bluuebunny/crossref_metadata_2025 huggingface dataset:
Voltammetric Study of Phase Separating Anode Materials in Li-Ion Battery Using Phase Field Model
Authors: Hussain Umair , Swaminathan Narasimhan , Phanikumar Gandham
Published: August 2024

The increasing demand for higher energy capacity in lithium-ion batteries has underscored the significance of modeling lithiation with alternative electrode materials, such as silicon (Si) and tin (Sn). This research addresses the need for comprehensive insights into the (dis)charging process, particularly focusing on the intricate phase transformations in the anode. Phase-field modeling has proven effective in capturing these transformations [2], revealing volumetric deformations of up to 300% during (dis)charging cycles [1]. Unfortunately, these deformations compromise material integrity, leading to reduced battery cycle life and reliability.

To address these challenges, our work presents a novel framework for modeling lithiation in materials exhibiting two-phase diffusion using phase field modeling. Unlike previous models limited to single-phase diffusion, our framework provides a more realistic representation of the diffusion process. This realism is achieved by incorporating the time-dependent voltage applied to the anode, a crucial factor in understanding the electrochemical response during lithiation [3].

Furthermore, we leverage the currents generated during the lithiation and delithiation processes to conduct a comprehensive voltammetric study. This study goes beyond existing research by considering the impact of phase separation on the currents developed during Li-ion battery operation. Our findings aim to contribute valuable insights into optimizing battery performance and addressing challenges associated with phase transformations, ultimately advancing the development of high-capacity anodes for lithium-ion batteries.

REFERENCES

[1] McDowell M. T., Lee S. W., Nix W. D., Cui Y. 25th Anniversary Article: Understanding the Lithiation of Silicon and Other Alloying Anodes for Lithium-Ion Batteries. Adv. Mater., Vol. 25 (36), pp. 4966–4985, 2013.

[2] Chen L., Fan F., Hong L., Chen J., Ji Y. Z., Zhang S. L., Zhu T., Chen L. Q. A Phase-Field Model Coupled with Large Elasto-Plastic Deformation: Application to Lithiated Silicon Electrodes. J. Electrochem. Soc., Vol. 161 (11), pp. F3164–F3172, 2014.

[3] Swaminathan, N., Balakrishnan, S., & George, K. Elasticity and Size Effects on the Electrochemical Response of a Graphite, Li-Ion Battery Electrode Particle. Journal of The Electrochemical Society, 163(3), A488–A498, 2016.

Figure 1
Designing High Stability Fluorinated Materials to Replace Carbonate Additives in Li-Ion Batteries Under Extreme Test Conditions
Authors: Usrey Monica Lee , Du Peng , Johnson Tobias , Kerber Brian M , Zhou Liu (Amy) , Guillot Sarah Lucienne , Homa Arthur , Sriramulu Suresh
Published: August 2024

Graphite-based Li-ion batteries require the formation of a solid electrolyte interphase (SEI) on the surface of the anode to prevent solvent co-intercalation and graphite exfoliation. Materials such as vinylene carbonate (VC) and fluoroethylene carbonate (FEC) that have been successfully deployed as SEI layer forming additives show limited utility under high voltage and high temperature conditions due to low electrochemical and/or thermal stability.1-3 Development of Li-ion batteries that meet the needs of automotive and other electrification applications require advanced electrolyte additives that can support operation under extreme conditions.

Koura has developed fluorinated additives that demonstrate improved stability and performance over conventional SEI layer forming additives under the high temperature and high voltage conditions relevant to the automotive industry. In this study, the performance of Koura’s fluorinated additives was compared to common commercial additives in the multiple cell designs, including 4.3V Gr/NMC811, to identify candidates to replace VC and FEC. Testing included 45°C cycling and 60°C storage. It has been found that these materials reduce gassing and increase capacity retention during high-temperature battery operation.

To gain a fundamental understanding of how these molecules function in the battery, including mechanisms of solvation, interfacial behavior, and bulk reactivity; and how the structure of the molecule contributes to its properties and behavior, comprehensive post-test analysis was conducted, including gas composition analysis and quantification via gas chromatography, bulk electrolyte composition analysis via NMR spectroscopy, and surface layer characterization via XPS and SEM. Also, performance of multiple structural variants was examined to develop a structure-property relationship to guide rational design of additives for advanced Li-ion batteries.

This presentation will summarize Koura’s efforts to supply advanced fluorinated materials for Li-ion batteries that satisfy the arduous demands of current and future applications. Specifically, we will present data showing the capability of fluorinated Koura materials to replace and/or enable existing Li-ion additives under extreme operating conditions, specifically high temperature and/or voltage. Multiple structures will be compared, where appropriate, to highlight our fundamental understanding of the structure-property relationships critical to designing next generation materials.

References:

Tobias Teufl et al 2023 J. Electrochem. Soc. 170 020531

Daniel Pritzl et al 2017 J. Electrochem. Soc. 164 A2625

Hiroshi Haruna et al 2017 J. Electrochem. Soc. 164 A6278
Addressing the Key Challenges of Lithium-Sulfur Batteries: A Comprehensive Overview and Future Perspectives
Authors: Gedif Elmineh Tsegahun
Published: August 2024

Introduction: Lithium-sulfur (Li-S) batteries represent a pioneering technology with the potential to revolutionize energy storage due to their high theoretical energy density and cost-effectiveness. Nevertheless, their practical implementation encounters various challenges, hindering widespread commercialization. This abstract aims to explore the critical hurdles facing Li-S batteries and proposes strategies to advance their development into a sustainable and efficient energy storage solution. The primary obstacles for Li-S batteries encompass issues related to the polysulfide shuttle effect, sulfur's poor conductivity, limited cycle life, and significant volume changes during charge-discharge cycles. Moreover, achieving stable and efficient sulfur cathodes and electrolytes remains a crucial concern for ensuring prolonged battery performance. This review focuses on a range of strategies and innovations addressing these challenges, including advanced material design, conductive additives, novel electrolytes, and modified separator designs, all aimed at enhancing electrochemical performance. Advanced techniques such as computational modeling and machine learning play a pivotal role in accelerating the discovery and optimization of materials and architectures for Li-S batteries. These methodologies enable precise prediction, design, and evaluation of materials, expediting breakthroughs in overcoming limitations. The future of Li-S batteries relies on multidisciplinary research encompassing material science, electrochemistry, engineering, and computational methodologies.

Keywords: Li – S batteries, Energy density, Cycle life, electrolyte design, cost-effectiveness
(Invited) Microwave-Assisted Synthesis and Characterization of Doped Ge Nanocrystals
Authors: Kauzlarich Susan M.
Published: August 2024

Ge is one of the quintessential semiconductors being considered in nanoform for optoelectronic applications. As a group 14 semiconductor, bulk Ge has a small bandgap and a large Bohr exciton radius, making it an attractive semiconductor for various applications, including solar cell technology, photodetectors, and integrated flash memory devices. I will present our work on doped and alloyed Ge nanoparticles via microwave-assisted synthesis and galvanic replacement. I will present new insights from this chemical route that may impact the nanoparticle synthesis of other covalently bonding semiconductors.
(Invited) Silicon Nanocrystals and Electrum Nanoclusters with High Quantum Yield for Light Converting Applications
Authors: Sychugov Ilya
Published: August 2024

While QDs are typically made of semiconductors, metals at low dimensions also turn to discrete electronic structure. The characteristic transition size from bulk to nanodot is lower, because Fermi level position is at the band middle, while discretization of levels starts from the band edge. Therefore, only for sizes of a metal entity ~ 1 nm a QD-like behavior manifests.

Here we show that metal nanoclusters Au16Ag7 of an electrum alloy (gold-silver) with adamantanethiolate ligands possess PL quantum yield of ~ 70% in a thiol-ene polymer matrix [1]. PL is in NIR range with a large Stokes shift. Due to parity-forbidden transition the PL lifetime is in microseconds. These characteristics are similar to silicon QDs, where optical transition is also partly forbidden. Luminescence from Si QDs (5-10 nm size) may also feature high quantum efficiency when a defect-free core with good surface passivation is prepared. We have demonstrated a new synthesis method, which can reduce precursor cost by an order of magnitude from the established HSQ-based technique [2]. Si QDs prepared in this way have near-unity internal and > 50% external (quantum yield) efficiency with a large Stokes shift. In both nanomaterials the re-absorption is suppressed, which is of value for several applications.

One such application is a semi-transparent photovoltaics for glazing in building-integration. It is based on a luminescent solar concentrator concept, where high efficiency and a large Stokes shift are necessary requirements for nanophosphors. In this configuration absorbed solar light is re-emitted and a large fraction of it is guided by total internal reflection to the edges for collection by standard solar cells. As a proof-of-concept we fabricated 20x20 cm2 prototypes, where Si QD-doped polymer layer is sandwiched between glass plates in a triplex geometry. Such “solar windows” feature high transparency (>80%), low haze (<3%), high color rendering index (~ 88) and, at the same time, deliver up to 0.6 W of electrical peak power under one sun [3]. Original measurement techniques were developed to characterize large-area devices [4,5].

References

[1] M. Jash, X. Lu, J. Zhou, and I. Sychugov, "Electrum Nanoclusters in Polymer Composites with Quantum Yield Exceeding 70%" submitted (2024).

[2]J. Zhou, J. Huang, H. Chen, A. Samanta, J. Linnros, Z. Yang, and I. Sychugov, "Low-Cost Synthesis of Silicon Quantum Dots with Near-unity Internal Quantum Efficiency" J. Phys. Chem. Lett. 12, 8909−8916 (2021).

[3] J. Huang, J. Zhou, E. Jungstedt, A. Samanta, J. Linnros, L. Berglund, and I. Sychugov, "Large-area Transparent “Quantum Dots Glass” for Building Integrated Photovoltaics" ACS Photonics 9, 2499 (2022).

[4] J. Zhou, J. Huang, and l. Sychugov, "Optical Center of a Luminescent Solar Concentrator" Opt. Lett. 47, 4985 (2022).

[5] X. Lu, J. Zhou, M. Jash, and I. Sychugov, "Luminescence Solar Concentrator Efficiency versus Edge Solar Cell Coverage" Opt. Lett. 48, 4197 (2023).
(Keynote) Light Driven H2 Generation in Pt-Tipped CdS Nanorods: Dependence on the Pt Size and CdS Rod Length
Authors: Lian Tianquan
Published: August 2024

Colloidal quantum confined semiconductor-metal nano-heterostructures are a promising class of photocatalysts for solar energy conversion. In these photocatalysts, the semiconductor domain serves as the light absorber and the metal as the catalyst. Such photocatalysts combine the superior light absorption and charge transport properties of the semiconductor with the superior catalytic activity and selectivity of the metal. Furthermore, both domains can be independently tuned to enhance the photocatalytic performance of the heterostructure. Among various semiconductor/metal heterostructures, metal-tipped colloidal semiconductor nanorods have attracted extensive interest because they have been reported to have high quantum efficiencies of light driven H2 generation and their morphology can be systematically tuned. The overall light driven H2 generation process involves multiple elementary charge separation and recombination steps in the semiconductor and across the semiconductor/metal interface as well as proton-coupled electron transfer reactions at the catalytic center. The change of the semiconductor or metal domains can often have effects on multiple competing processes involved in the overall reaction. As a result of these complexities, the mechanisms for the morphological dependence of the observed H2 generation efficiencies are not fully understood, hindering the rational design of these photocatalysts. In this talk, we use Pt tipped CdS nanorods (CdS-Pt) as a model system to examine the effect of Pt size and CdS rod length on their light driven H2 generation efficiency. We show that increasing the Pt particle size increases the overall H2 generation quantum efficiency through both increasing the rate of electron transfer from the CdS to Pt and enhancing the efficiency of water/proton reduction; H2 generation efficiency increases at longer CdS rod length by suppression of charge recombination across the Pt/CdS interface. Furthermore, because of rapid trapping of valence band holes, multi-exciton states in CdS nanorods can be long lived, enabling efficient multi-electron transfer to the Pt. Our work demonstrates that through systematic in situ study of elementary processes involved in the overall H2 generation, it is possible to rationally design and improve semiconductor-metal hybrid photocatalysts.
(Invited) Electrochemistry of CdSe Quantum Dots in Organic Solvents. from Stochastic Electrochemistry to Film Behavior
Authors: Alpuche-Aviles Mario A. , Corona-Elizarraras Luis
Published: August 2024

We present our electrochemistry results of CdSe quantum dots in two organic solvents: neat methanol and acetonitrile. In MeOH, the quantum dots (QDs) can be detected through stochastic collisions; that is, as agglomerates of QDs collide with an electrode surface, the photocurrent changes as a result of the CdSe entities that collide with the electrode surface.1 The experiment presented here uses Pt ultramicroelectrodes (UME), that is, electrodes with a diameter of 25 μm or less. Our results show that the CdSe can accumulate on the surface of the electrode, and the technique provides a high degree of control. By controlling the time the electrode collects QDs, one can control the amount of CdSe that accumulates at the electrode surface. After collecting CdSe on the surface, we perform cyclic voltammetry experiments to confirm that the electrode surface has changed. In acetonitrile (MeCN), we can perform CVs over large potential windows to study the electrochemistry of the deposited CdSe. The electrochemical response of the deposited CdSe resembles that of a film, although the surface has sub-monolayer coverages, as will be discussed from the images of scanning electron microscopy (SEM).

Figure 1 shows an example of a LSV in a region of interest where the current due to the CdSe significantly deviates from the background current. The LSV was run in the dark, so the current in the figure is a function of the density of states in the CdSe structures. It is also a function of the reversibility of the CV, i.e., mainly of the scan rate of the experiment. After the CV experiments, the Pt UME can be imaged in the SEM to correlate the electrochemical results with the CdSe deposited on the electrode surface. We will discuss our findings in terms of the results in the literature on CdSe electrochemistry (e.g., refs 2-5).

References.

(1) Subedi, P.; Parajuli, S.; Alpuche-Aviles, M. A., "Single Entity Behavior of CdSe Quantum Dot Aggregates During Photoelectrochemical Detection", Frontiers in Chemistry
9 (2021) DOI: 10.3389/fchem.2021.733642

(2) Kohl, P. A.; Bard, A. J., "Semiconductor electrodes. 13. Characterization and behavior of n-type zinc oxide, cadmium sulfide, and gallium phosphide electrodes in acetonitrile solutions", Journal of the American Chemical Society
99, 7531-7539 (1977) DOI: 10.1021/ja00465a023

(3) Hines, M. A.; Guyot-Sionnest, P., "Synthesis and characterization of strongly luminescing ZnS-capped CdSe nanocrystals", The Journal of Physical Chemistry
100, 468-471 (1996) DOI: 10.1021/jp9530562

(4) Zhang, J. Z., "Interfacial Charge Carrier Dynamics of Colloidal Semiconductor Nanoparticles", The Journal of Physical Chemistry B
104, 7239-7253 (2000) DOI: 10.1021/jp000594s

(5) Myung, N.; Ding, Z.; Bard, A. J., "Electrogenerated chemiluminescence of CdSe nanocrystals", Nano Letters
2, 1315-1319 (2002)

Figure 1
In Situ TEM Transformations of Colloidal Inorganic Nanocrystals and Their Surfaces
Authors: Reifsnyder Hickey Danielle
Published: August 2024

Nanocrystals are intriguing because their properties deviate from those of their bulk counterparts and are tunable with factors such as size and shape. Due to nanocrystals’ high surface area-to-volume ratios, their surfaces play a very important role in defining their physical properties, stability, and functionality. This can have important implications for many applications, including catalysis, photovoltaics, and plasmonics. Although colloidal inorganic nanocrystals are typically synthesized using long-chain, insulating organic ligands, many strategies have been explored to exchange the surface molecules into chemistries that enable conductivity between nanocrystals in close-packed films, affect the photoluminescence quantum yield, or enhance solution processability. This presentation will explore nanocrystals under in situ stimuli, including how their morphologies transform and the critical role of surface atoms, with the goal of making connections between their atomic structures and the resulting physical properties.
Stability in Photoluminescence and Photovoltaic Properties of Formamidinium Lead Iodide Quantum Dots
Authors: Svrcek Vladimir , Alessi Bruno , McDonald Calum , Mariotti Davide , Matsui Takuya
Published: August 2024

Formamidinium lead iodide (FAPI) thin films in the perovskite crystalline phase have piqued interest for single-junction solar cells due to their optimal bandgap, long photocarrier lifetime, and intrinsic structural stability. However, trap states on the surface and within the lattice impede the performance and stability of FAPI bulk crystalline film cells. Strategies such as film crystallization, deposition optimization, precursor engineering, and interface property tailoring aim to overcome these limitations. One approach involves forming FAPI quantum dots (QDs). By reducing the size, we achieve better quality and stable alpha-phase FAPI on a nanometer scale. In this contribution, we report synthesizing of alpha-phase FAPI QDs with a mean size distribution of 20 nm. These QDs exhibit a narrow photoluminescence emission peak at 1.61 eV and higher absolute quantum yields ranging from 70% to 86%. Compared to bulk FAPI with a 1.54 eV gap, a blue shift is observed due to the quantum confinement effect.

However, achieving degradation-free perovskite solar cells under prolonged light soaking remains a challenge. Furthermore, we investigate the stability of FAPI bulk and QDS films in a humid chamber and after exposure to AM1.5G light in a humid setting (RH ~ 30%, T ~ 28°C). Our approach allows us to form homogeneously dispersed films of quantum dots with thicknesses of several hundred nanometers. These films are studied for photoluminescence and photovoltaic properties. Prototype solar cells incorporating synthesized FAPI QDs showed a power conversion efficiency of around 8%. These findings indicate considerably more stability in photoluminescence and photovoltaic properties of FAPI QDs for enhanced light-soaking stability compared to bulk FAPI films.
Insights into Battery Thermal Runaway Reactions Via in Situ gas Analysis during Heating
Authors: Wiebenga Michelle , Yadav Vamakshi , Wang Lei
Published: August 2024

In order to prevent and mitigate lithium-ion battery thermal runaway, a better understanding of the chemical reactions responsible is needed. Here, we present an in situ method to quantitatively analyze gaseous products generated within lithium-ion battery cells during controlled heating. This laboratory-scale testing allows for cost- and time- effective evaluation of cell chemistries at early stages in the material development process. The findings combined with other techniques such as differential scanning calorimetry and temperature programmed decomposition provide insights into the reactions occurring in the lead-up to thermal runaway and provide a new method to assess thermal runaway propensity of lithium-ion battery cells as a function of chemistry (i.e., cathode, electrolyte) and state of charge.
Electrolytes with Controlled Polysulfide Insolvability for Lithium-Sulfur Batteries
Authors: Kautz David J. , Xu Wu
Published: August 2024

With the rise in manufacturing and commercialization of electric vehicles and home-scale integrated battery systems, low cost and high energy batteries are imperative for meeting the demand of the near-future energy requirements. Lithium-sulfur (Li-S) battery is widely known as a promising candidate for next-generation batteries due to its high theoretical specific energy (2600 Wh kg-1), abundance in material, and potentially low cost. However, there are many challenges unique to Li-S battery chemistries that impede the practical implementation of Li-S batteries. The foremost known challenge is inhibiting the shuttling effect of polysulfide (PS) species, Li2Sn (2 < n ≤ 8) that occurs during the discharge of the elemental S and the charge of the discharged product Li2S on the S cathode. The formed PS species can migrate from the S cathode to the Li metal anode and react with the Li resulting in loss of active materials and insulation of Li anode, and consequently reduced battery performance and cycle life. Managing the mechanism of PS formation and dissolution is paramount to developing a sustainable Li-S battery. Electrolyte formulation is a key strategy in overcoming the hurdles of Li-S batteries and controlling the degree of PS dissolution. Ether-based electrolytes are promising candidates due to their well-known compatibility with Li metal and their varying degrees of PS solvation and dissolution. This work focuses on designing electrolytes that optimizes the degree of PS dissolution and improving electrode-electrolyte compatibility with the elemental S cathode and the Li metal anode to enhance the cell stability and enable long-term cyclability. A series of electrolytes that have a more controlled degree of PS formation and solvability are developed to improve compatibility of the Li-S battery and enable superior cyclability.
Designing Better Li Metal Anodes for Next-Generation Batteries
Authors: Wood Marissa , Xiao Yiran , Freyman Megan C. , Wang Bo , Zhu Cheng , Li Sichi
Published: August 2024

Li metal batteries have the potential to significantly advance battery technology due to their substantially higher energy densities. However, robust high-capacity Li metal anodes are necessary to realize this approach, and current Li metal anode designs suffer from significant degradation over time due to non-uniform Li plating/stripping during cycling, which can lead to dead Li and/or Li dendrite growth. Carbon scaffold hosts can help mitigate this problem by creating a uniform electric field and providing abundant Li nucleation sites, but the relationship between the host architecture and performance is not well understood. We investigated the effect of scaffold architecture and chemistry on the resulting Li morphology and electrochemical performance using a combined experiment/theory approach. Carbon scaffolds with well-controlled geometries and varied porosities were fabricated using 3D printing and then characterized by SEM, Raman, and XPS before cycling in cells to evaluate their performance as hosts for uniform Li plating/stripping with both liquid and solid electrolytes. Atomistic and mesoscale modeling were used to predict how scaffold chemistry and microstructure affect Li nucleation probability and the formation of current density/stress hotspots that can lead to dendrite growth, and these results were used to help guide scaffold design. This work provides further insight into the relationship between anode architecture and Li metal cycling stability, which will facilitate the development of high-energy-density batteries in the future.

Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy, National Nuclear Security Administration under Contract DE-AC52-07NA27344.
(Invited) Plasma Reforming of Liquid Hydrocarbons
Authors: Lim Norleakvisoth , Gordon Michael J.
Published: August 2024

Engineering systems that more sustainably use our natural resources is central to both reducing the risks associated with CO2 emissions and making the long-term transition to a more circular, sustainable, and electrified economy. In particular, developing electrically driven technologies to leverage the energy density of liquids to produce clean fuels, e.g., H2, without making CO2, could be game changing. Here, we investigate the potential of directly exciting plasmas in liquid hydrocarbons to create multi-phase reaction environments, i.e., environments where plasma (ionized gas), H2, gaseous and liquid hydrocarbons, and solid carbon are all present simultaneously, to produce H2, unsaturated C2s, and carbon. The ultimate target is direct transformation of liquid hydrocarbons to gaseous H2 and solid, easy-to-separate carbon using electricity that can be provided from any source and/or points of use.

This talk will focus on our recent experiments to strike and sustain low and high frequency plasma discharges in liquid hydrocarbon jets to simultaneously generate gaseous H2, C2s, and solid carbon at high rates. Preliminary experiments show that (i) input energy is not wasted in simply vaporizing the liquid - so the system’s specific energy input preferentially drives hydrocarbon cracking; (ii) discharge drive frequency and plasma space time have a big effect on the H2 specific energy requirement (SER) and H2 generation rate, respectively; (iii) feedstock chemistry affects the H2 and C2 products observed; (iv) carbon particulates rapidly form in the liquid hydrocarbon, but they can be separated easily; and (v) the SER for H2 production is 25-30 kWhr/kg, roughly two times less than water electrolysis in practice (60 kWhr/kg). Hydrocarbon conversion, reaction rates, and characterization of the plasma (OES, high speed imaging), gas (MS), liquid (GC/MS), and solid phase (SEM, Raman) products as a function of plasma operating conditions (high and low AC drive frequency; liquid-plasma contact time) and hydrocarbon source will be discussed.
Insights Toward Thermal Stability and Electrolyte Distribution: A Hybrid Metrology Approach
Authors: Barnes Austin
Published: August 2024

Gas evolution in Li and Na ion batteries is a key problem as it is a sign of electrode degradation and electrolyte reduction. Gas evolution is caused by breakdown of electrolyte solvents and can release flammable gases leading to thermal runaway. As new and more stable electrodes, electrolyte, or electrolyte additives are implemented, it is crucial to monitor their performance and ensure thermal safety. Covalent Metrology is an analytical service lab based in Sunnyvale CA that serves as an extension of your battery R&D team. First, I will describe Covalent Metrology’s expertise, capabilities, and flexible workflows. I will then highlight some well-established analytical methods, such as GCMS and NMR to characterize volatile and non-volatile breakdown products of the electrolyte. Lastly, I will discuss the use of Scanning Acoustic Microscopy (SAM) and Glow Discharge Optical Emission Spectroscopy (GD-OES) to investigate the spatial distribution of electrolyte in a battery. We believe this hybrid metrology approach can provide important feedback toward developing better batteries more safely.
Additive Manufacturing of Architected Battery Components for Fast Charging Batteries
Authors: Orhan Asya , Ye Jianchao
Published: August 2024

Fast charging batteries require facile Li+ ion transport through the porous electrodes. Tape casted electrodes typically demonstrate sluggish ion transport with the increase of layer thickness due to the limited porosity and high tortuosity. Architecting the electrodes to introduce fast ion transport highways is a promising strategy to enhance the power density with limited sacrifice of energy density. In this work, we report our recent efforts in additive manufacturing (AM) of architected electrodes and separators. Two AM techniques are employed for the fabrication of electrodes and separators, including direct ink writing and projection micro stereolithography, respectively. A variety of geometries are designed, fabricated, and compared for the fast charging capabilities. The results show that proper design of the cell configuration and choice of material chemistry are critical to show the benefits from AM. The limitations, and future directions of AM application in batteries will also be discussed.
Structural Modification Strategy for Enhancing Electrochemical Performance of Electrodes Under High Current Cycling and First Principle Computational Research for Electrode Materials
Authors: Song Seunghyun , Kim Jihyun , Vallem Sowjanya , LI Man , Cheng Xiong , Bae Joonho
Published: August 2024

Recently, there has been significant interest in advancing lithium-ion battery technology due to its widespread use in various applications. Our research delves into this domain, focusing on enhancing the electrochemical properties of batteries through structural modification of electrode materials. Our work demonstrates the significant enhancements of electrochemical performance under high current cycling using structurally modified electrode materials . In first work, crumpled graphene oxide anode proves to be an effective strategy for enhancing its electrochemical properties, attributed to its advantageous crumpled morphology. This morphology allows for improved electrode stability and easier access for lithium ions, enabling them to interact with its larger specific surface area. In second work, we describe enhanced the drawback of reduced electrochemical performance during high-rate cycles by synthesizing multidimensional LFP-based carbon composite. The lithium ion diffusivity and electrode stability of the prepared composite are significantly improved in charging and discharging cycles by introducing graphene quantum dots alongside CNTs, exhibiting superior electrochemical properties even at high current densities. In third work, density functional theory simulation is employed for demonstrating the enhanced electrochemical properties of prepared electrodes by exploring their properties. Our research provides insights into electrode material design as an effective approach to enhancing the electrochemical properties of lithium-ion batteries.

Acknowledgement:

This work was supported by the National Research Foundation of Korea (NRF-2021R1A2C1008272). This work was supported by Ministry of Trade, Industry and Energy, KEIT, under the project title

"International standard development of evaluation methods for nano-carbon-based high-performance supercapacitors for electric vehicles" (project # 20016144).
Intergranular Shielding of Ultrafine-Grained Ni-Rich Layered Cathode for Advanced Lithium-Ion Batteries
Authors: Park Geon-Tae , Ryu Ji-Hyun , Sun Yang-Kook
Published: August 2024

To achieve carbon neutrality on a global scale, fuel-powered vehicles are being steadily phased out over environmentally recommended electrified vehicles (EVs) with low greenhouse gas emissions. In a battery, the cathode is among the foremost components, as it predominantly determines the LIB’s performance and price. However, since current fleet of layered oxide NCM and NCA cathodes have a relatively lower Ni content, they can extract only a limited amount of reversible capacity (210 mAh∙g-1), restricting the driving range of EVs. To achieve higher energy densities, many studies have focused on increasing the average fraction of Ni in NCM or NCA cathodes to more than 90%. However, the extraction of large amounts of lithium ions is seriously compromised by the rapid deterioration of both cycle life and thermal safety. Recent studies on X-doped cathodes (X = B, Nb, Ta, Sb, W, and Mo) have offered promising results by engineering their geometric microstructural configurations to suppress intergranular cracking.1,2 This approach has proven its potential to improve the electrochemical cycling performance of Ni-rich NCA, NCM(A), and NM cathodes. However, prolonged exposure of the Ni-enriched (Ni ≥ 95%) cathode to the electrolyte generally results in continuous oxidative decomposition of electrolytes and subsequent cathode structural transformation, rendering the cathode unsuitable for applications requiring long battery life.3 Herein, we propose a highly stabilized Ni-enriched (Ni ≥ 95%) layered cathode by adopting a multi-stage engineering strategy, i.e., the construction of an ultrafine-scaled microstructure and subsequent intergranular shielding of the refined grains. The formation of an F induced protective layer at the intergranular boundaries of the ultrafine grains in Li[Ni0.95Co0.04Mo0.01]O2 (denoted as Mo1-NC96) noticeably improved both the structural and chemical stability of the cathode, with a limited degree of structural degradation and gas evolution.

Reference
s
:

[1] U.-H. Kim, G.-T. Park, B.-K. Son, G.W. Nam, J. Liu, L.-Y. Kuo, P. Kaghazchi, C.S. Yoon, Y.-K. Sun, Nat. Energy, 5 (2020) 860-869.

[2] G.-T. Park, B. Namkoong, S.-B. Kim, J. Liu, C.S. Yoon, Y.-K. Sun, Nat. Energy, 7 (2022) 946-954.

[3] F. Kong, C. Liang, L. Wang, Y. Zheng, S. Perananthan, R.C. Longo, J.P. Ferraris, M. Kim, K. Cho, Adv. Energy Mater., 9 (2019) 1802586.
Charge-Sharing Based Stabilization of Nano-Porous Organic Electrode for Rechargeable Li-Ion Battery
Authors: Park Jihye , Gu Jun , Lee Dong Hwa , Shin Hosun , Lee Jung-Yong , Song Jae Yong
Published: August 2024

Organic-based lithium-ion batteries have garnered increasing attention due to their potential for cost-effectiveness, sustainability, and high energy density. Despite the promising theoretical prediction, the actual battery performance of organic-based electrodes has frequently fallen below the expected values. This discrepancy is primarily attributed to a low density of active sites, limited ion diffusivity, and high solubility to the electrolyte. This study introduces 5,10-dihydro-5,10-dimethylphenazine (DMPZ) as an organic active material, demonstrating superior electrochemical performance characterized by high capacity and prolonged cycle performance. To achieve a high capacity, a cryogenic milling is employed to create a porous nanostructure, enhancing the surface-to-volume ratio without altering the molecular structure. Consequently, the initial specific capacity of the porous DMPZ electrode reaches 184 mAh g-1 at 0.6 C, representing a remarkable 180% increase compared to non-milled DMPZ. To improve cycle stability, a charge-sharing reaction among organic active materials is facilitated by forming an organic nanocomposite comprising DMPZ and various n-type organic materials. The organic nanocomposite effectively mitigates the elution of organic active materials, ensuring unprecedented cycling stability with a capacity retention exceeding 90% over 500 cycles with initial specific capacity of 248 mAh g-1. C-rate tests at 1.2, 2, 4, and 8 C demonstrate outstanding rate capability, with an average capacity of 105 mAh g-1 at 8 C. The performance enhancement mechanism of the organic nanocomposite cathode is elucidated through experimental analyses, including ex-situ XPS, PiFM, and FTIR. These analyses collectively contribute to a comprehensive understanding of the mechanisms underlying the observed improvements in battery performance.
Energy Changing Paths for Li-Ion Batteries Under Nonequilibrium Process
Authors: Chen Hongjiang , Huang Hsiao-Ying Shadow
Published: August 2024

It has been discovered that the electrodes of Li-ion batteries have abnormal phase transition phenomena during nonequilibrium process. As a two-phase-coexistence material, LiFePO4 (LFP) shows single phase during both high-rate lithiation and delithiation. Furthermore, a far from equilibrium state results in LFP particles with meta-stable amorphous structures and layered oxides exhibiting two-phase-coexistence during high rate delithiation. It is well known that a stable single-phase structure is an important characteristic for the electrodes with better high-rate performance, since the energy barriers of nucleation and growth for new phases are eliminated. Understanding the mechanisms of the abnormal phase transition during nonequilibrium process is therefore essential for designing the electrodes with fast (dis)charging. In this work, we model the free energy of electrodes with a series of order parameters based on nonequilibrium thermodynamics and continuum mechanics. Developed governing equations for the kinetics of the order parameters reveal the mechanism of the abnormal phase transitions for LFP and layered oxides under high rate (de)lithiation. The generation of dislocations is cross-coupled with the chemical reaction of Li-ion on the surface of electrode particles. Such coupling is the origin of materials choosing various energy changing paths under different (dis)charging conditions and resulting in various lattice parameters and structures. The dislocation density is the key parameter for the path selection since it alters dislocation-induced energy. In the simulations for LFP and layered oxides, the changes of order parameters agree with the abnormal phase transition observed in existing experimental studies. Our study indicates a potential strategy of introducing dislocations with surface engineering for optimizing the (dis)charging path of electrode materials to obtain stable single-phase characteristics and promote the kinetic capability.
Simulation of Magnetic Separation of Metal Ions in Aqueous Electrolytes
Authors: Carlstedt Nicholas , Andrei Petru
Published: August 2024

The magnetic separation of metal ions provides an alternative solution to traditional separation techniques such as pyrometallurgy, hydrometallurgy, biometallurgy or electrodialysis. Compared to traditional techniques that either use large amounts of chemicals (usually inorganic acids combined with reducing agent), produce large amounts of sludge as solid waste, consume a large amount of energy, or are difficult to separate ions of different charges [1], the magnetic separation of the metal ions can separate ions based on their magnetic susceptibility. This method is environmentally friendly [2] and consumes a small amount of energy (particularly when the system is designed using permanent magnets instead of electromagnets). The goal of this presentation is twofold. First, we derive the set of transport equations that need to be used to simulate the magnetic separation of metal ions in aqueous solutions. Then, we use these transport equations to simulate the magnetic separation process in various magnetic systems and predict the efficiency of magnetic separation of different systems.

The mathematical model developed here is based on coupling the three-dimensional Navier-Stokes equations for flow transport with the drift (migration)-diffusion equations of ion transport [3] in the presence of magnetic field gradients. Both the drift-diffusion model and the Navier-Stokes equations include the magnetic force term as an additional driving force. By solving the entire system of equations self-consistently we analyze the effect of the diffusivity, concentration gradients, magnetic field gradients and fluid velocity over the capturing properties of the system. A detailed presentation of the mathematical model, underlying assumptions of the model, limiting cases, numerical implementation in three-dimensional structures, and simulations results will be presented at the meeting. In addition, we will present predictions for the magnetic separation of Li, Fe, Ni, Mn, and Co from the solution phase. Fortunately, these ions have significantly different magnetic susceptibility, which vary over more than 3 orders of magnitude, and which allows for the efficient extraction and separation of the elements from the solution and from each other.

References:

[1] K. H. Chan, M. Malik, and G. Azimi, “Separation of lithium, nickel, manganese, and cobalt from waste lithium-ion batteries using electrodialysis,” Resour. Conserv. Recycl., vol. 178, p. 106076, Mar. 2022, doi: 10.1016/j.resconrec.2021.106076.

[2] Z. Lei, B. Fritzsche, R. Salikhov, K. Schwarzenberger, O. Hellwig, and K. Eckert, “Magnetic Separation of Rare-Earth Ions: Property Database and Kelvin Force Distribution,” J. Phys. Chem. C, vol. 126, no. 4, pp. 2226–2233, Feb. 2022, doi: 10.1021/acs.jpcc.1c09748.

[3] J. Newman and K. Thomas-Alyea, Electrochemical Systems, 3rd Edition. John Wiley&Sons, 2004.
Optimization of Acetate-Based Electrochemical Baths for Electrochemical Deposition of High Purity Molybdenum
Authors: Stalcup Matt , Gayoso Veronica , Watkins Tylan S
Published: August 2024

Like other refractory metals, molybdenum (Mo) is particularly resilient in extreme environments. As a coating, Mo is desirable for use in corrosive, high-temperature, and high-abrasive environments. Current methods for applying Mo coatings are expensive and/or inadequate for the intended parts. Electrodeposition of Mo from NH4
+-containing electrolytes has been reported but the mechanism of deposition is not well known. Mo electrodeposition is achievable from high acetate-salt concentration electrolytes but are highly dependent on both pH and ammonium concentrations. We have investigated both parameters to determine what is the minimum concentration of ammonium required to achieve deposits and how the pH changes the oxygen incorporation in these films. This optimization has provided insight into the importance of available hydrogen to tune the oxygen content of the deposits.

Figure 1
Partial Applicability of Mixed Potential Theory in Unsteady Regime for Cu Electroless Deposition on Pt
Authors: Gyanprakash Maurya , Pala Raj Ganesh
Published: August 2024

Electroless deposition (ELD) has been practiced over many decades, but its underlying mechanism is incompletely understood. We explore the applicability of Mixed Potential Theory (MPT) in the unsteady regime during the electroless copper deposition (ELCD) on Pt surface pretreated by dipping Pt in SnCl2 and PdCl2. We demonstrate that ELCD occurs in the low and high potential zone (LPZ & HPZ) at two different reaction rates due to the under-potential deposition of Cu on pretreated Pt in LPZ. The Nyquist plot in HPZ shows one semicircle, while LPZ shows two semicircles. Single semicircle in HPZ suggests dependency only on catalytic potential available on the surface over which ELCD occurs. The two semicircles in LPZ indicate that besides the surface catalytic potential, the dependency is on the reaction intermediate of formaldehyde oxidation, limiting the relevance of MPT. MPT posits that reduction and oxidation in Cu ELD are independent of each other and the role of the surface is only in establishing the catalytic potential. To check the pertinence of MPT, we obtained the polarization resistance (RP) from the Nyquist plot of (a) ELCD solution, (b) CuSO4 with Tartrate and without Formaldehyde i.e. electrochemical copper deposition (ECCD). The RP so obtained shows a significant difference only in LPZ but not in HPZ because of which we argue that MPT is applicable only in the HPZ.
Manufacturing of Fe-Ni Composite Oxide Powder and Leaching Process Optimization Via Nickel Pig Iron(NPI) Raw Materials
Authors: Kim Myungsuk , Kim Hyun-Chul , Kim Jieun , Kim Dong-Hyun , Sim Jae Jin , Park Kyoung-Tae , Shin Jae Hong
Published: August 2024

The lithium-ion battery industry is experiencing rapid growth in response to the widespread adoption of electric vehicles, leading to a significant increase in demand for high-purity nickel compounds, a critical raw material. As a result, ensuring a smooth supply of nickel resources poses a critical challenge not only for the battery industry but also for enhancing the competitiveness of future clean energy industries. High-purity nickel production is predominantly carried out via the high-pressure acid leach (HPAL) process, which extracts nickel from nickel laterite ores. However, this process involves substantial initial capital investment and consumes significant energy due to high temperatures, high pressure, and strong acids. Additionally, this method is associated with environmental concerns such as water and soil pollution. Furthermore, an alternative approach is proposed, which involves adding sulfur to low-grade nickel pig iron (NPI) to produce the nickel matte, followed by an iron removal process to generate high-purity nickel sulfide. However, this method presents challenges such as waste generation from the iron removal process, high carbon emissions, and the production of large amounts of greenhouse gases. This study explored using anodic oxidation to induce oxidative reactions in NPI to nano-powder. This approach improves nickel recovery efficiency by increasing the surface area compared to the bulk state, allowing leaching at room temperature and atmospheric pressure. As a result, the process becomes simpler, with lower initial capital investment, making it economically viable. Additionally, the process requires less energy consumption, allowing for achieving the breakeven point at an earlier stage. This study compared the characteristics of the nano-powderized NPI under different voltage and current ranges. Furthermore, the nickel leaching efficiency was assessed based on leaching solution conditions.
(Invited) Oxide Semiconductor Gain Cell Memory
Authors: Chen Jian , Jana Koustav , Jiang Qi , Liu Shuhan , Toprasertpong Kasidit , Wong H.-S. Philip
Published: August 2024

The energy and delay consumed by the off-chip memory (DRAM) and memory-to-logic chip data movement becomes the bottleneck (known as the memory wall) for the computing systems nowadays, especially for abundant-data computing and neural network accelerators. Larger on-chip memory capacity with high bandwidth can be a solution, yet it is difficult to achieve using SRAM and DRAM. Oxide semiconductor FET (OSFET)-based gain cell memory on the logic platform provides higher density than SRAM due to 3D stacking and is an attractive complement to off-chip DRAM. OSFET with extremely low leakage is used as the write transistor for long retention time, while the read transistor can either adopt OSFET for multiple-layer stacking (OS-OS gain cell) or Si FET for higher read speed (Hybrid gain cell). Designing OSFET gain cell is more than simply choosing materials/device designs that have the lowest off-state leakage current for the longest retention time. Atomic Layer Deposition (ALD) Indium Tin Oxide (ITO) FET is chosen to balance retention time with memory bandwidth. With material, process, and device co-design, the ITO films deposited by ALD with TMIn precursor, 9:1 In:Sn cycle ratio, and 2nm thickness exhibited optimized characteristics for OSFET-based gain cell. The experimentally optimized device exhibits low off-current 2×10-18 A/µm, high on-current 26.8 µA/µm, low SS 70 mV/dec, and high mobility 27 cm2/Vs. It also shows good stability with small VTH shift < 0.2 V under 125 °C, low PBS shift < 0.35 V and low NBS shift < 0.1 V under 1000s bias stress. Oxide semiconductor transistors is an accumulation mode transistor that requires a gate electric field to turn off the transistor. The transistor design calls for nanometer-thin oxide semiconductor channels. Significant device design tradeoffs exists between high on-current, low off-current, short gate length scalability, and the setting of proper threshold voltages. This talk will give an overview of the above experimental achievements today and the device design considerations for future gain cell memories.