bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Nm-Scale Patterns and Selectivity: A Blessing or a Curse
Authors: Clerix Jan-Willem , Delabie Annelies
Published: November 2022

Area-selective deposition (ASD) is a promising technique for semiconductor device manufacturing. The replication of nanoscale patterns by ASD can simplify device fabrication process flows by reducing the number of lithography, etch and chemical-mechanical polishing steps. In addition, ASD could eliminate pattern overlay errors. ASD is of special interest as device dimensions scale and has recently been shown as viable approach for the fully self-aligned via, to enable interconnect scaling beyond the 3 nm node [1]. However, the dependence of the selectivity of ALD and CVD processes on the patterning process and pattern dimensions is poorly documented. This aspect will be investigated in the current presentation. We will discuss the fundamental mechanisms of ALD growth mechanisms and how they influence selectivity. Next, we will discuss an example of Ru ASD with defect mitigation in nm-scale patterns on full 300-mm wafers [2].

[1] Chen et al., IEDM21, 486-489.

[2] Clerix et al., Adv. Mater. Interfaces 2021, 2100846.
Targeted Dehydration As a Route to Site-Selective Atomic Layer Deposition at TiO2 Defects
Authors: Jones Jessica Catharine , Kamphaus Ethan , Guest Jeffrey R. , Cheng Lei , Martinson Alex B. F.
Published: November 2022

Crystallographic perfection in epitaxial thin film heterostructures can eliminate interface defects that dilute unique properties and reduce device performance. However, the requirement for epitaxial perfection greatly limits the selection of material candidates and deposition processes. Using selective interface reactions (SIRs), an atomic layer deposition (ALD)-based technique, we target transformation of undesirable defect sites at imperfect surfaces. Defects on the TiO2 surface affect the electronic properties, interfaces, and performance of optoelectronic devices that leverage TiO2 interfaces. We present first principles calculations to predict the difference in hydration/hydroxylation of pristine TiO2 terraces and minority atomic configurations (i.e. “defects”) including step edges and oxygen vacancies. We investigate hydroxylation differences through temperature dependent scanning tunneling microscopy (STM), and ultimately exploit these differences to selectively react ALD precursors at surface defect sites.
(Invited) Advances in Atomic Layer Processing of Hafnia-Zirconia Ferroelectrics
Authors: Lomenzo Patrick D. , Alcala Ruben , Materano Monica , Richter Claudia , Mikolajick Thomas , Schroeder Uwe
Published: November 2022

The limits of integrating ferroelectric materials on commercial semiconductor chips were demolished the moment ferroelectricity in hafnia and zirconia films was reported in 2011. This breakthrough moment in the history of ferroelectric materials was made possible by the fortuitous interplay between advances in atomic layer processing and the strong surface energy dependence of crystal phases in HfO2 and ZrO2. Aided by commercial investment in using both materials as high-k gate and DRAM dielectric materials, atomic layer deposition (ALD) processes are beginning to take full advantage of the completely solid-soluble hafnia-zirconia (Hf1-xZrxO2) ferroelectric system with new precursors and new insights obtained by systematically evaluating film growth conditions. The capability to precisely adjust the compositional profile and to alter oxidation conditions during atomic layer deposition film growth are giving an unprecedented level of control to engineer Hf1-xZrxO2 and doped HfO2 thin films for ferroelectric applications.

The latest advances in atomic layer processing of Hf1-xZrxO2 and doped-HfO2 are presented where the dynamic interaction between composition and film growth conditions provide an engineering roadmap to adjust the physical and structural properties of the dielectric films. Metal precursors play a crucial role in the ensuing film properties. The adjustability of the electrical and structural properties of Hf1-xZrxO2 with ozone exposure during ALD film growth is discussed with respect to the important role oxygen and oxygen vacancies have in the overall phase stability of these novel ferroelectric materials, as well as C incorporation caused by ALD precursors. Just as atomic layer deposition has proven to be instrumental in the discovery and stabilization of the ferroelectric phase in HfO2-based thin films, atomic layer etching (ALE) of HfO2/ZrO2-based layers is now being used to preserve ferroelectricity while pushing the thickness dimension to new limits, yielding high performance films for ferroelectric tunnel junction applications. Further innovations in atomic layer processing will continue to be a harbinger of high performance ferroelectrics in the coming years based on the current status and future outlook for ferroelectric Hf1-xZrxO2 and other emerging ferroelectric materials.
Electrocatalytic Applications of 2D Molybdenum Dichalcogenides By Atomic Layer Deposition
Authors: Zazpe Raul , Sopha Hanna , Rodriguez Pereira Jhonatan , Macak Jan M.
Published: November 2022

2D semiconductor transition metal dichalcogenides have attracted considerable attention due to their layered structure, suitable band gap, electrochemically active unsaturated edges and relatively good stability against photocorrosion. These properties result promising for different applications including, Li-ion batteries, photocatalysis and hydrogen evolution reaction (HER). Apart from the widely studied 2D MoS2, 2D selenide and telluride equivalents, MoSe2 and MoTe2, have recently gained considerable interest due to their higher electrical conductivity, wider inter-layer distance and narrower bandgap as compared to MoS2, high surface area and close to zero Gibbs free energy edges for hydrogen adsorption.

Unlike sulfide dichalcogenides, the lack of Se and Te precursors have prevented the synthesis of selenide and telluride dichalcogenides by ALD. In order to surpass such impediment, we present a set of novel in-house synthesized Se and Te compounds, which were successfully combined with commercial Mo precursor to synthesize MoSe2 and MoTe2 by ALD [1-5]. The as-deposited ALD MoSe2 and MoTe2 on substrates of different nature were extensively characterized by different techniques, which confirmed the chemical composition and revealed the growth of 2D flaky nano-crystalline MoSe2 and MoTe2.

In parallel, MoSe2 and MoTe2@TiO2 nanotube layers (TNTs) heterostructures were fabricated in a simple and fast fashion to explore and exploit the MoSe2 and MoTe2 photo- and electrocatalytic properties. TNTs act as excellent photoactive supporting material providing a high surface area, unique directionality for charge separation, and highly effective charge collection.

The presentation will introduce and describe the synthesis of the 2D Mo dichalcogenides, the corresponding physical and electrochemical characterization and encouraging results obtained in HER [4,5], photocatalysis [4-6] and Li-ion batteries [7].

[1] R. Zazpe et al, FlatChem (2020) 21 100166

[2] J. Charvot et al, Chempluschem (2020) 85 576

[3] J. Charvot et al, RSC Adv. (2021) 11 22140

[4] R. Zazpe et al, ACS Appl. Nano Mater. (2021) 3 12 12034

[5] R. Zazpe et al, Appl. Mater. Today (2021) 23 101017

[6] M. Motola et al, Nanoscale (2019) 11 23126

[7] H. Sopha et al FlatChem (2019) 17 100130
The Physicochemical Structure of Inorganics in PIM-1/Alox Hybrid Membranes Synthesized Via Vapor Phase Infiltration (VPI)
Authors: Jean Benjamin , Liu Yifan , Mcguinness Emily , Losego Mark D
Published: November 2022

Polymers of intrinsic microporosity (PIMs) represent a unique class of polymer membranes defined by their inherent microporosity, leading to excellent separations ability. However, the poor solvent stability of these organic membranes limits their use for organic solvent separations. Vapor phase infiltration (VPI) is an emerging technique adapted from atomic layer deposition (ALD) processes that infiltrates inorganic clusters into polymeric materials, generating hybrid organic-inorganic materials with improved chemical stability. VPI treated polymer of intrinsic microporosity 1 (PIM-1) has shown dramatically improved resistance to solvent dissolution while maintaining its microporosity, making it a much more robust membrane. However, the lack of clarity around the structure of the inorganic clusters within VPI synthesized hybrid materials limits the ability to design these hybrid membranes to optimize potential trade-offs between chemical stability, permeance, and separation performance.

Currently, most VPI literature refers to the inorganic components within the hybrid as “metal oxides” or “MOx”. This oversimplification does not fully describe the possible cluster structure or inorganic-to-organic bonding characteristics likely present in these hybrid structures. Moreover, the atomic-scale and long-range disorder of these inorganic clusters make them difficult to describe with traditional methods used for inorganic crystals or polymeric solids. Thus, a more sophisticated understanding of the inorganic structure is needed to inform both process and function design of these hybrid materials. This talk will discuss combined experimental and computational efforts to clarify the structure of inorganic clusters in VPI treated PIM-1/AlOx membranes. XPS and FTIR in conjunction with DFT calculations indicate that the final inorganic species is an oxyhydroxide species. Further, solid state NMR suggests the final inorganic cluster is a 6-coordinate species that is at least dimerized, with water molecules coordinating to the structure to fill out the coordination sphere. DFT calculations validate this claim as the lowest energy structure compared to the monomer form as well as other aluminum oxyhydroxide species. This interdisciplinary work explores the structural characteristics of PIM-1/AlOx hybrid membranes and its impact on the VPI treated material properties such as solvent stability.
Understanding How Organosilicon Additives Delay Electrolyte Decomposition on LiNi0.8Mn0.1Co0.1O2 (NMC 811) Cathodes Using in Situ Techniques
Authors: Ortiz-Ledon Cesar , Morris Louis Vincent , Hamers Robert J
Published: November 2022

Cathode materials such as LiNi0.8Mn0.1Co0.1O2 (NMC811) are of great interest for Li-ion battery (LIB) systems. By increasing the Ni content, the price decreases since Co is an expensive transition metal. In addition, NMC811 offers higher capacity and operating at high voltages, compared to other cathode materials (i.e., LCO, LMO, etc.). However, this cathode material suffers degradation from different sources. One of the main detrimental processes is oxygen loss from the lattice, which can cause decomposition of electrolyte components such as cyclic carbonates and further generate undesirable gassing in LIB systems. Several different organosilicon (OS) compounds have been reported to decrease gassing during storage with NMC622/Gr multi-layer pouch cells. Besides reducing gassing, OS compounds have been reported to increase the thermal stability of PF6
- and reduce HF, which is detrimental for LIB systems. Currently, the exact mechanism for how OS additives alleviate these undesired electrolyte degradation reactions is not well known.

In this study we performed a mechanistic investigation on the effects of OS3 (organosilicon additive) during Li the intercalation/deintercalation processes on NMC811. First, we explored how OS3 affects the electron transfer kinetics by performing variable scan rate cyclic voltammetry. Second, we studied the mass accumulated on NMC811 surfaces during the first cycle as a function of applied potential using in situ electrochemical quartz crystal microbalance (EQCM). Finally, we analyzed the chemical composition of the cathode surface layer and how it evolves as a function of potential using in situ attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) at stepwise points during the first cycle. Together, these techniques provide a comprehensive study of the reactions occurring at the NMC811 electrode surface during the first cycle, including lithium intercalation kinetics, mass deposition and dissolution, and the chemical composition of surface decomposition species as a function of potential, it was found that OS3 delays the onset of mass accumulation and therefore delays electrolyte degradation during the first cycle on NMC811 cathode materials as confirmed by the presence of new absorbance features on in situ ATR-FTIR. We successfully identified a potential mechanism of action of how organosilicon additives help to prevent the carbonate-based electrolyte to decompose on NMC811 surfaces. These studies further provide new insights into the mechanisms of performance enhancement observed with OS additives.
(Digital Presentation) Mitigation of Capacity Loss and Voltage Decay of Li-Rich Mn-Based Layered Oxide Cathodes By Coating with Oxygen-Deficient Perovskite Compounds
Authors: Lei Yike , Xiao Qiang Feng
Published: November 2022

Li-rich Mn-based layered oxide (LMLO) is a promising cathode for high energy density Li-ion batteries due to its high discharge capacity and low cost. However, the commercialization of LMLO is hampered by voltage fading, capacity decay and gas evolution during cycling due to interfacial side reactions. In this work, we designed a coating layer based on oxygen-deficient perovskite compounds La0.9Sr0.1CoO3 (LSCO) using the Pechini that can capture the oxygen released during charging and suppress side reactions. Scanning transmission electron microscopy exhibit the coating layer is quite uniform with 6 nm thickness, and X-ray photoelectron spectroscopy demonstrate that the content of oxygen is significantly lower on the surface than that in the bulk material due to the oxygen vacancies within the LSCO coating layer. Compared with the pristine material, LSCO coated LMLO material exhibits higher initial coulombic efficiency, lower voltage decay, improved cycle and rate capability. In particular, the capacity retention at 2 C rate increases by over 50% after 400 cycles from 55.6% to 84.8%. Electrochemical impedance spectroscopy results demonstrate similar Rct
after activation of the two types of electrodes (coated and untreated), the charge transfer resistance increases rapidly upon cycling for the untreated LMLO electrodes, while there is essentially no change in Rct
for LSCO-coated LMLO electrodes. Postmortem analysis demonstrates that the LSCO layer inhibits electrolyte decomposition and excessive side reactions, forming a stable and Li+ conductive surface films on the LMLO cathode displays better electrochemical performance.
(Battery Division Research Award) Structure-Property Relationships: A Journey From LFP to Lithium Metal
Authors: Yamada Atsuo
Published: November 2022

Conceptual importance of “Matastable Phase Diagram” and “Liquid Madelung Potential” will be demonstrated by picking up some of my mechanism-solving works on LFP and lithium metal.

In Li
x
FePO4, the ground state phase separation and metastable solid solution are energetically competitive, and the solid solution phase is induced in a non-equilibrium electrochemical reaction, playing critical role for fast kinetics. However, there had been no discussion or experimental report of the crystal structure, optical and transport properties of the metastable solid solution phase due to the extreme technical difficulties; the solid-solution phase Li
x
FePO4 is metastable during electrochemical process and disappears within a few seconds. We overcame this limitation by quenching Li
x
FePO4 (x = 2/3) at 350 °C to room temperature. This quenched phase remained stable for a couple of weeks, which enabled sufficient time to measure the several intrinsic properties, including polaron-crystallized superstructure, optical properties with emerging inter-valence charge transfer absorption, and enhanced conductivity over 103 in order.

Since the Li/Li+ redox potential (E
Li/Li+) positions outside of the thermodynamical potential window of the present electrolyte, suppressing side reactions is essential, which can be realized not only by kinetic suppression by SEI but also by thermodynamic stabilization viz. upshift of E
Li/Li+. Remarkable improvement of Coulombic efficiency is exemplified in (locally) salt-concentrated electrolyte, where E
Li/Li+ largely upshifts over 0.6 V. We revealed that the unusual upshift of E
Li/Li+ is primarily dominated by Coulombic energy penalty of Li+ in the electrolytes rather than the simple Nernst equation with extremely high Li+ activity coefficient.[1] Overall energetics was verified and directly quantified by introducing the “liquid Madelung potential (E
LM)” analogous to the conventional concept in solid-state science.[1] Namely, Li+ is electrostatically more stabilized by electron-localized solvents, while relatively less stabilized by electron-delocalized larger sized anion, thus decreasing the overall Coulombic energy gain of Li+ under progressive anion coordination.[1]

[1] N. Takenaka, S. Ko, A. Kitada, and A. Yamada, submitted (2022)

Figure 1
Evolution of Gesn Lasers Towards Photonic Integration into Practical Applications
Authors: Kim Youngmin , Assali Simone , Jung Yongduck , Burt Daniel , Zhang Lin , Joo Hyo-Jun , Koelling Sebastian , Chen Melvina , Luo Lu , Atalla Mahmoud , Ikonic Zoran , Tan Chuan Seng , Moutanabbir Oussama , Nam Donguk
Published: November 2022

GeSn alloys have emerged as a promising material for group IV light sources because alloying Ge with Sn increases the directness of the bandstructure, thus improving the efficiency of light emission. Despite several years of progress in GeSn lasers, however, the integration of such lasers into practical applications still faces challenges such as high threshold, low operating temperature, and large device footprint. In this report, we address these challenges via each of the studies containing thermal management, defect reduction, and nanowire growth approach. First, we demonstrate improved lasing characteristics including reduced threshold and increased operating temperature in GeSn microdisks directly sitting on Si, which is allowed by the enhanced thermal management over the conventional suspended microdisks. Although there is a concern about poor optical confinement of the sitting approach, we confirm the simultaneous achievement of excellent heat dissipation and superior optical confinement from the microdisk released on Si through experiments and theoretical simulations. We also demonstrate a decreased threshold in microdisk lasers fabricated using a high-quality GeSn-on-insulator (GeSnOI) substrate. Photoluminescence measurements show that the reduction of defects in GeSnOI leads to enhancement of spontaneous emission and reduction of the lasing threshold. Lastly, we present the potential for GeSn nanowire lasers having smaller footprints by observing clear cavity resonances in a single nanowire grown by a bottom-up growth approach. Our demonstrations provide guiding principles to push the performance of GeSn lasers to the limit towards a realization of practical group IV light sources.
(Digital Presentation) Quantum Computing in Si/Sige Quantum Dot Arrays
Authors: Vandersypen Lieven
Published: November 2022

Quantum computation has captivated the minds of many for almost two decades. For much of that time, it was seen mostly as an extremely interesting scientific problem. In the last few years, we have entered a new phase as the belief has grown that a large-scale quantum computer can actually be built. Quantum bits encoded in the spin state of individual electrons in Si/SiGe quantum dot arrays, have emerged as a highly promising direction. Recent highlights from our group include the operation of a device with six quantum bits and the demonstration of quantum operations with a fidelity above 99.5%. In this talk, I will present our vision of a large-scale spin-based quantum processor, and ongoing work to realize this vision.
(Digital Presentation) MOCVD Growth of Ga2O3, Algao and Heterostructures
Authors: Zhao Hongping , Bhuiyan A F M Anhar Uddin , Feng Zixuan , Meng Lingyu
Published: November 2022

Ultrawide bandgap (UWBG) gallium oxide (Ga2O3) represents an emerging semiconductor material with excellent chemical and thermal stability. It has a band gap of 4.5-4.9 eV, much wider than that of the GaN (3.4 eV) and 4H-SiC (3.2 eV). The monoclinic β-phase Ga2O3 represents the thermodynamically stable crystal among the known five known phases (α, β, γ, d, ε/κ). The breakdown field of β-Ga2O3 is predicted to be 6-8 MV/cm, which is much larger than that of the 4H-SiC and GaN. These unique properties make β-Ga2O3 a promising candidate for high power electronic device and solar blind photodetector applications. Single crystal β-Ga2O3 substrates can be synthesized by scalable and low cost melting based growth techniques. Metalorganic chemical vapor deposition (MOCVD) growth technique was demonstrated to produce high quality β-Ga2O3 thin films and its ternary (AlxGa1-x)2O3 alloys. Control of background and n-type doping in β-Ga2O3 will be discussed. Record carrier mobilities of 194 cm2/V·s at room temperature and ~10,000 cm2/V·s at low temperature were measured for MOCVD β-Ga2O3 thin films. Growth and fundamental understanding of β-(AlxGa1-x)2O3 are still limited. The incorporation of Al in beta-phase Ga2O3 has not been well understood, although it was predicted up to 60% of Al composition could be incorporated into β-Ga2O3. MOCVD growth of β-AlGaO targeting for Al composition of > 40% will be discussed. N-type doping capability as a function of Al composition in (AlxGa1-x)2O3 is another important fundamental question. Charge carrier transport properties in (AlxGa1-x)2O3 will be discussed. In addition, MOCVD growth of different phases of Ga2O3 and AlGaO will be presented.

Acknowledgement: The authors acknowledge the funding support from the Air Force Office of Scientific Research FA9550-18-1-0479 (AFOSR, Dr. Ali Sayir) and the National Science Foundation (1810041, 2019753, 1755479).
The Role of Long Lifetime Li-Ion Cells in a Sustainable Future
Authors: Eldesoky Ahmed , Kowalski Nicholas , Logan Eric R , Aiken Connor P , Bauer Michael , Harlow Jessie , Dahn Jeff R.
Published: November 2022

State-of-the-art Li-ion cells can have decades of lifetime (>40 years) and tremendous cycle life greater than 10000 cycles1. Such incredible cells greatly exceed the goal of 80% capacity retention after 800 cycles, promoted by some as sufficient for electric vehicles (EVs). However, by 2030 it is projected that more than 90% of all Li-ion batteries will be used to power vehicles2, with very few remaining for energy storage from intermittent renewables which must displace fossil fuels for power generation. The batteries in electric vehicles will represent a vast amount of energy storage capacity, which can be harnessed using vehicle to grid (V2G) technology. Batteries with that can maintain 80% of their capacity after a mere 800 cycles are unsustainable since most of the charge-discharge cycles in V2G will occur when the EV is stationary. For this reason, ultra-long-lived cells are a critical component of a sustainable future.

In this talk, we will discuss the important role of graphite material and upper cut-off voltage (UCV) on the lifetime of NMC811 cells, and how avoiding volume contraction in Ni-rich materials yields cells that should be eminently suitable V2G applications3,4. Additionally, we will discuss the results of a two-year study on the impact of C-rate, depth of discharge (DoD), UCV, and temperature on the lifetime of NMC811 cells. Finally, we will demonstrate that NMC cells with a low UCV, with an emphasis on Ni-rich materials, yield greater energy throughput compared to their higher energy counterparts due to their prolonged lifetime. The $/kWh metric is surely important when selecting a battery technology, but the levelized cost of energy over the battery lifetime is more important when batteries last for many decades.

References

Harlow, J. E. et al. A Wide Range of Testing Results on an Excellent Lithium-Ion Cell Chemistry to be used as Benchmarks for New Battery Technologies. Journal of The Electrochemical Society
166, A3031–A3044 (2019).

Pillot, C. The Rechargeable Battery Market and Main Trends 2018-2030. https://rechargebatteries.org/wp-content/uploads/2019/02/Keynote_2_AVICENNE_Christophe-Pillot.pdf (2019).

Eldesoky, A. et al. Impact of Graphite Materials on the Lifetime of NMC811/Graphite Pouch Cells: Part I. Material Properties, ARC Safety Tests, Gas Generation, and Room Temperature Cycling. Journal of The Electrochemical Society
168, 110543 (2021).

Eldesoky, A. et al. Impact of Graphite Materials on the Lifetime of NMC811/Graphite Pouch Cells: Part II. Long-Term Cycling, Stack Pressure Growth, Isothermal Microcalorimetry, and Lifetime Projection. Journal of The Electrochemical Society
169, 010501 (2022).
Development of Large Area All Solid-State Lithium-Ion Cells Using Scalable and Manufacturable Coating Processes
Authors: Colclasure Andrew M. , Brow Ryan , Schulze Maxwell
Published: November 2022

The NREL team has fabricated all solid-state full cells with sulfide-based electrolytes using fabrication techniques suitable for high speed/low-cost manufacturing, such as slurry and tape casting. Slurry coating is a well-established and cost-effective process feasible for large scale/continuous process (e.g., roll-to-roll processing). However, most solid-state cells fabricated to date have been small area (1 cm2) cells with single mAh capacities. These cells are generally fabricated by dry mixing of powders and compressing layers to hundreds of MPa up to GPa of pressure and high temperatures to condense powders into a coin-cell size battery. The use of such high pressures is not suitable for large-scale manufacturing. Further, the separator layer in this configuration is often prohibitively thick (hundreds of microns) resulting in poor rate capability and low energy density. NREL has demonstrated ability to cast thin (100 micron) electrically isolating sulfide-based separator layers and composite solid-state cathodes. Functioning large-area cells (30 cm2) have been fabricated by punching out sections of cast layers to make cells tested at modest pressures. The chemical reactivity of sulfide-based electrolytes with solvents for casting and active cathode oxide materials (NMC, NCA, etc.) is particularly challenging. Figure below shows all solid-state cathode (left) and anode/argyrodite separator (right) having dimensions of 5X6 cm. The anode, cathode, and separator all use a chloride argyrodite electrolyte (Li6PS5Cl). The anode active material is graphite and cathode is alumina coated NMA with high specific capacity (> 200 mAh/g). Initial performance testing will be shared.

Figure 1
Design of High-Performance Solid Electrolytes Guided By Crystal Structure Characterization and Understanding
Authors: Liu Zhantao , Liu Jue , Mo Yifei , Chen Hailong
Published: November 2022

Solid electrolyte is the key component in all-solid-state-batteries that is currently limiting the commercialization of this technology. An ideal solid electrolyte should have high room temperature ionic conductivity, low electronic conductivity, good compatibility with both cathode and anode, good mechanical properties, high air and moisture stability and low manufacture cost. Among these requirements, the improvement of ionic conductivity is prioritized as the conductivity of most existing solid electrolyte is still much lower than that of conventional liquid electrolyte.

The improvement of ionic conductivity and design and development of solid electrolyte materials are closely related to our understanding on the ionic diffusion mechanism in solids and the structure-property relationship. We believe that rational design of high-performance solid electrolyte should start from careful characterization and good understanding of the crystal structure. Here we report the crystal structure characterization on sulfides and halide solid electrolytes and the design and development of novel solid electrolytes based on our findings in structural characterizations. Ex situ high resolution synchrotron X-ray and neutron diffraction and pair distribution function analysis are used to understand the crystal structures in great details. In situ X-ray diffraction for different synthesis methods is coupled with variable temperature electrochemical impedance spectroscopy to understand the structure-property relationship in the solid electrolytes. The design, synthesis and electrochemical evaluation of several solid electrolytes will be presented and discussed.
Observation and Mitigation of Beam Damage Effects on the in Situ Experiment of Li-Ion Battery Cathodes: A Transmission X-Ray Microscopy Study
Authors: Rahman Muhammad Mominur , Wang Qinchao , Ge Mingyuan , Lee Wah-Keat , Yang Xiao-Qing , Xiao Xianghui , Hu Enyuan
Published: November 2022

Abstract

Advanced characterizations play critical roles in understanding the fundamental properties of important materials. For accurate characterization, it is always necessary to address the possibility of probe-induced damage. A typical example is the successful application of cryo electron microscopy with low dose electron to characterize highly sensitive samples (ref1-3). Unfortunately, there have been very few studies on the effects of radiation damage on Li-ion battery systems caused by synchrotron x-ray beam. In this presentation, we provide direct evidence of synchrotron x-ray beam damage during in situ characterization of battery materials, observed by transmission x-ray microscopy (TXM). The unique capabilities of this technique in obtaining both morphological and chemical information enabled us to study the beam damage issue caused by x-ray. Li-rich Li1.2Ni0.13Mn0.54Co0.13O2 material was characterized in situ to study the redox reaction mechanism of this material. Beam damage in the form of bubble formation in the liquid electrolyte was observed when the material was irradiated with x-ray during 2D/3D XANES (x-ray absorption near edge structure) image collection at Ni K-edge. The bubble formation in liquid electrolyte is most likely due to the decomposition of the electrolyte triggered by x-ray irradiation. This suggests beam damage issue needs to be considered not only for TXM which is commonly used to study the depth-dependent redox reaction in individual particles, but also spectroscopic techniques that employ similar energy range. Such damage may be related to the huge x-ray flux used in the in situ experiment. When filters were used to reduce the flux, the bubble formation was significantly reduced. We further show the evolution of the Ni redox during the cycling with suppressed beam damage, which should be more faithfully reflecting the situation.

Acknowledgement

This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technology Office of the US Department of Energy (DOE) through the Advanced Battery Materials Research (BMR) Program, including Battery500 Consortium under contract no. DE-SC0012704. This research used beamline 18-ID of the National Synchrotron Light Source II, a US DOE Office of Science user facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704.

References

J. Z. Chen et al., J. Struct.
Biol., 161, 92–100 (2008).

X. Wang, Y. Li, and Y. S. Meng, Joule, 2, 2225–2234 (2018).

X. Wang et al., Nano Lett., 17, 7606–7612 (2017).
Understanding Mechanisms of Ethylene Carbonate Gassing and Gas-Reducing Additives Using Isotopically Labeled Solvents
Authors: Kerber Brian M , Guillot Sarah Lucienne , Johnson Tobias , Peña-Hueso Adrián , Zhou Liu (Amy) , Du Peng , Usrey Monica Lee
Published: November 2022

Gas generation during Li-ion battery operation remains a problem that can affect both safety and operational lifetime of the battery. Electrolyte solvents are a key source of gas generation1 and while gas-reducing additives have been identified, the underlying mechanisms require more study to fully understand the role between solvent structure and gas generation. Understanding of these gassing mechanisms can lead to optimized electrolyte systems with reduced gassing for the next generation of Li-ion batteries. Previous studies in the literature2 have detailed the use of 13C-labeled EC and DEC to identify the proportions of CO2 and CO that are derived from solvent sources, which in turn can help inform mechanistic understanding on gas generation in Li-Ion Batteries.

As previously studied by Silatronix®, electrolytes containing organosilicon (OS) materials show significantly reduced gas generation during high temperature storage and cycling in pouch cells primarily through CO2 reduction.3 Studies utilizing simple carbonate blends indicated that EC was the primary source of CO2; therefore, it was hypothesized that OS materials reduce gassing by preventing EC decomposition during high temperature testing. In this work, 13C-labeling was used to identify the sources of gas species in ternary carbonate electrolytes after both first charge (SEI formation4) and high temperature storage (extended aging) to allow the effects of electrolyte additives gas reduction to be elucidated.

Gas component analysis was performed using a calibrated GC-MS, providing identification and quantification of each gas species (labeled and unlabeled). These data give insight into how the labeled carbonate solvent may decompose into the observed gas phase products during the first charge (i.e., during SEI layer formation) and high temperature storage. Ethylene carbonate (EC) is found to be the primary source of ethylene generation, as well as a significant source of CO2 and CO. With the addition of OS, the most notable effect is that the previously seen reduction in all gas components is due to not only reduction of EC-related sources, but reduction in non-EC gas sources as well.

1 Rowden, B.; Garcia-Araez, N., A Review of Gas Evolution in Lithium-Ion Batteries. Energy Rep. 2020, 6, 10-18.

2Onuki, M.; Kinoshita, S.; Sakata, Y.; Yanagidate, M.; Otake, Y.; Ue, M.; Deguchi, M., Identification of the Source of Evolved Gas in Li-Ion Batteries using 13C-labeled Solvents. Journal of the Electrochemical Society
2008, 155, A794.

3 Guillot, S.L.; Usrey, M.; Peña-Hueso, A.; Kerber, B.; Zhou, L.; Du, P.; Johnson, T., Reduced Gassing In Lithium Ion Batteries With Organosilicon Additives. Journal of the Electrochemical Society
2021, 168, 030533.

4 Ktristiina Heiskanen, S.; Kim, J.; Lucht, B., Generation and Evolution of the Solid Electroyte Interphase of Li-Ion Batteries. Joule
2019, Volume 3 Issue 10, 2322.
Silicon/Carbon Composite Anode Materials for Li-Ion Batteries from a Scalable and Continuous One-Step Gas Phase Process
Authors: Loewenich Moritz , Orthner Hans , Wiggers Hartmut
Published: November 2022

Silicon as an anode material has been intensively studied in academia, yet issues correlated to the vast volume change still hinder application in industry greater than a few mass percent. Some approaches reported can suppress the rapid capacity fade, which is observed for pristine silicon powders. However, they are usually based on complex processes or involve expansive chemicals, making them less interesting for commercial applications. Our approach focuses on the production of a long-term stable, silicon-based composite material in a single, easy-to-scale manufacturing process in a free-space reactor.

The newly developed composite consists of a silicon/carbon nanomaterial with a carbon-rich surface produced in a single-step gas phase process with production rates of already 100 – 500 g/h on the lab scale. Carbon is used as a composite component for two reasons: i) The incorporation of carbon in the range of 3-12 wt.% inhibits the formation of crystalline silicon within the silicon/carbon composites by disturbing the silicon-lattice, effectively preventing the formation of detrimental c-Li15Si4 phase during lithiation. ii) Furthermore, the carbon containing materials are less sensitive to oxidation and show enhanced cycling stability compared to pure silicon materials. By adjusting the process parameters, e.g. primary particle size d50,number can be tuned in the range of 40-120 nm. The electrochemical performance of the composite materials has been analyzed in half cells. For 75 wt.% active material electrodes, 90 % first cycle Coulombic efficiency and 75 % capacity retention after 200 cycles with an CCCV protocol at 0.5 C can be realized.

Figure 1
An Aqueous Binary Binder for Silicon-Based Electrodes
Authors: Zhou Bingyao , Mathew Kevin , Wang Guanyi , Xiong Jie , Yang Jian , Wu Qingliu , Lu Wenquan
Published: November 2022

The relatively low coulombic efficiency (CE), especially the high initial capacity loss (ICL), and short cycle life are two major obstacles limit the wide adoption of Si-based materials as anodes of commercial lithium-ion batteries (LIBs). In this work, we introduced an aqueous binary binder composed of polyacrylic acid (PAA) and a water-soluble polymer to a Si-based electrode. Used as anodes of LIBs, the Si-based electrodes with the binary binder exhibited lower ICL and longer cycle life than those with PAA binder. The improved battery performance is ascribed to the unique electrode structure with the binary binder. The analysis from Fourier-transform infrared spectroscopy (FTIR) reveals that the intermolecular hydrogen bonds has been formed between PAA and the new polymer. The formation of hydrogen bonds could affect the properties of slurry for electrode coating and the structure of dried electrodes. Compared to the PAA binder, the new binary binder increases the viscosity of aqueous slurries at low shear rates and prompts the shear thinning, which benefit the preparation of slurries with high stability. Observations from the electron microscopy reveal that a relative porous structure was generated in the electrodes with the binary binder, compared with those with PAA binder. The porous structure could not only facilitate the electrolyte transport, but also accommodate the large volume expansion of Si during the charge/discharge processes. In addition, a thin solid-electrolyte-interface (SEI) film was found at the surface of cycled electrodes with the binary binder.

Key words: aqueous binder coulombic efficiency Si-based anode lithium-ion battery
Novel Approaches for High Efficiency Electrochemical Energy Storage Devices Based on DNAs and Nanomaterials
Authors: Bae JoonHo , Li Man , Li Yang
Published: November 2022

In this talk, we present our approaches to realize high efficiency, high performance, next generation electrochemical energy storage devices based on DNAs and various nanomaterials. Firstly, novel electrochemical, battery-like capacitors using DNA-wrapped MWCNTs (denoted as CNT@DNA) as electrode materials are demonstrated. By using CNT@DNA, which were successfully assembled through a facial sonication treatment,. as template, a NiCo2O4 nanoparticle-anchored composite NiCo2O4-CNT@DNA was fabricated through situ precipitation coating process. Subsequently, the NiCo2O4-CNT@DNA and NiCo2O4-CNT (prepared without DNA) were used as the cathode materials to fabricate supercapacitors with high capacitive performance. The result of electrochemical test shows a high specific capacitance of NiCo2O4-CNT@DNA electrode of 760.0 F/g at 5 mV/s, which is higher than that of NiCo2O4-CNT electrode. The cycling performance of the NiCo2O4-CNT@DNA electrode displays a capacitance retention of 96.2% after 5000 cycles at the current density of 5 A/g. The above results demonstrate that the novel NiCo2O4-CNT@DNA composites can be desirable electrode materials for high performance supercapacitors in the future.

We also present our group's recent works on use of DNAs for advanced batteries including Li- S batteries and hybrid supercapacitors.
Synthesis and Size Control of Single Crystal Ni-Rich Layered Oxide Cathodes Using Statistical Analysis-Guided Molten Salt Method
Authors: Yang Zhijie , Lin Feng
Published: November 2022

Rechargeable Li ion batteries have been widely applied in daily lives. The demand for Li ion batteries with higher energy density has been increasing especially with the thriving development of electric vehicles in the past decade. Li(Ni1−x−yMnxCoy)O2 (NMC) is one of the most successful commercial cathodes with various transition metal (Ni, Mn, and Co) ratios. Higher Ni content in the composition of NMC gives rise to higher energy density but at the price of structural and thermal stability. Recently, synthesizing single-crystal cathode particles has been extensively investigated as a strategy to enhance the stability of NMC cathodes. Most commercial NMC cathode particles possess polycrystalline structure, which is prone to induce intergranular cracking and parasitic reactions with the electrolyte upon cycling due to grain boundaries and large surface area. In contrast, single crystal NMC cathodes show higher cycling stability than their polycrystalline counterparts. However, the synthesis of single crystal normally requires higher temperatures and longer calcination duration than that of the polycrystalline counterparts for solid state synthesis. Alternatively, molten salt synthesis of single crystals is less energy-intensive and capable of tuning particle morphology and size. However, there is not yet a systematic guideline for the molten salt synthesis of single crystal Ni-rich NMC cathodes. Herein, we studied the effect of different synthetic parameters on the performance of single crystal Ni-rich NMC cathodes. We applied statistical analysis tools to correlate the synthetic conditions with cathode properties and optimized the synthetic parameters. Furthermore, we investigated the effect of single crystal size on the cathode performance. Our findings provided new insights into the synthesis and understanding of single crystal Ni-rich cathodes.
A New Approach to Mitigate the Deterioration of Ni-Rich Cathode Materials: Electrolyte Exposure Time
Authors: Park Nam-Yung , Sun Yang-Kook
Published: November 2022

With the prevalence of electric vehicles, Ni-rich layered cathodes have been extensively developed to increase the energy density of Li-ion batteries (LIBs). However, cathodes with a high Ni content suffer from inherent structural and chemical instabilities, which lead to rapid capacity fading and thermal instability.1 In particular, the rapid capacity fading of Ni-rich layered cathodes is largely caused by microcracking and the resultant microstructural instability.2 In addition to microcracking, the time during which highly reactive Ni4+ ions are exposed to the electrolyte when the cathode is in a highly charged state also affects the deterioration of the cathode. Although the exposure time is not significant for cathodes with Ni contents of <60%, the calendar aging test of Ni-rich cathodes reveals that the exposure time, especially at high SoCs, critically affects the degradation of these high-Ni cathodes, as the internal surfaces of the particles are also exposed to the electrolyte via the microcracks.3 The exposure time is particularly pertinent for electric vehicle (EV) LIBs, as they remain stationary for long periods in the highly charged state and are operated intermittently. Consequently, the upper SoC limit of EV LIBs is commonly limited to ≈85%, but this limits the driving range and increases the cost of the batteries. Therefore, a holistic approach considering real-use behavior, as well as the properties of the material itself, is needed to overcome the limitations of Ni-rich cathodes.

Here, 1 mol% B doping of a core–shell concentration gradient (CSG) Li[Ni0.88Co0.10Al0.02]O2 cathode (CSG-NCA88) is shown to dramatically alter the microstructure of the cathode and effectively protect the particle interior from parasitic electrolyte attack. The B-doped CSG-NCA88 cathode, CSG-NCAB87, maintains its original microstructure even after holding for 500 h in the fully charged state, whereas irreversible structural damage occurs in the pristine CSG-NCA88 cathode during the prolonged electrolyte exposure. The long-term cycling results confirm that the capacity retention of the cathodes is determined by the electrolyte exposure time at a high SoC and that microstructural modification can effectively suppress the time-dependent degradation from electrolyte attack. The proposed CSG-NCAB87 cathode can be utilized at full capacity without restricting the SoC, thus realizing the development of economical high-energy-density LIBs.

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

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

[3] H.-H. Ryu, G.-T. Park, C. S. Yoon, Y.-K. Sun, Small, 2018, 14, 1803179.
Study on the Structural Degradation of the Polyaniline(PANi) Coated LiNi0.90Co0.85Mn0.15o Particles
Authors: Yoon Yeowon , Shin Seoyoon , Shin Moo Whan
Published: November 2022

The nickel content of the layered lithium transition metal oxide cathodes is proportional to the discharge capacity of energy storage systems. Ni2+ ion, the oxidation state of Ni, moves to the Li sites when Li+ ion is deintercalated during discharge process due to the similar size of ion (Ni2+: 0.069 nm, Li+: 0.076 nm). The spatial transition of Ni2+ ion causes gradual cation mixing and structure degradation of cathode, resulting in the failure of the battery. Also, thick cathode-electrolyte interphase (CEI) is formed on the cathode surface because of the transition metal dissolution, the degradation of electrolyte, and the residual gas such as H2O and CO2.

Coating technology is one of the strategies for the physical protection of the cathode surface and the control of CEI layer thickness. Polyaniline(PANi) is a conductive polymer with stable oxidation state. PANi can enhance the electrochemical property and structural stability as a protective layer. In this study, we synthesized PANi material by the oxidative polymereization and coated NCM with the synthesized PANi by sonication method.

The PANi-coated NCM(PANi@NCM) has uniform coating layer with 5 nm thickness. PANi@NCM exhibits an initial discharge capacity of 208 mAhg-1 and a capacity retention of 81% after 50 cycles at 45 oC in Figure 1(a) and (b). After the cycling test, pristine and coated cathodes were disassembled for the comparison of the microstructure. Pristine NCM only shows the structural transition from layered structure to structure in the XRD pattern of Figure 1(c). Cross-sectional SEM image of the pristine NCM after cycling test shows micro and macro cracks are distributed from the bulk to the surface of the cathode as shown in Figure 1(d). On the other side, cracks are barely observed on the PANi@NCM particles in Figure 1(e). The layered structure of PANi@NCM is maintained even after cycling test, which are confirmed by TEM analysis with FFT patterns and HAADF images. Figure (f) and (g) show the FFT pattern of the two cathode surfaces after cycling test. Mixed phase is observed on the pristine cathode surface, while the layered structure is maintained on the PANi@NCM surface. Also, the PANi@NCM maintains a thinner passivation layer compared with that of the pristine NCM (6 nm vs 35 nm). In conclusion, the PANi coating layer prevents the degradation of structure and the formation of thick CEI layer. The structural stability enhances the electrochemical performance.

Figure 1