bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Hydrogen Assisted Carbonate Electrolysis for Direct Air Capture of CO2
Authors: Lattimer Judith , Kastelic Matthew , McCatty Steve
Published: November 2022

Reduction of greenhouse gases is vital for the long-term environmental health of the planet. While there has been progress in reducing CO2 emissions at large point sources, a significant portion of the CO2 emitted each year in the United States is released from distributed sources, like cars, smaller factories, and farms. Direct capture of CO2 from ambient air is therefore necessary for the ultimate reduction of greenhouse gas emissions in the atmosphere. However, capturing the CO2 in ambient air presents a much greater challenge due to the dilute nature of the CO2, requiring different strategies than carbon capture from concentrated CO2 waste streams.

We are developing a novel process for the capture and containment of CO2 from air into a purified, concentrated CO2 stream that can be redirected for use as a feedstock for a wide variety of applications, including chemical manufacturing and syngas formation. This process involves the capture of CO2 in a concentrated KOH solution using a high-surface area air contactor to form potassium carbonate. The potassium carbonate is then efficiently electrolyzed in a hydrogen-assisted process to regenerate the CO2 at a low operating potential, increasing the electrical efficiency of the process while producing concentrated and purified CO2. In addition, water, hydrogen, and KOH are also regenerated as byproducts that can be recycled back into the CO2 capture and electrolysis processes, reducing both overall energy and chemical consumption.

Using a custom designed test stand and traditional electrolysis cell design, we have demonstrated voltage of <1.8 V at 100 mA/cm2 for potassium carbonate conversion to carbon dioxide at the anode, with concomitant H2 and KOH production at the cathode, based on potassium-selective ion exchange across the membrane. Furthermore, using a custom 3-compartment electrolysis flow cell and ion-selective membranes, we successfully demonstrated hydrogen-assisted carbonate electrolysis, with hydrogen consumption at the anode, hydrogen and KOH production at the cathode, and CO2 formation from potassium carbonate in an internal flow-through compartment, at 1.4 V at 50 mA/cm2. Further improvements in operating conditions and cell components and design should decrease the operating voltage significantly, to <1 V at 100 mA/cm2.

Acknowledgement: The project is financially supported by the Department of Energy’s ARPA-E Office under the Grant DE-AR0001495
Combined Electrodialysis and Peptide-Directed Struvite Recovery System
Authors: Wu Ivy , Park Ryan , Herring Andrew M.
Published: November 2022

Recovery of N and P as struvite (MgNH4PO4 6H2O) has gained interest in recent years as both a flow assurance measure and as a sustainable P source for fertilizer. Electrochemically precipitated struvite offers advantages compared to conventional precipitation methods by reducing the need for expensive additives and has the potential for coupling with renewable energy sources. However, high energy inputs to overcome the solution resistance of most wastewaters limit the feasibility of the technology. In this work, a coupled electrodialysis-struvite recovery system is presented to concentrate the wastewater (producing a separate desalinated stream) while producing struvite in a single unit operation. Furthermore, a common dental peptide was explored as a method to control and increase growth of struvite crystals at neutral pH. Cysteine-capped peptide was attached to a gold mesh substrate in a range of loadings (5-27ug/cm2). Chronoamperometry was conducted by first placing the peptide-loaded mesh in the struvite reactor filled with synthetic wastewater at pH 7.1 and then applying a range of potentials (0.5-0.99V) to the magnesium anode. White precipitates were observed and characterized as struvite by XRD. Struvite crystal morphology was investigated by SEM. We report that a peptide loading of 19 ug/cm2 led to a nearly 14% increase in struvite precipitated compared to bare Au with no peptide attached. Furthermore, longer, dendritic struvite crystals formed in the presence of peptide compared to orthorhombic crystals which formed without peptide. These results indicate that the peptide alters local supersaturation, leading to an increase in directional crystal growth. By demonstrating the utility of peptides for increasing struvite precipitation at neutral pH, our findings improve the viability of electrochemical struvite precipitation for a wider range of wastewater compositions and highlights how peptides can modulate crystal growth.
Continuous Ion Separations Using Non-Faradaic Capacitive AC Ratcheting
Authors: Kautz Rylan , Heffernan Ethan J. , Herman Alon , Ager Joel , Segev Gideon , Ardo Shane
Published: November 2022

Traditional electrochemical separations processes require Faradaic reactions for sustained currents. We discovered that this limitation can be overcome by oscillating the applied potential across an ion-permeable material that has an asymmetric electric potential profile. We demonstrated this phenomenon for the first time using a flashing ratchet consisting of a nanoporous anodized aluminum oxide membrane infiltrated with salt water and containing metallic contacts on either side. When a symmetric +/-300 mV square-wave potential was applied to the metallic contacts at a frequency of ~100 Hz, an open-circuit potential as large as ~50 mV was observed between Ag/AgCl electrodes immersed in the chloride-containing electrolyte and positioned across the membrane. While this open-circuit potential was determined to be a consequence of net ionic polarization, additional electrochemical data were also consistent with transport of neutral salt across the membrane via a proposed ambipolar transport mechanism. In comparison, application of a DC potential bias resulted in non-Faradaic charging, and a near-zero long-time open-circuit potential. Moreover, high ionic strengths and large pore sizes diminished ratcheting behavior, consistent will more complete screening of surface charges in the nanopores. Collectively, this work represents a new paradigm for direct ion pumping and salt separations that requires no Faradaic reactions or additional transport pathway for ions or electrons.
Design Principles for Flow Batteries: Cation Dependent Membrane Resistance and Active Species Solubility
Authors: Waters Scott E. , Thurston Jonathan R. , Armstrong Robert W. , Robb Brian H. , Marshak Michael , Reber David
Published: November 2022

Aqueous redox flow batteries are generally adapted from polymer electrolyte membrane fuel cells that use proton exchange membranes to balance the charge of the cell. Such membranes are well understood and exhibit excellent performance in acidic electrolytes via transport of protons. For neutral pH flow batteries however, the primary cation in solution is not H+, but the cation of the active material or supporting electrolyte salt.

The nature of the cation in solution, e.g., hydrated ionic radius and charge density, significantly affects the transport resistance through the membrane and thus the area specific resistance of the cell, a critical parameter that needs to be minimized for high power applications such as flow batteries. Additionally, different cations result in vastly different solubilities of active materials based on redox active anions such as ferrocyanides; the ammonium salt for example is ca. three times more soluble than the sodium salt (1.6 M vs. 0.5 M).[1] It is therefore critical to not only maximize the concentration of an electrolyte and thus its capacity, but to also choose cations that enable efficient transport across the membrane for efficient flow battery development.

Here, we study the cation dependent resistance of NafionTM 212 cation exchange membranes for 12 different alkali and alkylammonium cations and determine the solubilities of 13 ferrocyanides as well as 35 metal-organic chelates based on aminopolycarboxylate ligands. The latter are a particularly promising family of compounds for application in negative electrolytes in near neutral pH aqueous flow batteries with demonstrated discharge voltages as high as 2.1 V and excellent power performance.[2] We further discuss cation-compatibility for mixed cation electrolytes as well as membrane pretreatments that affect the cells area specific resistance and active species crossover.[3]

References:

[1] J. Luo, B. Hu, C. Debruler, Y. Bi, Y. Zhao, B. Yuan, M. Hu, W. Wu, T.L. Liu, Unprecedented capacity and stability of ammonium ferrocyanide catholyte in pH neutral aqueous redox flow batteries, Joule
2019, 3, 149–163.

[2] B.H. Robb, J.M. Farrell, M.P. Marshak, Chelated chromium electrolyte enabling high-voltage aqueous flow batteries, Joule
2019, 3, 2503–2512.

[3] S.E. Waters, J.R. Thurston, R.W. Armstrong, B.H. Robb, M.P. Marshak, D. Reber, Holistic design principles for flow batteries: Cation dependent membrane resistance and active species solubility, J. Power Sources
2022, 520, 230877.
Modeling Electrochemical Transport within a Three-Electrode System Towards Fast Charge Applications
Authors: Garrick Taylor R. , Gao Jing , Koch Brian
Published: November 2022

In support of GM's traction battery efforts, we derive and implement a method to describe the electrochemical performance of a battery cell through the combination of a modified Newman Pseudo 2-Dimensional model and a three-electrode experimental apparatus. To assess the capability of the method, we compare model results with experimental data for a lithiated graphite and lithium nickel manganese cobalt oxide system. The model is applied to simulate the electrochemical and transport processes within the battery cell to predict the negative electrode potential and positive electrode potential with respect to a lithium iron phosphate reference electrode, as well as the terminal voltage. We extend this discussion to cover applicability to fast charge considerations to avoid lithium plating at the anode during a fast charge event.

References:

1. Taylor R. Garrick, Jing Gao, Xingyi Yang, and Brian J. Koch. 2021 J. Electrochem. Soc. 168 010530
On Accuracy of Porous Electrode Design in the Presence of Negative Effects of Carbon-Binder Networks
Authors: Mistry Aashutosh , Trask Stephen E. , Dunlop Alison R. , Polzin Bryant , Mukherjee Partha P. , Srinivasan Venkat
Published: November 2022

Porous electrodes for Li-ion batteries are composed of energy storing active material particles, carbon-binder networks, and electrolyte filled pores 1. The carbon-binder networks improve the electronic conduction through the porous electrode, and are expected to improve electrode performance at finite currents. Accordingly, the porous electrode designs treat carbon-binder networks as a positive influence. In this talk, by using systematic experiments of electrochemical performance for different electrode compositions, we will show that the carbon-binder networks also exhibit negative effects 2. These negative effects deteriorate performance by decreasing the area available for intercalation reaction as well as increasing the resistance to ion transport. These effects are prominent for electrodes even with low carbon-binder content, e.g., 5%wt (of dry electrode). We will discuss the implications of these results in the context of predicting porous electrode performance 3, and in turn, designing these electrodes for different operations.

Liu et al. (2012) Particles and Polymer Binder Interaction: A Controlling Factor in Lithium-ion Electrode Performance, J. Electrochem. Soc. 159(3), pp. A214-A221, https://doi.org/10.1149/2.024203jes

Mistry et al. (2021) Quantifying Negative Effects of Carbon-binder Networks from Electrochemical Performance of Porous Li-ion Electrodes, J. Electrochem. Soc. 168(7), 070536, https://doi.org/10.1149/1945-7111/ac1033

Doyle, Fuller & Newman (1993) Modeling of Galvanostatic Charge and Discharge of Lithium/Polymer/Insertion Cell, J. Electrochem. Soc. 140(6), pp. 1526-1533, https://doi.org/10.1149/1.2221597

Figure 1
(Digital Presentation) Tailoring Solvation and Counterion Complexation in the Electrolyte for Enhanced Titanium Redox Flow Battery Performance
Authors: Ahmed Sheikh Imran Uddin , Torres Daniel , Usen Nazreen Mohamed Shahid , Sankarasubramanian Shrihari
Published: November 2022

The use of titanium (Ti) in redox flow batteries (RFBs) is of increasing interest as Ti is 100x as abundant[1] worldwide as vanadium (V) with a 10x lower cost of production. The half-cell potential of the Ti4+/Ti3+ redox couple is 0.1 V (vs. SHE) as compared to -0.26 V (vs. SHE) for V3+/V2+, which makes the Ti4+/Ti3+ redox couple less prone to parasitic hydrogen evolution reactions. Aiming to optimize electrolyte formulation for Ti-based RFBs, we measured the transport and kinetic parameters for the Ti3+/Ti4+ redox couple in various acidic supporting electrolytes [2, 3, 4] such as H2SO4, HCl, HNO3 and CH3SO3H (methanesulfonic acid). The solubility and electrochemical reversibility of the Ti3+/Ti4+ redox couple was examined with a view toward increasing the energy density and energy efficiency of Ti-based RFBs. The solvation sphere around the redox active species was manipulated by varying the counterion and by careful control of the redox active species to counterion ratio. The solvation and complexation behavior were correlated to the transport and kinetic properties through the impact of the solvent reorganization energy () on the electrochemical Thiele Modulus[5]. The kinetics of the Ti3+/Ti4+ redox couple diverged by >2x between the forward and reverse reactions and the diffusion coefficients were found to vary by an order of magnitude with varying complexation and solvation. Finally, we also demonstrate the predictive ability of the electrochemical Thiele Modulus by correlating the predictions based on the effectiveness factor to polarization performance of Ti symmetric cells.

References:

"Titanium Statistics and Information," S. Geological Survey, (2021).

Dong, Yongrong, et al. "Titanium-manganese electrolyte for redox flow battery." SEI Tech. Rev.84 (2017): 35-40.

Sankarasubramanian, Shrihari, and Vijay K. Ramani. "Redox flow battery." U.S. Patent No. 11,177,497. 16 Nov. 2021.

Savinell, R. F., et al. "Discharge Characteristics of a Soluble Iron‐Titanium Battery System." Journal of the Electrochemical Society3 (1979): 357.

Sankarasubramanian, S., Kahky, J., Ramani, V., PNAS, 116 (30), 14899 (2019)

Figure 1
(Invited) State of Charge Monitoring of Vanadium Flow Batteries Using Spectroscopic and Electrochemical Methods
Authors: Rybalchenko Maria , Quill Nathan , Buckley D. Noel , Lynch Robert P.
Published: November 2022

Vanadium Flow Batteries (VFBs) are a promising energy storage technology, particularly for large and medium scale applications. In a VFB, energy is stored in two vanadium electrolytes separated by a nafion membrane. The use of vanadium electrolytes in both half-cells minimises cross contamination issues which have plagued other flow battery chemistries. The electrodes, electrolytes and membrane are key areas of research for VFBs with the aim of improving efficiency, energy density and costs.

Accurately monitoring state-of-charge (SoC) is vital for any rechargeable battery system. It is important to monitor the SoC of both half-cells simultaneously because of imbalances which occur due to side reactions and unwanted vanadium transfer across the membrane. The electrolyte may be rebalanced by various techniques but only if the SoC of each half-cell is accurately known. There are multiple possible techniques to monitor the SoC of each half-cell. We measure SoC in-situ by analysing the absorbance spectra of the vanadium electrolytes as they are charged and discharged. We also accurately measure volume changes throughout the cycle to study the water transfer through the nafion membrane. This accurate SoC data which is obtained will be compared with other SoC techniques. It will also be used to study the performance characteristics of the battery.

Acknowledgements:

This research was funded by the Sustainable Energy Authority of Ireland (Award Number 18/RDD/341).
(Invited) Introduction and Overview of Area-Selective Thin Film Deposition
Authors: Parsons Gregory
Published: November 2022

Low temperature Area-Selective Deposition (ASD) is becoming an important need in semiconductor manufacturing to augment photolithography for improved resolution and alignment of printed features. Area-selective deposition is used routinely at temperature in excess of 800°C to form epitaxial transistor contacts, but for back-end applications, new ASD processes are needed that work at <400°C. This tutorial will introduce the challenges of low temperature ASD, and summarize recent advances in this field, including ASD via Atomic Layer Deposition (ALD) and Chemical Vapor Deposition (CVD), and understanding of feature size dependence and lateral “mushroom” growth. We will review approaches using surface passivation, including self-assembled monolayers and small molecule inhibitors, as well as approaches based on inherent differences in nucleation on different clean surfaces. Further, we will present emerging approaches that achieve patterning by taking advantage of native selectivity in nucleation and etching reactions, for example, where ALD and Atomic Layer Etching (ALE) can be combined, either in sequence or in parallel, to achieve desired outcomes. We will also review current modeling efforts, including methods to quantitatively analyze ASD and compare results for different materials and different processes, highlighting the challenges of understanding reactions for initial nucleation and nucleus removal.
(Invited) Gas Phase Coating of Particles for Energy Applications
Authors: van Ommen J.
Published: November 2022

Advanced materials, often relying on nanostructured particles as building blocks, are crucial in meeting grand challenges in energy: battery materials, electrocatalysts, phase change materials, etc. etc. Gas phase deposition techniques, such as chemical vapour deposition (CVD), atomic layer deposition (ALD), and molecular layer deposition (MLD) are excellent methods to make such nanostructured particles: particles of which the surface is either covered by an ultrathin film or by nanoclusters. When combined with proper particle handling, these coating methods are also very well suitable for scaling up. This requires adequate reactor technology to optimize the contacting of particles and gaseous reactants.

Gas phase coating such as CVD and ALD is already widely applied in the semiconductor industry. Although the underlying mechanisms are similar, there are quite some differences between gas phase deposition on wafers and coating particles. This tutorial will discuss recent developments and insights in the field of applying gas phase deposition to particles, with an emphasis on reactor technology, precursor utilization, operating conditions, and scaling up. I will show that we can produce nanostructured particles with very high precision in a scalable way. I will focus on energy applications, and will discuss how this approach can also be of value in light of the increasing demand for critical raw materials.
Chemical Stability of Atomic Layer Deposited (ALD) Alumina Thin Films in Aqueous Solutions
Authors: Fairach Selma , Willis Simon , Losego Mark D
Published: November 2022

Aluminum oxide (alumina) thin films deposited through atomic layer deposition (ALD) are of great interest in chemical barrier and corrosion protection applications. However, the stability of ALD alumina in aqueous solutions is still not fully understood. Due to its metastable amorphous phase, the hydration and degradation behavior of ALD alumina films behaves differently from its crystalline Al2O3 counterpart. A full understanding of why these films hydrate and/or dissolve requires the exploration of different deposition conditions and ion content in solutions used. This talk will discuss efforts to further elucidate the hydration and dissolution behavior of ALD alumina films. For this study, alumina thin films were ALD deposited onto silicon substrate at 150 °C using trimethylaluminum (TMA) and H2O. These films were then studied in Type 1 DI water, 2M NaCl, .5M NaCl, and .1M NaCl solutions at room temperature. Films were gently dried using a nitrogen gun and thickness was measured using a Cauchy ellipsometry model. After 15 days of immersion in Type 1 DI water, significant thickness growth is observed at twice (27 days) and 2.5 times (33 days) the normalized thickness. Similar hydration is not observed in salt-containing aqueous solutions nor upon exposure to air. We will discuss the possible effects of CO2 dissolution and carbonate formation as well as ionic species on the hydration and dissolution processes of these alumina films. Finally, we will show how a post-ALD plasma treatment to the film’s surface alters the hydration and dissolution behavior, improving stability in several aqueous conditions.
Seebeck Analysis of ALD Synthesized Thermoelectric Sb2Te3 Thin Films
Authors: Tahsin Sadiya , Baumgart Helmut
Published: November 2022

Thermoelectric materials have attracted significant attention due to their potential application in power generation and refrigeration systems, because they can convert thermal energy into electric energy from waste heat recovery. Thin thermoelectric films can be used to create thermoelectric generators, where the power they create does not result in any additional emissions. PbTe, PbSe and Sb2Te3, Bi2Te3
present excellent choices for thermoelectric energy harvesting devices. Among these, Sb2Te3
and its derivatives have high Seebeck coefficient and good electrical conductivity, which make these the most promising p-type material for low temperature thermoelectric device. The high figure of merit ZT values at relatively low temperature make these exceptional thermoelectric materials. This study investigates Seebeck coefficient measurements of Sb2Te3 thin film synthesized by Atomic Layer Deposition (ALD) technology using a Veeco Nanotech thermal ALD reactor. For the ALD synthesis of Sb2Te3 we used SbCl3 as precursor1 and (Si(CH3)3)2Te Bis(trimethylsilyl)telluride as precursor 2. Antimony trichloride Sb2Te3 is a solid ALD precursor requiring preheating to the melting temperature around 73 ℃ to generate sufficient vapor pressure. A typical film morphology of ALD Sb2Te3 is shown in the SEM micrograph of Fig.1. The efficiency of thermoelectric materials is expressed by the dimensionless thermoelectric figure of merit, ZT = S2σT/
k, where S is the Seebeck coefficient, σ is the electrical conductivity, and k is the thermal conductivity. Because the crucial Seebeck coefficient factors directly into the equation by the power of two to determine ZT and the power factor, it is imperative to optimize the thermoelectric thin film material for maximum Seebeck coefficient. Maximizing the figure of merit ZT is challenging because in thermoelectric materials the quantities S, σ and κ are interrelated in such a way as to make independent control of these variables to increase ZT not straightforward. An increase in S typically results in a decrease of σ. Following the Wiedeman- Franz law a decrease in σ produces a decrease in the electronic contribution to κ complicating matters.

Figure 1
Unveiling Hidden Chemistry between an Aluminum ALD Precursor and Li Metal Anodes
Authors: Kang Donghyeon , Mane Anil U. , Elam Jeffrey W.
Published: November 2022

Trimethylaluminum (TMA) is a widely utilized aluminum precursor for atomic layer deposition (ALD) in various aluminum-based coatings. For example, TMA produces Al2O3 with H2O,[1] AlF3 with HF-pyridine,[2] and Al2S3 with H2S [3] with well-defined ALD mechanisms. These ALD processes have been widely applied into various materials to introduce ultra-thin Al-based coating layers, including energy storage materials such as battery cathodes, anodes, and solid electrolytes. Our group demonstrated that the Al2O3 ALD process using TMA can be used for Li-metal anode coating to improve electrochemical stability and reduce Li-dendrite formation during battery cycling.[4]

Although many studies about ALD on Li metal anodes have been reported using TMA, most of them focus on Li-metal battery performance, instead of ALD chemistry. During deep investigation on ALD chemistry of TMA, we recently discovered an interesting chemistry between TMA and reactive metal substrate (i.e. Li metal). Based on our observation, TMA reacts with Li-metal during ALD cycles then producing a carbon composite layer on the top of Li metal, not following conventional ALD mechanisms. It may come from highly reactive nature both of TMA and Li metal. Despite of wide use of TMA, this phenomenon has not been reported to date because Li metal is passivated by several layers such as Li2CO3, LiOH and Li2O even stored in glovebox environment. In this presentation, we will discuss the chemistry between TMA and Li metal found by in-situ QCM, high-resolution XPS, SEM, and Raman studies. Then we will also demonstrate how this unexpected ‘side reaction’ can be utilized in Li-metal battery applications using liquid and solid electrolytes.

[1] 1. A. C. Kozen et al., ACS Nano, 9, 5884–5892 (2015).

[2] Y. Lee, H. Sun, M. J. Young, and S. M. George, Chemistry of Materials, 28, 2022–2032 (2016).

[3] X. Meng, Y. Cao, J. A. Libera, and J. W. Elam, Chemistry of Materials, 29, 9043–9052 (2017).

[4] L. Chen et al., Journal of Materials Chemistry A, 5, 12297–12309 (2017).

Figure 1
Atomic Layer Deposition of Metal Phosphates
Authors: Henderick Lowie , Dhara Arpan , Werbrouck Andreas , Dendooven Jolien , Detavernier Christophe
Published: November 2022

Since the introduction of lithium iron phosphate (LFP) as an electrode material for Li-ion batteries (LIB’s), metal phosphates in general have become increasingly important. The strong covalency of the P-O bonds typically results in a very good thermal and structural stability, which is one of the main reasons for the success of LFP as a LIB electrode. However, the applications of these metal phosphates are multi-fold. Apart from LIB’s, they have been proven to be promising towards e.g. electrocatalytic water splitting, biocompatible coatings or even as protective coatings for luminescent materials.

With these applications in mind, the research towards the deposition of these materials also becomes increasingly important. Atomic Layer Deposition (ALD) has emerged as a deposition technique with unique nanotailoring capabilities compared to conventional methods, particularly owing to its high thickness and compositional control. Down-scaling micro-electronic devices according to Moore’s law has already increased interest in the unique capabilities ALD can offer. However, in addition to using ALD for the fabrication of such devices, it can also offer a unique way to create model systems to gain a fundamental insight for a broad range of applications.

From this it can be seen why the combination of both research fields, i.e. ALD of metal phosphates, is gaining a lot of interest over the past years. Since the first metal phosphate has been deposited in 1969, a big challenge has been to find a suitable phosphate precursor. Today, the most popular choice proves to be trimethyl phosphate, i.e. TMP. It has allowed for the deposition of a variety of phosphates (e.g. aluminium phosphate, lithium phosphate, iron phosphate, etc.), but more research is required to further extent this research field. To stimulate this research, a comprehensive study on the currently (un)available literature is needed. It would e.g. allow to get a better understanding on the effect of different phosphate precursors and/or various reaction mechanisms during ALD can be better understood, as well as the potential applications of these materials (such as lithium ion battery applications). As such a study on ALD of metal phosphates was so far not yet available, we hope that this work can create a view that is of interest towards various scientific fields, and help to guide future thin film researchers.
Investigating the Thermo-Oxidative Degradation and Operational Limits for Hybrid AlOX–PET Fabrics Created Via Vapor Phase Infiltration (VPI)
Authors: Gonzalez Alan J , McGuinness Emily K , Losego Mark D
Published: November 2022

In vapor phase infiltration (VPI), vapor phase metalorganic precursors are diffused into polymers and further reacted with water vapor to form hybrid organic-inorganic materials. Hybrid materials created through VPI have shown utility in industrially relevant applications including membranes for chemical separation, photovoltaics, and catalysis. VPI can be conducted at different temperatures, with each processing temperature resulting in different chemical states that alter the properties of the hybrid material. In this project, polyethylene terephthalate (PET) fabrics are infiltrated with a trimethylaluminum (TMA) precursor and co-reacted with water vapor at a range of infiltration temperatures (60-140 ˚C) to create hybrid AlOX - PET fabrics. The purpose of this project is to develop a set of thermal operational limits for these hybrid organic-inorganic materials and translate techniques for thermal characterization from the textile community to the VPI community. Thermo-oxidative degradation for the hybrid fabrics was quantified through changes in degradation temperature and activation energies. Thermogravimetric analysis (TGA) was employed to quantify inorganic loadings (~20 weight percent inorganic), degradation temperatures, and the activation energy for degradation using the Flynn/Wall/Ozawa (FWO) method for decomposition kinetics. Most hybrid fabrics demonstrated lower degradation temperatures than neat PET, except for the fabric infiltrated at 140˚C which had increased degradation temperatures. Activation energies for the first thermal-oxidative degradation event for the 80˚C, 100˚C, and 140˚C fabrics decreased by a range of 62˚C to 84˚C compared to neat PET, while the 120˚C fabric’s activation energy slightly increased by 10˚C. Additionally, a new degradation event occurred for fabrics infiltrated at low temperatures which was explored through FTIR characterization and attributed to structural rearrangements of the inorganic component. Overall, this work demonstrates how VPI process conditions alter both the organic-to-inorganic chemical binding as well as the inorganic cluster structure in these hybrids and how these structural features affect thermophysical operational limits of the material.
(Digital Presentation) Design of High Barrier Property and Flexible Inorganic/Polymer Hybrid Film for Encapsulation of Flexible Electronics
Authors: Wen Di , Zhang Yinghao , Li Yun , Yang Fan , Chen Rong
Published: November 2022

Designing encapsulation film with both high barrier property and excellent flexibility has been challenging for the current brittle inorganic films owing to the strain-induced cracking. Inorganic/organic multilayer has been proposed due to the organic layer can function as buffers of the inorganic layer and defect-decoupling layer, realizing the improvement of flexibility and maintaining barrier property. Polydimethylsiloxane (PDMS) was widely used as an organic encapsulation layer due to its high stability, elasticity, and transparency. The introduction of PDMS helps the barrier film to resist distorting under the bending motions. However, the delamination and cracking occurred under bending motion in a small curvature radius due to the mismatched strain and coefficient of thermal expansion (CTE) between PDMS and inorganic films such as Al2O3. Realization of improving their strain and CTE mismatch is possible by doping nanoparticles into PDMS. The Al2O3/PDMS hybrid film with the doping of SiO2 fabricated via atomic layer infiltration (ALI) method showed mechanical stability and endure 1000 repetitive stretch tests with 1%, but the water vapor transmission rate (WVTR) was only 10-3 g/m2/day, which was attributed to the lower crosslinking density of PDMS result in higher free volume and chain mobility. It’s a challenge to develop a strategy for improving the crosslink density of PDMS. In this work, the PDMS-based composite substrate with engineered stiffness was developed by employing the addition of silane coupling agent and SiO2. Atomic layer infiltration (ALI) coupled with UV-curing was introduced for sub-surface cross-linking of PDMS in Al2O3/SiO2/PDMS hybrid film, and the resulted Al2O3/SiO2/PDMS hybrid film showed highly stretchable and barrier properties. The result indicates that Al2O3/SiO2/PDMS hybrid film is a promising encapsulation film applicable to flexible electronics.

Keywords: atomic layer infiltration (ALI), flexible film, encapsulation, UV-curing method, water vapor transmission rate (WVTR)

Refs.

Y. Li, D. Wen, Y. Zhang, Y. Lin, K. Cao, F. Yang, R. Chen, Highly-stable PEN as a gas-barrier substrate for flexible displays via atomic layer infiltration, Dalt. Trans. (2021) 16166–16175. https://doi.org/10.1039/d1dt02764f.

Zhang, D. Wen, M. Liu, Y. Li, Y. Lin, K. Cao, F. Yang, R. Chen, Stretchable PDMS Encapsulation via SiO2 Doping and Atomic Layer Infiltration for Flexible Displays, Adv. Mater. Interfaces. 9 (2022) 1–9. https://doi.org/10.1002/admi.202101857.
Precise Pore Size Tailoring and Surface Chemistry Modification of Polycarbonate Membranes Using Atomic Layer Deposition
Authors: Pathak Rajesh , Shevate Rahul , Rozyyev Vepa , Kang Donghyeon , Mane Anil U. , Elam Jeffrey W.
Published: November 2022

Physical and chemical surface modifications are commonly used in many applications such as energy generation and storage, microelectronics, water purification, gas separation, and medical/plant biology. In recent several years, sequential infiltration synthesis (SIS), a variant of atomic layer deposition (ALD), has emerged as a promising technology that uses self-limiting reactions to create hybrid organic/inorganic materials within the polymer-free volume. Herein, we employed ALD/SIS of Al2O3, SnO2, Ga2O3, TiO2, and In2O3 to precisely tune the pore size and surface characteristics of track-etched polycarbonate membranes. We used in situ Fourier transform infrared spectroscopy to elucidate the chemistry for Al2O3 SIS in polycarbonate and in situ quartz crystal microbalance measurements to probe the extent of Al2O3 infiltration during SIS in polycarbonate thin films. Next, we used scanning electron microscopy, thermogravimetric analysis, and water permeance measurements to probe the pore size reduction and conformality of SIS Al2O3 in the track-etched polycarbonate membranes. We then used water permeance measurements to compare the water flux for a series of membranes with similar pore size but different pore wall chemistry and compared these results with water contact angle measurements. Interestingly, the hydrophilic metal oxide coatings yielded higher water flux values compared to hydrophobic coatings. Finally, we examined ion-selective transport in the modified track-etched polycarbonate membranes and rationalized the results using zeta potential measurements of the ALD metal oxides.

Keywords: atomic layer deposition; sequential infiltration synthesis; metal oxides; hydrophilicity/hydrophobicity; permeability; surface charge; ion conductivity/selectivity.
A 3D Electrochemical Model for the Si/C Composite Active Particles
Authors: Gao Xiang , Xu Jun
Published: November 2022

SiO/Graphite (Gr) composite has attracted more and more interests in both the academic and industrial communities regarded as one of the most promising anode materials for the next generation of high-energy-density lithium-ion batteries (LIBs). This material achieves high capacity meanwhile maintaining a relatively good mechanical integrity compared to the pure Si anode. However, the heterogeneous composition of such an anode system brings in highly nonlinear and complex electrochemical behaviors compared to the single-material anode. The computational modeling provides an efficient and accurate way to explore the electrochemical behaviors of SiO/Gr composite anode. Herein, we propose a 3D model at the electrode level containing particle geometries based on a representative volume element (RVE) and study the electrochemical process of the half-cell charging. The effects of SiO proportion, charging rate, SiO distribution, and SiO particle size on the electrochemical performance are discussed. The addition of SiO in Gr anode leads to the ultra-high real-time C-rate (CR
) compared to the applied one within a specific time range, which is harmful to the active particles, especially under high C-rates. The results reveal that anode with higher SiO proportions performs a better rate capability. We also discover that moving SiO particles towards the separator and shrinking the SiO particle can benefit cell performance. Results provide an in-depth understanding of the electrochemical behaviors of the composite anode and guide the design for SiO/Gr anode materials in maximizing the theoretical capacity while maintaining better rate performance.
Oxidative Stabilization of Dilute Ether Electrolytes Via Anion Modification
Authors: Holoubek John , Yan Qizhang , Liu Haodong , Hopkins Emma , Wu Zhaohui , Yu Sicen , Luo Jian , Pascal Tod A. , Chen Zheng , Liu Ping
Published: November 2022

State of the art Li metal batteries typically rely on ether electrolytes with high salt concentration and/or fluorinated solvents to enable stable cycling. Their high manufacturing costs at scale have motivated us to consider dilute, non-fluorinated ether electrolytes. However, their poor oxidative stability has precluded their application in cells employing transition metal oxide cathodes, which operate at > 4 V vs Li/Li+. Herein, we present a possible route forward for the oxidative stabilization of these electrolytes, which enabled the reversible cycling of LiNi0.8Mn0.1Co0.1O2 at a cutoff of 4.4 V in electrolytes composed only of 1 M salt and 1-2 dimethoxyethane. Through computational and experimental material characterization, it was determined that this behavior was driven by a passivating interphase composed largely of perfluoro alkane species. This work provides a method for the oxidative stabilization of ether electrolytes with a low base materials cost.

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(Digital Presentation) Understanding of Single-Crystal Fabrication of High-Nickel Layered Oxide through Variation of Heating Process
Authors: Fung Kuan-Zong
Published: November 2022

Single-crystal processing of layered oxide cathode has received great attention recently. It has been recognized that Ni-rich layered oxide with grain size in mm range tends to provide better cycling performance due to better structural integrity against volume changing during charge/discharge cycles.

However, during heating/calcination process of oxide/carbonates/nitrates powder compacts, it may involve decomposition, chemical reactions, diffusion, oxidation, sintering, grain-growth.

For grain growth to take place at final stage of sintering, the powder compacts need to be heated to higher temperatures for certain period of time. On the other hand, the formation of Ni-rich layered oxides need air/oxygen for Ni oxidation and better crystallization. Thus, it is crucial to investigate the processing of single-crystal Ni-rich layered oxide based on the sintering behavior, thermal gravimetric analysis, and phase transformation. Furthermore, the lithiation/oxidation of Ni-containing oxides during single-crystal processing may involve charge compensation resulted from defect reactions. In this study, the affected electrical, optical, structural, and electrochemical properties of layered oxides will be discussed based on defect chemistry consideration. The structural, microstructural and electrical properties of decomposed precursors and doped layered oxides will be examined using XRD, SEM and DC/AC impedance measurements. CV and charge/discharge tests from assembled coin cells will be used to evaluate electrochemical properties of single-crystal Ni-rich layered oxides.
Ligand Elucidation of Dissolved Transition Metal Ions in Pristine and Degraded Electrolytes in Li-Ion Batteries
Authors: Szczuka Conrad , Allen Jennifer P. , Jakes Peter , Grey Clare P. , Eichel Rüdiger-A. , Granwehr Josef
Published: November 2022

During operation of a Li-ion battery, layered transition metal oxides release metal ions into the electrolyte. In addition to capacity loss, dissolved metal ions are mobile in the electrolyte and can deposit at the anode, enhancing Faradaic losses and posing the risk of dendrite formation.[1] In the electrolyte solution, transition metal ions are characterized mainly by their oxidation state and complexation behavior, which dictate the transport through the electrolyte. Additionally, mechanistic insights, indirect information about electrolyte degradation, and design of counter-measures might be extracted thereof. However, particularly the coordination sphere is difficult to access, due to inherently low concentrations and scarcity of suitable analytics.

In this work, the coordination sphere of dissolved transition metal ions is selectively probed by pulse Electron Paramagnetic Resonance (pEPR). pEPR selectively addresses isolated paramagnetic ions, masking analytical interference from other species in the battery. Because of its known impact on capacity fade, firstly Mn2+ is analyzed in premixed pristine and degraded electrolyte solutions. Carbonates with high dielectric constants such as ethylene carbonate (EC) are the dominant ligands, accompanied by electrolyte salt anions for charge compensation. If present, trace amounts of electrolyte degradation products such as fluorophosphates selectively form the first coordination sphere. The results from pEPR measurements, that have to be performed on frozen solutions at cryogenic temperatures, agree with paramagnetic NMR results at ambient temperatures. Furthermore, samples from batteries operating with vanadium-based cathodes were investigated. Depending on the storage conditions, V4+ ligands predominantly consist of decomposition products from the electrolyte solvent ethylene carbonate (e.g. ethylene glycol anions) or electrolyte salt LiPF6 (fluorophosphates).[2,3]

[1] C. Zhan, T. Wu, J. Lu, K. Amine, Energy Environ. Sci.
2018, 11, 243–257.

[2] C. Szczuka, R.-A. Eichel, J. Granwehr, ACS Appl. Energy Mater.
2022, 5, 449–460.

[3] C. Szczuka, P. Jakes, R.-A. Eichel, J. Granwehr, Adv. Energy Sustain. Res.
2021, 2, 2100121.
Low Pressure Growth of Pseudomorphic Gesn with 16.7% Sn Incorporation
Authors: Grant Joshua M , Abernathy Grey , Olorunsola Oluwatobi , Ojo Solomon , Amoha Sylvester , Wanglia Emmanuel , Saha Samir , Sabbar Abbas , Du Wei , Alher Murtadha , Li Baohua , Yu Shui-Qing
Published: November 2022

Alloys of GeSn offer promising optical advantages for high performance optoelectronic device applications monolithically integrated on Si operating in the near and mid-infrared spectrum. Investigations worldwide into the growth of GeSn alloys using various Ge and Sn precursors in conjunction with the chemical vapor deposition growth technique has been reported. The use of higher order Ge hydrides and/or higher growth pressures above 40 torr have been investigated to achieve relatively high incorporations of Sn. In this work, we successfully demonstrated the low pressure growth at 12 torr of GeSn alloy with 16.7% Sn composition. Instead of using a higher order Ge precursor, the alloy was grown via chemical vapor deposition using the commercially available percussors GeH4 and SnCl4. Material and optical characterizations were performed to study the crystalline quality and optical properties. The growth results demonstrate a novel growth window in the low pressure regime to achieve high Sn composition alloy material with high quality for the use in future devices and applications.
(Digital Presentation) Low Dimensional Channel Materials for Logic Transistors
Authors: Wong H.-S. Philip
Published: November 2022

A key technology future direction is CMOS + X, where X can be memory, photonics, spintronics, power electronics, nanomechanics, sensors and actuators, RF/mm-wave, and even quantum computing. Nanosystems of 3D integrated “X” technology (N3XT) is a key concept at the chip level. We must also go beyond a single chip from a wafer and focus on integrating chips into systems using MOSAIC (MOnolithic Stacked Assembled IC). I will give an overview of the new materials and device technologies that may need to be developed to realize this vision. In particular, low-dimensional materials are suitable for logic transistors in this 3D MOSAIC of N3XT chips vision because of the low temperature for device fabrication as well as the thin device layers.
Overview of Aging Mechanisms in Sige Hbts
Authors: Raghunathan Uppili , Ioannou Dimitris , Jain Vibhor , Pekarik Jack
Published: November 2022

SiGe HBTs offer significant performance advantage over Si BJTs with improved base resistance and base transit time. However, each faster technology iteration usually comes at the cost of reduced breakdown parameters. As a result, devices are often restricted to smaller operation biases, and rely on fully utilizing these imposed limits to attain maximum circuit performance. Both high voltage and high current operation have been shown to take a toll on a device’s aging behavior. One unintended consequence of technology scaling is that it forces designers to consider alternate circuit architectures and operate these devices under non-traditional modes such as reverse active, off-state, and saturation. Although not as optimal for device performance as forward active operation, these modes enable improved radiation hardening, power savings and even simpler circuit design.

A bipolar transistor’s operation can be categorized into four main modes as shown in the figure below based on the applied voltage to the base-emitter (VBE) and base-collector (VCB) junctions. Due to the asymmetrical junction engineering for vertical HBTs, the forward-active mode is usually the most optimized for device performance. Because it is the most utilized mode, it is also the most characterized for device reliability. In this paper, in addition to the mixed mode stress used to characterize SiGe bipolars, we will discuss some of the recent learning in SiGe HBT reliability in the other less-understood modes of operation. We begin with a brief overview of SiGe HBT reliability physics including hot carrier generation (Auger vs. Impact-Ionization), the temperature dependence of competing mechanisms and the physical damage responsible for electrical degradation. Using measurements and simulations, we discuss in detail the device degradation under off-state and saturation modes. We demonstrate how the hot carrier generation physics responsible for degradation in the forward-active mode is still applicable in the other regions of operation.

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