2020

Here, we present a proof-of-concept electrochemical detection method for detection of per- and polyfluoroalkyl substances (PFASs) in water. PFASs are persistent and globally distributed environmental contaminants. The strong carbon-fluorine bonds of PFASs make them resistant to physical and metabolic degradation leading to bioaccumulation and adverse health outcomes in humans and wildlife. The quantitative determination of PFASs in environmental matrices has been dominated by the use of HPLC-negative electrospray ionization- tandem MS. However, the high purchase and maintenance costs limit the availability of this method for routine on-site screening analyses. Therefore, there is a critical need to develop a low-cost, sensitive, portable method for detection of PFASs in water. Our detection method is based on the high surface activity of PFASs which lowers the energy barrier for bubble nucleation. We developed a sensitive electrochemical transducer that reports the change of surface tension in the form of an electrical current which is directly related to the concentration. The limit of detection of our detection method is 20 nM (or ~10 μg/L) with a dynamic range of three orders of magnitude. With the addition of a preconcentration step, our method achieves the limit of detection of interest:14 pM (or 70 ng/L, which is recommended by the U.S. Environmental Protection Agency for PFOS and PFOA—the two dominant PFAS contaminants— in drinking water individually or combined.)
(Invited) X-Ray Reflectivity Studies of Interfaces in Lithium-Ion Batteries
Authors: Steinrueck Hans-Georg
Published: February 2020

In lithium-ion batteries (LIBs), the arrangement of electrolyte molecules directly at the electrode interface, and the corresponding electric double layer (EDL) are expected to govern the interfacial ion transport during charge/discharge and the electrochemical stability, i.e. the origin and properties of the solid electrolyte interphase (SEI). The SEI is formed on anode surfaces due to electrolyte decomposition at low potentials outside the electrolyte's electrochemical stability window, and dictates cell chemistry, cycle life, and electrochemical reversibility.

Towards this end, the first topic of this talk covers an Ångstrom-resolution combined experimental and theoretical structural determination of solid–liquid interfaces relevant to LIBs, specifically a baseline organic electrolyte containing various concentrations of lithium hexafluorophosphate (LiPF6) salt at a metal oxide interface. We find good agreement between our x-ray reflectivity (XRR) and molecular dynamics (MD) simulations. These show well defined interfacial layering of electrolyte molecules and that solvent molecules in the first interfacial layer are aligned surface-parallel. Furthermore, we observe reorientation of solvent molecules in the presence of ions [1,2].

The second portion of this talk describes a multi-property characterization study of the physical and chemical properties as well as the nucleation and growth of the SEI on silicon anodes relevant to LIBs. We combined in situ XRR, linear sweep voltammetry (LSV), and ex situ x-ray photoelectron spectroscopy (XPS) to develop a holistic understanding of the SEI formation mechanism and properties on native oxide terminated single crystalline Si electrodes. Our self-consistent findings show the formation of two distinct inorganic SEI layers, and reveal the critical role of the surface oxide in the surface electrochemistry of silicon anodes. These novel insights will be discussed with regard to the performance of LIB in general [3,4,5]. Finally, we will present recent results from combining in situ XRR and precision electrochemical measurements to understand origins of coulombic efficiencies, capacity fading, and charging rate capabilities in thin film silicon batteries.

­­­­References

H.-G. Steinrück, C. Cao, Y. Tsao, C. J. Takacs, O. Konovalov, J. Vatamanu, O. Borodin, M. F. Toney, Energy Environ. Sci., 11, 594-602 (2018)

Horowitz, H.-G. Steinrück, H.-L. Han, C. Cao, I. I. Abate, Y. Tsao, M. F. Toney, G. A. Somorjai, Nano Lett. 18, 2105-2111 (2018)

Cao, H.-G. Steinrück, B. Shyam, K. H. Stone, M. F. Toney, Nano Lett.16, 7394-7401 (2016)

Cao, H.-G. Steinrück, B. Shyam, M. F. Toney, Adv. Mater. Interfaces 4, 1700771 (2017)

C. Cao, I. I. Abate, E. Sivonxay, B. Shyam, C. Jia, B. Moritz, T. P. Devereaux, K. A. Persson, H.-G. Steinrück, M. F. Toney, Joule (accepted 2018)
Cross Sectional Mapping of Nano-Mechanical Properties of Composite Electrodes for Lithium Ion Batteries Using Bimodal Mode Atomic Force Microscopy
Authors: Masuda Takuya , Sakai Hiroki , Taniguchi Yukinori , Uosaki Kohei
Published: February 2020

Lithium-ion batteries (LIBs) have been widely used for various applications including portable devices and electric vehicles. Improvement of the cyclability and capacity is an important challenge. In the manufacturing process, active materials, conductive additives and binders are mixed in a solvent at a certain ratio and the slurry is casted, dried and pressed on a metallic foil current collector to yield a composite film. The composite films are assembled together with an electrolyte solution and a separator in coin or laminate cells. The packing density and mechanical strength of each material are important parameters for the cell performance because the volume expansion and resulting mechanical stress may cause a destruction of the electrical connections between binders, current collectors and the active materials during the charge/discharge processes. Young's modulus is one of the most important mechanical properties because it is an indicator of the mechanical strain in a material under a certain amount of stress.

Nanoindentation has been used to measure the Young's moduli of various materials. However, it has a few restrictions as follows: (i) sample surface has to be destructed in nanoindentation and (ii) it has a limited spatial resolution, typically a few micrometers, due to the size of the disruption. Although recent atomic force microscopy (AFM) techniques allow non-destructive and high-resolution Young's modulus mapping by measuring force curves at each point using relatively weak force of<100 nN, this method is not applicable for stiff materials with modulus larger than 100 GPa because their sample deformation is too small to be detected by the cantilever deflection. Here, a newly developed technique, bimodal AFM that allows nanoscale mechanical mapping for a wide range of Young's modulus from 0.1 to 200 GPa in a non-destructive manner, was applied to LiCoO2-based positive and graphite-based negative composite electrodes before and after the charge-discharge cycles in a coin cell for a demonstration.

Reference: H. Sakai, Y. Taniguchi, K. Uosaki, T. Masuda, “Quantitative cross-sectional mapping of nanomechanical properties of composite films for lithium ion batteries using bimodal mode atomic force microscopy”, 2019, 413, 29-33.
Study of Sulfur-Based Electrodes By Operando Acoustic Emission
Authors: Lemarie Quentin , Idrissi Hassane , Thivel Pierre-Xavier , Alloin Fannie , Roué Lionel
Published: February 2020

The acoustic emission (AE) technique has been widely used since the 70’s for detecting anomalies such as leakages and cracks on large structure (e.g. bridges, pressure containers, and pipe lines). The analysis of the AE signals (transient elastic waves) can also be used to characterize the degradation mechanisms (crack growth, friction, delamination, matrix cracking, corrosion, etc) of various materials subjected to a stress by mechanical, pressure or thermal means. Recently, AE technique has also been used to evaluate the degradation of metal hydride electrodes for Ni-MH [1] and Si-based electrodes for Li-ion batteries [2,3]. Cracking of the active material and gas evolution are the main sources of AE signals identified in these studies.

In the present study, the AE technique is used for studying upon cycling the mechanical degradation of S-based electrodes for Li/S batteries. The AE signals were recorded by a piezoelectric transducer fixed on the back of the working electrode. S-based electrodes made with two different binders (PVdF vs. CMC) and two different current collectors (standard Al foil vs. porous 3D carbon paper) were studied. In all cases, AE signals were mainly detected during the first plateau of the first discharge, suggesting that the electrode degradation mostly occurs during the initial dissolution of the S8 particles. AE signals were also detected during a few subsequent cycles when CMC binder is used. This is attributed to a better propagation of the AE signals through the electrode thanks to an improved adhesion of the electrode to the current collector in comparison to PVdF binder. This is confirmed by further mechanical resistance testing (peel and scratch tests). The use of a carbon paper as a current collector combined to CMC binder greatly improves the electrochemical performance of the S electrode by preventing the collapse of the electrode upon cycling. This electrode also presents an increased amount of AE signals, suggesting that the carbon fibres of the C paper act as an AE waveguide.

This study demonstrated that AE could be used as an efficient tool to monitor the morphological degradation of S-based electrodes upon their cycling and offers relevant information for optimizing their formulation and architecture.

A. Etiemble, H. Idrissi, P. Bernard, L. Roué. New insights into the pulverization of
LaNi5-based alloys with different Co contents from electrochemical acoustic emission measurements. Electrochim. Acta 186 (2015) 112-116

A. Tranchot, A. Etiemble, P-X. Thivel, H. Idrissi., L. Roué. In-situ acoustic emission study of Si-based electrodes for Li-ion batteries, J. Power Sources 279 (2015) 259-266.

A. Tranchot, P-X. Thivel, H. Idrissi, L. Roué. Influence of the Si particle size on the mechanical stability of Si-based electrodes evaluated by in-operando dilatometry and acoustic emission. J. Power Sources 330 (2016) 253-260.

Figure 1
Battery Charakterisation Using Optical Methods
Authors: Rahe Christiane
Published: February 2020

The fast advance of electromobility demands the maximizing of energy density and lifetime of any given battery. Such needs for precise information can only be satisfied with the help of adequate simulation models. During the last years, several battery models have been proposed [1, 2, 3].

This publication focuses on physical-chemical battery (p-c-b) models as they allow insights into single electrochemical processes and their effect on the whole system and reliable predictions of the battery behavior. P-c-b models are based on the underlying chemical and physical equations describing the internal battery processes. They require input parameters, which need to be adapted to the specific characteristics of the examined cell and especially the used materials. Input parameters need to be determined in detailed analyses on the opened cell. However, existing methods for model parameterization are insufficient and time intensive: Existing methods are limited in terms of mathematical constraints.

In this work, a measurement method for determining the material diffusion parameter is described and applied to different samples based on microscopy. An optical cell is used to track the lithiation progress of graphite anodes introducing color changes upon intercalation. Out of these data, the diffusion coefficient of lithium in graphite is calculated. Furthermore, a parameter study on different graphite anodes is conducted. Single parameters of the graphite anodes are changed to execute a parameter study: the influence of porosity and particle size is shown and analyzed.

The results of the parameter study can be used to define the input parameters for the next generation of battery models. Furthermore, the results indicate that the proposed measurement method offers several advantages (as easy adaptable and quick measurable) compared to existing methods. The proposed method can be adapted to other cell types and models.

[1] M.Ecker, et all. Parametrization of a Physico-Chemical Model of Alithium-Ion Battery doi:10.1149/2.0551509 J. Electrochem. Soc. 2015 volume 162, issue 9, A1836-A1848

[2] D.Cittanti, et all. Modeling Li-ion batteries for automotive application: A trade-off between accuracy and complexity, doi: 10.23919/EETA.2017.7993213, IEEE Xplore 27.07.2017

[3] A. Kashkooli, Multiscale modeling of lithium-ion battery electrodes based on nano-scale X-ray computed tomography, doi: 10.1016/j.powsour.2015.12.134, J. Power Sources, 2016, vol. 307, p. 496-509