bluuebunny/crossref_metadata_2025 huggingface dataset:
(Keynote) Monodisperse Nanoparticles of Ternary Spinels for Electrochemical Energy Conversion and Storage
Authors: Robinson Richard D. , Rowell Jonathan L. , Meyer Talisi E.
Published: August 2024

Ternary spinel nanoparticles are an exciting materials system that have been increasingly pursued for a variety of energy applications such as supercapacitors and as electrocatalysts for the oxygen reduction reaction. For example, Cobalt-manganese spinel oxides, in particular, have demonstrated outstanding performance as supercapacitors and electrocatalysts.

Despite their exemplary performance in multiple electrochemical applications, there are few reports in the literature with high-quality ternary spinel nanoparticles, such as Co-Mn-O. Most reports show aggregated and polydisperse products that typically contain impurity phases like rock salt.

In this work, we demonstrate the synthesis of monodisperse nanoparticles of ternary spinels using colloidal chemistry. To overcome challenges for ternary spinel oxides we use oxidized amines as a route to form the high-oxidation state complexes needed for stable spinel oxides, and modify the ligand binding to obtain colloidally stable nanoparticles. For the sulfide spinel system, we show the use of amino acids as a low-cost sulfur source. Finally, we extend this work to access high entropy nanoparticles for electrochemical applications.
(Invited) Parameter Prediction in Colloidal Quantum Dot Solar Cells Using Residual Neural Networks Trained on Experimental Data
Authors: Lee Hoon Jeong , Chiu Arlene , Lin Yida , Chintapalli Sreyas , Kamal Serene , Thon Susanna Mitrani
Published: August 2024

Colloidal quantum dots (CQDs) are an attractive third-generation material for photovoltaics, especially as infrared materials for multi-junction solar cells. Characterization and materials parameter prediction both play a critical role in the rising efficiencies in this field. However, there are numerous materials properties that need to be measured in order to fully characterize a device, leading to high research costs and slow development times. Here, we leverage recent advancements in machine learning (ML), along with a recently-demonstrated multimodal spectral characterization method [1], to predict complex materials parameters in CQD solar cells from simple current density-voltage (JV) curves, using an algorithm trained on experimental data.[2]

Past work ML prediction of materials properties has focused on using simulated data due to the difficulty in collecting enough experimental data to fully train an algorithm. While it is not feasible to fabricate thousands of devices in a typical research lab, it is possible to measure several thousand points on a single device. We used a micrometer-resolution 2D characterization method with millimeter-scale field of view to acquire enough training data using only a handful of devices, while learning the spatial relationships between materials parameters. Photoluminescence, trap state density, transient photovoltage, transient photocurrent, and carrier mobility were predicted (Figure 1) by five different residual neural networks, each using a ResNet block and containing over 300k learnable parameters. The design of the networks were based on the ResNet50 architecture [3]. We also implemented a novel neighborhood approach to reduce errors and account for spatial correlations in device behavior, leading to insights into transport mechanisms and correlation lengths in CQD thin films. This method could be used to study a wide range of material systems and devices, ultimately leading to a universal prediction model that greatly simplifies the characterization process for optoelectronic devices and accelerates development times.

References

[1] Y. Lin, T. Gao, X. Pan, M. Kamenetska & S. M. Thon, Local Defects in Colloidal Quantum Dot Thin Films Measured via Spatially-Resolved Multi-Modal Optoelectronic Spectroscopy. Advanced Materials 32, 1906602 (2020).

[2] H. J. Lee, A. Hofelmann, Y. Lin, & S. M. Thon, Predicting Materials Parameters in Colloidal Quantum Dot Photovoltaic Devices Using Machine Learning Models Trained On Experimental Data. 2022 IEEE 49th Photovoltaic Specialists Conference, 0862-0866 (2022).

[3] O. Elharrouss, N. Almaadeed, S. Al-Maadeed, & Y. Akbari, Image inpainting: A review. Neural Processing Letters 51, 2007–2028 (2020).

Figure 1
(Invited) Evolution of the Solid Electrolyte Interphase in Si Nanoparticle Based Li-Ion Battery Anodes: Insights from Ab Initio Simulations of Core-Level Spectroscopies
Authors: Hernandez Bertran Michael , Molinari Elisa , Prezzi Deborah
Published: August 2024

Silicon nanoparticles (c-Si NPs) are considered promising candidates for the active material in Si-based anodes, offering high gravimetric capacity and helping to mitigate volume expansion effects. However, the formation of an unstable Solid Electrolyte Interphase (SEI) around the nanoparticles leads to increased irreversible lithium consumption, resulting in reduced capacity and poor cycling stability. In this context, core-level spectroscopies are established techniques to assess the evolution and composition of the SEI. While X-ray spectroscopies provide valuable insights into atomic and electronic structures, interpreting them in complex systems could be challenging, highlighting the need of theoretical insights from ab-initio approaches. Our study focuses on the changes occurring in c-Si NPs and the SEI during the initial charge cycle, leveraging post-mortem core-level spectra at various states of charge (SOC). We employ a multi-edge analysis coupled with a fitting approach based on known experimental references and theoretical simulations. Additionally, we demonstrate how comparing experimental spectra with theoretical references allows tracking changes at the NP level, including amorphization and surface oxidation. Finally, we discuss some of the limitations of our theoretical description and propose addressing them through machine learning approaches. This work is supported by the European Union’s Horizon 2020 research and innovation program (BIG-MAP, Grant No. 957189, also part of the BATTERY 2030+ initiative, Grant No. 957213).
(Invited) Extended Hubbard Functionals for Accurate Modeling of Li-Ion Battery Cathode Materials
Authors: Timrov Iurii
Published: August 2024

Designing novel cathode materials for Li-ion batteries necessitates accurate first-principles predictions of their properties. Density-functional theory (DFT) employing standard (semi-)local functionals encounters challenges due to pronounced self-interaction errors within the partially filled d shells of transition-metal (TM) elements. Here, we demonstrate the efficacy of DFT with extended Hubbard functionals in accurately predicting the "digital" change in oxidation states of TM ions for mixed-valence phases at intermediate Li concentrations in phospho-olivine and spinel cathode materials. The resulting voltages exhibit remarkable agreement with experimental data [1,2].

Our approach involves the use of onsite U and intersite V Hubbard parameters computed from density-functional perturbation theory with Lowdin-orthogonalized atomic orbitals, thus circumventing empirical factors [3,4]. Notably, the incorporation of intersite Hubbard V interactions proves indispensable for the precise prediction of thermodynamic quantities, particularly when electronic localization occurs amid inter-atomic orbital hybridization.

Extending our investigation to vibrational spectroscopy, we calculate Raman spectra for these materials and find very good agreement with available experimental data [5]. Leveraging the robust and accurate computational framework based on extended Hubbard functionals, we embark on a high-throughput screening of Li-containing compounds, aiming to unveil novel and promising candidates for cathodes [6]. Our findings underscore the pivotal role of advanced DFT methodologies in advancing the discovery and design of high-performance battery materials.

[1] I. Timrov, F. Aquilante, M. Cococcioni, N. Marzari, PRX Energy 1, 033003 (2022).

[2] I. Timrov, M. Kotiuga, N. Marzari, Phys. Chem. Chem. Phys. 25, 9061 (2023).

[3] I. Timrov, N. Marzari, M. Cococcioni, Phys. Rev. B 98, 045141 (2021).

[4] I. Timrov, N. Marzari, M. Cococcioni, Phys. Rev. B 103, 085127 (2018).

[5] L. Bastonero, N. Marzari, I. Timrov, in preparation.

[6] C. Malica, L. Bastonero, M. Bercx, N. Marzari, I. Timrov, in preparation.
(Invited) A Facile Three-Dimensional Lightweight Current Collector Strategy for High Energy Density Lithium Metal Batteries
Authors: Kim Ju-Myung , Jia Hao , Simmons Ashley , Zhang Yuepeng , Zhang Ji-Guang , Xu Wu
Published: August 2024

Despite the great achievement in the development of rechargeable lithium (Li) metal batteries (LMBs) with high energy densities, their practical application is still facing difficulties due to the intrinsic issues of Li metal anode (LMA) including high reactivity and dendritic Li formation which cause low Coulombic efficiency, constant loss of Li and electrolyte, and unstable solid electrolyte interphase (SEI) layer, etc. Additionally, from the structural point of view, LMA which consists of Li foil on the two-dimensional copper (Cu) current collector brings the formidable loss of the areal capacity that leads to less specific energy density since Cu is non-faradaic and one of the heavy metals. Further, the “hostless” feature of LMA induces more issues like volume expansion and limited utilization of Li. To address such issues, a metal-coated polymeric three-dimensional (3D) scaffold is designed here. In this study, Cu is selected as an electronic conductivity provider, and electrospun polyimide (PI) is chosen as a 3D scaffold because of its high thermal stability and good mechanical properties. Cu-coated PI (Cu@PI) was produced via a facile electroless process. Driven by the structural/material uniqueness, the developed 3D Cu@PI current collector enables a uniform/continuous Li-ion conduction pathway thus leading to dense Li deposition and enhancing the electrochemical performance of LMBs containing the electrochemically deposited Li on Cu@PI and the specific energy density due to the great reduction in substrate weight. We anticipate the suggested new strategy of 3D structured LMAs would lead to a facile route toward the high energy density LMBs beyond the conventional technologies.
Investigation of Dry-Made NMC 811 Electrodes with Varying Binder and the Conductive Agent Contents
Authors: Uzun Kubra , Alolaywi Haidar , Thapa Santosh , Cheng Yang-Tse
Published: August 2024

Lithium-ion battery electrode materials consist of active materials (AM), conductive agents, and binders. Although conductive agents and polymeric binders occupy a small portion of the electrode, they play an indispensable role. Conductive agents are needed to improve the electronic conductivity of the electrode, while binders ensure mechanical integrity by providing particle/particle cohesion and electrode-film/substrate adhesion. Optimizing the interactions of active materials, conductive agents, and binders is crucial for achieving the desired electrode performance and durability. Although multiple studies have explored the impact of electrode composition for slurry-based electrodes, it is still unclear how composition affects the electrodes made by dry processes. In this study, we performed a detailed investigation of the effects of the different electrode compositions by changing the ratio of polyvinylidene difluoride (PVDF) binder and carbon black (CB) for dry-made LiNi0.8Mn0.1Co0.1O2 (NMC 811) electrodes. The electrostatic spray deposition method was used as a dry electrode fabrication process due to its many advantages, such as reduced energy consumption and inexpensive processing requirements. We investigated electrodes of four different compositions, 96:3:1, 96:2:2, 90:7.5:2.5, and 90:5:5 (AM:PVDF: CB), corresponding to PVDF/CB mass ratios of 1:1 and 3:1.

We found that electrodes with a high PVDF/CB ratio of 3:1 have larger impedance than electrodes with a low PVDF/CB ratio of 1:1 due to the insulating aggregates of PVDF alone, causing deteriorated electrochemical performance. At the PVDF/CB ratio of 1:1, an even distribution of PVDF/CB on the AM particle surfaces and in the pores between the AM particles was observed. For both PVDF/CB ratios of 1:1 and 3:1, increasing the total amount of PVDF and CB (e.g., decreasing the AM amount) in the composite electrode enhanced both the C-rate and cycling performance. However, electrodes with the PVDF/CB ratio of 1:1 at high AM content (96%) still showed a comparable C-rate performance to that with lower AM content (90%). Thus, dry-made electrodes with high AM content can achieve a good high C-rate performance, especially for high-energy-density applications.

This study provides a better understanding of the effects of CB/PVDF, which is key to finding an optimal structure and composition of the dry-made electrodes.
(Invited) Carbon Sulfonation Using Plasma: Trial to Enlarge Treatment Capacity
Authors: Takeuchi Nozomi , Deng Siqi , Yao Kaixun , Takahashi Katsuyuki , Tachibana Kosuke , Hieda Junko , Li Oi Lun
Published: August 2024

Heterogeneous catalysis is a promising technology in conversion of biomass to biofuels because of its high reactivity, easy post-separation, and great recyclability compared to homogeneous catalysis. Various functionalized catalytic materials have emerged as promising alternatives to the homogeneous liquid acid catalyst, such as carbon materials, metal–organic frameworks, and metal nanoparticles. Among them, carbon materials such as carbon nanotube, graphene oxide, carbon black, and so on have been investigated as catalysts for cellulose hydrolysis to produce glucose.

Carbon materials show considerable catalytic activity by functionalization with active acidic groups including hydroxyl groups (-OH), carboxyl groups (-COOH), and sulfonic groups (-SO3H). Hydroxyl and carboxyl groups on the carbon catalysts act as connection center to access cellulose, where sulfonic group serves as the active site to cut off the linkage between glucose units in cellulose. So, the surface modification of carbon materials with these functional groups, namely, carbon sulfonation process, becomes the determining step to producing efficient carbon acid catalysts. Conventional methods for the carbon sulfonation are the hydrothermal and reflux method, in which hazardous chemicals are necessary, such as concentrated sulfuric acid (95–98%), chlorosulfonic acid, fuming sulfuric acid, or 4-benzenediazoniumsulfonate under elevated temperature for dozens of hours.

As a green and effective carbon sulfonation process, we have utilized plasma generated in contact with dilute sulfuric acid. Recently, we have investigated the mechanism of carbon sulfonation in GLIP processes. Active species produced near the gas–liquid interface such as •OH, SO3, and HOSO2• probably play important roles in carbon sulfonation. We are currently trying to enlarge the treatment capacity of carbon sulfonation by two methods, namely parallel plasma generation with ballast capacitors and large-area plasma generation by a dielectric barrier discharge. Also, effects of gases used for plasma generation such as air and Ar on the carbon sulfonation are investigated.

This work was partially supported by the Environment Research and Technology Development Fund (JPMEERF20223R01) of the Environmental Restoration and Conservation Agency of Japan.
(Invited) Numerical Simulation of an Atmospheric Pressure Streamer Discharge and Induced Chemical Reactions
Authors: Komuro Atsushi
Published: August 2024

Streamer discharges are a type of non-thermal plasma produced by high-voltage electrical discharges, and have great potential as highly reactive chemical reaction fields. This is mainly due to the generation of high energy electrons that produce chemically active species. The applications of non-thermal plasma have attracted considerable interest in a wide range of industries. However, each radical has a different role in the plasma application and their reaction mechanism is also different. It's therefore important to understand exactly when, where and how much of these reactive species are produced in order to improve the treatment efficiency of atmospheric pressure plasma applications. Against this background, the aim of this study is to develop a simulation model capable of accurately predicting the chemical reactions of radicals. With a sufficiently validated simulation model, it would be possible to use such a model to design chemical reaction fields.

The model consists of the first-order electrohydrodynamic model for electrons and positive and negative ions within the drift-diffusion approximation. Axis-symmetric coordinates were used to simulate the streamer discharge in air at atmospheric pressure. The electron transport and source parameters were calculated using two-term bltzmann equation and published electron impact cross-sections. The chemical reaction model used in this study includes electron impact collisions (excitation, ionisation, dissociation, recombination, attachment and detachment), ion recombination and the reactions of neutrals. In order to demonstrate the validity of the simulation, the light emission of the discharge is first compared between experiment and simulation. Then the spatial and temporal variations of each radical are simulated and compared with the simulation. In this talk, I will present the process of validation and verification (V&V) of the streamer discharge simulation and then the mechanism of radical production revealed by the simulation.
Enabling Fast Charging of High Loading Batteries Via Operando Microscopy Diagnosis of Lithium Plating Limits
Authors: Gopal Rajeev , Sittisomwong Poom , Bai Peng
Published: August 2024

While lithium-ion batteries have undergone substantial development, enabling their widespread adoption in consumer electronics, a critical need persists—achieving faster charging even at lower temperatures. This realization is hindered by lithium plating, which reduces capacity and cycle life.

A possible strategy involves engineering the electrolyte to improve the ionic transport across/into the graphitic anode. Based on recent studies and simulation results, the traditional carbonate-based electrolyte was replaced with a more promising ether-based electrolyte and tested in our specially designed operando capillary full cells. Here the axial lithiation of graphite could be monitored in real-time and lithium plating precisely correlated to the voltage response. Lithium-ion transport at the face of the electrode was further evaluated with our in-plane imaging setup. The demonstrated performance improvements were then investigated in larger high loading cells at different temperatures and cycling conditions.

Our results reveal significantly better charging characteristics for the ether-based electrolyte, not only showing better particle activation but also increasing the capacity (as much as 40%) before the onset of lithium plating. This prompts a compelling inquiry into the roles played by ether driven solid electrolyte interface (SEI) formation and possible co-intercalation processes. How might these mechanisms contribute to the observed enhancements, and what implications could they have for the broader landscape for fast charging batteries.

Figure 1
Molecular Understanding of Li Metal Anode
Authors: Yu Weilai , Cui Yi , Bao Zhenan
Published: August 2024

Developing new liquid electrolyte is a promising approach to enable the next-generation high-energy Li metal battery for wide-ranging application such as electric vehicles (EV). However, the high reactivity of Li metal interface renders it crucial to form favorable solid-electrolyte interphase (SEI), via active electrolyte decomposition, for highly reversible operation of Li-metal anode (LMA). Therefore, deeply understanding how the molecular structures of electrolyte species precisely control both the interfacial reactivity and the operational reversibility of LMA, can further guide and inspire new electrolyte systems with progressively improved battery performance.

Herein, we systematically investigated the impact of Li salts with different imide anions dissolved in ether-based solvent, on the resulting Coulombic efficiencies (CE) of LMA, whereas beneficial and detrimental molecular motifs were first identified. By leveraging the non-washing XPS protocol newly developed at Stanford, we managed to uncover the distinct molecular reactivity leading to reductive bond cleavage as well as new bond formation at Li-metal potential. Such nanoscale reactivity of SEI-forming reactions was discovered to profoundly govern the macroscopic performance of LMA, which simultaneously emphasized the significance of electric double layer (EDL). Importantly, aided by gas-titration experiments to quantify the by-products in SEI, we revealed the critical molecular origins of irreversible capacity loss of LMA during continuous Li-metal plating and stripping. These new insights allow us to formulate rational strategies of molecular engineering to design LMA interface with high reversibility and minimal side reactivity.
Characterization of Processes Occurring at Various Interfaces By Scanning Electrochemical Microscopy (SECM)
Authors: He Rong , Zhou Meng , Luo Hongmei , Tenent Robert
Published: August 2024

Scanning electrochemical microscopy (SECM) is an in-situ probe technique that can directly monitor the electrochemical processes occurring at different interfaces. SECM has been proven as a powerful characterization tool with a wide variety of applications in redox processes, near-surface reactions, reaction kinetics, and electrochemical imaging. In this work, we focused on the use of SECM measurement methods to detect electrochemically active materials formed at the cathode electrolyte interface (CEI) and study the cathode degradation process of lithium-ion batteries (LIBs). We demonstrated the direct electron transfer between the cathode and the electrolyte, and the evolution of reactive species released during CEI formation by applying the SECM generation/collection mode. Our work highlights the application of SECM in characterizing cathode–electrolyte interphase of LIBs, providing a deeper fundamental understanding of LIB degradation mechanisms and new perspectives for future rational design of stable cathode-electrolyte interfaces for LIBs.
The Effect of Shape in Porous Electrodes on Cell Resistance and Chemo-Mechanical Stresses
Authors: Lin Tiras Y , Roy Thomas , Worsley Marcus Andre , Bucci Giovanna
Published: August 2024

In contrast to conventional planar electrodes, the use of electrodes with a three-dimensional (3D) shape has been shown to be an effective way to increase both the power and energy densities of a Li-ion battery. These 3D shapes allow batteries to overcome some of the capacity and rate performance trade-offs. For instance, they enable higher active-material loading, while keeping the transport pathways fixed and allowing for better material utilization. There are a variety of ways electrodes can be shaped: each electrode can be individually shaped and separated by a planar separator, or they can be completely intertwined with one another. In this talk, we consider both cases: a half cell with an electrode shape described by a sine wave and a full cell following an interdigitated design, where alternating planar fins protruding from the cathode and anode sandwich the electrolyte. First, we seek to understand how the electrode shape affects the electrical resistance of the cell based on a simple electrostatics model with a linearized Tafel expression. We identify the regimes of electronic to ionic conductivity ratios, Wagner numbers, and porosities that benefit most from electrode shaping, with a particular focus on low temperature electrolytes with reduced conductivity. Next, battery cycling is known to cause volumetric expansion and contraction of the electrodes. Therefore, we explore the chemo-mechanical stresses that arise in the same shaped electrodes with a solid electrolyte. To do so, we solve for the mechanical equilibrium for stress and deformation in the presence of an applied isotropic strain. By examining the stress concentrations at the electrode/electrolyte interface, we elucidate the likely failure mechanisms – interface delamination, crack propagation – of shaped electrodes in comparison to planar electrodes. Overall, we aim to provide design guidelines for how electrode shapes can be chosen to provide both low cell resistance and acceptable mechanical resilience.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL release number: LLNL-ABS-857536.
Understanding Organic Components of Solid Electrolyte Interphase on the Lithium Metal Anode
Authors: Lopez Jeffrey
Published: August 2024

Lithium ion batteries have become the dominant form of energy storage used in consumer electronics and, recently, electric vehicles. However, high costs have prevented widespread deployment of lithium ion batteries for applications other than portable electronics, and the safety issues associated with liquid organic electrolytes remain to be addressed. In order to enable the greater utilization of electric vehicles, allow for grid scale energy storage, and meet the demands of new electronic applications, new materials for high energy density batteries must be developed. High capacity electrode materials like lithium metal have the potential to facilitate these technologies, but lithium metal electrodes are presently limited by significant side reactions, poor quality deposition, and the potential to form hazardous dendrites. Therefore, it is important to develop a clear understanding of the surface reactivity and growth behavior of the lithium metal at the interface with the electrolyte in order to enable stable long-term cycling.

The products that form as a result of electrolyte decomposition reactions at the electrode interface are known to be extremely important in determining the final cell performance, yet characterizing the organic components of the solid electrolyte interphase (SEI) proves to be challenging with typical techniques. In this presentation we will discuss a combination of in operando and ex situ techniques developed in efforts to more comprehensively characterize the reaction intermediates and organic SEI products of electrolyte reduction reactions. Specifically, we employ electron paramagnetic resonance (EPR) spectroscopy to identify radical intermediates and clarify electrolyte reduction mechanisms. Furthermore, SEI product formation with respect to electrochemical potential and time will be described using data obtained from in operando ATR-FTIR. ATR-FTIR is a powerful method for characterizing organic species, but typical materials such as Ge, Si, and ZnSe react with lithium metal during deposition. In this talk, the development of a diamond based operando cell and its application to the characterization of organosulfur and fluorinated electrolytes will be discussed. With the understanding developed from these two techniques we provide new insights into the formation and chemical nature of SEI components that promote stable cycling of lithium metal electrodes.
Cracks in Polycrystalline Li(NiMnCo)O2 Particles Enable Rapid Discharging of Li-Ion Batteries
Authors: Min Jinhong , Li Yiyang
Published: August 2024

The degradation of capacity in Li-ion batteries during charging and discharging cycles has been a persistent challenge in advancing battery lifetime. Among the commonly accepted causes of capacity degradation is the formation of cracking along the grain boundaries of polycrystalline NMC particles. These cracks are known to occur from the anisotropic expansion and contraction of the crystal lattice induced by the (de)intercalation of lithium.

To address this issue, single crystalline NMC particles were introduced, lacking grain boundaries and seemingly less prone to developing cracks. batteries utilizing single crystalline particles exhibited improved capacity retention. However, in terms of rapid charging and discharging, these single particle batteries experienced a sudden increase in overpotential compared to polycrystalline particle batteries. Yet, a clear explanation for this abrupt rise in overpotential during rapid charging and discharging in single crystalline particle batteries has remained elusive.

In this study, we investigated the rate-capability of individual single and polycrystalline NMC particles using an innovative high-throughput single-particle electrochemistry platform. Based on our rate-capability findings, we argue that the cracks, previously identified as a factor contributing to capacity degradation, are actually a crucial element enabling rapid charging and discharging in polycrystalline particles.
Li-Sn Alloyed Layer Containing Artificial SEI on Li-Metal Anode for Superior Lithium Metal Batteries: Development and Understanding of Anode/Electrolyte Interfacial Phenomena
Authors: Amardeep Amardeep , Freschi Donald J. , Sang Lingzi , Liu Jian
Published: August 2024

Modern civilization and cutting-edge technologies and tools are highly dependent on energy storage devices and demand efficient and long-lasting high-energy-density storage devices. Lithium metal batteries have surpassed their competitors concerning energy density due to their inherent high specific capacity (3860 mAh/g) and the lowest electrochemical potential (-3.04 V vs. standard hydrogen electrode), proving to be one of the most favorable energy storage devices for smart and mobile gadgets, electric automobiles, grid storage, etc. However, safety-threatening and performance-decay challenges associated with lithium metal anodes, such as lithium dendrite formation, uncontrolled parasitic reactions between Li-metal and electrolyte, low coulombic efficiency, dead Li-formation, etc., restrict its employment in practical batteries. The root cause of the dendrite formation is poor Li-ion conductivity of bulk lithium metal, which results in an uneven electric field distribution, leading to non-uniform Li deposition/stripping upon repeated charge/discharge. Herein, a facile chemical reduction process is being opted to fabricate a highly Li-ion diffusive Li-Sn-based artificial SEI layer on the lithium metal surface to prevail over the above-mentioned issues. Therefore, upon careful concentration investigation of reactants, 25 mM precursor concentration (SnCl4 in EC: DMC in 1:1 volume ration) demonstrated the best electrochemical performance, revealing a cumulative capacity of over 700 mAh/cm2 at a current density of 1 mA/cm2 for 1 h in a symmetric cell. Physical characterizations (XRD and SEM-EDS) showed a thin layer containing Li-Sn alloys along with LiCl formed at the lithium metal surface. Possessing high Li-ion diffusivity, Li-Sn alloyed hybrid anode illustrated a gradual decrease in the charge transfer resistance on increasing the concentration, thus, lower overpotential in symmetric cells, in contrast to pristine Li-metal. However, an increase in the electrical resistance has been observed on increasing the precursor concentration due to the presence of the insulating LiCl phase in the protective layer. Moreover, in-situ optical microscopy demonstrated more uniform and on-surface Li-deposition for the hybrid electrode, whereas mossy and dendritic growth on bare Li-metal. Full cells prepared with Li-Sn alloyed anode against NMC532 cathode illustrated stable cycling up to 150 cycles; contrastingly, the cell with pristine Li-metal showed a drastic capacity fade just after 100 cycles, demonstrating the inclination towards safer lithium metal batteries.
Design Principles for Architected Battery Electrodes
Authors: Bucci Giovanna , Lin Tiras Y , Brady Nicholas , Cross Nicholas R. , Li Hanyu , Ehlinger Victoria Marie , Roy Thomas , Orme Christine , Worsley Marcus Andre
Published: August 2024

The properties of rechargeable lithium-ion batteries are determined by the electrochemical and kinetic properties of their constituent materials as well as by their underlying microstructure. The discovery of 2D and 3D mesoscale architectures tailored to diverse applications remain an open challenge and it cannot be approached empirically. In this work, we leverage the design flexibility offered by several additive manufacturing methods (e.g. direct ink write, projection micro-stereolithography, etc.) to engineer the architecture of device electrodes. To explore this vast design space, we employ theoretical analyses and topology optimization techniques to determine printable electrode shapes. Our analyses produce general design guidelines, and three-dimensional CAD representations that optimize the battery architecture over specific performance metrics. In this talk, we show examples of electrode design driven by extreme operating conditions (e.g., low temperature) or by mechanical resilience. We also demonstrate an integrated workflow for model validation and guided experiments. For Li-metal anodes, our objective is to identify regimes of morphologically stable growth--where deleterious effects of dendrite growth might be avoided by microstructural design. For manganese-oxide cathodes, we develop physical models that capturethe pseudocapacitive response of the material and use them in inverse analyses to optimize the cathode architectures.
Electrodeposition of Pt1-XMx (M=Ni,Co) Alloys for Magnetic Thermometry
Authors: Rus Eric D , de Lima Corrêa Eduardo , Dennis Cindi L , Moffat Thomas P
Published: August 2024

Electrodeposited Pt1-xMx (M=Ni,Co) alloys were studied for possible use in a magnetic thermometry application. The effects of boric acid and potential on the deposition process and on magnetic properties of the resulting films were examined. Both alloy series showed a monotonic decrease in platinum content as the potential was stepped to progressively more reducing potentials. While films in the Pt1-xNix series were all face centered cubic (fcc), those in the Pt1-xCox series showed a transition from fcc to hexagonal close packed as the films became more cobalt rich. For the Pt1-xNix system, the presence of B(OH)3 during deposition was accompanied by decreased Coulombic efficiency at more reducing deposition potentials, increased oxygen incorporation, and decreased magnetization relative to films deposited in the absence of boric acid.[1] For the Pt1-xCox system, the presence of B(OH)3 also resulted in lower Coulombic efficiency and in lower magnetizations over an intermediary potential range. In contrast to the Pt1-xNix, the decreased Coulombic efficiency for the Pt1-xCox system was also accompanied by a strong suppression of the deposition process. For both series, the Curie temperature decreased with increasing platinum content, allowing the magnetic thermosensitivity to be optimized for a particular temperature range of interest by appropriate selection of the deposition potential.
Electrochemical Quartz Crystal Microbalance Study on the Electrodeposition of Fe, Co and Fe-Co Alloys
Authors: Ispas Adriana , Bund Andreas
Published: August 2024

Cobalt-iron alloys are interesting soft magnetic materials which are used for example in magnetic sensors and transducers. They can be obtained by different techniques such as PVD, magnetron sputtering, or casting. One easy and not very expensive way to produce these alloys is the electrochemical deposition technique, which was also chosen in this study.

This contribution will describe the electrodeposition of Co, Fe and Fe-Co alloys (Fe70Co30) from an aqueous sulphate-based electrolyte containing boric acid as a buffer and sodium citrate and citric acid besides the metal sulphates. Potentiostatic step experiments and cyclic voltammetry were performed in parallel to electrochemical quartz crystal microbalance. Thus, we could identify the potential at which the deposition of the metals sets in, the mass of the deposited species as well as the current efficiency. We could also extract the partial current due to hydrogen evolution reaction and the partial current due to individual metal or their alloys from the total current density. The morphology and structure of the deposited films were investigated by means of SEM and XRD, respectively. The grain size of the deposits was calculated from the XRD data using Scherrer equation. Addition of citric acid to the electrolyte results in the smaller grain size of the deposited Fe-Co films.
Preparation of Oriented Nanoporous Magnetite Films by a Template-Free Solution Process from Iron Oxyhydroxide Films
Authors: Shinagawa Tsutomu , Kanemoto Yuya , Ohtaka Atsushi
Published: August 2024

Nanoporous oxide films composed of nanocrystal assemblies with an aligned crystallographic orientation are key nanostructures for efficient interfacial reactions. However, a simple, template-free method for their formation remains a challenge. Layered metal hydroxide (LMH) films are a promising precursor for spontaneous formation of nanoporous oxide films.[1-4] LMHs have a layered structure comprising 2D sheets of edge-shared octahedral hydroxide, i.e., brucite structure, with or without interlayer anions and water molecules. Calcination of LMH results in dehydration, anion elimination, and volume shrinkage, leading to the spontaneous formation of nanoporous oxides.

In this study, we have prepared nanoporous and ferrimagnetic magnetite (Fe3O4) films by using layered iron hydroxides, namely, green rust (GR), as a precursor. Generally, GR has a brucite-type structure containing Fe2+ and Fe3+ ions, and is highly susceptible to oxidation by oxygen in water and air, leading to the formation of iron oxyhydroxides (FeOOH). Here, GR films were electrochemically deposited on FTO substrates in an aqueous solution containing Fe2+ and NO3
− ions at room temperature. Drying the GR films in air resulted in the formation of two-type FeOOH films, depending on the electrodeposition condition. Characterization using X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and FT-IR spectroscopy revealed that one is [010]-oriented γ-FeOOH films, and the other is [001]-oriented δ-FeOOH films. The obtained FeOOH films had a mille-feuille like morphology with 500–700 nm thickness. Heat treatment of these two-type FeOOH films under vacuum at 500 °C resulted in the formation of [110]- and [111]-oriented nanoporous Fe3O4 films. The obtained Fe3O4 films showed a ferrimagnetic behavior in VSM measurements and had a nanoporous structure comprising nanoparticles with 50–100 nm diameter.

Finally, a possilble interpretation for the observed orientation relationships between the FeOOH and Fe3O4 was also discussed on the basis of pyrolysis intermediates of FeOOH and similarity in their atomic arrangements.

References

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Molecular Dynamics Study of Adhesion-Related Structural Properties for PVDF-HFP Polymer Binders
Authors: Jeong Seung Weon , Lee Sangheon , Lim Hyung-kyu
Published: August 2024

The current lithium-ion battery (LIB) market is expanding rapidly. Binders are essential to maintaining the high capacity and longevity of batteries. These binders can be classified into organic binders used for cathodes and aqueous binders used for anodes. Among them, Poly(vinylidene fluoride) (PVDF) binder is a representative organic binder that offers excellent electrochemical stability. To solve low adhesive force and weak mechanical strength of conventional PVDF binders, hexafluoropropylene (HFP) is added to improve these properties. However, the present poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) binders still show lower adhesive force than other polymeric binders, and therefore further research works are necessary.

In this study, we employ classical molecular dynamics (MD) simulations to investigate the structural properties of the PVDF-HFP copolymers. To create realistic disordered PVDF-HFP polymers, we develop a computational scheme that can randomly arrange the angles and sequences of the constituent polymer chains. By varying the ratio of randomly arranged PVDF-HFP copolymers to 0/100, 5/95, 10/90, 15/85, and 20/80, we build a solution model that mimics the HFP concentration of PVDF-HFP (0–20%, Sigma Aldrich) used in the actual experiments. N-methyl-2-pyrrolidone (NMP) used as solvents. To create a large-scale model, we utilize the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) and set parameters by using OPLS force field. This allows us to build a simulation model containing approximately 40,000 atoms consisting of 10 PVDF-HFP polymers and 1500 NMP monomers.

After creating the simulation model, approximately eight steps of molecular dynamics simulation are performed by referring to the process of making the actual polymer film. In this process, NMP molecules are evaporated to produce a polymer film consisting only of PVDF-HFP polymers. Then we perform the adhesion analysis by applying forces to five polymer film models with different composition ratios in various conditions. Throughout these processes, we find the characteristic changes depending on the composition ratio. Finally, we will present the possible routes that can lead to the enhanced adhesive properties of PVDF-HFP, which is a key requirement to the development of high performance binders.
Enabling Rhenium Electrodeposition in Water-in-Salt Electrolytes through Isolated Anodic Reactions
Authors: Rutledge Amanda , McBride Michael , Hooks Daniel E
Published: August 2024

Perfluorosulfonic Acid (PFSA)/Polytetrafluoroethylene (PTFE) copolymer and cation-exchange membranes were used to elongate the use water-in-salt electrolytes for rhenium electrodeposition. Water-in-salt electrolytes are a common technique used to minimize the amount of free water in solution by including high concentrations of salts, thus solvating the water molecules and lowering activity of the solution. This expands the electrochemical window in which deposition is possible and minimizes unnecessary hydrogen evolution reactions (HER) in the electrodeposition system by reducing available protons.

Lithium chlorine (LiCl) is a common salt for this purpose due to low costs. However, in the LiCl electrolyte, the necessary oxygen evolution reaction (OER) competes with chlorine evolution, which increases water activity and is visually identifiable with a color change from clear to yellow. When chloride ions are depleted, further deposition is no longer possible, and the electrolyte breaks down.

A solution to this issue is using membranes to isolate the anode and cathode, thus preventing the chlorine evolution reaction from occurring. Since rhenium is a system with a small electrochemical window, possible oxide intermediates, and an overpotential for hydrogen evolution, the system requires the use of a stable water-in-salt electrolyte for elongated deposition.

In this experiment, three membranes were examined to compare the impact on rhenium depositions in an H-cell. To compare the impact of each membrane, the change of pH of the DI side of the H-cell was monitored across time alongside the volume changes on both sides of the H-cell as a function of time due to LiCl inclusion. The quality and thicknesses of the coatings was examined by SEM as well as the impact on the morphologies of the rhenium of the deposits between each of the membranes.
The Resurgence of Hydrogen Depolarized Anodes: A Catalyst for Change in Industrial Electrochemistry
Authors: Akuzum Bilen , Hackl Lukas , Bandaru Siva Rama Satyam , Pohlman Garrett
Published: August 2024

This presentation delves into the remarkable history of Hydrogen Depolarized Anodes (HDAs) and their relevance to modern industrial electrochemistry. HDAs were originally developed in the early 1970s, but their use has been confined to fuel cell technology and power generation. In the wake of a growing green hydrogen economy and the escalating price of precious metal catalysts, this technology is now emerging as a useful tool to boost the energy efficiency and lower both capital and operational costs of electrified chemical manufacturing processes. Our discussion recounts the evolution of HDA technology, from its conceptual beginnings to its current role as an innovative solution in electrochemical processes.

The recent renaissance of HDAs is driven largely by economic and environmental factors. As chemical industries strive to electrify their processes, they also grapple with the rising cost of conventional anode materials. The increasing affordability and availability of hydrogen presents HDAs as a viable and efficient alternative. This shift is not just about cost-saving; it's about embracing a technology that aligns with the principles of sustainability and circular economy.

We will explore various applications where HDAs are making a significant impact, such as in the manufacturing of acids and bases, the production of metals such as iron, copper, and zinc, and more experimental processes such as cement production. These examples not only demonstrate the versatility of HDAs, but also underscore their potential in achieving higher energy efficiency than conventional technologies and reducing environmental footprint of a range of industrial operations.

Furthermore, our talk will illuminate how HDAs are a stepping stone towards a broader adoption of hydrogen as a cornerstone of industrial electrochemistry. The implementation of HDA technology is more than an innovation; it's a transformative step forward, signaling a new era in chemical manufacturing where sustainability and efficiency go hand in hand.
Minimize Energy Consumption of CO2 Release in a Flow Electrolyzer By Optimizing Direct Air Capture Solvents
Authors: Xin Gao , Omosebi Ayokunle , Patrick Aron , Liu Kunlei
Published: August 2024

Under the 2015 Paris Agreement, almost 200 nations have committed to the global goal of limiting the rise in average temperatures to 2.0 °C above preindustrial levels, with an even more ambitious aim of striving for 1.5 °C. Achieving the 1.5 °C objective requires a 45% reduction in global greenhouse gas emissions by 2030, ultimately reaching net-zero emissions by 2050. Numerous industries are increasingly making commitments to combat climate change by minimizing their CO2 emissions. However, certain sectors face challenges due to the current high costs associated with emissions reduction through available technologies, though these costs are expected to decrease over time. Moreover, in specific industries like cement production, there are emissions sources that cannot be entirely eliminated, such as those arising from the inherent calcination process. Given these constraints, realizing the emissions reduction pathway to the 1.5 °C target requires the adoption of negative emissions processes, including technologies like direct air capture (DAC), to actively remove CO2 from the atmosphere.

The operational concept of the DAC process explored in this study is based on the utilization of both the solvent-based method and alkaline water electrolysis. This involves regenerating the solvent through pH fluctuations generated by a carbonate electrolyzer. As depicted in Figure 1, the consumption of OH- ions during O2 evolution leads to a decrease in pH at the anolyte loop, while the production of OH- ions through water splitting causes an increase in pH at the catholyte loop. Consequently, the lowered pH environment facilitates the release of CO2 gas from dissolved carbon species such as CO32-, while the heightened pH environment promotes the formation of alkaline hydroxides for carbon capture in an air absorber.

In this work, we will aim to analyze the energy consumption per mole of CO2 released from the anolyte loop of a flow electrolyzer. Utilizing a combination of theoretical predictions and experimental validations, significant insights were obtained for optimizing the DAC solvent. This optimization involves minimizing energy consumption by adjusting alkalinity levels and incorporating supporting electrolytes.

Figure 1