bluuebunny/crossref_metadata_2025 huggingface dataset:
Ion-Pairing Effects on the Absolute Oxidation Potential of the Fc/Fc+ Redox Couple in Complex Non-Aqueous Environments
Authors: Hymel John , McDaniel Jesse
Published: November 2022

Ferrocene (Fc) is commonly used as an internal redox couple in electrochemical measurements. Therefore, understanding how the absolute oxidation potential of Fc is modulated by different solvents and ion concentrations is important for facilitating the comparison between different experimental measurements. Standard implicit solvation models are unable to examine these systems since they lack atomistic detail of the solvent structure and ion coordination. Using polarizable forcefields fit to ab initio quantum chemistry calculations, we have computed the absolute oxidation potential of the Fc/Fc+ redox couple in water, acetonitrile, 1,2-dichloroethane, and trichloromethane. Since experimental measurements are often taken in mixtures of nonaqueous solvents and ionic liquids, we have computed the oxidation potential of Fc in mixtures of acetonitrile and 1,2-dichloroethane with an ionic liquid, [BMIM+][BF4-]. In order to elucidate the effect ion-pairing has on the thermodynamics of this electron transfer process, we relate the differential solvation free energy of Fc/Fc+ to anion coordination sampled in molecular simulations. Quantification of these solvation/environmental effects has important implications in how the thermodynamics of electron transfer processes are modulated by ion concentration fluctuations in the electrical double layer at electrode interfaces.
Direct Observation of the Sporicidal Action of Hydrogen Peroxide on Bacillus atrophaeus Spores By Optical Trapping Raman Microscopy
Authors: Bertz Morten , Molinnus Denise , Schoening Michael J. , Homma Takayuki
Published: November 2022

Hydrogen peroxide (H2O2), a strong oxidizer, is frequently used for chemical sterilization in aseptic food processing. Due to their inherent robustness, bacterial spores, i.e. spores of Bacillus atrophaeus, are commonly employed to evaluate the efficacy of the sterilization procedure [1]. Despite its widespread use, however, the details of the sporicidal action of H2O2 are not yet fully understood, with various mechanisms being discussed in the literature [2,3]. Here, we employ optical trapping Raman microscopy to elucidate the sporicidal mechanism of H2O2. Optical trapping Raman microscopy allows us to isolate, investigate, and manipulate individual spores from a sample (Fig. 1A). Combining optical microscopy with the real-time, label-free chemical information obtained from Raman spectroscopy directly reveals the sequence of steps that lead to oxidative spore death after H2O2 exposure (Fig. 1B).

We find that spore degradation begins with the fast, cooperative release of dipicolinic acid (DPA), a key spore biomarker and a major component of spore’s core. This indicates a breach of the inner membrane surrounding the core. The onset of DPA release depends on the concentration of H2O2. DPA outflux is accompanied by the formation of oxidation products (mostly carbonyl compounds) and oxidation continues after exchange of DPA with the surrounding medium is complete. The remaining spore shell then slowly disintegrates and continues to shrink on a timescale of hundreds of seconds. Simultaneous observation of spore morphology and size by optical microscopy and particle tracking corroborates this three-step mechanism.

The presented assay allows on-line monitoring of spore composition and morphology, which directly reveals the mechanism underlying the sporicidal action of H2O2. In addition, trapped spores can be exposed to different chemical or physical stimuli (temperature, light, chemical composition of the surrounding medium, etc.) to investigate a variety of industrially relevant sterilization conditions.

Jildeh, Z. B., Wagner, P. H. & Schöning, M. J. Sterilization of Objects, Products, and Packaging Surfaces and Their Characterization in Different Fields of Industry: The Status in 2020. physica status solidi (a)
218, 2000732 (2021).

Setlow, P. & Christie, G. What’s new and notable in bacterial spore killing. World J Microbiol Biotechnol
37, 144 (2021).

Setlow, P. Spores of Bacillus subtilis: their resistance to and killing by radiation, heat and chemicals. J Appl Microbiol

101, 514-525 (2006).

Figure 1
(Invited) Micro-Enabled Technologies for Next-Generation Health Monitoring
Authors: Zheng Hanjia , GhavamiNejad Amin , GhavamiNejad Peyman , Odinotski Sarah , Poudineh Mahla
Published: November 2022

To enable personalized and precision medicine, it is crucial to monitor patient health status and bring information on disease-related agents and therapeutic drug molecules into the clinic. This requires new technologies to interrogate different body fluids that are rich sources of biomarkers, such as whole blood and interstitial fluid (ISF). Such technologies enable rapid, sensitive and - ultimately - real-time and continuous analysis of the clinically important biomarkers. Biophysics, materials chemistry and polymer and molecular engineering, as well as micro and nanofabrication, are crucial tools in this endeavor.

At IDEATION Lab, we apply innovative engineering solutions to advance patient health monitoring using two main technologies: Microneedles and Microfluidics. In the first part of my talk, I will present our new transdermal biosensing technologies powered by engineered hydrogel microneedles (HMNs), aptamer probes, and in-situ metallic nanoparticle synthesis for minimally invasive, on-needle, and real-time measurement of clinically important biomarkers in ISF. Our HMN assays expect to pave the way for the next-generation of polymeric-based wearable biosensors. In the second part, I will discuss a real-time biosensor driven by microfluidic techniques that continuously updates specific biomolecules’ fluctuating concentration levels with picomolar sensitivity directly in whole blood. For the first time, our microfluidic assay enables measuring the dynamic changes in blood insulin which is an important knowledge gap in diabetes management.

The new advances reported in this talk, enrich the level of information that can be collected from different body fluids, and provide new means and potentials for highly accurate patient health status monitoring, thus transforming the field of personalized and precision medicine.
(Invited, Digital Presentation) High-Throughput Electrochemical Sensing for Cancer Diagnostics
Authors: Lee Hakho
Published: November 2022

Analyzing circulating extracellular vesicles (EVs) or exosome promises to improve cancer diagnostics and enable serial patient monitoring during therapy. Establishing clinical EV tests, however, faces practical challenges: complex and lengthy sample workup; limited throughput and sensitivity of conventional assays; high equipment or test costs; and lack of clinically validated markers. In this presentation, we report key advances toward clinical EV analyses: i) development of a high-throughput assay strategy, HiMEX (high-throughput magneto-electrochemical exosome), and ii) assessment of EVs as a biomarker of colorectal cancer (CRC). HiMEX integrates magnetic capture with electrochemical detection within a single platform; we enrich cancer-specific EVs directly from plasma samples and profile their protein expression. This approach renders the assay fast (<1 hour) and scalable; we implemented a compact assay system for parallel detection (96-well format). Applying HiMEX, we profiled circulating EVs in clinical samples EVs were found to carry key protein signatures of tumor tissues, and by using a combination of markers, we achieved high diagnostic accuracies (>95%). Preoperative EV tests further showed this method’s prognostic potential for categorizing patients into high- and low-risk groups for 5-year disease-free survival. These outcomes demonstrate HiMEX’s clinical utility for timely, informed cancer care.
Atomic Layer Deposition on an Optical Fibre: Enhancing the Evanescent Field of a Tilted Fibre Bragg Grating Optical Sensor
Authors: Barry Sean , Albert Jacques , Mandia David , Zhou Wenjun
Published: November 2022

Tilted fibre Bragg gratings (TFBGs) are a class of optical fibre based sensor that are presently employed for temperature and pressure detection in transportation, building, and other infrastructure applications. The working principle of these sensors is that a Bragg grating in the core both diffracts light modes to the surface of the fibre, and breaks their symmetry. This produces very surface-sensitive modes that can interact with the fibre surface.

Our discovery of several gold metal deposition processes has permitted the coating of a TFBG with gold: this allows a surface plasmon resonance (SPR) to exist in the gold, and can sense the surface in two important ways: firstly, the shift from a localised plasmon in gold nanoparticles to a continuous plasmon in a closed metal film allows the detection of the thinnest conductive layer of gold. Gold metal grown by atomic layer deposition (ALD) using (Me3P) Me3Au(III) has a growth per cycle of 0.50 Å with oxygen plasma and water as co-precursors. The fibre sensor showed that a continuous plasmon formed at 84 ALD cycles, suggesting that the thinnest optically conductive film of gold metal formed at 4.2 nm (which is demonstrably better than a sputtered film, which showed this shift at 6.5 nm).

This ALD gold coated fibre also showed significant sensitivity to the surrounding refractive index (SRI). The SPR can reach several nanometers into the space surrounding the fibre, and the SRI can invoke a shift in the wavelength of the cladding mode. With an ALD grown stack of 50 nm Al2O3/50 nm Au0, the SPR was 150% more sensitive to an external refractive index, and the nature of the surroundings could be interrogated through changing the polarization of the affected modes.

This contribution will discuss the two aspects of sensing that a TFBG can provide, and show the effect of alumina, gold, and an alumina/gold stack on the extent and sensitivity of the SPR.
(Invited) Development of Fuel Cell-Based Electrochemical Micro Gas Sensor for Monitoring Anesthetic Organic Compounds
Authors: Dong Dongmei , Landi Diego , Flores Emily , Bhansali Shekhar
Published: November 2022

Surgical procedures require administering anesthetic agents in concentrations between 0.5 and 2.0% to maintain a patient's sedation. Maintaining the concentration of the anesthetic agents within the specified range is vital in preventing overdose or awareness during procedures. There is an increasing demand for developing an accessible, low-cost, wearable anesthetic sensor to ensure patient and personnel safety. This work focuses on fulfilling the clinical demand by developing a transcutaneous biosensor device that can accurately measure and monitor the concentration of anesthetic agent isoflurane (1-chloro-2,2,2-trifluoromethyl difluoromethyl ether) in the human body at a lower cost per unit to address this unmet need. The approach utilizes the creative form of a micro-fuel cell sensor that is composed of a proton exchange membrane (PEM) sandwiched between two metal electrodes to measure the isoflurane excreted through the subject's skin. At the anode, the isoflurane oxidative reaction generates electrons transferred to the cathode electrode. The oxygen reduction reaction is triggered by protons moving across the PEM at the cathode. Isoflurane concentration is measured in terms of electrical signals from the electrons traveling in the external circuit that produce a current proportional to concentration. Furthermore, we investigate the impact of different catalysts, platinum-group metals (PGM) and PGM-free, on the voltage and current output. The fuel cell-based electrochemical biosensor exhibits excellent sensitivity, linearity, and a low detection limit. Higher accuracy in the ultra-low concentration range of sub 40ppm is achieved by imputing the obtained data into a principal component regression (PCR) algorithm. This work highlights an integrated microsensor to monitor transcutaneous isoflurane concentration continuously. Current research enables understanding the dynamic interaction between sensing surface area and volatile anesthetics excreted through the patient's skin. Furthermore, creating a novel approach for non-invasive wearable healthcare devices for detecting volatile organic compounds in the human body.

Figure 1
Anodic Aluminum Oxide(AAO)-Based Chemi-Capacitive Sensor Toward Ethanol Gas
Authors: Lim Gi hwan , Kim In Yea , Kim Chae Yoon , Lee Min-Jeong , Kim Jaehun , Kim Dong Hyun , Lim Jae-Hong
Published: November 2022

The transducer elements for such sensor arrays need to be small, low-power, and compatible with conventional microprocessing technology. The transducers include chemiresistive gas sensor, FET gas sensor, capacitive gas sensor, and inductive gas sensor. Of these transducers, chemicapacitors and chemiresistors are the best suited for low-power sensor arrays. The change of electrical properties such as conductance or capacitance upon exposure to analytes can be used to detect chemical and biological agents, respectively. Chemiresistors are simply implemented in many application fields, but they have disadvantages such as instability and cross sensitivity. Whereas chemicapacitors are known to provide superior sensitivity and recovery time because capacitance can response to very thin layers of chemoselective material down to a single molecular monolayer, resulting in the elimination of the duration time for capacitance change. In this work, the room-temperature capacitive ethanol gas sensing properties of AAO (anodic aluminum oxide) were studied and the underlying mechanisms were analyzed based on its electrode configuration and detection frequency. Figure 1 shows the progress of the experimental progress according to each electrode patterns and thicknesses.

The sensor sensitivity of the chemocapacitive sensor toward ethanol was affected by the humidity because it has higher dielectric constant than ethanol. Therefore, the surface treatment of AAO was carried out by silanization using APTES and HMDS. The degree of hydrophobicity of AAO surface was determined by measuring the water contact angle by the Sessile Drop method. After surface treatment was performed in each method, the sensitivity of the sensor to the wet air was also measured.

Through silanization, similar sensor sensitivity to ethanol was obtained, and at the same time, sensor sensitivity to wet air was minimized as illustrated in Figure 2. In this study, the sensor characteristics were optimized by the electrode pattern and thickness, and the gas selectivity of the sensor was improved through surface treatment.

Figure 1
Characterization of Noble and Transition Metal Doped-ZnO Sensing of VOC Analytes Using Broadband Dielectric Spectroscopy
Authors: Amoah Papa K. , Baumgart Helmut , Obeng Yaw
Published: November 2022

Metal-oxide (MO) semiconductor-based gas sensors such as SnO2 and ZnO, have traditionally been the common materials of choice to be used for gas detection based on the mechanism of chemosensitivity. They are some of the most economic and efficient gas sensing materials, and they show a relatively quick response to several volatile organic compounds (VOCs). Doping of the MO nano surface lattices with noble and transition metals has been shown to further enhance their gas-sensing performance by improving the catalytic properties of the MO, ameliorating their response kinetics and selectivity toward a particular gas. However, the chemosensitivity method requires electrical contacts to the MO sensor material connecting the electrical circuits to detect electrical changes of the MO in response to volatile analytes. This approach introduces inherent errors into the measurements due to the need to make physical electrical contacts with the sensing MO semiconductor surface. In this talk, I will discuss the use of a microwaves-based detection technique known as Broadband dielectric spectroscopy (BDS) to rapidly interrogate a dynamic range of material characteristics such as polarizability, phase, electrical conductivity, etc. This technique eliminates the introduction of parasitic measurement errors which come about due to electrical contacts. Specifically, we show that the microwave signal propagation characteristics (i.e., S-parameters) induces chemical changes which allow us to characterize the detection of VOCs using ZnO doped with a selection of noble and transition metals as the sensing material, at temperatures under 100 °C.
How Emerging Sensor Technologies Contribute to Artificial Intelligence; Machine Learning and Deep Learning Data Acquisition Techniques
Authors: Sabar Mishes Fwangshak Sabar Mishes
Published: November 2022

Computers Munge on Data and Without data to munge computers can as well be famished; to say literally.

Deep Learning as an off-shoot of Machine Learning which itself is a sub-field of Artificial Intelligence relies solely on advancements in emerging computing Technologies which provide the computing capacity for running large scale data processing ; most importantly these include (i.e. but not limited to)advanced high level computing power and myriad data acquisition Sources as the ubiquitous Sensors proliferating the technology space of portable computing devices and IoT.

Sensors Technology help in data collection in several be-spoke ways for these emerging computing technologies(since without data computers are famished typically and with deep learning sufficient data is basically needed)to be able to perform deep learning operations required for inferencing useful informative insights from crude-data.

Today data is being generated in an unprecedented manner, as a result of the emergence of several sensor technologies; this has become the leverage for all deep learning computations and its successes today.

In this Paper review i will be overviewing and discussing how these emerging sensors technology has been able to complement the computing power today to facilitate deep Learning technologies.
Practical Strategies for Longitudinal in-Home Sleep Tracking in Diverse Populations
Authors: Andrew Trisha L.
Published: November 2022

Longitudinal monitoring of sleep metrics, night-to-night sleep quality, and weekly sleep patterns is important for enabling healthy aging and, more importantly, understanding and mitigating cognitive decline with aging. Recent work has shown that longitudinal changes in selected sleep metrics, such as total sleep time, time in the rapid eye movement (REM) versus non-REM sleep phases, and non-REM slow wave activity, is closely correlated with decline in cognitive function in older populations. Further, evidence also suggests that sleep disturbance in middle-aged and older populations can contribute to cognitive decline and heighten the risk of Alzheimer's Disease (AD) by increasing beta-amyloid burden. In older, at-risk populations, persistent sleep disturbances and/or shifts in sleep patterns also precede an AD diagnosis and may even appear years before cognitive decline, indicating that clinically-accurate, longitudinal sleep tracking can allow for on-time therapeutics and interventions before onset of AD symptoms.

However, clinical-grade wearable sleep monitoring is a challenging problem since it requires simultaneous monitoring of brain activity, eye movement, muscle activity, cardio-respiratory features, and gross body movements. This requires multiple sensors to be worn at different locations as well as uncomfortable adhesives and discrete electronic components to be placed on the head. As a result, existing wearables either compromise comfort or compromise accuracy in tracking sleep variables.

I will describe our lab's recent work in developing a suite of fabric-based sensors and garment-integrated sensing systems for in-home sleep tracking, focusing particularly on our efforts at enabling clinically-accurate sleep phase recognition. Our best-performing solution is PhyMask, an all-textile sleep monitoring solution that is practical and comfortable for continuous use and that acquires all signals of interest to sleep solely using comfortable textile sensors placed on the head. We show that PhyMask can be used to accurately measure all the signals required for precise sleep stage tracking and to extract advanced sleep markers such as spindles and K-complexes robustly in the real-world setting. We validate PhyMask against polysomnography and show that it significantly outperforms other commercially-available sleep tracking wearables, including the Fitbit wristband, the Oura Ring, and the Muse, Phillips SmartSleep and Dreem headbands.

Figure 1
(Digital Presentation) Biomimic Nanotemplating Assay Based on Molecularly Imprinted Polymers for the Impedimetric Detection of Sars-Cov-2 and Influenza A Spike Proteins in Untreated Saliva
Authors: Siavash Moakhar Roozbeh , del Real Mata Carolina , Shafique Houda , Jalali Mahsa , de Vries Justin , Strauss Julia , Abdel Fatah Tamer , McLean Myles , Isaac Hosseini Imman , Mahshid Sahar Sadat , Liang Chen , Mahshid Sara
Published: November 2022

With the continuously fluctuating incidence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), critical gaps in the field of rapid diagnostic testing have been exposed, particularly in the diagnosis of viral respiratory infections. Current gold standard methods rely on real time quantitative polymerase chain reaction (RT-qPCR) for the detection of viral nucleic acids, but these tests are challenged with long turnaround times, costly centralized laboratory equipment and the need for trained personnel to execute the protocols. With the growing number of emerging variants that can evade both immune responses and inoculation, addressing current testing challenges is critical to manage the spread of viral infections. Here, we propose the design of a novel assay based on our previously studied gold nano/micro islands (NMIs) as a core for the fabrication of an ultrathin molecularly imprinted polymer (MIP) for the impedimetric detection of SARS-CoV-2 and Influenza A spike proteins (SPs) in untreated saliva within 10 minutes. The proposed electrofabrication protocol is rapidly adaptable to a diverse repertoire of protein biomarkers; in this work, we demonstrate the impedimetric detection of the SARS-CoV-2 original strain, Alpha B.1.1.7, Delta B.1.617.2 and Omicron B.1.1.529 variant SP, as well as the Influenza A SP within physiologically relevant ranges and at a low limit of detection to enable the diagnosis of acute infections. Validation was performed at two unique test sites with 51 SARS-CoV-2 patient samples to demonstrate an overall 100% sensitivity and 100% specificity of the NMIs/MIPs assay. Robust quantification of the electrochemical assay was confirmed against RT-qPCR, which effectively enabled statistically significant (p < .0005) viral load quantification on a rapid, miniaturized, and ultrasensitive platform. This novel technology presents the development of a quantitative and versatile electrochemical assay with the potential for the rapid detection of current and future viral respiratory infections, which can guide future electrochemical clinical and commercial point-of-care testing platforms.
Photon-Pen Writing for Metal Oxide-Based Versatile Nanosensors
Authors: Bae Garam , Jang Moonjeong , Kwon Yeong Min , Song Wooseok , Lee Sun Sook , An Ki-Seok
Published: November 2022

Low-temperature processes and simplification of lithographic techniques are key challenges for the fabrication of solution-processed metal oxide-based nanodevices. Recent breakthroughs in location-specific synthetic methodologies involving inkjet printing and photon-activation routes have enabled lithography-free and bottom-up fabrication of such devices. However, a revolutionary strategy to resolve room-temperature direct fabrication of metal oxide-based materials still remains elusive. Here, a pertinent route enabling wafer-scale, location-specific direct-writing, termed “photon-pen writing (PPW),” of functional metal oxide-based devices is proposed. Using PPW, fabrication of elaborate patterns of metal oxides is demonstrated through location-specific dechlorination and subsequent oxidation via thermal energy transfer of a focused infrared laser in ambient environment. By tailoring process parameters, precise manipulation of the chemical and structural features of the PPW-produced metal-oxide patterns are demonstrated. The versatility of the PPW process by realizing a highly sensitive, stable, uniform, and wafer-scale nanosensor array for gas and light detection using PPW-ZnO channel and PPW-ITO electrodes is demonstrated, with 4.1% of response at 50 ppb NO2 and 2.93 ± 0.23 µA of photocurrent for 0.76 mW cm−2 , 254 nm UV light. A new route toward wafer-scale production of bespoke nanosensor arrays onto single chip for next-generation nanoelectronics is introduced.
(Digital Presentation)Empirical Methods for Modeling NOx Sensor Performance Errors in Combustion Applications
Authors: Woo Leta , Rash Tyler
Published: November 2022

Combustion technologies require gas sensors for monitoring and controlling the exhaust and to meet increasingly stringent environmental regulations. NOx compounds (NO and NO2) in diesel exhaust can lead to poor air quality and act as both pollutants and greenhouse gases. Aftertreatment strategies have been developed to mitigate NOx and usually require information about the NOx sensor output. The design and operation of aftertreatment strategies rely on an understanding of sensor behavior and deviations. However, sensor specifications provided by suppliers typically only reflect the minimum requirements necessary to meet basic application needs. Supplier information about sensor performance can therefore be too general whereas more detailed information could allow more flexibility and potentially cost savings during early development of the overall aftertreatment system and strategy.

The approach and application of a methodology for predicting nominal sensor output and standard deviation is presented. The prediction is in the form of an empirical NOx sensor performance model that relies on experimental data for a specified population of sensors. Inputs include the concentration of exhaust components (e.g., NO, NO2, O2, etc.), physical state (e.g., temperature, pressure, etc.), as well as additional information about sensor condition and location (e.g., as-received brand-new sensors, tailpipe position, etc.). The output would be a dynamic real-time estimate for the NOx sensor broadcast signal and standard deviation for the defined population. Experimental data are primarily collected using a laboratory high-flow test bench that simulates exhaust conditions.

We present an approach that includes understanding exhaust conditions to determine the initial factors of interest as well as reasonable ranges of values for those factors. We then investigate the correlation of the factors with the measured error of the NOx sensor broadcast value using a design of experiments (DOE) response surface methodology (RSM) with ten factors. The population was defined as nine as-received brand-new NOx sensors tested simultaneously in the laboratory high-flow test bench. Least squares fitting with a linear regression model seemed to adequately describe the correlation of mean sensor signal shifts with changes in the ten factors. Methods for validation of the model and planned next steps are discussed.
Cationic MOF-Based Cu/Mo Bimetal Doped Multifunctional Carbon Nanofibers As Efficient Catalyst for High Sulfur Loading Lithium-Sulfur Batteries
Authors: Pan Hui
Published: November 2022

High sulfur loading is the key to achieve high energy density promised by lithium-sulfur (Li-S) batteries. However, serious problems such as low sulfur utilization, poor rate performance and cycle stability have been exposed during the scaling up of the sulfur loading for freestanding cathodes. To address these issues, the adsorption/catalytic ability of high sulfur loading cathode toward polysulfides must be improved. Herein, based on excellent properties of cationic MOFs, we proposed that Cu-Mo bimetallic nanoparticles embedded in multifunctional freestanding nitrogen-doped porous carbon nanofiber (Cu-Mo@NPCN) with efficient catalytic sites and high sulfur loading capacity could be prepared by facile transition metal-based anion exchange of cationic MOFs. And the sulfur embedded in Cu-Mo@NPCN was directly used as freestanding sulfur cathodes, enabling a high areal capacity, good rate performance, and cycling stability even under high sulfur loading. The freestanding Cu-Mo@NPCN/10.3S achieves high areal capacity of 9.3 mA h cm-2 and volumetric capacity of 1163 mA h cm-3 at 0.2 C with a sulfur loading of 10.3 mg cm-2. This work provides new insights into freestanding sulfur cathode engineering for high-performance Li-S batteries and would advance the development of cationic MOF-derived bimetallic catalysts in various energy storage technologies.

Figure 1
Antimony Nanobelt Asymmetric Membranes for High Capacity Sodium Ion Battery Anodes
Authors: DiCesare Jake , Wu Ji , Williams Logan , Sheppard Olivia
Published: November 2022

The standard lithium-ion battery (LIB) using graphite electrodes has become exceedingly important in today’s world. Everything from electric cars to solar energy storage systems need these batteries, and the capabilities and progress of these devices rely on the steady advancement of battery technology. However, lithium is a scarce resource and is projected to run out with the ever-increasing demand we are placing on it. For this reason, we are investigating sodium ion batteries (SIB) as an alternative to LIB.

While many methods have been studied to improve SIB capacities and lifespans, our method stands out by using antimony nanobelts incorporated into an asymmetric membrane structure as a high performance anode material for SIB due to its theoretical capacity of 660 mAh g-1 compared to hard carbon-based SIB (300 mAh g-1). In addition to the asymmetric membrane structure, we use a carbon coating around the membrane which can further improve performance and stability. Embedding these group V nanomaterials within an asymmetric membrane structure coated in carbon will accommodate the large volume expansion of Sb-based SIB anode, enhance mechanical strength, and prevent rapid capacity loss due to leaching of cracked materials.

Herein, we demonstrate that the capacity and the cycling performance of SIB can be significantly improved over not only current SIB but also LIB. Preliminary results indicate that Sb nanobelts incorporated into an asymmetric membrane exhibit increased performance as a sodium-ion battery anode compared to Sb nanoparticle membranes, furthermore, dip coating the asymmetric membranes with a carbon based solution increases both capacity and cycling performance compared to membranes with no extra carbon coating. The batteries made using the dip coated Sb nanobelt asymmetric membranes show a specific capacity between 630 and 650 mAh g-1 with a capacity retention of 99.4 percent over 45 cycles and an initial capacity loss of only 14 percent. In addition to electrochemical tests, we have also characterized the samples using scanning electron microscopy, energy dispersive x-ray spectroscopy, thermal gravimetric analysis, powder x-ray diffraction spectroscopy, and RAMAN spectroscopy to identify and quantify the materials in the membranes and starting materials. Using these characterizations, we were able to confirm the chemical composition and morphology of the Sb and C in our membranes. Thereby a scalable and cost-effective method of increasing capacity of NIB, while maintaining relatively good life cycle longevity has been developed by our research laboratory.
A Flame-Retardant Polymer Electrolyte for Safe and Long-Life Lithium Metal Battery
Authors: Cheon Hyeong Jun , Chang Mincheol
Published: November 2022

With the increasing demand for batteries with high energy density, lithium metal anode-based batteries are suitable candidates. Although lithium metal is an attractive material with excellent theoretical specific capacity (3860 mAh/g) and very redox potential (-3.04 V vs. strandard hydrogen electrode), it causes electrolyte leakage, combustion, and explosion problems due to dendrite growth. In the case of conventional liquid electrolytes, dendrites grow more freely and flammable organic solvents are used, making them unsuitable for use with lithium metal anodes. On the contrary, solid polymer electrolyte-based batteries have the advantage of being able to achieve higher energy density as well as better stability to lithium metal. However, the organic component of the solid polymer electrolyte is still flammable, and the polymer/ceramic composite material is also generally flammable, so the safety issue cannot be completely avoided. Here, we show that the addition of a flame retardant effectively reduces the flammability of solid polymer electrolytes. The solid electrolyte consisted of a combination of PEO and flame retardant DMMP, and the composed LFP/solid polymer electrolyte/Li cell exhibited improved cycle stability and ionic conductivity.

Figure 1
“Water-in-Salt” and Nasicon Electrolyte-Based Na-CO2 Battery
Authors: Im Eunmi , Baek Kyungeun , Park Jaehyun , Seo HoJun , Kang Seok Ju , Moon Geon Dae
Published: November 2022

Super concentrated electrolytes, referred to as “water-in-salt (WiS) electrolytes”, have been received attention due to their wide electrochemical stability window, cost-effectiveness, and non-flammability. However, the free water molecules present in WiS electrolytes prevent the use of Na-metal as the anode for Na-gas batteries.

In this study, we develop a Na-CO2 battery with WiS and Na-super-ionic conductor (NASICON) electrolytes that were used as energy storage cells and CO2 gas utilization. The NASICON separator allowed us to fabricate a hybrid Na-CO2 battery comprising Na metal as the anode material and WiS as the cathode electrolyte without damage of Na metal. Additionally, linear sweep voltammetry (LSV) with corresponding differential electrochemical mass spectroscopy (DEMS) measurements rendered the direct observation of H2 evolution retardation with increasing WiS concentration. Furthermore, we introduced a nano-sized Ru catalyst onto the current collector using Joule heating method for reducing the overpotential gap. Consequently, the Na-CO2 batteries with Ru@carbon current collector reduced the overpotential gap and exhibited a cycling endurance of over 75 cycles.
Title: Static Cell and Porous Electrode Model for Cycling Behavior of Aqueous Organic Redox Active Materials
Authors: Sosa Jordan D. , Aziz Michael
Published: November 2022

Aqueous Organic Redox Flow Batteries (AORBs) have shown growing potential as a stationary energy storage technology for regulating intermittent renewable sources. For long charge/discharge duration systems, the capital cost of a redox flow battery asymptotically approaches the cost of the electroactive material.[i] Therefore, for commercialization of this technology, proper evaluation of the redox active electrolytes is needed. The capacity retention over time and over cycling is one of the most vital criteria for evaluation. For very stable electrolytes with fade rates less than about 10% per year, disentangling cycle-denominated and time-denominated fade can be very difficult for flow batteries due to longer cycle time and noise due to pumping and splashing. Thus, we have used a sealed, static, non-flow cell to achieve capacity measurements with greater cycling frequency and reduced noise, as shown in Figure 1. To isolate decomposition from crossover through the membrane or apparent capacity fade due to changes in the resistance of the cell, we use volumetrically unbalanced, compositionally symmetric cells with potentiostatic cycling.[iii]

For proper capacity fade rate evaluation, material properties of the electrode and electrolyte should be considered when setting up cycling protocols because the amount of accessed charge depends on these properties. Thus, simulations from porous electrode models that consider these material properties can inform appropriate cycling conditions.

Using Newman’s porous electrode theory[iv] to model our static cell, we have simulated the spatial distribution of ions and potentials over time in response to time-varying applied potentials. From the transient behavior, we simulated the potentiostatic cycling of these cells. The simulations show how the physics inside porous electrodes and cycling performance depend on material properties. For example, the diffusivities can affect the spatial distributions of ions across a porous electrode, as shown in Figure 2 (left), as well as the minimum acceptable time for cycling and the accessed capacity for given cycling parameters, as shown in Figure 2 (right). Using the same porous electrode model for simulations, we aim to show differences between apparent and real capacity fade.

[i] F. R. Brushett, M. J. Aziz, and K. E. Rodby. ACS Energy Lett. 2020, 5, 879−884

[ii] D. G. Kwabi, Y. Ji, and M. J. Aziz. C
hem. Rev. 2020, 120, 14, 6467–6489

[iii] M.A. Goulet and M. J. Aziz, “Flow Battery Molecular Reactant Stability Determined by Symmetric Cell Cycling Methods”. Journal of The Electrochemical Society, 165 (7) A1466-A1477 (2018)

[iv] J. Newman and C. W. Tobias, J. Electrochem. Soc., 1962, 109, 1183

Figure 1
Optimization of Pulsed Polarization Condition for Efficient Electrochemical CO2 Reduction
Authors: Kouchi Keisuke , Azumi Kazuhisa
Published: November 2022

Introduction

Massive emission of CO2 gas from fossil fuel combustion causes the severe global greenhouse effect. Electrochemical reduction of CO2 using renewable energy has been attractive due to its simple methodology, while the conversion efficiency may be lessened due to undesirable side reactions such as water decomposition. In this study, CO2 was covered to CO on Ag electrode in aqueous KHCO3 solution using potentiostatic pulse polarization, and optimal pulse condition to improve the conversion efficiency was explored.

Experiment

An electrochemical cell was composed of a cathode compartment containing an Ag working electrode (W.E.) and an Ag/AgCl reference electrode and an anode compartment containing a Pt counter electrode. Two compartments were separated by a Nafion membrane. An Ag-W.E. was mechanically polished and potentiostatically pulse-polarized in a CO2-saturated 0.1 M KHCO3 solution to form CO. After some polarization period, the conversion efficiency ( η=[CO]/([CO]+[H2]) ) of CO2 to CO was evaluated by using gas chromatography as a function of various parameters such as cathodic polarization potential (E
c) and time (t
c), rest potential (E
a) and time (t
a), KHNO3 concentration, etc.

Result and discussion

When E
c was varied, the highest η was obtained around –1.5 to –1.6 V. When t
c was varied at E
c = –1.6 V, the highest η was obtained around t
c = 3 s, as shown in Fig. 1. The t
a did not affect η. These results reveal that the t
c influences the conversion efficiency viacontrolling the diffusion layer thickness of reactants such as CO2 molecular. The highest η at the optimal pulse condition was ca. 0.9 and is comparable to the value obtained by the previous work using ionic liquid solution (T. Oguma et al., Electrochemistry, 88 (2020) 451–456).

Fig. 1. Relationship between the cathodic polarization time t
c and reduction efficiency

Figure 1
Cryptology Based on Laplace Transform of Hyperbolic Function and Matrix Decomposition Method
Authors: Akram Zaryab
Published: November 2022

Cryptography is the art of coding and decoding the communication. Cryptography ensures the security of delicate information over some confidentiality breaching resources. In the recent age Cryptography has turned into a battleground of some of the world’s best mathematicians and computer scientists. A number of transforms like Sumudu transform, Laplace transform, Fourier transform, Kamal transform, Mellin transform, Jafari transform, Aboodh transform, N-transform, ELzaki transform, MAHGOUB transform are frequently used in cryptography. Cryptography is of great importance in every field of life including data transmission, data storage, E-Commerce, confidential communication such as credit card transactions and Emails. Cryptography has been a hot topic among the researchers from 4000 years ago until now. In this work, a new cryptographic technique will be introduced. . In this work mathematical transformation known as Laplace transform on hyperbolic function is used for advancement of security purpose in the field of computers and telecommunications, this concept is known as Cryptography. This work includes a mathematical method known as “Laplace Transform” along with “Matrix Decomposition or Triangularization method” in cryptographic process (Encryption and Decryption). Both these mathematical concepts are used in this work to create a new cryptographic technique for the security of data and information in the world of computer. In this technique, Laplace transform on hyperbolic functions along with Matrix decomposition method will be incorporated. The Laplace Transform of hyperbolic function and Lower Triangular Matrix will be used as encryption and inverse Laplace Transformand upper triangular matrix will be used for decryption. Furthermore, the technique will also be explained with its applications.
Mixed Metal Cathodes for CO2 Electroreduction Using Solid Oxide Electrodes
Authors: Kamboj Vipin , Ranjan Chinmoy
Published: November 2022

Electroreduction of CO2 to fuels through the use of renewable energy provides a beneficial route and it decreases the reliance on fossil fuels. The electrochemical reduction of CO2 to hydrocarbon fuels (CHx) is highly energy inefficient owing to kinetic limitations which are a direct consequence of multistep-multielectron transfer process. The selective formation of CO from CO2 is energy efficient. CO thus formed, serves as a valuable source of energy as it can be directly used as a fuel. Moreover, it can be further converted into hydrocarbon fuels via Fischer-Tropsch reactions using green hydrogen. We hereby propose Ni(M)x/YSZ based electrodes for electroreduction of CO2 on solid oxide cells at high temperature (~800∘C). Electrodes were fabricated on commercial standard YSZ supports using Ni(M)x/YSZ and LSM/YSZ mixtures which were respectively employed as materials for that cathode and anode. Characterisation of the developed electrode architecture was carried out via electron microscopy and X ray diffraction.

The behaviour of electrodes during CO2 electrolysis was analysed through online mass spectrometry and operando Raman spectroscopy. Ni/YSZ electrodes displayed sustained performance only upon the addition of H2 to the fuel mixture. The reaction progressed through a reverse water gas shift reaction (RWGS) (CO2 + H2 à CO + H2O) along with water electrolysis where CO originates from non-electrochemical RWGS reaction.

Electrochemical impedance spectroscopy was employed to analyse the reactions. Three electrode assembly was used to compare the electrochemical performance of the various electrodes. The pure Ni/YSZ cathodes showed deactivation under pure CO2 atmosphere. Mixed metal oxide electrodes such as Ni(M)x exhibit enhanced performance for CO2 electrolysis in both pure CO2 as well as in the presence of 5% H2. Catalytic performance of the electrodes was evaluated by varying fuel mixtures composition and temperature. Kinetics of electrode performance were evaluated using distribution of relaxation time formalism. Mixed metal oxide such as Ni(M)x showed improved kinetic with significant improvement in charge transfer resistance.

Figure 1
Insights into the Effect of Pb on Formic Acid Electro-Oxidation on Pt
Authors: Veenu Veenu , Roychowdhury Dwaipayan , Ranjan Chinmoy
Published: November 2022

Formic acid is a promising energy carrier and electrochemical formic acid oxidation can serve as an important reaction within fuel cells. Although Pt remains the best-known catalyst, but the major currents contributing pathways is indirect oxidation pathways, which leads to poor activities at low potentials. The surface adatoms like Pb have been known to promote the direct oxidation pathways significantly. We have carried out theoretical calculations, and experiments to probe the reason for this enhancement. Theoretical results show an upshift of Pt energy levels above the Fermi energy upon adsorption of Pb on the Pt surface, which influences the binding energy of the adsorbates. Reaction free energy calculations of typical intermediates from water (H2O) and formic acid (HCOOH) molecule indicate that Pb adsorption suppresses the adsorption of Hydrogen atoms at potentials typical of underpotential deposition on Pt electrode. This results in larger number of vacant sites on the Pt surface which is now able to carry out formic acid oxidation to CO2. The calculations were supported by electrochemical experiments of underpotentially deposited hydrogen and potential dependent apparent activation energies.

Figure 1
Integrated Method of Pretreatment, Saccharification and Electro-Fermentation of Saccharum Spontaneum to Produce Bioethanol Using Microbial Consortium
Authors: Dhungana Pradip , Rajbhandari Jarina
Published: November 2022

Production of lignocellulosic ethanol using microbial consortium can be an economical strategy. Consortium of ligninolytic and cellulolytic microbe(s) that can depolymerize lignin and hydrolyze cellulose along with fermenting yeast (CDBT-2) can replace the separate techniques used for biomass pretreatment and hydrolysis prior to fermentation. So, the aim of this study was to screen fungi capable of producing laccase (lignin depolymerizing enzyme) and cellulase (converts cellulose to fermentable sugars), and use the strains along with Saccharomyces cerevisiae (CDBT-2) to develop an integrated method of simultaneous pretreatment saccharification and electro-fermentation of Saccharum spontaneum powder to produce ethanol. 18-s rRNA sequencing and BLAST analysis of screened isolates confirmed, cellulolytic isolate (F1) resembled as Aspergillus niger and, ligninocellulolytic isolate (F2) resembled to Ganoderma sessile. These fungi were used along with CDBT2 for ethanol production. Different consortiums sets of these isolates were tested for fermentation efficiency. All the analysis were done using crude untreated as well as hot water pretreated S. spontaneum powder to compare the ethanol production efficiency. In controlled environment of 28oC, shaking at 80 rpm and 5.0 pH, culture with consortium of G. sessile and CDBT2 produced higher ethanol with yield 57 mg/g biomass powder followed by consortium of G. sessile, A. niger and CDBT2 with yield of 44±0.18 mg/g biomass. Monoculture of G. sessile produced higher amount of phenol ie 292.48±17.74 µg/mL. Similarly, G. sessile, A. niger and CDBT2 consortium produced higher furfural of 58.48±3.86 µg/mL. However, the amount of phenol and furfural generated were very low in both cases. The ethanol yield was higher in crude biomass compared to hot water pretreated S. spontaneum powder. In addition, electro-fermentation of crude S. spontaneum enhanced ethanol production by 12% with G. sessile and CDBT2 consortium while 18% with the set of G. sessile, A. niger and CDBT2 consortium. This monophasic method of integrated pretreatment saccharification and electro-fermentation can be an alternative approach for lignocellulosic bioethanol production as it does not require separate pretreatment and fermentation approach.

Keywords: Bioethanol, Saccharum
spontaneum, microbial consortium, simultaneous saccharification and fermentation, and electro-fermentation

Figure 1