bluuebunny/crossref_metadata_2025 huggingface dataset:
Micropatternable Ink Composed of MAX Phase ZIF-8 for Gas Sensing Applications
Authors: Chen Chen , 夏 胜辉 , Liu Jinhong , Leatt Kyle , Thundat Thomas , Khosla Ajit
Published: August 2024

Gas sensing technologies have gained significant attention due to their applications in environmental monitoring, industrial safety, and medical diagnostics. In this study, we report the development and characterization of a micropatternable ink composed of MAX phase ZIF-8 (Zeolitic Imidazolate Framework-8) for gas sensing applications. The ink was prepared utilizing a shear mixing technique in an ice water bath, using water (0.1 wt% polyvinylpyrrolidone (PVP), average molecular weight is 10,000) as the solvent. The resulting hybrid nanomaterial, ZIF-8/Ti3C2, was investigated for its physicochemical and gas adsorption properties. Raman spectroscopy and X-ray diffraction (XRD) confirm the well-defined two-dimensional layered nanostructure of ZIF-8/Ti3C2. Fourier-Transform Infrared Spectroscopy (FTIR) indicates the presence of functional groups, such as hydroxyl, carboxyl, and titanium-oxygen bonds, on the surface of ZIF-8/Ti3C2. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis confirms the homogeneous distribution of ZIF-8 nanoparticles on MXene nanosheets. It is observed that the particle sizes of ZIF-8 and Ti3C2 were 20 nm and 1 µm respectively. Thermogravimetric (TGA) analysis demonstrate that ZIF-8/Ti3C2 exhibited excellent thermal stability, with a mass loss of only 25% at 800°C. The ink exhibited specific gas adsorption properties, with the maximum quantity of N2 adsorbed measured at 150.1564 cm3/g and the maximum quantity of CO2 adsorbed measured at 4.4095 cm3/g. Additionally, gas absorption properties were investigated for various volatile organic compounds (VOCs), including formaldehyde, acetone, methane, ethanol, and toluene. In order to fabricate microstructured gas sensors, we employed atomized spraying technology to print the ZIF-8/Ti3C2 ink onto substrates such as glass, gold, and polyethylene terephthalate (PET), utilizing a 10 mm × 10 mm mask. Prior to printing, oxygen plasma treatment was performed on all substrates to reduce the contact angle and to enhance ZIF-8/Ti3C2 ink-substrate adhesion. The printed samples were subsequently vacuum-dried at 120°C for 30 minutes to obtain the final patterned structures. The thickness of the ZIF-8/Ti3C2 layer on different substrates was characterized. The results demonstrate the feasibility of utilizing the ZIF-8/Ti3C2 ink for the fabrication of microstructured gas sensors on various surfaces. The incorporation of MXene nanosheets within the ZIF-8 structure enhances the gas adsorption properties, thereby enabling highly sensitive gas sensing applications. The micropatternable ink offers versatility in terms of substrate choice, opening up possibilities for the integration of gas sensors in different environments. This work provides a foundation for the development of advanced gas sensing technologies, contributing to the advancement of healthcare, environmental monitoring, and industrial safety systems.
(Invited) Long-Term, in vivo Measurement of Biomarkers Using Molecular Switches
Authors: Soh Hyongsok Tom
Published: August 2024

Biosensors that can detect specific analytes – continuously, in vivo, in real time – would offer exciting capabilities for fundamental research and clinical medicine. However, their development has proven difficult due to biofouling, probe degradation and signal drift that often occur in vivo. In nature, evolution has solved similar problems through the use of nanostructures. By drawing inspiration from nature, we have developed a synthetic biosensor that can continuously detect specific target molecules - continuously, in vivo, in real time – for prolonged periods. Specifically, our system is stable for more than one month in undiluted serum in vitro, and retains excellent stability for multiple days, even when implanted in the blood vessel of live rats. In this way, our work provides a generalizable design foundation for a new generation of biosensors that can continuously operate in vivo for extended durations.
Development of Dual-Gel System for Wearable Electrochemical Sensors
Authors: Fan Ruolan , Andrew Trisha L.
Published: August 2024

With the innovation of materials and rapid development of wearable technology, wearable electronics—particularly textile-based systems—have broadened perspectives in health monitoring, therapy, and disease diagnosis.

Bioelectronics interpret analyte information into real-time electrical signals with high sensitivity. Realizing the selective detection of analytes in biofluids often requires bioreceptors, such as enzymes, antibodies, and DNA, along with corresponding electrochemical detection techniques.

Enzymatic sensors have relatively complex sensing structures among others. Enzymes function as biocatalysts at the sensing interface, facilitating electron transfer from analytes to the electrode surface. To enhance overall data acquisition, redox mediators are typically incorporated into these systems.

Wearable bioelectronics are currently fabricated by depositing functional materials onto conformal flexible substrates using techniques such as spin coating, spray coating, printing, etching, and other technologies. However, seamlessly integrating multi-layer textile-based biosensors necessitates specific screen mesh and inkjet angles that ultimately limit the manufacturing process.

Here, we propose a dual-gel system consisting of a base gel embedding functional materials (redox mediators and bioreceptors) and an encapsulation gel to stabilize the base gel while offering antifouling properties. The thin dual-gel film is fabricated through blade-casting followed by photo-initiated Chemical Vapor Deposition (piCVD) and can seamlessly adhere to various rough fabric surfaces. Moreover, this solvent-free process largely prevents bioreceptor degradation, promising better manufacturing sustainability.

Glucose detection on flexible electrodes utilizing such a dual-gel system is exemplified as a proof-of-concept. This unique dual-gel system is expected to contribute to the development of textile-based electronics with greater versatility and improved sensing performance.
Gas Phase Aldehydes Detection in Exhaled Breath in Screening of Barrett's Esophagus
Authors: Rafiee Mohammad , Hejazi Reza , Nikzad Nastaran
Published: August 2024

Aldehydes, e.g., acetaldehyde, have been classified as toxic and carcinogenic volatile organic compounds (VOCs) and are recognized as one determinant of upper aerodigestive tract cancer like Barrett's esophagus. Measuring aldehyde levels in breath provides information about the aldehydes released by abnormal cells, the level of aldehyde dehydrogenase (ALDH2) activity, and risks and diseases associated with high levels of acetaldehyde, which include liver disease and lung and upper digestive cancers. Devices currently available for breath analysis are state-of-the-art, high-resolution mass spectrometry instruments. These instruments have some drawbacks such as size, initial cost, and operational expense. Electrochemical sensors are capable of miniaturization and are available as portable and handheld breathalyzers. The non-invasive nature of breath analysis and its easy sampling makes smaller devices a more attractive alternative, particularly for continuous monitoring and point-of-care (POC) testing.1 However, the lack of an exchangeable/disposable sensing element, the resulting memory effect, and the need for frequent recalibration is the main drawback of currently available electrochemical breathalyzers.

Herein we examine the feasibility of a POC testing device for aldehyde in exhaled breath to assess the medical application of such a device in noninvasive diagnostic testing for Barrett’s esophagus. To improve the selectivity of the method we harness the unique catalytic activity of the aminoxyl radical/oxoammonium redox couple toward aldehyde oxidation. The highly selective/sensitive device offers the capability for use in the detection of Barrett's esophagus, ideally at early stages, without the need for a high-cost screening test. Our functional sensing element consists of a screen-printed electrode (SPE) in which the graphene oxide-based is the working electrode. Exposing this electrode to simulated breath that contains aldehyde, while applying the required potential for oxidation of the aminoxyl radical (4-acetamido-TEMPO known as ACT), generates an electrocatalytic current proportional to the aldehyde concentration in the breath. These simple, sensitive, durable, and inexpensive electrodes may contribute to the development of a single-use reliable aldehyde sensor for personal or law enforcement applications.

1. M. Mayer, M. Rafiee, Electrocatalytic Detection of Ethanol and Acetaldehyde by Aminoxyl Radicals: Utilizing Molecular Catalysis for Breath Analysis. Analyst 147, 2022, 3420 – 3423.
Development of an Electrochemical Biosensor for GFAP with Carbon-Based Substrate for Traumatic Brain Injury
Authors: Santana Alicea Dasairy L , Vazquez Yolimar , Cunci Lisandro
Published: August 2024

This study concentrates on creating an electrochemical biosensor designed for the real-time identification and monitoring of biomarkers, specifically Glial Fibrillary Acidis Protein (GFAP). The intended applications involve the diagnosis and prognosis of Traumatic Brain Injury (TBI). TBIs pose a significant global health challenge, impacting millions each year, and existing diagnostic methods, such as neuroimaging, face constraints related to cost, radiation exposure and a greater delay in providing a diagnosis. The suggested biosensor exploits electrochemical techniques, offering benefits such as non-invasiveness and swift results. The primary objective is to advance wearable microelectrodes for TBI detection, with an emphasis on utilizing bodily fluids like sweat as practical samples. Moreover, the biosensor's versatility makes it well-suited for various environments, including extreme conditions.

The objective of this research is to enhance the precision of TBI diagnosis and prognosis, thereby ultimately improving the efficacy of point-of-care treatment. Our methodology involves the utilization of the Capture Systematic Evolution of Ligands by Exponential Enrichment (Capture-SELEX) technique to create a highly specific aptamer designed for the detection of Glial Fibrillary Acidic Protein. The biosensor we are developing will feature electrodes modified with aptamers and a carbon-based substrate, enabling continuous real-time monitoring of the target substance. The primary objective of our biosensor is to identify GFAP, thereby reducing risks associated with exposure to radiation, and healthcare costs. To ensure the long-term stability of our biosensor, our design centers around a carbon-based substrate. Carbon-based nanomaterials have garnered significant attention in biosensor applications due to their diverse range of properties, encompassing chemical stability, biocompatibility, functionalization, and biodegradability.
Wearable, Battery-Free, Self-Powered Electrochemical Sensors for Personalized Health Monitoring
Authors: Bandodkar Amay J
Published: August 2024

Recent advances in materials, mechanics, and device architectures form the foundations for rapidly emerging classes of sensors with mechanical characteristics that allow for conformal interfaces with the soft, curvilinear surfaces of the human body. While the field of tissue-integrated biophysical sensors exhibits commendable progress in capturing clinical quality thermal, kinematic, and electrophysiological information, the advancement of complementary biochemical sensors severely lags due to unique challenges associated with seamless integration of delicate biochemical receptors, transducing components, and suitable packaging materials. In this talk, I will discuss non-traditional approaches to address some of these grand challenges. Specifically, I will discuss three technologies that my lab is developing -1) wearable, biofuel cell-inspired sensors for sweat monitoring 2) wearable, soft microfluidics with in-built valving and pumping capabilities for precise, on-demand sensing, and 3) AI-powered, wearable wound monitors for early prediction of chronic wounds.
Advancing Wearable Cardiovascular Monitoring: Integration of Flexible Piezoresistive Sensors for Robust Pulse Waveform Detection
Authors: Jafarizadeh Borzooye , Chowdhury Azmal Huda , Pala Nezih , Wang Chunlei
Published: August 2024

Wearable, flexible piezoresistive pressure sensors have diverse applications, spanning electronic skin, robotic limbs, and cardiovascular monitoring. Recent advancements in wearable health monitoring devices utilizing these sensors show promise for continuous cardiovascular monitoring. However, a substantial gap exists between laboratory development and market availability for pressure sensor based pulse monitoring. Challenges include the lack of effective testing schemes ensuring robust wearable operation and the necessity of bulky signal acquisition equipment, limiting adaptability. This study addresses these challenges by integrating the outputs of multiple flexible, skin-mountable piezoresistive sensors to create a robust wearable platform. This platform encompasses both sensing and miniaturized signal acquisition for arterial pulse waveform monitoring. The single piezoresistive sensor in our design exhibits sensitivity (1.4 kPa-1 at 2 – 8 kPa). This robust signal allows for the use of simple, compact signal collection devices mounted on a wristband. Moreover, the capability of the the system allows for detection of the three distinct peaks associated with the full pulse waveform, including the systolic, diastolic, and reflected diastolic peaks. In validation, a comparison between the wrist pulse waveform obtained with the compact signal collection device and a standard sourcemeter (Keithley 2460) confirms the capability of our wearable system to resolve the three distinct peaks. This work contributes to bridging the gap between research and practical applications, offering a potential solution for widespread adoption of continuous cardiovascular monitoring technology in diverse settings.
Bioinspired Diffuse Reflectance Coatings for Fabric-Based Radiative Coolers
Authors: Patamia Evan Douglas , Yee Megan , Andrew Trisha L.
Published: August 2024

As global temperatures rise due to anthropogenic climate change, thermal comfort becomes an increasingly critical area of research. While most buildings are equipped to cool and heat their interiors, this process is very energy intensive; a smarter approach is to enable personal thermal management using clothing and textiles. In particular, we are interested in the ability to use textiles and clothing to cool bodies in extreme heat, both to maintain comfort and prevent deaths in urban deserts due to heat stroke. One innovative category in this realm is radiative coolers—surfaces adept at manipulating light to passively regulate temperature. These coolers achieve sub-ambient surface temperatures by selectively reflecting or refracting sunlight wavelengths (200nm-2.5µm) while emitting infrared light (8-13µm). This unique capability allows them to maintain cooler temperatures, even when exposed to direct sunlight and the open sky. Coatings facilitating this cooling action typically consist of a porous media filled with refractive gaps, requiring specific substrates and custom production processes, thereby limiting their applications. Furthermore, the necessity of low light transmission presents issues in creating fabrics that radiatively cool while still retaining high breathability and durability. In this study we present a method whereby an optically active coating comprised of a mixture of CaCO3 and BaSO4 microcrystals was applied to multiple fabric substrates to create a radiative cooler. Through the use of photoinitiated chemical vapor deposition (pICVD), a 5 µm thick layer of a hydrophilic polymer polyhydroxyethyleneacrylate (pHEA) was deposited on the fabric substrate. Subsequently, through serial immersion in solutions containing Ca and Ba ions and solutions containing CO3 and SO4 ions, inorganic microcrystals were grown directly on the surface of the fabric. These microcrystals formed with a large polydispersity, endowing the coating with excellent reflective properties in the solar spectrum. Mie scattering calculations confirmed that the CaCO3 and BaSO4 microcrystals were primarily responsible for scattering. Further simulations using finite difference time domain software revealed, surprisingly, that surface-immobilized crystals provided the highest reflection efficiency, indicating that composite fibers with embedded particles are not as efficient. Upon outdoor testing, the device showed a cooling ability of 8°C compared to an uncoated fabric, achieving a maximum cooling of 4°C below ambient temperature. Washing and durability testing of the coating found no degradation in the material's performance, affirming its resilience and long-term effectiveness.
Bismuth Oxychloride Nanoflakes Based Wearable Colorimetric Sensors for Efficient Monitoring of UV Exposure
Authors: Ramaiyan Kannan , Troche Kyle , Boyle Timothy J , Garzon Fernando H.
Published: August 2024

Ultraviolet radiation from sunlight is essential for human health in many ways such as facilitating vitamin D synthesis while excessive exposure can cause adverse effects such as premature aging, sunburn, and skin cancers. In the USA, between 2007 and 2011, nearly five million adults were treated for skin cancer annually with average treatment costs of $8.1 billion each year. Hence, monitoring daily exposure to sunlight is essential to avoid developing health risks. Colorimetric UV sensors change color as a function of UV exposure, provide onsite information about the level of exposure, and can act as a personal wearable device to assist in making informed decisions on sunlight exposure. These sensors utilize radiation-induced reactions on a dye to produce a color change. We developed a BiOCl based wearable UV sensor for monitoring UV exposure where a white-to-black color transformation is induced due to the creation of oxygen vacancies in BiOCl. This color transformation is not quantifiable in bulk BiOCl; hence BiOCl was purposely dispersed on filter paper to form petal-like nanostructures that help quantify the color change. Four different dye molecules, 6-carboxyfluorescein, 5-carboxyfluorescein, rhodamine-B, and Prussian blue were evaluated, where 6-carboxyfluorescein gave the best color contrast. The sensor responds to UVA, UVB, and UVC and with proper UV filters can be made selective for specific UV radiations. This unique colorimetric UV sensor can help manage personal UV exposure and reduce the risk of sun exposure ailments.

Reference:

Kyle Troche, Kannan Ramaiyan, Timothy J. Boyle, Fernando H. Garzon, “Bismuth Oxychloride Nanoflakes Enabled High Sensitivity Colorimetric UV Dosimetry” ACS Appl. Nano. Mater. 2023, 6, 7.
(Invited) Empowering Clean Energy Manufacturers with Low-Temperature Plasma: A Novel Approach to Real-Time Thin Film Metrology
Authors: O'Leary Jared
Published: August 2024

Thin films, or micro- and nano-scale materials with unique functional properties, enable many clean energy industries, such as lithium-ion batteries, solar cells, and carbon conversion. Minimal-waste manufacturing of high-performance thin films will be vital for achieving society’s net-zero carbon emission goals. Because existing thin film sensors cannot operate within most sections of manufacturing lines, manufacturers often complete hundreds of processing steps before they can test (a small portion of) their products and detect problems. Current thin-film manufacturing thus often yields many low-quality products, or off-spec products that must be discarded. A real-time, in-situ metrology strategy can create unprecedented opportunities for implementation of smart manufacturing practices and advanced process control solutions to realize higher thin film throughput and performance.

SirenOpt has developed a real-time low-temperature plasma-based thin film metrology sensor. The sensor is compact, can be integrated within existing manufacturing lines, and can collect multiple thin film property measurements (such as thickness with a precision of 1/10th of a nanometer, density, resistivity, chemical composition, and contaminate identification) in parallel and in real-time, thus allowing for the collection of critical manufacturing data that is otherwise unobtainable. SirenOpt is currently applying the sensor to industrial thin film coating processes such as Lithium-ion battery electrodes, where this flexible sensor can be used to accelerate R&D and process optimization, improve quality control, and enable real-time process control.
Mixed Potential Sensors for the Detection of Hydrogen Leaks from Geologic Reservoirs
Authors: Brosha Eric L. , Kreller Cortney R. , Guiltinan Eric J. , Otto James Shawn , Davis Jon Eric , Boukalfa Hakim
Published: August 2024

Large-scale hydrogen (H2) geologic storage presents a viable alternative to surface storage that is both safer and more economical. One option being considered by DOE is H2 storage in salt formations. These formations have been successfully used for gas storage for decades due to their extremely low permeability and may see significant investment as the US ramps up its R&D efforts in this field. New Mexico has a unique advantage in that bedded salt formations are located strategically in areas where excess energy production can be harnessed for hydrogen production. However, bedded salt is more permeable than domal salt, necessitating sensor deployment to monitor H2 containment. Robust sensors that can provide early leakage detection will be an essential component of the safety of H2 operating facilities. In a LANL-funded Mission Foundations Research (MFR) project, we prepared several zirconia-based mixed potential hydrogen sensors utilizing a tin-doped indium oxide electrode for H2 leak detection to test its stability in subsurface environments. Previous electrochemical sensor work has shown this type of sensor in a hydrogen safety sensor role represents a significant improvement over currently available sensors as it has an extremely stable baseline and limited cross sensitivity to other gaseous compounds.1 The feasibility of this technology will be demonstrated through a hydrogen permeation experiment to measure rates of underground hydrogen permeation between boreholes drilled underground at the DOE Waste Isolation Pilot Plant (WIPP) site. This experiment will (1) establish the use of this novel sensor in geologic H2 storage applications and (2) investigate the feasibility of H2 storage in bedded rock salt.

Acknowledgement

This research is supported by the Los Alamos National Laboratory, Laboratory Directed Research and Development (LDRD) Office, Missions Foundation Research Charter (Debora Wagner Program Manager).

References

E. L. Brosha, C. J. Romero, D. Poppe, T. L. Williamson, C. R. Kreller, R. Mukundan, R. S. Glass, and A. S. Wu, “Field Trials Testing of Mixed Potential Electrochemical Hydrogen Safety Sensors at Commercial California Hydrogen Filling Stations,” Journal of the Electrochemical Society
164 (13) B681-B689 (2017).
(Invited) Probing Local Ion Insertion through Operando AFM
Authors: Tsai Wan-Yu , Balke Nina
Published: August 2024

Electrode volume change during ion insertion or intercalation has been one of the main failure mechanisms for several energy storage devices, especially Li-based batteries. Fundamental understanding of the relationship between the amount of the ions/charge stored and the induced volume changes of the hosting electrodes, and how this relationship impact the materials’ performance are necessary to develop the next generation batteries. However, most of the studies on the volume change were based on bulk techniques, which study the entire electrode including binders and additives. Here, we use operando atomic force microscopy (AFM), which allows tracking local volume changes and other mechanical responses with sub-nanometer spatial resolution under the conditions close to the device operation.

In this work, we monitored electrode volume change via operando AFM and demonstrated the electro-chemo-mechanical coupling behaviors during proton insertion into WO3 materials. The concept of mechanical cyclic voltammetry (mCV) curves was developed, and the relationship between electrochemical current and strain was investigated with simplified models. The results revealed multiple ion-intercalation processes with different mechanical responses are involved during electrode cycling. Local heterogeneity was investigated via mCV mapping, confirming that the charging mechanisms varied across the electrode. These local variations could be further correlated to local morphology, crystal orientations, or chemical compositions. We further demonstrate that the mCV approach is applicable to a variety of energy storage materials (e.g., birnessite, MXene and metal nitrides) with the increasing complexity of current-deformation relationships.
(Invited) Revolving the Mechanical Stress in Batteries by Using Microcantilever
Authors: Li Zhi , Jiang Keren , Thundat Thomas
Published: August 2024

Although the generation of mechanical stress in the anode material is suggested as a possible reason for electrode degradation and fading of storage capacity in batteries, only limited knowledge of the electrode stress and its evolution is available at present. Here, we show real-time monitoring of the interfacial stress of a few-layer MoS2 system under the sodiation/desodiation process using microcantilever electrodes. During the first sodiation with a voltage plateau of 1.0 to 0.85 V, the MoS2 exhibits a compressive stress (2.1 Nm−1), which is substantially smaller than that measured (9.8 Nm−1) during subsequent plateaus at 0.85 to 0.4 V due to the differential volume expansion of the MoS2 film. The conversion reaction to Mo below 0.1 V generates an anomalous compressive stress of 43 Nm−1 with detrimental effects. These results also suggest the existence of a separate discharge stage between 0.6 and 0.1 V, where the generated stress is only approximately one-third of that observed below 0.1 V. This approach can be adapted to help resolve the localized stress in a wide range of electrode materials, to gain additional insights into mechanical effects of charge storage, and for long-lifetime battery design.
Numerical Modelling of Nanopores
Authors: Gyasi Agyemang Eugene
Published: August 2024

Nanopores are used for resistive pulse sensing of single analytes and as nanopipette probes for electrochemical scanned probe microscopy. The current-voltage responses of nanopores display a rich range of behaviors, which arise due to interactions between the electric fields (applied potential and surface charges), ion concentrations, and fluid flows.1 To understand these behaviors and interpret experimental results, numerical simulation of the coupled physics are typically performed.2 Yet despite simulations of conical nanopores being commonplace, they remain challenging. As the electric double layer requires resolution of concentrations and electric fields at sub-nm length scales, while concentration enhancements and depletions occur 10s of μm inside the pore simulations must resolve differences over length scales that vary by ~5 orders of magnitude. While various strategies have been employed to make these simulations more manageable including simulating a small portion of the pore, ignoring surface charge beyond a certain distance [others]. However, no consensus exists as to best practices or the impact of these simplifications.

In this work we assess the impact of commonly made simplifications and describe best practices for efficient modelling of conical nanopores to ensure accurate results are readily obtained. Suggestions include effective choices of mesh, initial conditions, and the handling of semi-infinite boundaries.

(1) Lan, W.-J.; Holden, D. A.; White, H. S. Pressure-Dependent Ion Current Rectification in Conical-Shaped Glass Nanopores. J. Am. Chem. Soc. 2011, 133 (34), 13300–13303. https://doi.org/10.1021/ja205773a.

(2) White, H. S.; Bund, A. Ion Current Rectification at Nanopores in Glass Membranes. Langmuir 2008, 24 (5), 2212–2218. https://doi.org/10.1021/la702955k.
(General Student Poster Award Winner, 3rd Place)
Lithium Niobate Coatings on Lithium Iron Phosphate Cathode Materials for Applications in Lithium-Ion Batteries
Authors: Gee Carol-Lynn , Dunn Devon , Gates Byron D.
Published: August 2024

Lithium-ion batteries have become a crucial tool in countering global fossil fuel reliance; when paired with electric motors, they provide an alternative to petroleum-based energy storage for internal combustion engines. Typical cathode materials used in lithium-ion batteries present a unique set of challenges. Some of the electrochemical materials that have a relatively high performance also have serious impacts on the environment and human health.1 Other materials that lack these specific drawbacks, such as lithium iron phosphate (LFP), face other issues. For example, LFP suffers from a relatively low electrical conductivity and a relatively slow lithium-ion diffusion, both of which affect the general electrochemical performance of this material. These weaknesses can be addressed using coatings applied to LFP nanoparticles. Carbon coatings have already been shown to improve the performance of LFP nanoparticles, but materials with higher ionic conductivities have remained relatively undeveloped.2 By synthesizing a composite coating of both carbon and lithium niobate, further improvements to LFP nanoparticles were sought to enable a wider range of applications for this cathode material.

In this work, lithium niobate coatings on carbon coated LFP nanoparticles were synthesized using a low temperature solvothermal method. Lithium niobate coatings have been shown to improve the specific capacity, rate capability, and durability of other cathode materials for lithium-ion batteries.3 Half-cells were fabricated to examine the effect of adding a lithium niobate coating to the carbon coated LFP cathode materials. Electrochemical testing techniques such as galvanostatic cycling and cyclic voltammetry were used to compare the properties and performance of the composite coated LFP relative to the carbon coated LFP. The composite coatings were also characterized using transmission electron microscopy, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. This coating method has resulted in the successful synthesis of lithium niobate coatings on carbon coated LFP nanoparticles with an observed improvement in durability.

Goodenough, J. B.; Kim, Y. Challenges for Rechargeable Li Batteries. Mater.
2010, 22 (3), 587–603.

Wang, J.; Sun, X. Understanding and Recent Development of Carbon Coating on LiFePO4 Cathode Materials for Lithium-Ion Batteries. Energy Environ. Sci.
2012, 5 (1), 5163–5185.

Kim, J. H.; Kim, H.; Choi, W.; Park, M.-S. Bifunctional Surface Coating of LiNbO3 on High-Ni Layered Cathode Materials for Lithium-Ion Batteries. ACS Appl. Mater. Interfaces
2020, 12 (31), 35098–35104.
A Data-Driven Modeling Framework for Lithium Metal Battery Health Estimation
Authors: Ma Wenting , Ha Sara , Pozzato Gabriele , Saatchi Alireza , Aliahmad Nojan , Littau Karl , Onori Simona
Published: August 2024

The Achilles' heel of LMB, despite its high theoretical energy density, has been its limited lifespan and variability in aging trajectories due to coupling of multiple failure mechanisms. Effective health estimation could enable timely maintenance actions before failure and a rapid LMB development iteration. Data-driven methods capture a wide spectrum of failure mechanisms and incorporates aging behavior variability. Recent work around data-driven LMB health estimation rely on empirical correlations observed specific to the datasets [1][2], and lack adaptability for a wide variety of experimental conditions and cell behaviors, especially those with a flat discharge capacity retention followed by abrupt decline.

In this work, we cycled 36 LMB cells across various temperatures and charge/discharge rates. The examined cells exhibit significant cell-to-cell variabilities even under identical experimental conditions, and consistent abrupt capacity fade behaviors. We extracted an extensive inventory of non-invasive features based on cycle-to-cycle variation of LMB external voltage-current measurements throughout aging, and managed to accurately track LMB capacity fade with quantified confidence intervals using these features combined with machine learning tools. The identified features provide not only reliable and robust LMB health monitoring performance, but also starting points for further first-principal modeling and experimental investigation to demystify LMB aging mechanisms. The abundance of discovered features, along with an automatic and time-efficient correlation mining pipeline, enables the generalizability of our proposed framework toward a wide variety of LMB cells.

References

[1] Iurilli, P., Luppi, L., Brivio, C.: Non-Invasive Detection of Lithium-Metal Battery Degradation. Energies 15(19), 6904 (2022)

[2] Liu, X., Zhang, X.-Q., Chen, X., Zhu, G.-L., Yan, C., Huang, J.-Q., Peng, H.-J.: A generalizable, data-driven online approach to forecast capacity degradation trajectory of lithium batteries. Journal of Energy Chemistry 68, 548–555 (2022)
Enhanced Capacity Retention Utilizing Hybrid Carbon Nanotube and Modified Separator in Li-Sulfur Batteries
Authors: Shweta Shweta , Kumar Satyam , Bhattarai Mohan , Choudhary Sunny , Morell Gerardo , Katiyar Ram S
Published: August 2024

Lithium-sulfur batteries (LiSBs) hold significant promise for high-energy storage; however, further concerted efforts are required to address challenges such as the shuttle effect, durability issues, and volume expansion to unlock their full potential. This study introduces an innovative approach to enhancing LiSBs' performance, involving the fabrication of a sulfur cathode using hybrid carbon nanotubes and modified separator. The modified separator exhibited high-rate capabilities, retaining over 80% capacity (~665 mAh/g) across 50 cycles. Cyclic voltammetry analysis indicated that the modified separator enhanced lithium-ion transportaion and a diffusion-controlled charge storage mechanism. Overall electrochemical performances suggest the potential of the proposed technique as an alternative for stabilizing LiSBs.
Influence of Temperature on the Nucleation and Adsorption Kinetic Mechanisms for Copper Corrosion
Authors: Cannan Caitlyn M. , Thurman Kira A. , Cannan Caitlyn W. , Kempler Paul A.
Published: August 2024

Copper is a valuable catalyst that is widely used in electrochemical devices, particularly in the generation of clean, renewable energy and the CO2 reduction reaction (CO2RR). Gaining insight into the fundamentals of corrosion/deposition of Cu in an electrochemical cell can aid in the design of more durable and efficient devices. To take advantage of the capabilities of Cu and comprehend the broader impacts, it is crucial to understand the kinetics of nucleation and adsorption mechanisms and conduct a thorough investigation of the underlying principles. Here, we utilize a model system with Cu underpotential deposition (UPD) on an Au(111) electrode surface in sulfuric acid electrolyte and investigate the impact of temperature change on the kinetics of Cu corrosion/deposition. The Transient technique, chronoamperometry, is employed to differentiate and illustrate the effects of the nucleation process and adsorption of ions. At temperatures below 20°C, peaks indicate the nucleation and adsorption processes can be identified individually. At temperatures 20°C and above, more adsorption characteristics are seen which may be due to the interactions between less-ordered monolayers at the interface, further demonstrated by the loss of nucleation characteristics. Electrochemical devices operate across a wider temperature range in practical uses. The aim of this study is to examine and quantify the influence of temperature on the nucleation and adsorption mechanisms for the kinetics of Cu in order to optimize the durability of Cu-containing electrochemical devices.
Electrical Cleaning of Rough Spherical and Bumpy Abrasive Particles Charged by Corona Ions in Post-CMP
Authors: Khanmohammadi Abbas , Ahmadi Goodarz
Published: August 2024

This study describes electrostatic methods for effective post-CMP (Chemical Mechanical Polishing) cleaning of contaminated wafers with rough spherical and bumpy abrasive particles. The case when corona ions charged the particles was studied. The extended JKR adhesion model for rough surfaces was used in the analysis. Charges were uniformly distributed across the entire particle surface for the corona charging. Removal of charged rough spherical and bumpy particles was investigated. The electric fields necessary to detach alumina particles with different numbers of bumps, contact asperities, and charges from wafer surfaces with varying roughness levels were evaluated. The present model predictions were compared against experimental data for the detaching polystyrene latex particles from an aluminum oxide substrate. It was shown that the model predictions for the electric detachment fields agree with the corresponding experimental data for the selected range of parameters. The model provides an approach for removing rough spherical and bumpy particles charged by corona ions in diverse applications, including post-CMP cleaning.
(Dielectric Science and Technology Poster Award, 2nd Place) Activation of Amine Chemistries for the Enhanced Particle Removal Efficiency of CeO2 Nanoparticles Via Megasonic Processing Conditions
Authors: McDonnell Elizabeth Maeve , Keleher Jason J.
Published: August 2024

With the persistent advancement of semiconductor technology, the demand for high-efficiency device manufacturing processes has surged. Chemical Mechanical Planarization (CMP) is a cornerstone for achieving angstrom-scale surface uniformity crucial for integrated circuits (IC) and logic devices. Shallow Trench Isolation (STI) CMP involves the selective removal of bulk oxide to electrically isolate active components on wafer surfaces. The modulation of the Ce3+ to Ce4+ surface state is essential for improved performance in both CMP and post-CMP (p-CMP) applications. Ce3+ is ideal for oxide material polishing due to its strong adherence to oxide surfaces, while Ce4+ is optimal for p-CMP cleaning, given its weak bond to oxide surfaces. Current p-CMP industry-standard methods utilize mechanical approaches, such as polyvinyl alcohol (PVA) brush scrubbing. However, this process induces high levels of shear force (SF), leading to secondary defects on the wafer surface (i.e. scratches, corrosion, increased surface roughness). To address these limitations, non-contact cleaning methods utilizing megasonic energy have emerged, which rely on generating reactive oxygen species (ROS) to induce particle removal. Thus, this study focuses on enhancing ceria particle removal during post-CMP cleaning by employing amine-based chemistries coupled with megasonic energy. While preliminary results imply that the mechanical cavitations induced by megasonic waves improve cleaning efficiency, this method will be optimized via the introduction of amine-based chemistries. Specifically, this work aims to leverage the unique properties of amines coupled with megasonic energy to facilitate enhanced ceria removal through electron donation, inducing a reduction in the oxidation state of ceria from Ce³⁺ to Ce⁴⁺. This approach improves particle removal while limiting secondary defects, enhancing redox activity induced by megasonic waves and chemical interactions. The mechanisms behind this method will be validated with CeO2 oxidation state kinetics, interfacial frictional changes, wafer surface roughness analysis, and SEM validation of particle removal efficiency.
Investigating Slurry Flow Patterns in Chemical Mechanical Polishing (CMP) Using Computational Fluid Dynamic (CFD) Simulations
Authors: Sadri Mofakham Atefeh , Ahmadi Goodarz , Seo Jihoon
Published: August 2024

Chemical Mechanical Polishing has emerged as a leading area approach for planarizing wafer surfaces during semiconductor manufacturing due to its ability to provide defect-free and uniform surfaces. Achieving nanoscale planarity on a wafer and die is one of the most significant steps in the process [1]. As part of the CMP process, it is essential to understand the interactions between consumables to facilitate the production of smooth and mirror-like surfaces [2], [3]. Simulation and numerical modeling have become critical means for elucidating intricate flow patterns to probe the underlying fundamentals of CMP processes. The computational fluid dynamics (CFD) simulations provide a detailed understanding of fluid flow behavior for various conditions [4], [5]. This study uses a three-dimensional CFD simulation to provide an understanding of the slurry flow pattern and its effects on CMP performance. Several CFD simulations were performed to study the effect of different parameters on slurry flow patterns. The simulations provided information on the interaction between the slurry, the wafer surface, and the polishing pad, in addition to the abrasive distribution, slurry velocity, and pressure variations within the CMP tool. It was observed that changing the pad and wafer rotation speeds, the wafer-pad gap size and the center-to-center distance affect the slurry flow conditions. For the same rotational speeds, as the center-to-center distance decreases, the flow velocity increases toward the wafer edge. Moreover, with the same rotation speed, the pad rotation dominates the wafer rotation speed.

[1] B. Suryadevara, Advances in Chemical Mechanical Planarization (CMP). Woodhead Publishing, 2021.

[2] J. Seo, Journal of Materials Research, 36, 235–257, 2021.

[3] A. R. Mazaheri and G. Ahmadi, J Electrochem Soc, 150, G233, 2003.

[4] J. Tu, K. Inthavong, and G. Ahmadi, Springer Science & Business Media, 2012.

[5] G. Ahmadi, “Chapter 2 -, R. Kohli and K. L. Mittal, Eds., Oxford: William Andrew Publishing, 2012, pp. 81–105.
Amine-Based Chemistries for the Megasonic Removal of Alumina Nanoparticles from Oxidized Silicon Carbide
Authors: Smith Piper M , Keleher Jason J.
Published: August 2024

Increasing demand for improved Integrated Circuit (IC) technology has propelled the advancement from silicon as a semiconductor material to Wide Band Gap (WBG) materials (i.e., Silicon carbide (SiC), Gallium nitride (GaN)) due to their intrinsic properties (i.e., increased thermal stability, wear resistance, etc.). While these traits make WBGs ideal semiconductor materials, the Chemical Mechanical Planarization (CMP) process becomes difficult as these surfaces are more chemically inactive. To overcome this, the CMP process has shifted to incorporate more aggressive chemical and mechanical conditions (i.e., highly oxidative chemistries, increased shear force, etc.) to reach desired material removal rates (MRR). Traditional post-CMP (pCMP) cleaning processes combine high shear forces via a Polyvinyl Alcohol (PVA) brush with oxidative cleaning chemistries to remove CMP residue. This, however, results in secondary defect generation (i.e., scratches, pitting, brush debris) on the substrate surface. A low-shear force, non-contact cleaning process via megasonic energy is one way to combat secondary defect generation. The megasonic energy serves a dual function of reducing the substrate’s surface boundary layer, which allows for enhanced surface interaction with various cleaning solutions while also generating reactive oxygen species (ROS) that activate the chemistry. This work focuses on amine-based cleaning chemistries for oxidized SiC substrates. The introduction of the amine leads to a reduction of the oxidized surface, allowing for a weakened residue-substrate bond for an improved particle removal efficiency (PRE). Initial results have shown that amine-based standard clean 1 (SC-1) produced comparable results to previously utilized cleaning chemistries (i.e., Supramolecular chemistries), with a PRE of 11.4%. The PRE of SC-1 increases significantly in proportion to sonication power, with the highest PREs ranging between 90% to 96%. This work will provide insight into oxidized SiC surface behavior by incorporating other amine-based cleaning chemistries.
Bending Dielectric Elastomer Actuators
Authors: Wilson Katelyn , Deliwala Nikhil , Clarke D. R. , Soundappan Thiagarajan
Published: August 2024

Dielectric Elastomer Actuators (DEAs) are a type of electroactive polymers that transform electric energy into mechanical work and are capable of large strains and high energy densities. DEAs are often described as “artificial muscles” because they exhibit strains, energy density, and responsiveness similar to natural human muscles. Their applications as soft robotic grippers, artificial arms, underwater robots, and aerial robots have previously been demonstrated. Single-layer DEAs have a simple design, with a dielectric layer sandwiched between compliant electrodes. However, by alternating positive and negative electrodes, multilayer DEAs can exhibit larger forces and strains than single-layer DEAs. DEAs are actuated by applying voltage and forming an electric field, generating a Maxwell stress between the electrodes. The process of fabricating a multilayer DEA consists of spin coating and curing layers of elastomer, stamping carbon nanotubes (CNT), and making connections to the electrodes. By alternating positive and negative electrodes, multilayer DEAs are constructed, which can exhibit larger forces and strains than single-layer DEAs. When electrically activated, DEAs expand laterally; however, by fabricating a bimorph DEA actuator, we demonstrate bending DEAs. A bimorph DEA consists of a multilayer DEA layer attached to a thicker inactive elastomer layer. When the bimorph is actuated, only the DEA layer expands, causing the actuator to bend. We study the relationship between the bending and stiffness of the inactive layer. By changing the shape of the DEA to a triangle or wing-like shape, we also emulate the high-frequency flapping of birds. Work begun on characterizing the voltage-controlled deflection of bimorph DEAs and understanding the mechanics of the bending of a simple beam in terms of forces at Harvard University will be continued on the Navajo Reservation at Navajo Technical University.