bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrolyte with New Composition for High Nickel Lithium Ion Batteries
Authors: Liao Chen , Yang Jianzhong , Son Seoung-Bum , Rodrigues Marco-Tulio , Abraham Daniel P.
Published: July 2021

We previously reported1-4 the in situ electrolyte additives to selectively synthesize the beneficial lithium tetrafluorophosphate components in high yield (> 98%) and maximize the battery performance. The in situ method is particularly of interest to scale up electrolyte preparation since it would alleviate any requirements of extra separation and purification of the desired additives.

Here we used a new strategy of change both the composition and materials in the standard electrolyte to formulate advanced electrolytes for lithium ion batteries (LIBs). New electrolytes for high voltage LIBs were demonstrated to be more effective than the previous additives. The LIBs containing Ni-rich cathodes cycled with the new electrolytes in optimal composition rendered better electrochemical performance than cells cycled with the start-of-art Gen2 electrolyte when cycled between 3.0 to 4.2 V, exhibiting effective suppression of the impedance rise during aging. 1H Nuclear Magnetic Resonance spectra of cycled new electrolyte suggested their capabilities in preventing the transesterification reactions on anode surface, while X-ray photoelectron spectroscopy and inductively coupled plasma mass spectrometry analysis indicated its ability to form a stable cathode interface and mitigate structural damage on the cathode surface. Further analysis also indicated the benefits of the new composition electrolyte in protecting the cathode bulk structure.

[1] J. Yang, I. Shkrob, K. Liu, J. Connell, N. L. Dietz Rago, Z. Zhang and C. Liao, Journal of The Electrochemical Society, 2020, 167, 070533.

[2] C. Liao, eTransportation, 2020, 5, 100068.

[3] J. Yang, I. Shkrob, Q. Liu, N. L. Dietz Rago, Y. Liu, K. Liu, Z. Zhang and C. Liao, Journal of Power Sources, 2019, 438, 227039.

[4] I. A. Shkrob, B. Han, R. Sahore, A. P. Tornheim, L. Zhang, D. P. Abraham, F. Dogan, Z. Zhang and C. Liao, Chemistry of Materials, 2019, 31, 2459-2468.
Ni-Rich Li[Ni0.9Co0.045Mn0.045Al0.01]O2 (NCMA) Cathode with Optimized Microstructure for Microstrain Control
Authors: Park Nam-Yung , Yoon Dae Ro , Sun Yang-Kook
Published: July 2021

Layered Ni-rich cathode materials Li[Ni
x
Co
y
M
1-x-y
]O2 (M = Mn and Al are denoted as NCM and NCA, respectively) has been common cathodes for the batteries of electric vehicles (EVs). Recently, Li[Ni
x
Co
y
Mn
z
Al1-x-y-z
]O2 (NCMA), a hybrid of NCM and NCA cathodes, has received significant attention owing to the announcement by General Motors of its intention to deploy NCMA cathodes for Li-ion batteries (LIBs) in its next EVs.1 The NCMA cathode can provide high discharge capacity with stable cycle life owing to strong Al-O bonding which strengthens the host layered structure. However, an introduction of the high concentration of Al dopant for stabilization of Ni-rich cathodes is restricted as an electrochemically inactive Al lowers the capacity of cathode.

For Ni-rich cathodes, it is well acknowledged that increasing the Ni composition in the cathodes for higher capacity leads to the deterioration in both cycling performance and thermal stability.2 The fast capacity fading of Ni-rich cathode is mostly attributed to the H2–H3 phase transition at the charged state, and the extent of H2–H3 phase transition increases with increasing Ni fraction in the cathodes. As the phase transition induces a lattice volume change generating microcracks in the particles, the alleviation of internal microstrain is required to suppress the microcrack formation in the cathode particles and to improve the cycling stability of Ni-rich cathodes.

To reinforce the mechanical stability of Ni-rich NCMA cathodes, we proposed a hybrid structure cathode in which Li[Ni0.92Co0.04Mn0.03Al0.01]O2 in the interior of the particle is encapsulated by Li[Ni0.845Co0.067Mn0.078Al0.01]O2 that acts as a buffer against the microstrain. Similar to the tempered glass which has different states of stress in the surface and bulk material to increase the strength,3 the proposed cathode structure suppresses the formation of microcracks by creating a non-uniform spatial distribution of microstrain within the cathode particle. The electrochemical performance of the proposed cathode is correlated with the microstructure, and the mechanism suppressing the formation of microcracks in the Ni-rich NCMA cathode is demonstrated.

Reference
s
:

[1] General Motors Co. LYRIQ Show Car Leads Cadillac Into Electric Future, 2020; https://media.gm.com/media/us/en/cadillac/news.detail.html/content/Pages/news/us/en/2020/aug/0806-lyriq.html (accessed December 2020).

[2] H.-J. Noh, S. Youn, C. S. Yoon, Y.-K. Sun, J. Power Sources, 2013, 233, 121.

[3] A. L. Zijlstra, A. J. Burggraaf, J. Non-Cryst. Solids, 1968, 1, 49.
Ni-Rich Li[Ni1−x−YCoxBy]O2 Cathode Materials for Next Lithium Batteries
Authors: Ryu HoonHee , Yoon Dae Ro , Sun Yang-Kook
Published: July 2021

To achieve a longer driving range of electric vehicles (EVs) per charge, it is necessary that the development of advanced cathode materials, which largely determine the capacity of lithium-ion batteries. Currently, classical cathodes deployed in current EVs, layered Li[NixCoy(Al orMn)1−x−y]O2 (Al = NCA or Mn = NCM) oxide materials, has achieved the best performances for commercialization. However, these cathodes should be further improved to be competitive in the global market.1 Ni-rich NCA and NCM cathodes, delivering ever-closer to their theoretical specific capacity, are considered as promising candidates. However, increasing Ni content compromises battery lifetime and thermal stability due to rapid capacity fading and an abundance of unstable Ni4+ species, as observed in LiNiO2.2,3 Therefore, the development of new cathode materials that can overcome rapid capacity fading is necessary.

In this presentation, we suggest a novel cathode material by introducing boron to the binary system Li[Ni0.9Co0.1]O2 (NC90) to create a new class of layered cathode materials, Li[Ni1−x−yCoxBy]O2 (NCB), to supplement NCM and NCA.4 The microstructure of NCB cathodes was tailored by adjusting the boron fraction, as the shape and dimensions of the primary particles depend on the boron fraction. The dramatic difference between the particle microstructure of an NCB cathode and those of NCA and NCM cathodes was confirmed. The NCB cathode exhibited a higher capacity with outstanding capacity retention, compared to the conventional NCA and NCM cathodes. A series of NCB cathodes with 0.5, 1.0, 1.5, and 2 mol% B systematically characterized to investigate the capacity fading mechanism and to determine the optimal microstructure for better cycling stability.

References

D. Andre, S.-J. Kim, P. Lamp, S. F. Lux, F. Maglia, O. Paschos, B. Stiaszny, J. Mater. Chem. A
2015, 3, 6709.

H.-H. Ryu, K.-J. Park, C. S. Yoon, Y.-K. Sun, Chem. Mater.
2018, 30, 1155.

D.-W. Jun, C. S. Yoon, U.-H. Kim, Y.-K. Sun, Chem. Mater.
2017, 29, 5048.

H.-H. Ryu, N.-Y. Park, D. R. Yoon, U.-H. Kim, C. S. Yoon, Y.-K. Sun, Adv. Energy Mater.
2020, 10, 2000495.
Physics-Based Impedance Model of Lithium Sulfur Batteries
Authors: Teo Linnette , Parke Caitlin D. , Schwartz Daniel T. , Subramanian Venkat R.
Published: July 2021

Time domain physics-based models for lithium sulfur have been developed with mechanisms of the reaction cascade and precipitation reactions, allowing for a deeper understanding of internal states of the battery.1 Such models are able to capture voltage curves well during discharge. However, there have been challenges to reproduce charging curves accurately. It has been suggested that the charge and discharge reaction pathways are different,2 and/or precipitation rates and expressions to take into account numerical instability associated with dissolution when charging need to be improved.3,4 Since it is challenging for existing physics-based models to demonstrate macro-reversibility, we aim to see if there is evidence of micro-reversibility as impedance modeling would require these mechanistic models to work over much smaller changes in state-of-charge. Applying such models to the frequency domain can also give us detailed insight on proposed mechanisms and processes that occur across a larger range of timescales that are not available during a slow charge/discharge.

Fronczek and Bessler5 have simulated electrochemical impedance spectroscopy (EIS) spectra based on mechanisms in the widely accepted one-dimensional model developed by Kumaresan et al..1 They are the first to demonstrate this with a physics-based modeling approach using a potential step in the time domain and performing FFT on the current relaxation to obtain the impedance. We aim to extend this further by comparing to experimental trends seen in the literature6,7 and explore qualitative features in the EIS spectra based on physical processes. We use a different computational approach by transforming the governing equations in the Kumaresan model to the frequency domain. We present this system of linearized ordinary differential equations and solve them in a manner consistent with numerical approaches demonstrated previously.8

Acknowledgement

This work was supported by the Advanced Battery Material Research (BMR) Program (Battery 500 Consortium).

References

K. Kumaresan, Y. Mikhaylik, and R. E. White, J. Electrochem. Soc., 155, A576 (2008).

Q. Wang et al., J. Electrochem. Soc., 162, A474–A478 (2015).

K. Yoo, M.-K. Song, E. J. Cairns, and P. Dutta, Electrochimica Acta, 213, 174–185 (2016).

N. Kamyab, P. T. Coman, S. K. Madi Reddy, S. Santhanagopalan, and R. E. White, J. Electrochem. Soc., 167, 130532 (2020).

D. N. Fronczek and W. G. Bessler, Journal of Power Sources, 244, 183–188 (2013).

S. Waluś, C. Barchasz, R. Bouchet, and F. Alloin, Electrochimica Acta, 359, 136944 (2020).

Z. Deng et al., J. Electrochem. Soc., 160, A553–A558 (2013).

M. Pathak et al., J. Electrochem. Soc., 165, A1324–A1337 (2018).
(Invited) Designing Intercalation for High-Valent & Uniform Redox Reactions
Authors: Chueh William C.
Published: July 2021

Many electrochemical materials attain high-valent oxidation state during operation, such as electrocatalysts for oxygen evolution reactions and positive electrodes for lithium-ion batteries. For the latter, the high voltage enabled by high valent redox can further increase the energy density of batteries. In oxides, achieving high oxidation states is typically accompanied by substantial bond contraction as well as participation of the O 2p electronic states, both of which are known to affect the stability and reversibility of the redox reaction. In addition to high valent redox, another desirable characteristic of electrochemical reaction is uniformity. This is especially true for intercalation electrochemistry, since the uniformity directly establishes the mechanical stress within the electrode.

In this talk, I will use lithium- and sodium-intercalating layered oxides as a prototypical system for establishing design rules for high-valent and uniform redox. For the first part of the talk, I will discuss the convergence of three phenomena that control the stability of high valent redox: short covalent bonding, mitigation of local strain energy through point defect formation, and coulombically stabilization of oxidized species. In the second part of the talk, I will rationalize unexpected mesoscale heterogeneities such as apparent phase separation in layered oxides, and provide practical design rules on engineering more uniform electrochemical devices.
Aqueous Li4Ti5O12/LiMn2O4 Cell with a Li-Ion Conducive Solid Electrolyteseparator and an Electrodeposition of Zn to an Anode
Authors: Seki Hayato , Yoshima Kazuomi , Yamashita Yasunobu , Takami Norio , Matsuno Shinsuke
Published: July 2021

Li-ion batteries (LIBs) with non-aqueous electrolytes have high-energy density, highpower density, and long-cycle performance. However, generally LIBs have a risk due to their flammable organic electrolytes. Until now, a lot of attempt to reduce the risk of LIBs have been conducted such as all-solid-state battery. We have focused on Li-ion batteries with aqueous electrolytes with safer and low cost, but the electrochemical stability window of aqueous electrolytes is narrower than that of the organic electrolytes in LIBs. The stable operating voltage window of an aqueous electrolyte is approximately 1.23 V thermodynamically, beyond which the electrolysis of H2O occurs along with the evolution of H2 or O2 gas. To achieve an aqueous Li-ion battery with high discharge voltage, a suppression of H2 gas on the anode is needed.

In this study, we report the widening of the overall electrochemical stability window with a Li-ion conductive solid electrolyte (SE) separator composed of NASICON-type Li-Al-Ti-P-O glass ceramic and an electrodeposition of Zn to an anode. We utilized a SE separator to suppress the H2 gas evolution on the anode electrode by preventing H+ migration from a cathode electrolyte. And we tried to electrodeposit Zn to the anode, since Zn shows a high hydrogen over voltage. A cathode, an anode, and an aqueous electrolyte was used as LiMn2O4, LiTi4O12, and 12 mol/L LiCl respectively. A Li-ion conductive solid electrolyte with a thickness of 150 μm and the conductivity of 10-4 S/cm at 25°C was used as the SE separator. We fabricated a LTO/LMO cell with the SE separator and a porous separator(1. Typical charge/discharge curves with SE separator and electrodeposition of Zn to LTO anode is shown in Fig. 1 (a). The aqueous LTO/LMO cell exhibited an average discharge voltage of over 2.4 V, a coulombic efficiency of over 94%, and good cycle perfromance. Compared to a cell with porus separator and no electrodeposition of Zn, the evolution of H2 gas on the LTO anode during charge in the LTO/LMO cell was kinetically suppressed and decreased to 1/6 as shown in Fig. 1 (b).

Figure 1
TaN-Based Combined Barrier+Liner Materials to Beat the Interconnect Bottleneck
Authors: Nies Cara-Lena , Kondati Natarajan Suresh , Nolan Michael
Published: July 2021

In order to prolong the lifetime of Cu as an interconnect metal in CMOS devices, as transistors continue to decrease in size, materials that combine properties of diffusion barriers and seed liners are needed. Such a material will have to allow for successful electroplating of Cu and must be as thin as possible in order to facilitate the coating of high-aspect ratio interconnect vias. One possible way to achieve such a material is presented in this study. Through density functional theory we investigate the behaviour Cu on Ru-doped and Ru passivated ε-TaN (1 1 0). Adsorption and diffusion of one and two Cu atoms on these surfaces were studied initially, in order to understand the early stages of film growth. This showed that while adsorption and surface diffusion were more favourable on the Ru passivated surface, Ru dopants act as a nucleation site for Cu atoms and enhance the metal-surface interaction.

To understand the growth mechanism of Cu films on these surfaces in more detail, and to discover the optimum Ru content for the surface, large Cu sheets are adsorbed to the Ru passivated surface as well as to Ru-doped surfaces with a variety of surface doping concentrations.

On the Ru-doped films, Cu spontaneously transitions into a two-layer structure, while atoms remain in a single layer on the Ru-passivated surface. However, ab initio molecular dynamics and activation energies of pathways for migration of atoms to form further layers show that the Ru dopants inhibit further 3D growth of the Cu structures.
Boosting Static and Dynamic Performance of Integrated Solid-State Diodes By Peripheral Integration of Nanostructured Porous Silicon
Authors: Paghi Alessandro , Strambini Lucanos , Toia Fabrizio , Sambi Marco , Marchesi Marco , Depetro Riccardo , Morelli Marco , Barillaro Giuseppe
Published: July 2021

Over the past two decades, different nanomaterials have been proposed for the design of novel silicon-based electronic devices or to push the performance of existing ones, leveraging the unique properties of charge carriers traveling in meso-to-nano scale structures.

Porous silicon (PSi) is the nano- (n-PSi) to micro- (m-Psi) structured form of silicon achieved by anodic etching of a silicon wafer in acidic HF-based electrolytes. However, the low mobility and reduced lifetime of charge carriers traveling in n-PSi have been mainly perceived such as a deterioration the bulk silicon properties, thus hampering the use of n-PSi in micro and nano electronics to date.

Here, we show that the integration of n-PSi in specific regions of a solid-state diode significantly improves both static and dynamic electrical performance of the diode, with respect to the unmodified device. Specifically, leveraging the unique mobility and lifetime of charge carriers traveling in the n-PSi layer, we achieve a significant increase of the breakdown voltage (>2x) and reduction of the turn-off time (about 30%). This improvement is shown to be robust with respect to n-PSi preparation conditions and diode typologies. Two dimensional (2D) TCAD simulations further corroborate that the improvement of the electrical performance of n-PSi modified diodes is related to the strong mobility and lifetime reduction of carriers in the nanostructured porous silicon layer. Remarkably, no significant drawbacks are observed after the peripheral integration of n-PSi in solid-state diodes, thus confirming the beneficial effect of n-PSi when employed for the modification of micro and nano electronic devices.

A. Paghi, L. M. Strambini, F. F. Toia, M. Sambi, M. Marchesi, R. Depetro, M. Morelli, G. Barillaro, Peripheral Nanostructured Porous Silicon Boosts Static and Dynamic Performance Of Integrated Electronic Devices, Advanced Electronic Materials 6, 2000615 (2020).
(Invited) Heterogeneous Integration – Packaging that leverages Silicon Technology
Authors: Iyer Subramanian S.
Published: July 2021

Electronics Packaging refers to the electrical interconnection of heterogeneous dies using a hierarchy of packaging constructs. Today’s packaging is based on organic substrates called FR4 – glass reinforced epoxy laminate material with coarse pitches and solder-based connections. which have not shrunk over the last several decades. More recently however, packaging is undergoing materials and integration innovations that promise to usher in an era of package and board level scaling. These borrow extensively from silicon technology. We will address two such approaches: The Silicon Interconnect Fabric (Si IF), where we attempt to replace the PCB with a Silicon wafer that has fine wires and directly connects to heterogeneous dielets using solderless thermal compression bonding, to build large heterogeneous Systems on Wafers; and Flextratetm, a PDMS based flexible biocompatible substrate, that uses a fan-out wafer level processing approach to similar things. The talk will address the materials and processing challenges of these approaches.
(Invited) Heterogeneous Integration As Enabler for Future Applications and Products
Authors: Braun Tanja , Becker Karl-Friedrich , Töpper Michael , Aschenbrenner Rolf , Schneider-Ramelow Martin
Published: July 2021

Future electronic systems like autonomous systems using high performance computing (HPC) and edge computing systems, sensor integrated systems and bio-integrated devices will required more and more functions which cannot be managed by a single chip, even if advanced SoC (System on Chip) concepts are used. Heterogeneous integration will be the next step and will pass beyond current SiP (System in Package) approaches. This concept of true heterogeneous integration is highly important for next-gen devices based on future CMOS-nodes, SiGe, SiC, III/Vs like GaAs or GaN and all different kinds of MEMS.

Besides die and package stacking, embedding dies is a key technology for heterogeneous system integration. There are two main approaches for embedded die technologies: Fan-out Wafer and Panel Level integration, where dies are embedded into polymer encapsulants and Chip in Polymer, where dies are embedded into the substrate.

Besides multiple die packaging also the integration of passive components as capacitors or resistors as well as the integration of shielding layers, antennas and e.g. resonators in and on package is a key for future applications. Co-design of chip and package for miniaturized heterogeneous packages will also give benefits especially for high frequency applications as 5G and beyond. The extension of advanced process design kits (PDK) towards packaging technologies including larger process tolerances and a much larger number of materials and processes would also support the approach of chip and package co-design.

Another trend is moving from planar embedding technology to 3D shaped integration. Conformal electronics offer a functional shape adapted system with embedded electronics for e.g. sensors with aligned sensing direction, 3D shaped high frequency antennas or geometrically adapted electronics to the environment.
(Invited) Design of Photoelectrocatalytic Materials and Interfaces for Artificial Photosynthesis
Authors: Toma Francesca Maria
Published: July 2021

The agenda of the Sustainable Development Goals of the United Nations calls for an increase in the share of renewable energy worldwide in the next ten years. Artificial photosynthesis, which is the conversion of sunlight, water, and carbon dioxide into chemicals, offers a promising alternative. Energy is stored in chemical bonds of molecules such as hydrogen or hydrocarbons, and this energy can be released upon need. Semiconductor materials and catalysts are the most important constituents of artificial photosynthetic systems. Herein, we will present an approach to design strategies for the synthesis and integration of photoelectrocatalytic materials for selective and stable operation.
Untapped Potential: The Need and Pathways to High-Voltage Aqueous Redox Flow Batteries
Authors: Perry Mike L. , Rodby Kara E. , Brushett Fikile R.
Published: July 2021

With the increasing desire to decarbonize, decentralize, and fortify the power grid, we must develop cost-effective electrical-energy storage (EES) technologies that can support a diverse set of large-scale applications1. Redox flow batteries (RFBs) are a potential energy storage solution that is increasingly competitive, on a capital cost basis, for EES applications that require longer discharge durations due to their unique decoupling of energy and power2. Both non-aqueous RFBs (NAqRFBs) and aqueous RFBs (AqRFBs) are possible, but AqRFBs are currently the dominant class of RFB chemistries due to their significantly lower solvent cost, inherently higher electrolyte conductivity, and relative safety (i.e., reduced flammability). The major advantage of NAqRFBs is they are not limited by the electrochemical stability window (ESW) of water, allowing for higher cell voltages. Most techno-economic studies, to date, have considered the maximum OCV of AqRFBs to be ≤1.5 V due to the common misconception that the ESW of water is limited to ~1.5 V. However, through careful consideration of electrolyte composition, cell design, and operating practices, AqRFBs with potentials >1.5 V can exist with minimal and/or manageable water splitting. Development of such systems would increase the attractiveness of this class of chemistries and is a promising pathway to low-cost RFB systems, especially since most NAqRFBs have not been able to stably achieve >3 V (generally, the voltage needed to overcome other techno-economic barriers of NAqRFBs to make them competitive).

We have performed basic techno-economic analyses to demonstrate the impact of higher cell voltages (up to 2.5 V) for AqRFB capital cost , and also consider the secondary benefits that can arise from the flexibility provided by higher power and energy densities. A major benefit seen at cell voltages ≈ 2 V or higher is significantly lower projected capital costs. There are multiple challenges to realizing AqRFBs with such high potentials, and we will discuss some potential pathways to enabling realistic systems. This includes the mitigation and remediation of hydrogen and oxygen evolution, as well as stability issues with other RFB components. We will also point out the need for fundamental research on a variety of topics, and new experimental protocols, that can assist the community in developing AqRFBs with higher OCVs.

We hope this perspective will inspire the field to reexamine the perceived upper limits of AqRFB chemistries and to explore options for achieving high-voltage systems.

References

Intergovernmental Panel on Climate Change. Global Warming of 1.5 C. https://www.ipcc.ch/sr15/ (2018).

Darling, R. M., Gallagher, K. G., Kowalski, J. A., Seungbum, H. & Brushett, F. R. Pathways to low-cost electrochemical energy storage: a comparison of aqueous and nonaqueous flow batteries. Energy Environ. Sci.
7, 3459–3477 (2014).
The Influence of Current Density on Transport of Vanadium Cations through Three Exemplary Membranes
Authors: Darling Robert M. , Saraidaridis James D , Shovlin Christopher , Fortin Michael
Published: July 2021

Transport of a redox active molecule through the separator in a flow battery is an important source of inefficiency and electrolyte imbalance. This transport occurs by diffusion, migration, and convection, with driving forces that change with state of charge. Typically, only diffusive permeability and conductivity are measured to characterize transport in membranes, because they are straightforward experiments. The Nernst-Planck-Einstein equation for transport in electrolyte solutions suggests that this may be sufficient because the transference number of an ion can be calculated from its diffusion coefficient and conductivity.

We measured transport of four vanadium cations through Nafion (cation exchange), Fumasep FAPQ-330 (anion exchange), and polybenzimidazole as a function of current density. The measurements were made using a cell with three membranes and four flow compartments designed to collect vanadium passing through sample separators and into receiver compartments. These experiments were augmented with independent sorption and conductivity measurements to assist interpretation in the context of Nernst-Planck-Einstein.

The figure shows the sum of the partial current densities of V2+ and V3+ versus current density for the three membranes. Partial currents at zero total current are proportional to diffusive permeability and slopes at currents greater than zero approximate transference numbers. Transport of vanadium cations is hindered by an anion exchange membrane more than a cation exchange membranes as expected. The gaps in transport observed at zero current widen as current increases. Further data, not shown here, taken with VO2+ and VO2
+ ions on the same membranes indicate that transport is strongly influenced by the nature of the cation. All experimental results are compared to predictions from Nernst-Planck-Einstein.

Acknowledgements

This work was supported as part of the Joint Center for Energy Storage Research, an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences. The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357.

Figure 1
(Invited) Electro-Optical Techniques to Measure Traps in Organic-Based Devices: Why the Methods Originally Developed for Silicon-Based Devices Must be Modified
Authors: Gomes Henrique L , Medeiros Maria Carmo Raposo
Published: July 2021

Electrical techniques to detect traps are a crucial part of the development of a new electronic materials and devices. Since most of our electronic technology relies on silicon, the well-established methods to measure traps were originally developed for silicon-based devices. The intense work developed in the 60’s to map all electronic defects in silicon brough the technology to today’s standards. Among the techniques developed are the deep level transient spectroscopy, photo-induced current spectroscopy, and admittance spectroscopy. Blood and Orton wrote and excellent textbook on these methods [1]. The methodology behind these techniques is the following: Traps are first filled using a voltage pulse or a light pulse, then the kinetics of the charge carrier release is measured usually as function of temperature. This allow us to determine the trap signature (energetic depth and cross-capture section). In organic semiconductors this methodology often does not apply, this is because the traps are extremely deep. A trap with an energetic depth of 0.1 eV is considered a very deep trap in silicon, but in organic electronics, is just a shallow trap. Traps in an organic semiconductor may have an energetic depth higher than 0.5 eV they can be so deep that a charge carrier may take minutes, hours or even days to be released. This makes unpractically the use of the popular methods to study traps in silicon. To detect the presence of the traps and their effects on the device performance the standard methods developed for silicon must be modified.

In this contribution we present a methodology to detect the presence of deep traps in organic based devices. This methodology relies on the measuring the trap filing process and not the trap emptying process. To perform this analysis, the traps must be first emptied, so the device is first brough into a state called “trap emptied state”. This state is then frozen to a specific low temperature and the trap filling recorded at that temperature. To reach a “trap empty state” several methods can be used, namely high temperature while the device is kept under short circuited conditions and/or light exposure for certain types of traps. This methodology was used to detect the effect of traps in organic- based transistors. Transistor devices produced by spin coating and by ink-jet printing methods were studied and presented in this work. The use of this methodology revels the presence of metastable traps that only become active above certain temperatures (200 K, 240 K, and 310 K). This type of metastable traps is only observed organic thin film transistors.

[1] J. W. Orton and P. Blood “Electrical Characterization of Semiconductors: Measurement of Minority Carrier Properties (Techniques of Physics)”, Academic Press (November 11, 1990).
(Invited) Simulations of Ion Diffusion throughout Perovskite Based Solar Cells - Device Level Electrochemistry
Authors: Bitton Sapir , Tessler Nir
Published: July 2021

Defect chemistry plays a major role in the operation of perovskites cells. On one hand they are behind the remarkable self-healing,[1] while on the other they dictate the level of traps, non-radiative recombination,[2] as well as promote ion migration.[3] Moreover, once ions reach the electrodes the device degradation is accelerated.[4, 5] Combining the various reports it seems that if the perovskite would not lose its constituents it would self-heal and if it do lose them it is game-over. We claim that ion migration into the blocking layer is the most important electrochemical process standing in the way of long-term stability. As we will show at the presentation, a significant part of the electrochemistry behind ion leakage and consequently electrode reactions, is captured by a semiconductor device model that accounts for mixed electronic-ionic conduction.[6] While the mere transport of ions introduces no device degradation, introducing oxidation/reduction reactions at the electrodes reproduces the effect of light & bias on device stability. Lastly, we’ll discuss if it is possible to design the device to mitigate this ion leakage out of the perovskite layer.

References

[1] D. R. Ceratti et al., "Self-Healing Inside APbBr3 Halide Perovskite Crystals," Advanced Materials, vol. 30, no. 10, p. 1706273, 2018, doi: 10.1002/adma.201706273.

[2] J. M. Azpiroz, E. Mosconi, J. Bisquert, and F. De Angelis, "Defect migration in methylammonium lead iodide and its role in perovskite solar cell operation," Energy Environ. Sci., 10.1039/C5EE01265A vol. 8, no. 7, pp. 2118-2127, 2015, doi: 10.1039/C5EE01265A.

[3] D. Meggiolaro, E. Mosconi, and F. De Angelis, "Formation of Surface Defects Dominates Ion Migration in Lead-Halide Perovskites," ACS Energy Letters, vol. 4, no. 3, pp. 779-785, 2019/03/08 2019, doi: 10.1021/acsenergylett.9b00247.

[4] F. Galatopoulos, I. T. Papadas, G. S. Armatas, and S. A. Choulis, "Long Thermal Stability of Inverted Perovskite Photovoltaics Incorporating Fullerene-Based Diffusion Blocking Layer," Advanced Materials Interfaces, vol. 5, no. 20, p. 1800280, 2018/10/01 2018, doi: 10.1002/admi.201800280.

[5] B. Rivkin, P. Fassl, Q. Sun, A. D. Taylor, Z. Chen, and Y. Vaynzof, "Effect of Ion Migration-Induced Electrode Degradation on the Operational Stability of Perovskite Solar Cells," ACS Omega, vol. 3, no. 8, pp. 10042-10047, 2018/08/31 2018, doi: 10.1021/acsomega.8b01626.

[6] S. Bitton and N. Tessler, "Electronic-ionic coupling in perovskite based solar cells: Implications for device stability," Applied Physics Letters, vol. 117, no. 13, p. 133904, 2020, doi: 10.1063/5.0023902.
(Invited) New Insights on Charge Transport in Organic and Polymer Thin-Film Transistors
Authors: Dodabalapur Ananth , Wang Xiao , Liang Kelly , Mcculley Calla
Published: July 2021

There have been many reports of thin-film transistors based on semiconductors with mobilities in the range 1-20 cm2/Vs in the past few decades. The mobilities and mean free paths are simply too low for the application of conventional semiconductor transport theories based on solutions to the Boltzmann transport equation (BTE). We will present a very general solution based on the statistical nature of charge transport and introduction of a factor related to the probability of mean free path exceeding the minimum transport length. We are then able to apply the BTE with appropriate scattering mechanisms and obtain very good results that agree well with experiment. This approach is very well suited to thin-film transistors based on polymer and organic semiconductors with room temperature mobilities in the range 1-20 cm2/Vs. We compare theory with experimental results for DPP-based polymers and also oxides.

Charge transport depends on carrier densities and electric fields in complex ways. We describe these dependencies in detail. Scaling down channel dimensions of organic and polymer semiconductor based thin-film transistors to submicron and nanoscale dimensions, required for higher speed operation, presents several challenges. Successful scaling will enable vastly improved device performance and hence the prospects are certainly very enticing. One of the biggest challenges is in making relatively low-resistance contacts. A more thorough understanding of velocity saturation mechanisms and charge transport at high electric fields is also necessary. We describe charge transport in oxide and polymer TFTs with an emphasis on scaling. We show that for some TFTs, scaling of the channel width facilitates scaling down of channel length and a nanostripe or nanogroove array channel geometry has advantages. Finally, we describe hybrid TFTs – with multiple materials that are better suited to scaling down.
(Invited) Organic Electrochemical Transistors for Bio-Signal Classification Using Reservoir-Computing
Authors: Kleemann Hans , Cucchi Matteo , Petrauskas Lautaro
Published: July 2021

Organic electrochemical transistors (OECTs) emerged as a new class of devices holding great promise for applications in neuromorphic circuits. Due to the interplay of ionic and electronic conductivity, OECTs show properties of synaptic plasticity. In particular, the coupling of individual transistors through a common liquid electrolyte induces a complex non-linear dynamic response of OECT-networks, which is ideal for reservoir computing. In this contribution, we employ a densely integrated network of polymer fibers as a non-linear element for classification through reservoir computing. The polymer network is grown via field-directed electropolymerization, which enables the fabrication of fiber networks with controllable directionality and conductivity. The complex coupling between the individual fibers is employed in a delayed feedback loop to demonstrate chaotic behavior proving a sufficient level of complexity for reservoir computing. Using a benchmark ECG data set, we show that such a delayed feedback reservoir is capable of classifying heartbeat signals with excellent accuracy. The reservoir system we are proposing can be fabricated on flexible and even bio-degradable substrates using state-of-the-art printing and deposition techniques. Furthermore, the polymers in our reservoir might also be used as the active sensor materials, e.g., for ECG detection. Overall, this work shows how an organic neuromorphic system might be employed for real-time health-monitoring and power-efficient on-chip classification of bio-signals.
(Invited) Multi-Gate Contact-Controlled Transistors
Authors: Sporea Radu Alexandru
Published: July 2021

Contact effects are a central focus in the development of high performance thin-film transistors (TFTs) and circuits, motivated by the increased speed and current density achievable by reducing contact energy barriers. Conversely, the rectifying properties of contacts have been utilised to create devices in which the current is, for the most part, controlled by the contact properties and bias conditions rather than the semiconductor channel [1]. These transistors operate at lower speeds but bring operational advantages such as geometrical and bias stress tolerance and have been extensively studied in their operation [2] and potential applications [3, 4] in varied material systems [5-7].

We have recently introduced the Multimodal Transistor (MMT), in which channel conductance and charge injection at the source are controlled independently by individual gates [8], offering important benefits to the functionality of analog and mixed signal circuits. These devices build on earlier innovations which modulate contact barriers [1, 5, 6, 7, 9-11] and take advantage of the recent acceptance into the mainstream of multi-gate TFTs [12, 13] to enable constant transconductance, high-speed switching, low output conductance, low-voltage saturation, and robustness against geometrical variability.

Here, the structure and operation of MMTs (Figure 1) is briefly reviewed and challenges and opportunities for this device are discussed, focusing on the specifics of solution-processed and organic implementations.

[1] J. M. Shannon et al., IEEE Trans. Electron Devices, 60, 2444–2449 (2013).

[2] A. Valletta et al., J. Appl. Phys. 114 064501 (2013).

[3] R. A. Sporea et al., Scientific Reports
4 4295 (2014).

[4] Bestelink, E. et al., IEEE Sens. J., 20 (24), 14903 (2020).

[5] Zhang, J., et al, PNAS
116, 4843 (2019).

[6] Lee, S. and A. Nathan, Science
354, 302 (2016).

[7] Jiang, C. et al, Science 363, 719 (2019).

[8] E. Bestelink et al., Advanced Intelligent Systems, 2000199 (2020).

[9] Torricelli, F. et al, Nat. Commun. 7, 1 (2016).

[10] Yoo H. et al., Sci. Rep.
7, 1 (2017).

[11] Uemura T. et al., Adv. Mater.
26, 2983 (2014).

[12] Myny, K. et al., IEEE JSSC
46 (5), 1223, (2011).

[13] Lee S. et al., JSID 27, 507, (2019).

Figure 1. A) Schematic cross-sections of the multimodal transistor (MMT) showing its principle of operation: conduction state is set by the channel gate CG2, while current magnitude is controlled by source gate CG1. B) output characteristics of a nanocrystalline silicon MMT indicating the early saturation and constant transconductance, gm
. C and D) are transfer characteristics obtained by varying CG1 and CG2 voltages, respectively.

Figure 1
(Invited) Numerical Exploration of Spiking Neuron Circuits in Organic Potft Technology
Authors: Calvet Laurie Ellen , Coulson Paoline , Iniguez Benjamin , Romanjek Krunoslav
Published: July 2021

Spike-based neural networks have been shown to hold more computational power than other architectures and their integration into mainstream computing is projected to herald a new age for information technology. Implementation using a flexible Thin Organic Large Area Electronics TOLAE process is a promising low cost way to integrate neuromorphic circuits into sensors, however its feasibility has never been demonstrated. Here we simulate spiking neuron circuits based on the characteristics of a gravure printed scalable organic thin film transistor technology. We then explore the variability of the parameters to show how much variation the circuits can support. Our results demonstrate the feasibility of OTFT technologies for spiking neuromorphic hardware.

Figure 1
A 1 mWh Advanced Iron-Chromium Redox Flow Battery and 200 Kw Li-Ion Battery Hybrid Unit
Authors: LI Liyu
Published: July 2021

An aqueous-based true redox flow battery has many unique advantages, such as long lifetime, safe, non-capacity decay, minimal disposal requirement, and flexible power and energy design. All these make it a great candidate for the vast renewable energy storage market. The key issue with this technology is the cost and availability of the energy-storage media. Due to the limited vanadium resources, it is very difficult for the widely studied vanadium-based redox flow battery to be commercially used for fast-growing renewable energy storage market.

Iron-chromium redox flow battery was invented by Dr. Larry Thaller’s group in NASA more than 45 years ago. The unique advantages for this system are the abundance of Fe and Cr resources on earth and its low energy storage cost. Even for a mixed Fe/Cr system, the electrolyte cost is still less than 10$/kWh. The major issue with this system is the continuous capacity decay due to hydrogen generation, which makes this system impractical for long-term operations.

In the past two years, this limiting problem was successfully solved by researchers at Creek Channel, Inc.1,2 By using a special system design, the hydrogen generation level was largely reduced, down to less than 0.5% per full cycle. A capacity recovery system was also successfully developed, which can compensate the system capacity loss due to hydrogen generation. More than 1000 cycles of operation have been carried out using a system with a kW-scale stack and 100 L electrolyte over a few months. Stable system capacity and stable continuous operation were successfully achieved.

With these breakthrough results, a demonstration project of 30 MWh capacity using containerized product is being developed at Lion Creek Co. Ltd. For a 20’ ISO container-sized product, the deliverable energy is 250 kWh, and the max discharge capacity is 35 kW. For a Two 40’ ISO container-sized product, by using a hybrid design integrating with a 200 kW and 100 kWh Li-ion battery, the deliverable energy is 1100 kWh, and the long-duration discharge power can be as high as 330 kW. Larger projects can be readily built up using multiple 1.1 MWh units. The cost for such these products is lower than 100$/kWh, and the energy storage cost using this product is less than $0.02/kWh. With this energy storage cost, it is possible to achieve our ambitious 100% renewable energy goal in the near future.

In this poster, we will present our recent progress on the development of a 1 MWh advanced Fe-Cr redox flow battery and 200 kW Li-ion battery hybrid unit.

US 10777836 B1. Redox Flow Battery Systems Including a Balance Arrangement and Methods of Manufacture and Operation.

US 10826102 B1. Fe-Cr Redox Flow Battery Systems Including a Balance Arrangement and Methods of Manufacture and Operation.

Figure 1
Stable and Highly Soluble Anolyte for Non-Aqueous Redox Flow Batteries
Authors: Bheemireddy Sambasiva R. , Zhao Yuyue , Li Zhiguang , Zhang Lu
Published: July 2021

Redox flow batteries (RFBs), in which electric charge is stored in redox-active materials (redoxmer) dissolved in liquid electrolytes, show significant potential for grid-scale energy storage applications. Because of the liquid nature, RFBs feature remarkable flexibilities, including decoupled energy and power that is highly desired for adapting various scales of energy storage requirements. Aprotic organic solvents are extensively studied as they can significantly extend the electrochemical window, leading to higher cell voltage and energy density of RFBs. To that end, developing redoxmers with high solubility and stability in non-aqueous solvents are actively pursed in order to realize the full potentials. Inorganic-based redoxmer materials showed good cyclability in aqueous redox flow batteries. Designing non-aqueous compatible redoxmers based on traditional inorganic-based materials encounter critical technical and economic limitations such as low solubility, inferior electrochemical activity, and high cost. In this presentation, a ferrate(III) based low potential redoxmer (anolyte) will be discussed. The synthesized redoxmer showed high solubility in acetonitrile (>2 M) with redox potential of ~-1.36 V (vs Ag/Ag+) and deliver very stable cycling performance evidenced by the symmetric H-cell cycling. The design approach for non-aqueous compatible redoxmers based on traditional inorganic-based materials may represent a promising strategy for constructing high energy dense and stable RFBs.
Bipolar Diimide Based Molecule for Nonaqueous Symmetric Redox Flow Battery
Authors: Nambafu Gabriel , Shao Minhua
Published: July 2021

Redox flow batteries (RFBs) allow decoupling of power and energy capacity, a unique feature that makes them a promising energy storage technology for large scale applications[1]. In recent years, there has been a massive development in aqueous organic RFBs. However, their commercialization has been hindered by low energy density owing to low solubility of redox active materials and narrow electrochemical stability window of water which limits the cell voltage[2] .

Nonaqueous redox flow batteries based on organic redox active material are a regarded as an alternative to aqueous organic RFBs[3] . Apart from enjoying the advantages of organic redox active materials such as low cost, diverse molecular structure and tailorability, nonaqueous RFBs also benefits from using organic supporting electrolytes which provide a wider voltage window (2-5V) facilitating a high energy capacity and low-cost storage system[4, 5] .

Herein, a diimide based molecule is designed, chemically modified, analysed and employed as bipolar redox active materials for a total organic symmetric redox flow battery. Cyclic voltammetry studies show three redox couples, two anodic one electron transfer and one cathodic two electrons transfer redox transitions which are electrochemically reversible. The potential difference between the cathodic peak and the inner and outer anodic peaks leads to a promising cell voltage of 1.51V and 2.22V respectively in redox flow battery application. This work suggests an alternative way to design a multielectron redox active materials for symmetric batteries.

Figure 1: Cyclic voltammogram of 0.002M diimide based molecule in 0.1M tetrabutylammonium hexafluorophosphate in dimethylformamide recorded on a glassy carbon working electrode with a scan rate of 50 mV/s.

Acknowledgement

The work described in this paper was fully supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. T23-601/17-R)

References

[1] P. Alotto, M. Guarnieri, F. Moro, Renewable and Sustainable Energy Reviews. 29 (2014) 325-335.

[2] J. Luo, B. Hu, M. Hu, Y. Zhao, T.L. Liu, ACS Energy Letters. 4 (2019) 2220-2240.

[3] S. Shin, S. Yun, S. Moon, Rsc Advances. 3 (2013) 9095-9116.

[4] W. Wang, V. Sprenkle, Nature Chemistry. 8 (2016) 204-206.

[5] M. Hayyan, F.S. Mjalli, M.A. Hashim, I.M. AlNashef, T.X. Mei, Journal of Industrial and Engineering Chemistry. 19 (2013) 106-112.

Figure 1