bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Porous Lithium Lanthanum Zirconium Oxide (LLZO) Anode Host Structures for Li-Metal Batteries
Authors: Hegazy Amir , Higashiya Seiichiro , Mckinney James , Efstathiadis Harry 
Published: November 2022

Lithium metal batteries are considered to be a leading candidate for next generation batteries due to their higher energy density and potential for safer operation when combined with solid-state electrolyte materials. However, they are still facing different challenges. A key challenge of lithium metal batteries is the volume expansion over cycling due to the non-uniform deposition of lithium on the anode leading to lithium dendrite formation compromising the battery safety, and poor lifetime. Herein, we report the use of porous Lithium Lanthanum Zirconium Oxide (LLZO) anode structures, in which lithium from the cathode is deposited into the pores during initial charging. The goal of this study is to study postmortem the lithium deposition in the porous host after different cycling conditions to measure the 7Li and 6Li isotopes depth profile by nuclear reaction analysis (NRA), namely, Proton Induced γ-Ray Emission (PIGE) and by Deuteron Induced Particle Emission (DIPE), respectively. The advantages of using NRA are that it gives an absolute measurement of Lithium without sample reliant calibration, it is a nondestructive technique, highly selective for specific light nuclides such as Lithium, and it is not affected by coordination effect.
We demonstrate two different fabrication methods of porous LLZO structures, namely, electrospinning and electrospraying. Then, the fabricated LLZO structures are tested electrochemically using a half cell configuration to examine plating/stripping behavior as a function of current density and to track the overpotential evolution over cycling. Finally, the cycled anodes are investigated using NRA in particular Li concentration inside porous anode, at separator/anode interface and anode/current collector interface. Characterizing the concentration gradient of Li species within the porous and at the various interfaces can help define the current density limitations of solid-state Li metal batteries and identify Li loss failure modes so that cell lifetime can be improved.
The Search for the Materials That Are Attractive to "Natural" Li Diffusion
Authors: Ociepa Jozef 
Published: November 2022

"Natural" Li diffusion is defined as the process of Li atom/ions migration under a concentration gradient and activated by thermal energy from atomic vibrations of the host structure at room temperature. This process of passive Li diffusion is important for a better understanding of the active diffusion processes that are happening in lithium-ion batteries (LIBs), where external energy component such as electrical potential is applied. It is expected that materials that exhibit good “natural” Li diffusion properties will perform much better under the external electrical potential. This approach offers a unique opportunity to observe the free movement of lithium atoms/ions into the solid structure and simplify the understanding of diffusion processes especially if single-crystal structures are used. The single-crystal structures are free from grain boundaries and the lithium diffusion process is limited to lattice diffusions such as interstitial, vacancies, and dislocations. This approach allows for categorizing materials that are attractive to lithium diffusion based on the pure lattice component. The characterizing techniques are Auger electron spectroscopy (AES) for tracing Lithium concentration on the surface (Li-KVV peak at 52 eV) and Low Energy Electron Diffraction (LEED) for surface crystallography changes. The lithium concentration gradient is created on the surface of the host material by the evaporation of ultra-thin film of lithium with an effective thickness of 10 Angstrom under ultra-high vacuum conditions.
The data obtained from these experiments are showing different lithium diffusion behavior on the selected materials and there is an indication of three categories of the studied materials. 1-Rapid lattice diffusion of Li into HOPG and no change in the surface crystalline structure. 2-Moderate lattice diffusion of Li into CVD Diamond, SiC-6H, LiNbO3, and TiO2 and some change in the surface crystalline structure. 3-No lattice diffusion of Li into Si single crystals, Ga2O3 and SrTiO3, and no long-range order in the surface crystalline structure.
Most likely rapid diffusion occurs only in graphite but there are several materials with moderate diffusion properties, and these are potential for novel LIBs electrodes or chemically stable interfaces with enhanced performance. The materials with passive no-diffusion properties present challenges in application to LIBs as there is a special need to create active diffusion paths because there is no lattice diffusion contribution.
In addition, this method of tracing lithium passive diffusion using AES is suitable for comparing fabricated polycrystalline LIBs electrodes as a metrology tool for quality control.
Investigating Mixed Cationic and Anionic Redox Chemistry in Chalcogen Based Cathodes for Li-Ion Batteries
Authors: Nagarajan Sudhan , Hwang Sooyeon , Balasubramanian Mahalingam , Thangavel Naresh Kumar , Arava Leela Mohana Reddy 
Published: November 2022

Current state-of-the-art Li-ion batteries are reaching their theoretical limit with respect to the capacity, a property largely limited by cathode materials that have so far relied solely on cationic-redox of transition-metal ions (e.g., M3+/4+ in LiMO2 where M is Co, Ni, and Mn) for driving the electrochemical reactions. Recently, the introduction of new anion-redox cathode materials can lead to a doubling of capacity by accommodating multielectron redox chemistries that have gained research interest. (1) However, current anion-redox cathode materials based on Li-rich layered oxides (represented by the formula Li1+xM1-xO2 where M is Co, Ni, and Mn) suffer from voltage fade, large hysteresis, and sluggish kinetics, which originate mysteriously from the anionic redox activity of oxygen ligand itself. (2) It is widely accepted that the covalency between transition metal – oxygen ligand in traditional cathode materials needs to be altered to take advantage of anion redox chemistry. Here, we present an alternative approach of incorporating improved metal – ligand covalency by less electronegative chalcogen sulfur ligands in the cathode structural framework where the metal d-band penetration into ligand p-band thereby utilizing mixed anionic and cationic redox chemistry. (3) Through this design strategy, we investigated anion redox activity in layered cathode material based on Li2SnS3, and their lithiation/delithiation properties were evaluated through in-depth electrochemical analysis. Further, the charge contributors during electrochemical reactions were identified by spectroscopy analysis, and morphological evolution due to mixed anionic and cationic redox reactions were evaluated using high-resolution transmission electron microscopy(HR-TEM) and high annular dark field-scanning transmission electron microscopy(HAADF) investigations.The results reveal the multi redox induced structural modifications and its surface amorphization with nanopore formation during cycling. Findings from this research will inspire Ni and Co free chalcogen cathode design and various functional materials in the pursuit of next generation cathode materials.
References

J. R. Croy, M. Balasubramanian, K. G. Gallagher, A. K. Burrell, Review of the US Department of Energy’s “Deep Dive” effort to understand voltage fade in Li-and Mn-rich cathodes. Accounts of chemical research
48, 2813-2821 (2015).

G. Assat, J. M. Tarascon, Fundamental understanding and practical challenges of anionic redox activity in Li-ion batteries. Nature Energy
3, 373-386 (2018).

S. Nagarajan, S. Hwang, M. Balasubramanian, N. K. Thangavel, L. M. R. Arava, Mixed Cationic and Anionic Redox in Ni and Co Free Chalcogen-Based Cathode Chemistry for Li-Ion Batteries. Journal of the American Chemical Society
143, 15732-15744 (2021).
Facile in-Situ Polymerized Polymer Electrolytes in All Solid-State Lithium-Ion Batteries
Authors: Sankara Raman Ashwin , Jhulki Samik , Johnson Billy , Narla Aashray , Yushin Gleb 
Published: November 2022

With the push towards renewable energy sources and “green” technologies, lithium-ion batteries (LIBs) have proven to be necessary across multiple technological realms, the biggest of which is currently the electric vehicle (EV) and grid storage markets. But the popular choice of liquid organic electrolytes in LIBs suffers from safety concerns, which motivated significant innovations in safer solid-state electrolytes. Among them, solid polymer electrolytes (SPEs) have shown great potential due to their processability, flexibility and tunability of physical properties. The past decade has seen rapid evolution in the development of SPE LIBs, but most of them still stand inadequate. SPEs are typically processed either by using solvents, or by using them in their solid state, to blend with the active electrode materials. While these systems are often subject to additional compression to promote continuous electrolyte-electrode interface, they still suffer from the almost unavoidable formations of voids, and inhomogeneous contact between the active materials and the SPEs. Furthermore, most of these processes require excessive amounts of SPEs, and yet result in a large interfacial resistance.
Here we introduce a novel one-step manufacturing strategy for polymer electrolytes in solvent-free SPE LIBs. The process involves in-situ polymerization of a liquid-monomer precursor directly infiltrated into a dry jelly roll or individual electrodes to form SPE cells. Our microscopy and FIB experiments confirmed a near-perfect polymer infiltration in porous cathodes, while electro-chemical tests confirmed excellent characteristics of cathode-electrolyte interfaces. The cycling performance of lithium iron phosphate (LFP) half cells using thus produced and infiltrated SPE showed very good stability and columbic efficiency. In addition to single-ion conductive SPEs, we tested hybrid SPE systems where Li salts were added into the single-ion conductive SPEs to improve rate and capacity utilization.
Study of a Rechargeable Lithium-Ion Battery Based on a Copper Hexacyanoferrate Cathode
Authors: Muñoz Eduardo , Rojas Victor , Cáceres Gustavo , López Silvana , Navarrete Emilio , Herrera Francisco , Caballero Álvaro , Gomez-Camer Juan Luis 
Published: November 2022

Rechargeable lithium-ion batteries are among the most promising battery technologies to meet energy conversion and storage requirements. However, this technology is still limited due to its high cost, which prevents its use on a large scale. Therefore, cheaper energy storage systems with long cycle life, high power/efficiency, and safety are in great demand and interest. Prussian blue analogs are promising candidates for use in large-scale energy storage applications due to their long-life cycles, high power density, and high energy efficiency [1]. Along with the change of the transition metal, some structural parameters and some fundamental properties of these compounds can be changed, affecting some parameters such as the battery's storage capacity.
This work studied the electrochemical insertion of lithium ions into Copper Hexacyanoferrate (CuHCF). This compound was synthesized by a hydrothermal process using a factorial design for determining the significance variables, i. e., precursor concentrations, temperature, and reaction time, on the electrochemical performance of the battery. The samples obtained were characterized by FESEM, TEM, XRD, and TGA. The results show cubic structures with a high degree of crystallinity and an evident dependence of the crystallite size (50 - 140 nm) with the variation of the synthesis conditions. Finally, lithium-ion batteries were measured using a CuHCF cathode (theoretical charge 85.1 mAhg-1). The capacity values depended on the crystallite size, obtaining the best results in the synthesis under lower concentrations, reaction time, and temperature. This sample was submitted to deep charge/discharge cycles at a rate of C/20, where the capacity value was close to 60 mAhg-1 (right image). This demonstrates the influence of the crystallite size on the material's performance, managing to find the optimal synthesis conditions to maximize the battery capacity.

References.

[1] 1. Marzhana Omarova, Aibolat Koishybay, Nulati Yesibolati, Almagul Mentbayeva, Nurzhan Umirov, Kairat Ismailov, Desmond Adair, Moulay-Rachid Babaa, Indira Kurmanbayeva, Zhumabay Bakenov, Electrochim. Acta, 184 (2015) 58-63.

Figure 1
Thermal Runaway Reactions Modeling in Lithium-Ion Batteries
Authors: Gundlapally Santhosh R 
Published: November 2022

Lithium-ion batteries are ubiquitously used as power source in a variety of applications due to their superior performance and reliability. However, thermal runaway of Li-ion batteries is a serious concern due to risks associated with such catastrophic event, and hence elucidating the different chemical reactions involved in the thermal runaway phenomenon is a highly active area of research. It is both cost and time prohibitive to experimentally assess the different battery pack designs for the possibility of thermal runaway event, and hence mathematical models play critical role in the battery safety research. Thermal runaway of battery pack is usually initiated by one or a small group of cells which are affected by abuse conditions such as internal short circuit, nail penetration, overcharging, etc., and then depending on the battery pack design and thermal management, thermal runaway can propagate to neighboring cells resulting in fires that can sustain for long time. Since understanding chemistry leading to thermal runaway at cell level is crucial, many studies, both experimental and modeling, have focused on this topic.
Some of the important reactions involved in the onset of thermal runaway are primary SEI decomposition, secondary SEI formation due to reaction between electrolyte and intercalated lithium ions, electrolyte decomposition, separator melting, and cathode decomposition. Since it is difficult to directly measure the different species involved in these reactions, calorimetric based approaches are used to determine the reaction parameters; DSC and ARC are widely used for this purpose. The model consists of system of differential equations which can be solved as a function of time for species fractions and cell temperature. In this work, we have developed flexible and easy to use framework for solving thermal runaway model equations. Both the electrochemical reactions and thermal runaway reactions are solved together with the aim of tighter two-way coupling between these two different processes. Using this model, we analyze the different reaction mechanisms proposed in the literature. We discuss the models for pressure build up in the cell, venting, and combustion of the vented gases.
(Invited) Imaging and Measuring Electronic Materials
Authors: Niefind Falk , Winchester Andrew , Pookpanratana Sujitra 
Published: November 2022

Photoemission (PES) has been an essential metrology in the field of materials physics for over 30 years. The electronic band structure of a solid is a fundamental property which defines how a material will be used and integrated into device form. Topographic features and defects can impact electronic structure, therefore influence extrinsic properties when integrated in device form. Developing metrology that is sensitive to electronic properties at these length scales is desired. Here, we apply lab-based photoemission electron microscopy (PEEM) to gain insight in key structure – function relationships.
Controlling doping during growth of semiconductors is critical as it has impact on device engineering – whether to form components in logical circuits or regions for Ohmic contact formation. For some semiconductor nanowires (NW), the doping density is varied along the long axis of the NW and knowing where the transition and its strength between doping regimes is important for device engineers. Here, we have imaged GaN NW grown with n-doped and n++-doped regions of approximately 6 μm in length and 200 nm in diameter that have been dispersed on a silicon substrate. Using a deep ultraviolet photon source, we observe an inflected change in the contrast along the long axis of the NWs (about 2 μm from one end) which we attribute to the n-n++ interface. This inflection is about 100 nm wide, and provides insight into the space-charge region formed at this electronic interface.
We will also present on expanding our lab-based PEEM capability with integration to a tunable laser-based deep UV system (80 MHz, 140 fs). This added capability will provide additional imaging sensitivity to polar semiconductors such as III-nitrides. We will present some initial results with this system currently being commissioned on device-grade GaN and β-Ga2O3.
(Invited) Modeling Oect Devices for Circuit Simulations
Authors: Calvet Laurie Ellen , Li Zonglong , Tseng Hsing , Weißbach Anton , Kleemann Hans 
Published: November 2022

Organic electrochemical transistors (OECTs) can be distinguished from conventional organic thin film transistors (OTFTs) by the use of an electrolyte in their gate stack. This results in a unique set of device properties, most notably, mixed ionic and electronic transport. Modeling of these devices has mainly been realized using MOSFET-like equations (often called the ‘Bernards model’) and extensions, which use a circuit diagram to include the different parasitics and capacitances involved [1]. While these models provide qualitative agreements with OECT devices, their quantitative agreement may not be sufficient for realizing circuit simulations. Physically, the discrepancy between the model and the devices are likely to stem from the assumption that the electrolyte behaves as a parallel plate capacitor, as in a conventional MOSFET. Recently, another model based on thermodynamics has been proposed that treats the OECT as a thermodynamic binary system with entropic mixing as the driving force for device operation [2]. Here we explore these different models and then show how they can be used to understand circuit behavior of OECTs.
The authors thank the ANR and the Bundesministerium für Bildung und Forschung (BMBF) for funding of the BAYOEN project under contract ANR-21-FAI1-0006-01 and 01IS21089.
[1] J Rivnay et al Organic electrochemical transistors. Nature Reviews Materials, 3(2):1–14, 2018
[2] M. Cucchi et al ‘Thermodynamics of Organic Electrochemical Transistors’, accessed on researchsquare.com, https://doi.org/10.21203/rs.3.rs-1143463/v1

Figure 1
Process Development of Amorphous Indium Tin Gallium Oxide (ITGO) Thin Film Transistors
Authors: Powell Eli , Kabir Muhammad Salahuddin , Zhu Bin , Manley Robert G. , Hirschman Karl D. 
Published: November 2022

The invention of portable electronic devices had a huge impact on the growing interest in flat panel displays. Since the first report in 2004 on amorphous Indium Gallium Zinc Oxide (a-IGZO) thin film transistors (TFTs), many companies have become interested in this material. The main advantage of a-IGZO over conventional amorphous silicon TFTs is its steep subthreshold, low off state current, and high channel mobility. However, the demand for larger displays with higher resolution and refresh rates is driving the demand for TFTs with higher performance, while avoiding the cost and complexity associated with low temperature polycrystalline silicon. There is an increased focus on alternative amorphous oxide semiconductors for use as TFT channel materials, due to the success of a-IGZO.
The focus of this study is an investigation on Indium-Tin-Gallium-Oxide (ITGO) TFTs. Unpassivated bottom-gate devices were fabricated with a 30nm a-ITGO film, sputter deposited with 1% and 10% oxygen gas ambient, followed by a 2 hour anneal at 300oC in oxygen. Devices fabricated with PO2 = 1% resulted in a highly conductive channel. Devices with PO2 = 10% displayed semiconducting behavior and a shallow subthreshold. This trend held for all device dimensions tested; lengths of 24µm, 12µm, and 6µm with a width of 24µm. Compared to a-IGZO devices with a length of 4µm, ITGO devices with a length of 12µm exhibit an equivalent current drive, implying a 3 to 4 times improvement in mobility.
Following aging in room ambient for multiple days, a-ITGO devices displayed improved yet left-shifted transfer characteristics. In unpassivated a-IGZO devices, similar behavior can also be observed and is attributed to an inhomogeneous trap distribution across the channel. As the exposed channel reacts with room air, oxygen vacancies are filled resulting in a more homogeneous trap distribution. A radial variation of device performance from the center of the wafer to the edge was also observed. When measuring devices towards the edge of the wafer a considerable left shift in transfer characteristics was observed. This variation in device performance is believed to be attributed to non-uniformities in the as deposited ITGO film and will be related to material optical parameters.

Figure 1
(Invited) Challenging for High-Performance Oxide-TFT Based Inverters
Authors: Nomura Kenji 
Published: November 2022

Metal oxide-Thin-film transistor (oxide-TFT)-based inverter circuit is a critical technology for the development of next-generation cost-effective ubiquitous device applications for wearable information and healthcare technology. However, in contrast to the success of n-channel oxide-TFT that already implemented in state-of-art high-performance flat-panel-displays, the development of oxide-inverter technology, especially p-channel oxide-TFT, still remains the largest challenging in oxide-TFT technology. The absence of reliable high-performance oxide-TFT inverter is mainly attributed to the insufficient device performances of p-channel oxide-TFTs, and especially large off-current causes large device power-consumption. Therefore, developing p-channel oxide-TFT exhibiting a low off-current and sharp s-value is indispensable for low-power operational oxide-inverter circuits.
This talk discuss how we improve p-channel oxide TFT performance for oxide-TFT-based inverters. After we review the recent progress of oxide-TFT-based inverter and p-channel oxide-TFTs, we identify the current issues and the remaining challenging for oxide-inverters.
To improve the device performances of p-channel oxide-TFT such as SnO-TFT, I present an atomically-ultra-thin oxide channel technology, which offers several advantages such as effective gate control of a conductive metal oxide channel in full-carrier depletion operation mode. This is a promising to improve the devcie performances for several oxide-TFTs having a high carrier-doped oxide channel. To the end, we discuss the device characteristics for oxide-TFT-based-inverter for the ultra-thin oxide-TFT-based CMOS and NMOS inverters.