bluuebunny/crossref_metadata_2025 huggingface dataset:
Alkali Chloride Molten Salt Corrosion Testing Using a Rotating Cylindrical Electrode
Authors: Townsend Ty , Chidambaram Dev
Published: November 2022

Next generation nuclear reactors utilizing alkali chloride molten salts are currently under development. These reactors operate at a higher temperature and more efficient than current nuclear reactors. Molten salt reactors necessitate research to develop knowledge of corrosion of the structural materials for this application. Static corrosion tests may fail to account for the effects that fluid flow may have on corrosion and molten salt flow loops can be complex and uneconomical. A rotating cylindrical electrode (RCE) can simulate the effects of flow on the corrosion of structural components and are more elementary than a flow loop. We have developed a rotating cylindrical electrode apparatus to study the effects flow may have on corrosion of structural materials in alkali chloride molten salts using accelerated electrochemical corrosion testing techniques and surface characterization techniques which are then compared to static alkali chloride molten salt corrosion. Results and analysis of the effects of fluid flow on accelerated electrochemical corrosion of structural materials will be presented.

Acknowledgement:

This research is being performed using funding received from the DOE Office of Nuclear Energy's Nuclear Energy University Programs under awards DE-NE0008889 and DE-NE0008236, and the US Nuclear Regulatory Commission (USNRC) under contract 31310018M0032. Dr. Kenny Osborne and Ms. Nancy Hebron-Isreal serve as the program managers for the DOE and NRC awards, respectively.
Review of Redox Potential Control Options for Molten Salt Reactors
Authors: Simpson Michael
Published: November 2022

Redox potential control is a fundamental requirement to minimize corrosion of metals in neutron irradiated molten salts, including fission reactor fuel, fission reactor coolant, and fusion reactor blanket. In this presentation, the focus will be placed upon metallic redox buffers—including beryllium, zirconium, and lithium. The study of beryllium for this function spans several decades and includes use in the Molten Salt Reactor Experiment (MSRE) in addition to proposed use in a fusion blanket. A fascinating aspect of this subject is the phase behavior of the metallic redox buffer. Evidence has been published that some of the metals—including beryllium and lithium actually dissolve into their host salts in the zero oxidation state. This provides the capability for a fast, homogenous reaction sans mass transfer limits. But redox buffering has also been reported from the reaction of molten salt with zirconium metal rods. It is proposed that these reactions can be categorized as either short range (homogenous) or long range (electrochemical cell) electronically mediated reactions. Data on metal solubility, electrochemical measurements, and corrosion control will be presented from the MSRE to very recent work in support of the Versatile Test Reactor. Open questions will be posed with the intention of encouraging the audience to propose new theories and experiments to test those theories.
Materials Exposure Testing in Chloride Molten Salts for Nuclear Applications
Authors: Townsend Ty , Chidambaram Dev
Published: November 2022

Advanced nuclear reactors using alkali chloride molten salts are actively being developed for deployment as safer next generation reactors. These reactors operate more efficiently and can enable a more flexible nuclear fuel cycle. These designs require the development of the understanding of corrosion at operational conditions. Static corrosion studies fail to capture the effects of flowing electrolyte on the corrosion in these systems. To simulate the effects of flow, we have designed and commissioned an apparatus for such corrosion studies. This study explored the corrosion of alloys in LiCl-KCl eutectic molten salt. After long-term exposure under simulated flow conditions, corrosions samples were evaluated using gravimetric analysis, scanning electron microscopy and energy dispersive spectroscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy and the results are compared to corrosion under static conditions. Results and analysis of the effects of fluid flow on the corrosion on structural materials will be presented.

Acknowledgement:

This research is being performed using funding received from the DOE Office of Nuclear Energy's Nuclear Energy University Programs under awards DE-NE0008889 and DE-NE0008236, and the US Nuclear Regulatory Commission (USNRC) under contract 31310018M0032. Dr. Kenny Osborne and Ms. Nancy Hebron-Isreal serve as the program managers for the DOE and NRC awards, respectively.
Spectroelectrochemistry of the Electrolytic Reduction of Trivalent Lanthanides in LiCl-KCl Eutectic Molten Salt
Authors: Moon Jeremy , Chidambaram Dev
Published: November 2022

Understanding the speciation of dissolved lanthanides and actinides in molten salts and the chemical behavior of those species is vital to the development of homogenously fueled molten salt reactors and pyrochemical reprocessing of used nuclear fuel. The coupling of spectroscopy and electrochemical analysis can provide complimentary information about the chemistry and speciation of elements dissolved in molten salt mixtures, which is crucial for managing, amongst other concerns, corrosion issues in the process. We have developed a custom furnace with optical pathways for spectroscopic measurements and provisions for the insertion of electrodes into samples inside the furnace. Absorbance spectra were recorded during the electrolytic reduction of trivalent lanthanides in LiCl-KCl molten salt. The absorbance spectra yield insight into the progression of the electrolytic reduction of the species of interest while the electrolytic reduction provides a means of studying the electronic structure and transitions of soluble reduced species of the lanthanides and potentially monitoring changes to concentrations of the oxidized and reduced species.

Acknowledgements:

This research is being performed using funding received from the DOE Office of Nuclear Energy's Nuclear Energy University Programs under award DE-NE0008889 and the US Nuclear Regulatory Commission (USNRC) under contract NRC-HQ-13-G-38-0027. Dr. Kenny Osborne and Ms. Nancy Hebron-Isreal serve as the program managers for the DOE and NRC awards, respectively.

This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1447692. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation, the U.S. Department of Energy, or the United States Government.
Predicting Corrosion and Enhancing Lifetime of Nuclear Dry Storage Canisters
Authors: Upadhyay Vinod , Mendez Julio , Palani Siva , Legg Keith , Rose Alan
Published: November 2022

Nuclear technology for power generation provides a cleaner, environmentally friendly source of energy, and is more reliable than solar or wind energy. However, the used nuclear fuel rods require periodic replacement which, unlike wind and solar energy, also requires safe storage because they are still hot and radioactive. In the USA, safe storage of used nuclear fuel relies mainly on interim dry cask storage systems. The absence of a permanent safe storage strategy, such as a geologic repository puts an unexpected strain on the dry storage canister (DSC) encasing the used nuclear fuel, which must last for 50 years or longer - a particularly difficult problem for power stations located in coastal areas. As these containers cool after long exposure time corrosion such as galvanic, pitting, and stress corrosion cracking might set in and cause weld and other failures, leading to leakage. The challenge therefore, is how to protect the DSC welds from corrosion and be sure that the protection will last their required lifespan. We have investigated electrochemically and computationally the likelihood of corrosion in a DSC system, have evaluated a technology that may be used to extend their protection, and briefly discussed the findings.
Identifying, Predicting and Preventing Localized Corrosion in Kr-85 Storage Canisters from the Reprocessing of Nuclear Fuel
Authors: Demarest Charles , Scully John R. , Asmussen Matthew
Published: November 2022

During the reprocessing of nuclear fuel radioactive gases are released from the fuel matrix. These gases need to be separated and stored to prevent release into the environment. It is proposed that certain risk factors, which are elucidated herein, caused accelerated corrosion of the interior canister walls breaking containment of legacy storage canisters. The main risk factor of concern is the effect of Rb-85. Rb-85 is produced from the radioactive beta minus decay of Kr-85. The main question is whether an environment containing Rb as a decay product causes corrosion of the canister materials at an accelerated rate. If this does occur, the the corrosion threat will grow with time as more rubidium is produced.

Based on the environment within the canister, and the risk factors of the system, a corrosion lifecycle has been developed and is briefly discussed. Stage 1 represents the canister at high temperature of 600°C after it has been sealed and hot isotactic pressed (HIP) for 4 hours. In this stage it is possible for oxides to form on the canister walls due to the residual oxygen in the canister from loading. It is possible that the presence of Rb will interact with the canister material and disrupt the formation of iron and chromium oxides. These Rb oxides, if present, may not inhibit corrosion thus causing an increase in the corrosion rates. Stage 2 represents the canister cooling from 600°C to ambient. In this stage wet thermal oxides will form on the canister walls as the temperature drops below the deliquescence point and water droplets appear, setting up the conditions for aqueous corrosion, like stage 1 the possible formation of RbxCryOzwhich may not be as protective as other oxides, can cause an increase in corrosion rates. Stage 3 represent oxide and environmental interactions. In this stage the environmental risk factors, such as the presence of cathodic reactants oxygen, hydron and peroxide, will create conditions to enable aqueous corrosion. Stages 4 through 8, describe the stages of pitting, uniform corrosion, and galvanic corrosion. Because the material chosen for the canister is 4130 low alloy steel, and the welding material used was 304 stainless steel, there is the possibility of galvanic corrosion. This can increase the uniform corrosion rate, and lead to more pitting events causing depassivation of the surface, or deeper pit penetration. The chosen canister materials are also at risk of pitting attack, the risk of which is increased as the canister is likely driven to alkalinity from the products of the cathodic reaction. Pitting is especially dangerous to the canister which needs to maintain containment for 100 years.

This work looks to test the risk factors and develop a mechanistic understanding of the canister’s corrosion process with the goal of recommending a material that will be able to maintain containment for the needed 100 years if nuclear fuel were to start being repressed in the United States.
(Invited) High Entropy Multication Oxide Battery Materials
Authors: Bridges Craig A. , Prasad Thapaliya Bishnu , Borisevich Albina , Fan Juntian , Dai Sheng
Published: November 2022

High entropy oxides (HEOs), in which multication occupation of a single crystallographic site plays an important role in the properties, have become relevant in energy storage [1,2], catalysis [3.4], and many more areas. In a subset of these compounds the entropy, rather than enthalpy, plays a dominant role in stabilizing a single-phase structure at high temperatures. In other cases, the multication occupation merely contributes to stability and properties, but the entropy remains dominant in the stability. The field originated with high entropy metal alloys (HEAs)[5], and then expanded to oxides, borides, sulfides, and more. In the case of HEOs, the first example is the rock salt (Mg0.2Ni0.2Co0.2Cu0.2Zn0.2)O, which has generated a great deal of interest in this class of materials.[6,7] It has been shown that HEOs are of interest for high ionic conductivity and electrochemical energy storage. We have examined the electrochemical performance of new high entropy elecrolytes and found an effect of composition on the cycling performance. Samples were prepared through sol-gel routes and high energy milling of starting binary oxides. We have investigated the synthesis using high temperature in-situ X-ray diffraction on a Panalytical diffractometer equipped with an XRK900 stage. STEM/EDS studies on ex-situ samples will be presented that show elemental distribution, with Raman and EIS measurements providing information on ionic diffusion. The results of this study will be highly impactful for the growing community of researchers investigating the design and synthesis of the new class of materials, the high entropy oxides.

[1] Q. Wang, et. al., Multi-anionic and -cationic compounds: new high entropy materials for advanced Li-ion batteries, Energy Environ. Sci., 2019, 12, 2433; [2] D. Berardan, et. al., Room temperature lithium superionic conductivity in high entropy oxides, J. Mater. Chem. A, 2016, 4, 9536.; [3] H. Chen, et al., Mechanochemical Synthesis of High Entropy Oxide Materials under Ambient Conditions: Dispersion of Catalysts via Entropy Maximization, ACS Materials Lett. 2019, 1, 1, 83–88; [4] H. Chen, et. al., Entropy-stabilized metal oxide solid solutions as CO oxidation catalysts with high-temperature stability, J. Mater. Chem. A 2018, 6, 11129-11133; [5] Y. Lu, et. al., Sci. Rep. 4, 6200 (2014); Y. F. Ye, et. al., Mater. Today 19 (6), 349 (2016); Zhang, Y., et. al., Nature Commun. 6, 8736 (2015); [6] C. M. Rost, et. al., Nature Commun. 6, 8485 (2015); [7] B. Jiang, et. al., Probing the Local Site Disorder and Distortion in Pyrochlore High-Entropy Oxides. Journal of the American Chemical Society 2021, 143, (11), 4193-4204
(Invited) Rechargeable Solid State Batteries: Development and Advances for Automotive Applications
Authors: Gattu Bharat , Atienza Dianne , Moazzen Elahe , Parrondo Javier , Dhindsa Kulwinder , Dale Nilesh , Zamani Somayeh , Ueda Naoki
Published: November 2022

Lithium ion batteries have been marked by steady progress over the past few decades owing to their high volumetric and gravimetric energy storage densities. The advent of LIBs resulted in the consistent shift of automotive industry towards hybrid EV's and BEV's. The Nissan Leaf, introduced in Japan and the United States in December 2010, became the first modern all-electric, zero tailpipe emission five door family hatchback to be produced for the mass market from a major manufacturer. Newer models targeted at different customer segments are under development at Nissan and there has been need for more efficient, cost effective and safer LIBs to cater to the needs of the commute.

More recently, efforts at Nissan have been diverted towards solid state batteries owing to their ability of surpassing the traditional liquid electrolyte based battery due to higher energy / power densities as well as safety. As a part of Nissan Ambition 2030, research is heavily focused towards development of ASSBs both in terms of chemistry as well as manufacturing technologies. The presentation showcases the efforts of Nissan towards the path of automotive electrification and progress in material, electrode and cell level technologies based on lithium ion batteries and solid state batteries.
Study on Aluminum Corrosion in Lithium Perchlorate-Based Super-Concentrated Electrolyte Solution
Authors: Watanabe Hikari , Yoshida Yurina , Shitanda Isao , Itagaki Masayuki
Published: November 2022

For realizing sustainable world, Lithium-ion batteries are required to have higher energy density. Aluminum metal have been dominantly used as a current collector of positive electrode. A mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) containing 1 mol dm-3
Lithium hexafluorophosphate (LiPF6) has been used as an electrolyte solution, however, aluminum corrosion may occur due to this electrolyte solution under high voltage condition. On the other hand, super-concentrated electrolyte solution (SCES), which consists of only two or three times as much solvent as lithium salt, has been attracting attention as a new electrolyte solution of Lithium-ion battery. Motsumoto et al. proposed that aluminum corrosion was remarkably suppressed in lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)-based SCES. However, the electrolyte solution containing fluorine has the problem which is the dissolution of the active material due to the decomposition product of the electrolyte solution．In the present work, we investigated aluminum corrosion in the lithium perchlorate (LiClO4)-based SCES as a fluorine-free solution.

The LiClO4 based SCES was prepared by dissolving LiClO4 into DMC as the molar ratio of 1 : 2. For comparison, DMC solution containing 1 mol dm-3 LiClO4 was also prepared. Linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) were measured. X-ray photospectroscopy (XPS) was performed to evaluate the decomposition product on the aluminum electrode. Anodic current of the dilute electrolyte solution is observed at 3.9 V vs. Li/Li+. By contrast, in the LiClO4 based SCES, the anodic current is less than 100 µA cm-2 when polarized to 6 V vs. Li/Li+. In the dilute electrolyte solution, the ClO4
- anion is decomposed to form Cl-, which promotes aluminum corrosion. By contrast, the SCES has high oxidative stability, suggesting that the liquid structure of the SCES differ from that of the dilute electrolyte solution. two intense peaks appear at 196 and 198 eV in in XPS spectra of Cl 2p for the aluminum surface after LSV measurement in the dilute electrolyte solution. On the other hand, a weak peak is observed at approximately 199 eV in XPS spectra of Cl 2p for the aluminum surface after LSV measurement in the SCES. This result suggests that the ClO4
- anion is not decomposed in the SCES.

References

[1] K. Matsumoto, K. Inoue, K. Nakahara, R. Yuge, T. Noguchi, and K. Utsugi, J. Power Sources, 231, 234-238 (2013)．

[2] J. Wang, Y. Yamada, K. Sodeyama, C. Chiang, Y. Tateyama, and A. Yamada, Nat. Commun., 7, 1-9, (2016).
New Developments in the High-Energy-Density Solid-Liquid Storage Technology for Redox Flow Batteries
Authors: Nguyen Trung Van , Li Yuanchao
Published: November 2022

The environmental impact of the use of fossil fuels for energy can be reduced if electricity, which represents one-third of all energy uses, can be generated totally from renewable/sustainable sources such as wind and solar. However, this is only possible if cost-effective long-duration storage technologies are available to allow the highly variable and unpredictable wind and solar energy sources to become reliable baseline energy sources like coal, nuclear or natural gases. Redox flow battery (RFB) energy storage systems are highly suitable for this large-scale, long-duration storage application because while their power output scales with the size of the battery, their energy content resides in the amount of active materials that are stored in external tanks and can be easily scaled up for longer duration.1

The conventional redox flow batteries store electrical energy in the form of some aqueous or non-aqueous soluble ions or compounds in the electrolyte solution. Because of the low solubility (< 2M) of most ions and compounds in aqueous and non-aqueous solvents, these redox flow battery systems have low energy density.2–4 For example, the commercialized all-vanadium RFB system has an average energy density of 20 Wh/kg while that of the lithium-ion battery system is 100-265 Wh/kg.5 To store enough energy for 3-5 days in these RFBs requires a very large volume of solution in a large number of tanks, making these RFB systems expensive due to the cost of tanks and the fluid distribution system and floor space.

Our group recently developed a new storage approach that can greatly increase the energy storage density while still enabling the flow battery concept.6 In this approach, the reactants are stored as both soluble ions and their undissolved solid forms and only the liquid containing the soluble ions is circulated through the batteries. This approach potentially enables >4X increase in the storage energy density. This technology was recently demonstrated in a hydrogen-vanadium (VI/V) system, and new test results and findings in this area will be presented in this talk.

References

H. Zhang, W. Lu, and X. Li, Electrochemical Energy Reviews, 1–15 (2019).

D. G. Kwabi et al., Joule, 2, 1894–1906 (2018).

M. Wu, T. Zhao, H. Jiang, Y. Zeng, and Y. Ren, Journal of Power Sources, 355, 62–68 (2017).

C. Ding, H. Zhang, X. Li, T. Liu, and F. Xing, The Journal of Physical Chemistry Letters, 4, 1281–1294 (2013).

A. Manthiram, ACS Central Science, 3, 1063–1069 (2017).

Y. Li and T.V. Nguyen, “A Solid-Liquid High-Energy-Density Storage Concept for Redox Flow Batteries and Its Demonstration in an H2-V System,” Paper ID APEN-MIT-2021_023, Applied Energy Symposium: MIT A+B, Aug. 11-13, 2021, Cambridge, MA, USA.
Novel Anolyte Redox Active Organic Molecules for Redox Flow Battery Applications
Authors: Stracensky Thomas , Maurya Sandip , Mukundan Rangachary , Mukerjee Sanjeev
Published: November 2022

Non-aqueous redox flow batteries (NARFBs) offer several advantages over traditional aqueous electrolyte-based redox flow batteries, such as higher cell voltage, potentially higher energy density, and flexible operating temperatures. However, the current aqueous chemistries use toxic metals such as Vanadium and Chromium and highly acidic and oxidative acid mixtures. The efforts to develop metal-ligand based chemistries to tap the benefits of NARFBs have met with mixed success and only V(acac)3 based symmetric NARFBs have shown potential for long term operations. Even so, the solubility of V(acac)3 in non-aqueous solvents is low to compete with their aqueous counterpart. Moreover, modification of V(acac)3 to enhance the solubility has resulted in poor redox cyclability. As a result, recent research trends have shifted from the development of Metal-ligand complexes to small redox-active organic molecules (ROMs), which could provide higher solubility. However, due to the developing field, a few ROMs have been reported as stable electron donors and acceptors in their oxidized and reduced states. Therefore, we have focused on developing highly soluble anolyte materials with stable redox states. This presentation will discuss the design principle, synthesis, and electrochemical analysis of novel anolyte ROMs. The additional information about the kinetics, bulk electrolysis, and the performance in the full cell will also be discussed.
(Digital Presentation) Electrochemical Metallization Cell Based Memristive Neuron Chip Fabricated with 28nm CMOS Process for Real-Time Unsupervised Learning and Pattern Recognition
Authors: Woo dae Seong , Jin Soo-Min , Kim Hea-Jee , Kim Dong-Eon , Jin Hong-Uk , Choi Hyun-Do , Shim Tae-Hun , Park Jea-Gun
Published: November 2022

Abstract

Spiking neurons communicate with other neurons using sparse and binary signals in a human brain, so they can achieve real-time processing of the information with ultra-low power consumption[1,2]. Thereby, spiking neurons are essential elements for building an energy-efficient biomimetic spatiotemporal system. Recently, to emulate the behavior of biological neuron, many researches for memristive device-based neurons with peripheral circuits (i.e., sense-amplifier or reset circuit)[3] and complementary metal-oxide-semiconductor (CMOS) neurons with capacitors have been reported[4]. Most of the reported memristive device-based neurons required a high operation voltage (>1.2 V) for emulating integrate function of a biological neuron. In addition, complementary metal-oxide-semiconductor-based neurons could not achieve high neuronal density due to using a capacitor in emulating integrate function.

In this study, therefore, we propose an electrochemical metallization cell based memristive neuron chip fabricated with 28-nm CMOS process having a low operation voltage (<0.7 V) for emulating integrate function. In addition, since the proposed electrochemical metallization cell based memristive neuron chip does not require a capacitor for emulating integrate function, it can realize a high neuronal density. The memristive neuron chip exhibited a typical integrate-and-fire function; particularly, the frequency of generating a spiking output signal exponentially increased with the input voltage amplitude. Moreover, a spiking neural network was designed using the memristive neuron chip and the software program consisting of a crossbar synaptic memristor array, simplified spike-timing-dependent-plasticity learning rule, and current-to-voltage converters. Using the co-designed spiking neural network with software and hardware, real-time unsupervised learning was realized. Finally, using the trained spiking neural network, a real-time classification for the MNIST hand-written image taken by a live webcam was successfully performed in an inference process.

Acknowledgement

This research was supported by National R&D Program through the National Research Foundation of Korea(NRF) funded by Ministry of Science and ICT(2021M3F3A2A01037733).

Reference

Mead, C. Neuromorphic Electronic Systems. Encycl. Comput. Neurosci.
78, 1979–1979 (2015).

Douglas, R. Neuromorphic Analogue VLSI. Annu. Rev. Neurosci.
18, 255–281 (1995).

Tuma, T., Pantazi, A., Le Gallo, M., Sebastian, A. & Eleftheriou, E. Stochastic phase-change neurons. Nat. Nanotechnol.
11, 693–699 (2016).

Aamir, S. A., Müller, P., Hartel, A., Schemmel, J. & Meier, K. A highly tunable 65-nm CMOS LIF neuron for a large scale neuromorphic system. Eur. Solid-State Circuits Conf.
2016-Octob, 71–74 (2016).

Figure 1
Scalable Preparation of Nanostructured Hybrids of Transition Metal Sulfide/Oxide With Carbon Materials for High-Performance Supercapacitors
Authors: Lonkar Sunil , Busa Chiara , AlTeneiji Mohamed
Published: November 2022

The ever-growing demands and rapid development of energy storage devices and systems pressed the need for low-cost yet highly performing electrode materials. The transition metal oxide and sulfide-based hybrids holds great promise as the active electrode materials in supercapacitors, due to their large surface area and variable oxidation states. These properties enable significantly high energy storage via electrical double layer and pseudocapacitive charge storage mechanisms. Herein, we discuss a facile, scalable, and environment-friendly preparation process to produce transition metal sulfide and oxides based on resource rich metals such as Mn, Fe, V etc. and their hybrids with carbonaceous materials, such as carbon nanotubes and graphene. This strategy encompasses solvent-less mixing of a metal salt, surfeit yet non-toxic abundant elemental sulfur and carbon precursor under continuous ball milling and thermo-annealing. The resulting nanohybrids were thoroughly investigated by means of several techniques. XRD, HRTEM, SEM, Raman and BET could gather insights on the morphology and the fine material structure, as well as on the spectroscopic properties. Finally, the electrochemical properties as supercapacitor components were investigated in regards with varyingly increasing carbon content. The nanohybrids were tested in both aqueous and organic electrolytes for bettering energy and power performances. Charge storage performances and components stability in both symmetric and asymmetric devices were assessed via CV, GCD, EIS.
Understanding Ageing Mechanism of Carbon Electrodes in Double Layer Capacitors Operating in Organic Electrolytes
Authors: Marcerou Elodie , Daffos Barbara , Taberna Pierre-Louis , Simon Patrice
Published: November 2022

Electrochemical double layer capacitors (EDLCs) are energy storage devices that can complement Li-ion batteries (LiBs) for high power uptake applications[1]. However, EDLCs suffer from limited energy density (about 10Wh/kg compared to 250 Wh/kg for LiBs). A way to increase the energy density still maintaining high power capability and long cycle life is the next challenge of this technology. An approach to achieve this objective is to increase the voltage window. Nevertheless, using a high voltage window lead to a faster ageing. So, a better understanding of degradation process during the ageing is needed to improve EDLCs storage and their cycle life.

In this work, degradation mechanisms at porous carbon electrodes have been investigated in non-aqueous electrolytes, following an ageing protocol previously reported [2]. Electrochemical performances before and after ageing have been compared. Then, post-mortem analyses were performed using various analytical methods. Raman spectroscopy allowed us for better understanding of degradation processes occurring at the carbon/electrolyte interface. Leading to a partial amorphization of the positive porous carbon electrode. The carbon disorder was further correlated with possible degradation mechanisms during ageing to explain the performance decrease.

References:

[1] P. Simon and Y. Gogotsi, ‘Perspectives for electrochemical capacitors and related devices’, Nature Materials, p. 13, doi: https://doi.org/10.1038/s41563-020-0747-z.

[2] Y. Liu, B. Soucaze-Guillous, P.-L. Taberna, and P. Simon, ‘Understanding of carbon-based supercapacitors ageing mechanisms by electrochemical and analytical methods’, Journal of Power Sources, vol. 366., pp. 123-130., 2017, doi: https://doi.org/10.1016/j.jpowsour.2017.08.104.

Figure 1
Copper Screen Printed and Fired for Metallization of Silicon Solar Cells
Authors: Druffel Thad
Published: November 2022

Silicon solar cells almost exclusively include a front side metallization using silver that is deposited by screen printing and fired in belt furnaces. In 2020, the industry was consuming approximately 10% of the global supply of silver, and recent calls to dramatically increase photovoltaic production will add to the module price pressures from this precious metal. The ideal replacement for silver is copper; however, oxidation during firing and diffusion of copper into silicon has kept the industry from adopting copper. In this talk we will present results from a copper paste that was formulated to be screen printed and fired in a belt furnace without the use of an inert gas. The data presented will include the oxidation of the copper after the firing and the SiN etching performance of the paste. LIV data for the cells will be presented along with data describing the durability of the cell in an accelerated test.
Progress Towards the Scalable Production of Perovskite Solar Cells Using a High Throughput Roll-to-Roll Platform
Authors: Druffel Thad
Published: November 2022

The Perovskite Solar Cell has garnered a fair amount of excitement over the past few years that can be attributed to the high efficiencies obtained using very simple solution phase deposition processes. Most of the research has focused on high efficiency and durable devices using techniques that won’t scale such as spin coating in highly controlled environments. The perovskite material itself is very defect tolerant and as such lends itself extremely well to solution phase deposition over very large areas. The other thin films within the device, namely the hole transport and electron transport materials (HTM and ETM) can be very low cost metal oxides. The work in this presentation outlines techniques to mount these three layers onto a roll-to-roll platform running at high speeds in ambient environments. Devices are built on a flexible plastic substrate and tested using LIV measurements. The morphology of the thin films are characterized using XRD, SEM and UV-Vis. Stability measurements of the devices are also included in the talk.
Solution Phase Deposition of Metal Oxides Directly Onto Perovskite Absorbers
Authors: Druffel Thad
Published: November 2022

Perovskite solar cells have been discussed as a low-cost alternative to traditional technologies based on the simple deposition mechanisms and inexpensive materials. These materials include metal oxides that are relatively straightforward to manufacture and can be suspended in inexpensive solvent systems including water, alcohols and aromatic hydrocarbons. However, these solvents are not appropriate for the perovskite materials and hence most efforts do not include the deposition of a metal oxide onto a perovskite. In this talk we will discuss the avenues to establish direct deposition of metal oxides onto a perovskite. This includes solvent choice, metal oxide choice, ligands and interfacial layers. The talk will then demonstrate the successful deposition of metal oxides by scalable solution phase processes with efficiencies greater than 18%. Results will include means to assess the potential damage to the films with an emphasis towards scalable manufacturing.
Electrochemical Characterizations of Ternary MnO2/Cus/Rgo Materials for Supercapacitor Applications
Authors: Singhal Rahul , Singhal Kushagr , Patel Rudra , Lemaire Peter , Ponnada Sreekanth , Sharma Rakesh
Published: November 2022

Supercapacitors are considered as a new class of energy storage device because of their high power density, environmentally friendliness, long cycleability, and flexible design capabilities. MnO2 and CuS have been found to be promising for supercapacitor applications because of their low cost, abundance in nature, and are environmentally friendly. Besides this, reduced graphene oxide emerged as most promising carbon materials for energy storage applications because of its high specific surface area, good electrical conductivity, and ability to attach metal oxide without

any agglomeration. Recently, it has been reported that ternary nanocomposites have superior electrochemical performances because of their synergistic effect, which help to enhance the charge movement within the electrode material. We already reported that the specific capacitance of CuS and MnO2 as 158 F/g and 300 F/g at current densities of 0.5 A/g, respectively [1,2]. In this work we have synthesized MnO2/CuS/rGO ternary nanocomposite by hydrothermal method. The physical characterization of the synthesized materials was carried out using X-Ray diffraction, scanning electron microscopy, differential scanning calorimetry(DSC), and thermogravimetric analysis (TGA). All electrochemical measurements were conducted in standard three-electrode configuration, using a platinum wire, Ag/AgCl, and MnO2/CuS/rGO as a counter, reference, and working electrode, respectively. The results related to physical characterization, specific capacitance, cycleability, and energy density will be presented.

Reference:

Rahul Singhal, David Thorne, Peter K. LeMaire, Xavier Martinez, Chen Zhao, Ram K. Gupta, David Uhl, Ellen Scanley, Christine C. Broadbridgeand Rakesh K. Sharma, AIP Advances 10, (2020) 035307; https://doi.org/10.1063/1.5132713.

Rahul Singhal, Justin Fagnoni, David Thorne, Peter K. LeMaire, Xavier Martinez, Chen Zhao, Ram K. Gupta, David Uhl, Ellen Scanley, Christine C. Broadbridge, Mani Manivannan, MRS Advances, 4 (13) 777-782 (2019), https://doi.org/10.1557/adv.2019.86
(Invited) Tutorial on Semiconductor Advanced Packaging
Authors: Lau John H
Published: November 2022

In this lecture semiconductor advanced packaging is defined. The kinds of advanced packaging are ranked based on their interconnect density and electrical performance and are grouped into 2D, 2.1D, 2.3D, 2.5D, and 3D IC integration, which will be presented and discussed. Key enabling technologies such as flip chip and fan-out will be briefly mentioned. The trends and challenges (opportunities) of advanced packaging will be discussed. Also, in this lecture, chiplet design and heterogeneous integration packaging are defined. The chiplet design and heterogeneous integration packaging such as those given by Xilinx, AMD, Intel, TSMC, and Samsung will be presented and discussed. The lateral communication between chiplets such as the silicon bridges embedded in organic build-up package substrate (Intel’s EMIB and IBM’s DBHi) and fan-out epoxy molding compound (Applied Materials’ chip-first face-up, Unimicron’s chip-first face-down, TSMC’s LSI, SPIL’s FO-EB, ASE’s sFOCoS, IME’s EFI, and Amkor’s S-Connect Fan-Out Interposer) as well as flexible bridges will be presented. Key enabling technologies such as thermocompression bonding and hybrid bonding will be briefly mentioned. The trends and challenges (opportunities) of chiplet design and heterogeneous integration packaging will be discussed.
Role of Heat Release from Inter-Electrode Chemical Crosstalk in Thermal Runaway Propagation Characteristics of Lithium-Ion Battery Modules
Authors: Karmakar Avijit , Zhou Hanwei , Mukherjee Partha P.
Published: November 2022

While lithium-ion batteries are continually increasing in energy and power density, thermal safety still remains a significant concern. In some thermal abuse scenarios, thermal runaway can be triggered by the exothermic reactions from inter-electrode chemical crosstalk between the cathode and the anode without an internal short circuit. Under these circumstances, the thermal runaway temperature is lower than the separator's thermal shrinkage temperature, implying that the cell's catastrophic thermal runaway occurs without a large-scale short circuit produced by separator failure. These cell failures must be managed such that the neighboring cells in a battery module are not affected, a phenomenon known as thermal runaway propagation. In the present work, we employed a high-resolution cell-level thermal runaway model constructed from the accelerating rate calorimetry data of a commercial Li-ion cell to characterize the cell-to-cell thermal runaway propagation behavior for a basic square arrangement of lithium-ion battery module connected by tabs. We determined safe practices under the effects of different ambient conditions, inter-cell spacing, trigger cell location, and external heating power. Additionally, we have identified the critical pathways for the thermal runaway propagation in the battery module and quantified their statistical distribution in terms of the thermal runaway propagation speed, heat release from exothermic reactions, and heat dissipation to the surroundings. The findings from the study are believed to be of immediate relevance for the safer design of lithium-ion battery packs.
Improved Adhesion of Copper Seed Layer Using Vacuum Ultraviolet Light for Direct High-Speed Sputtering
Authors: Endo Shinichi
Published: November 2022

The dry process is progressing in the manufacturing process of semiconductor packages. The semi-additive process for forming the rewiring layer is required to be finer and more reliable than ever. The interface between the insulating resin and the copper wiring is being smoothed in order to reduce transmission loss during high-frequency communication. The conventional electroless plating method using the anchor effect is disadvantageous for smoothing. Therefore, a sputtering method is used to form the seed layer. In general, copper spatter has weak adhesion to resin, so titanium spatter is combined to increase the adhesion strength. However, etching in the lithography process requires two types of processes, titanium and copper.

We investigated the improvement of copper sputtering adhesion to glass epoxy resin by a high-speed sputtering device. Adhesion strength was improved by performing plasma treatment and vacuum ultraviolet treatment as pretreatment for high-speed sputtering. Surface modification was analyzed and evaluated by XPS. We report on the process and evaluation method that contribute to the dryness of the packaging process.
Understanding the Nanostructures in the Electrolytes By Small-Angle X-Ray Scattering
Authors: Li Tao
Published: November 2022

The solution solvation structure of the liquid electrolyte directly affects transport properties, which ultimately determines the performance of batteries. It has been predicted that the nanoscale aggregates in the liquid electrolytes, especially as the salt concentrations increase. However, little is known about these structures due to the limitation of the traditional methods. Herein, we demonstrate that small-angle X-ray scattering-wide angle X-ray scattering (SAXS-WAXS), even ultra-small-angle X-ray scattering (USAXS) could be applied to capture these larger aggregates in the electrolytes, including conventional organic electrolytes, high concentration electrolytes, water-in-slat electrolytes, and redox-active electrolytes. Raman, neutron scattering, IR, and molecular dynamics (MD) simulations further support the proposed structures. This work highlights the fundamental structure analysis in nanoscale, which will prompt better electrolytes in the future.
(Invited) Building Nanostructured Film from Colloidal Nanocrystals through Electrophoretic Deposition
Authors: Ha Don-Hyung
Published: November 2022

Over the last few decades, a tremendous research effort has been dedicated to realizing colloidal nanocrystals (NCs) as useful devices. Contrary to the well-established synthesis of colloidal NCs, the fabrication method to transfer the NCs to a nanostructured film has not studied well, despite the importance of using NCs as integrated devices. Especially, an advanced fabrication technique is crucial for further improving device performance along with the fine colloidal synthesis and NC device applications. As an advanced technique, electrophoretic deposition (EPD) can be introduced to mitigate the limitations of traditional tools, such as spin-coating, drop-casting, and spray coating, by creating desirable NC thin films from colloidal solutions using an electric field. We found several key controllable parameters such as solvent, surfactant ligand, and voltage, to tune the NC film’s morphology as well as the mechanism of the NC deposition. To clearly understand the mechanism of the deposition, in-situ technique was also developed by utilizing a light scattering method, which can provide the real time tracking analysis.
(Invited) Ligand Exchange at Chalcogenide and Perovskite Nanocrystal Surfaces Examined Via Isothermal Titration Calorimetry
Authors: Greytak Andrew B
Published: November 2022

I will describe our group’s efforts to quantify ligand association and exchange reactions on semiconductor nanocrystal (NC) surfaces via isothermal titration calorimetry (ITC). ITC provides a direct thermal measurement of reaction progress. As shown in earlier work by our group and others examining ligand exchange on chalcogenide and pnictide quantum dots, ITC is able to access the enthalpy change of reaction, equivalency, and effective equilibrium constants, including in cases that are challenging to resolve by NMR alone. Here, we will describe the extension of this approach to ligand exchange reactions on halide perovskite NCs, and to ligand exchange on chalcogenide NCs in aqueous solution. Such advances are needed to contribute a quantitative description of NC surface chemistry toward applications such as advanced optoelectronic devices, bioimaging probes, and photocatalysis.
(Keynote, Digital Presentation) First-Principles Study of Optical and Electronic Properties of Carbon Quantum Dots
Authors: Buerkle Marius , Dsouza Slavia Deeksha , Mariotti Davide , Svrcek Vladimir
Published: November 2022

We study the optical and electronic properties of carbon-based quantum dots using first-principles calculations. Based on time-dependent density functional theory we calculated absorption and emission of carbon quantum dots, we focus on the influence of surface (edge) functional groups. We can show that nitrogen groups on the carbon edges are decisive for the emission properties of small carbon quantum dots and could give rise to charge-carrier multiplication which has been suggested by recent experiments. Moreover, we explain the stability, with regard to the absorption in the optical range, of carbon quantum dots under ambient conditions. Here, we demonstrate that surface oxidation does only influence the absorption in the visible light range but does give rise to variation in the UV absorption.
(Keynote) New Materials and Spectroscopies for Colloidal Quantum Dot Solar Cells
Authors: Thon Susanna Mitrani , Chiu Arlene , Lin Yida , Lee Hoon Jeong , Chintapalli Sreyas , Qiu Botong
Published: November 2022

Colloidal quantum dots (CQDs) are an attractive third-generation material for photovoltaics due to their solution-processability, lightweight and flexible nature, and bandgap tunability, allowing them to be used as infrared materials for multi-junction solar cells. Here, we describe several methods for building new lead sulfide-based CQD materials and thin films for improving efficiencies in both single-junction and multi-junction solar cells.

First, we demonstrate that the power conversion efficiency in single-junction PbS CQD solar cells is limited in part by the performance of the hole transport layer (HTL), traditionally made from ethanedithiol-passivated lead sulfide CQDs, due to the sub-optimal carrier mobility and doping density in this material. We use sulfur doping of the HTL, as well as incorporation of 2D transition metal dichalcogenide nanoflakes to address these issues and demonstrate absolute power conversion efficiency improvements of greater than 1% in single-junction devices.

Next, we demonstrate a micrometer-resolution 2D characterization method with millimeter-scale field of view for assessing CQD solar cell film quality and uniformity. Our instrument simultaneously collects photoluminescence spectra, photocurrent transients, and photovoltage transients. We use this high-resolution morphology mapping to quantify the distribution and strength of the local optoelectronic property variations in CQD solar cells due to film defects, physical damage, and contaminants across nearly the entire test device area, and the extent to which these variations account for overall performance losses. We also use the massive data sets produced by this method to train machine learning models that take as input simple illuminated current-voltage measurements and output complex underlying materials parameters, greatly simplifying the characterization process for optoelectronic devices.

Finally, we use artificial photonic band engineering as a method for achieving spectral selectivity in absorbing PbS CQD thin films for applications in multi-junction photovoltaics. We show that a structured periodic CQD thin film is able to maintain a photonic band structure, including the existence of a reduced photonic density of states, in the presence of weak material absorption, enabling modification of the absorption, transmission, and reflection spectra. We use a machine learning-based inverse design process to generate CQD thin film photonic structures with targeted absorption, transmission, and reflection spectra for multi-junction photovoltaics and narrow bandwidth photodetectors.