bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation for Elucidating a Formation Mechanism of 6-Coordinated Si in Phosphate Glass
Authors: Sakakibara Arata , Tamura Tomoyuki
Published: December 2024

Phosphate glasses are materials that are expected to have a wide range of applications, including highly ion-conductive materials in fuel cells and biomaterials that supply therapeutic ions. Diffusion of ions in glasses plays an important role in designing glasses for these applications. The diffusion of protons is one of the most important properties of fuel cells, and the diffusion of network-modified cations such as Na+ and Ca2+ ions is closely related to glass dissolution and hydration reactions. In general, these diffusion properties are strongly dependent on the atomic-scale glass structure. We found that the difference in the morphology of PO4 tetrahedra (P-Qn
: number of bridging oxygen) greatly affects the diffusion of protons and Na+ ions in phosphate glass, where these ions can diffuse much more easily near P-Q2
than near P-Q3
, and suggested that ionic conductivity and glass solubility can be designed by controlling the P-Qn
distribution of phosphate glasses [1]. We also suggested that the P-Qn
distribution can be controlled using 6-coordinated Si (6cSi), which is formed in phosphate glasses containing more than 40 mol% P2O5 [2]. However, the formation mechanism of 6cSi is not clear. In this study, we aim to elucidate the formation mechanism of 6cSi in phosphate glasses based on first-principles molecular dynamics (MD) simulations.

The glass models for 55.0P2O5-21.3SiO2-23.7Na2O (mol%) were generated by quenching from the melt using classical MD simulations with the DL POLY [3] program. Subsequently, first-principles MD simulations using the SIESTA code [4] were performed to observe the reaction process from 4cSi to 5/6cSi. Atomic energies were calculated using orbital decomposition of the total energy by the OpenMX code [5]. For these electronic structure calculations, a localized basis with the GGA-PBE functional was used.

In obtained models, atomic energies for non-bridging oxygen (NBO) are higher than those for bridging oxygen (BO). In the first-principles MD simulation, the formation of chemical reaction from "4cSi + P-Q2
" to " 5/6cSi + P-Q3
" was observed as shown in Fig. 1. The energy decreases by the change from a NBO in P-Q2
to a BO in P-Q3
is larger than the energy increase by the change for 4cSi to 5c/6cSi.

It will be possible to design highly functional glasses by applying the 6cSi formation mechanism and controlling the amount of 6cSi formed.

Reference:[1] K. Takada, T. Tamura, H. Maeda, and T. Kasuga, Phys. Chem. Chem. Phys. 23, 14580 (2021). [2] K. Takada, T. Tamura ,and T. Kasuga, RSC Adv. 12, 35043 (2022). [3]T. Todorov et al., J. Chem. 16, 1911 (2006). [4] J. Solar et al., J. Phys. Cond. Matt. 14, 2745 (2000). [5] T. Ozaki, Phys. Rev. B 67, 155108 (2003).

Figure 1
Study on Catalyst and Binder Degradation Analysis during Electrode Degradation Using EIS in PEMFC
Authors: Yoo Donggeun , Park Kwonpil
Published: December 2024

Research is underway to reduce the cost of PEMFCs by decreasing the loading amount of Pt catalyst, which necessitates research on catalyst structures and binders to compensate for the resulting decrease in performance and durability. Recent studies have focused on improving performance using binders such as high oxygen permeation ionomer (HOPI), but research on the durability of such binders is lacking. The primary challenge in studying binder durability lies in the difficulty of binder degradation analysis. Since the binder in the catalyst layer exists in small quantities within the catalyst layer, and degradation is difficult to distinguish from membrane degradation, it is crucial to develop analysis methods to identify binder degradation. Distribution relaxation time (DRT) analysis is a method that utilizes Electrochemical Impedance Spectroscopy (EIS) to analyze resistance in detail by representing it as distribution relaxation time peaks. By using DRT analysis, the resistance in EIS can be subdivided into ORR charge transfer resistance, oxygen transfer resistance, and proton transfer resistance and changes in the ion transfer resistance of the catalyst layer can be analyzed in situ to observe binder degradation. In this study, we aim to analyze the degradation of catalyst and binder ionomer during electrode degradation using EIS in situ. In addition, we compare the electrochemical analysis results and post-analysis results with the EIS analysis results to examine the suitability for EIS analysis.

Electrode degradation was carried out using the DOE catalyst degradation protocol. Characterization during electrode degradation included I-V, EIS, mass activity, CV, LSV, while post-degradation analysis involved AFM, XRD, XRF analysis to analyze electrode catalyst and binder degradation.

As catalyst degradation progressed, the cell's performance decreased, leading to increased charge transfer resistance (CTR), decreased electrochemical surface area (ECSA), and decreased mass activity. Catalyst degradation was observed through changes in ORR charge transfer resistance in DRT analysis, while binder degradation was confirmed through changes in proton transfer resistance in DRT results and Warburg-like response impedance. The results obtained from the postmortem of degraded MEAs matched well with the results obtained from DRT analysis.
Influence of Alkaline-Metals Co-Doping on Luminescence Intensity of Er-Doped Up-Conversion Oxide Phosphors
Authors: Koikawa Tomoki , Brik Mikhail G. , Yamamoto Tomoyuki
Published: December 2024

Up-conversion (UC) phosphors, which can convert lower energy photons to higher energy ones, have been widely investigated owing to a wide range of applications, including bioimaging to visualize information in living organisms [1], solar cells to improve power conversion efficiency [2], and security inks to prevent counterfeiting [3]. However, in device applications, there are two big problems to overcome, those are 1) UC efficiency and 2) lifetime for long term use. Currently materials containing fluoride are often used for UC phosphors, but several types of oxides with rare-earth ions such as Y2O3:Er, Yb [4] and CaWO4:Er [5] have been reported as efficient UC phosphors with long lifetime. UC phosphors using organic solvents have also been reported to improve emission intensity, but they are difficult to apply to devices and are virtually unusable. To improve UC efficiency, it was reported that UC luminescence intensity can be enhanced by a co-doping of alkaline-metals in CaTiO3:Er [6].

In this study, we have investigated the influence of alkaline-metal co-dopings on UC luminescence intensity of various types of oxides doped with Er ions. All the samples were prepared by a conventional solid state reaction method. The systematic analysis were carried out for the synthesized samples, i.e., the crystal structures and the phase analysis were examined by X-ray diffraction, the elemental analysis by X-ray fluorescence, energy levels and electronic structure analysis by diffuse reflectance with UV-vis spectrometer equipped with integration sphere, surface morphology and grain size observation by scanning electron microscope. In addition to such experimental analysis, first-principles calculations within a density functional theory have also been conducted to interpret the influence of alkaline metal co-dopings on the geometrical and electronic structures.

As an example of our current UC measurements, UC luminescence spectra of CaMoO4:Er with and without alkaline-metal co-dopings are shown in Fig. 1, in which significant enhancement of UC luminescence has been achieved by alkaline-metal co-dopings in CaMoO4:Er.

References

[1] J. W. Chung et al., Appl. Spectrosc. Rev., 51 (2016) 678-705.

[2] A. Gha et al., Sol. Energy Mater. Sol. Cells, 230 (2021) 111234.

[3] H. Jia et al., ACS Material Lett., 4 (2022) 1306-1313.

[4] H. Guo et al., Opt. Mater., 31 (2009) 583-589.

[5] X. Che et al., Opt. Mater., 58 (2016) 449-453.

[6] H. N. Lui et al., Phys. Status Solidi A, 214 (2017) 1600899.

Fig.1 Up-conversion luminescence spectra of CaMoO4:Er excited by 980 nm with Na(blue), K(green), Rb(purple) co-dopings and without (red) ones

Figure 1
Distinctive Electrochemical Surface-Enhanced Raman Spectroscopy and Its Application for DNA-Sensor
Authors: KIM Donghyeon , Kim Nakyung , Kim Jihee , Kang Mijeong
Published: December 2024

Raman scattering is used in basic research on the physical chemistry of molecules and practical analysis applications for molecular detection. To obtain sufficient intensity of Raman scattering, Surface-enhanced Raman Scattering (SERS) is adopted, in which signals are amplified by the localized surface plasmons of metallic nanomaterials. Electrochemical surface-enhanced Raman spectroscopy (EC-SERS) is employed to further enhance SERS signals. Conventional EC-SERS further enhances signals by simply biasing the SERS substrate and forming a resonance condition in which a charge transfer between the SERS substrate and Raman-active molecules can occur.

We amplified Raman signals using an electrochemical reaction in a different way from conventional EC-SERS. We provided a potential to the SERS substrate in the presence of a plasmonic precursor to generate secondary plasmonic layer and to induce additional chemical enhancement, resulting in the significant amplification of SERS signal. To deepen our understanding of the phenomena occurring in the EC-SERS process, we fabricated a nanoporous Au substrate and systematically varied its characteristics (e.g., pore size, thickness of a porous layer) and observed the dynamic response of the EC-SERS signal. The condition of the SERS substrate that maximizes the EC-SERS signal was explored.

An application experiment was conducted to detect DNA with high sensitivity under these experimental conditions. DNA capture was achieved via a sandwich hybridization procedure: capture DNA was immobilized onto the SERS substrate and bound to a portion of the target DNA, while probe DNA with a tethered Raman-active probe bound to the remaining portion. Raman-active probes were positioned near SERS substrate only in the presence of target DNA. EC-SERS signals were measured by inducing a secondary plasmonic surface through an electrochemical reaction. We confirmed that these EC-SERS could serve as effective DNA-sensor, providing higher detection sensitivity than SERS.
(Invited) Enhancement of Li-Ion Intercalation Kinetics in High-Concentration Electrolytes
Authors: Dokko Kaoru , Zhi Zhou , Takeshita Kousuke
Published: December 2024

Highly concentrated electrolyte (HCE) solutions containing over 3 mol dm–3 of Li salts have attracted attention recently owing to their unique physicochemical and electrochemical properties such as high thermal and electrochemical stability, unusual Li+ ion transport processes, and good compatibility with next-generation batteries containing Li anodes. Certain HCEs enhance the charge-transfer reaction rate at the electrode/electrolyte interface in Li-ion batteries. The solvation structure of Li+ in HCEs significantly affects the electrochemical interfacial reaction kinetics. In the organic electrolytes of lithium-ion batteries, the desolvation process of Li+ ion at the electrode/electrolyte interface is the rate-limiting process of the charge transfer reaction.1 Our group has found that the rate of charge transfer reaction of Li+ intercalation electrode is affected not only by Li+ solvation structure but also by the activity of Li+ (aLi+)and viscosity in the electrolyte.2 In this study, the charge transfer resistance (Rct) of the LiMn2O4 (LMO)/electrolyte interface in the electrolyte with various Li salt concentrations was evaluated to determine the effect of Li+ activity and viscosity on the charge transfer kinetics. LMO thin-film electrodes were prepared using the polyvinylpyrrolidone (PVP) sol-gel method. The electrochemical measurements of the LMO thin-film electrode were performed using a three-electrode cell. Li metal was employed as both the counter and reference electrodes and a LMO thin film as the working electrode. The mixtures composed of LiN(SO2CF3)2 (LiTFSA) and monoglyme (G1) were used as model electrolytes. Electrochemical impedance spectroscopy (EIS) was conducted at 30 oC and 3.9 VLi to determine Rct. In the range of concentration less than 1.8 mol/L ([LiTFSA]/[G1] =1:4 in molar ratio), Rct decreases with increasing LiTFSA concentration, while it increases at higher than 1.8 mol L-1. The minimum Rct at 1.8 mol L-1 can be attributed to the combined effects of electrolyte viscosity and Li+ activity in the electrolyte. Further results including the reaction kinetics in other electrolytes also will be presented.

Acknowledgements: This study was partially supported by the JSPS KAKENHI (Grant No. JP22H00340 and JP 23K17370).

References:

Abe et al., J. Electrochem. Soc., 151, A1120 (2004).

Ugata et al., J. Phys. Chem. C, 127, 3977-3987 (2023).
(Invited) Innovation in Electrochemical Systems: Recent NSF Trends, Investments and Research Opportunities
Authors: Read Carole J
Published: December 2024

NSF is an independent federal agency created by Congress in 1950 "to promote the progress of science; to advance the national health, prosperity, and welfare; to secure the national defense..." With an annual budget of about $9.06 billion (FY 2024), we are the funding source for approximately 24 percent of all federally supported basic research conducted by America's colleges and universities. In many fields such as mathematics, computer science and the social sciences, NSF is the major source of federal support. This talk will highlight recent research investments by NSF’s Division of Chemical, Bioengineering, Environmental, and Transport Systems (CBET) in innovative fundamental research supporting electrochemical systems for industrial decarbonization, energy storage, net zero fuels, and environmental clean-up applications. Funding opportunities will also be highlighted for fundamental and translational research projects of interest to the PRiME research communities.
(Invited) Patent Citation Analysis to Guide Research and Innovation
Authors: Taylor Earl Jennings
Published: December 2024

Patents are widely understood to provide exclusive protection for inventions for a limited time, currently 20 years from filing. The legal protection provided by patents consists of market advantage and/or defensive purposes vis-à-vis competitors [1]. Per United States laws, patents are to have the attributes of property [2]. Consequently, patents are often referred to as intellectual property and their claims may be simply considered as the “metes and bounds” or boundary lines of said property. As such, during the examination (i.e. prosecution) of a patent application, "neighboring" as prior art (published patent applications, patents, technical publications and the like) as well as prior art upon which the pending patent application would “trespass” are identified in office actions from the U.S. Patent & Trademark Office. Prior art which impacts the patentability of a patent application results in the inventor adjusting the boundary lines (i.e. limiting the claims) in order to overcome the rejections. Alternatively, the inventor is forced to abandon the patent application.

Consequently, the examination of patent applications provides a rich landscape of prior art. Additionally, once the subject patent application is published, it becomes prior art and may be cited during the examination of subsequently filed patent applications. These forward citations can provide a guide to research and innovation [3].

The presentation will begin by differentiating research, innovation and invention and then expand on the patent – property analogy as particularly related to prior art citations. The presentation will conclude with a case study of the use of forward patent citations to guide research initiatives and innovation.

[1] E. Jennings Taylor and Maria Inman 2017 Electrochem. Soc. Interface
26 45

[2] E. Jennings Taylor and Maria Inman 2017 Electrochem. Soc. Interface
26 41

[3] E. Jennings Taylor and Maria Inman 2017 Electrochem. Soc. Interface
26 57
(Invited) Innovative Alkaline Electrolyzer for Electrochemical Production of Ammonia from Diverse Waste Nitrogen
Authors: Li Wenzhen , Chen Yifu , Liu Hengzhou , Gu Shuang
Published: December 2024

NH3 is an essential nutrient for life, but its production through anthropogenic N2-fixing process has caused alarming damages to ecosystems and human health. Excessive NO3
- leakage into water bodies due to overfertilization has led to the formation of "dead zones" in coastal areas. Denitrification generates N2O, which is 300 times more potent than CO2. Restoring the balance between the generation and elimination of Nr is an urgent task for humanity. A promising approach is to convert other forms of Nr to NH3 in an electrochemical reactor, which could reduce the environmental impact of Nr and decrease the NH3 demand from the Haber-Bosch process, while also reducing the use of fossil-derived H2.

In this presentation, we report our innovative membrane-free alkaline electrolyzer (MFAEL), which can transform diverse reactive nitrogen (Nr) into NH3 as the sole N-containing product. By properly choosing the conditions of NH3 collection from MFAEL, continuous production of pure NH3 can be realized without the need for additional separation procedures. A mixture solution of H2O-NaOH-KOH with 40 wt.% of water is typically used as the reaction medium at 80~200 °C to dissolve and digest the nitrogen species including nitrate, nitrite, urea, amino acids, and proteins. Taking advantage of the high alkalinity of the reaction medium, ammonia evolves instantly once it is generated with the assistance of an airflow, which is subsequently collected in an acidic trapping solution as ammonium salts. Our tests with pure nitrogen-containing compounds showed that the MFAEL system is capable of converting both inorganic and organic forms of nitrogen to NH3 with high selectivity. Pure nitrogen-containing compounds [(NH4)2SO4, KNO3, KNO2, urea, and amino acids] with 0.2 mmol of nitrogen are added into the MFAEL, in all cases the amount of evolved ammonia matches the amount of added nitrogen (i.e., ~100% recovery of nitrogen) regardless of its form in the specific chemical, suggesting the high efficiency of the MFAEL in extracting and transforming total nitrogen into ammonia as a single product. An ultrahigh NH3 partial current density of 4.22 ± 0.25 A cm−2 with a faradaic efficiency of 84.5 ± 4.9% can be achieved at 4.5V cell voltage, 85oC. In addition, the MFAEL is highly robust and can handle insoluble wastes, as demonstrated by the ~100% nitrogen recovery (to ammonium sulfate) for a nitrogen-rich algae sample (with 11.5 wt.% of nitrogen content). Techno-economic analysis (TEA) suggests the potential economic feasibility of the nitrogen waste-to-NH3 process by coupling electrodialysis (ED) for Nr concentration and the MFAEL process for Nr conversion, offering an all-sustainable route for upcycling waste nitrogen into the pure N-based fertilizer and chemical products.
(Invited) A Random Forest–Based Artificial Intelligence Model Decoupling Ion Concentrations from Effluent Conductivity in Capacitive Deionization: Implications and Future Directions
Authors: Kim Hoo , Choi Byeongwook , Ullah Zahid , Jeong Nahyeon , Cho Kyung Hwa , Park Sanghun , Baek Sang-Soo , Son Moon
Published: December 2024

Effluent conductivity is a widely used parameter in evaluating the performance of desalination processes, such as capacitive deionization (CDI) and pseudocapacitive deionization (BDI), due to its simplicity in measurement. However, the conversion of effluent conductivity to ion concentration is often inaccurate, necessitating a more reliable method for real-time monitoring of effluent ion concentrations. To address this issue, a random forest (RF)-based artificial intelligence (AI) model was developed, demonstrating excellent prediction accuracy for both CDI (R2 = 0.86) and BDI (R2 = 0.95) data for effluent conductivity. Furthermore, the model successfully predicted the concentration of individual ions (Na⁺ and Cl⁻) from the conductivity values, with an even higher accuracy than that of the effluent conductivity prediction. The impact of sampling interval on the model's performance was also investigated for both conductivity and ion concentrations. The results showed no significant difference in the model's error value for sampling intervals up to <80 s. These findings highlight the potential of the RF model as a valuable tool for predicting ion concentrations in CDI/BDI processes, which can serve as key indicators in assessing desalination performance.

By providing a more reliable method for predicting ion concentrations, the RF model can contribute to the optimization and automation of CDI and BDI systems, ultimately leading to more efficient and cost-effective desalination technologies. The ability to decouple ion concentrations from effluent conductivity can lead to more accurate monitoring and control of desalination systems, enabling operators to make informed decisions and optimize process performance. Future directions for this research could include the expansion of the RF model to incorporate additional input variables, such as pH, temperature, and flow rate, to further enhance its predictive capabilities, and improving robustness of the model under conditions more closely resembling industrial settings. Such implications and future directions of the research will be discussed in further details in the presentation.
Harnessing Hemp: A Natural Solution for PFAS Removal in Water
Authors: McGhee Sakiya T , Silent Simone , McGhee Saniya , Ridgeway Madison , Milligan Kimberly
Published: December 2024

Per- and polyfluoroalkyl substances (PFAS) represent a class of synthetic organofluorine compounds characterized by numerous fluorine atoms bonded to an alkyl chain. These chemicals are extensively utilized in the manufacturing of materials resistant to oil, heat, grease, stains, and water. The persistence of PFAS in the environment, coupled with their bioaccumulative nature, poses a significant threat as they can contaminate drinking water supplies. Our primary objective is to investigate the ability of hemp plants, when placed in a hydroponic system, to extract PFAS from water. This study leverages the bioaccumulative properties and hydrophilic nature of hemp, which make it well-suited for hydroponic growth. Specifically, we aimed to determine the extent to which hemp plants can extract perfluorooctanoic acids (PFOAs) from water. The experimental procedure commenced with the germination of hemp seeds using the wet paper towel method, where the seeds were placed between damp paper towels until sprouting occurred. Subsequently, we established a positive control comprising 228 microliters of PFOA diluted in 3 liters of spring water, along with a negative control consisting solely of 3 liters of spring water. Sixteen hemp plants were divided into two groups, with half assigned to the positive control hydroponic system and the remainder to the negative control hydroponic system.Throughout the experiment, samples were collected at three-day intervals to monitor the reduction in PFOA contamination. We anticipate that the hemp plants will significantly reduce the levels of PFOAs in the water. Results from the negative control group, which contained no PFOAs, should confirm the absence of PFOAs in the plants. Conversely, results from the positive control group, featuring a predetermined quantity of PFOA, are expected to indicate PFOA presence in the plants, signifying a decrease in water contamination. In conclusion, our research represents a crucial step towards ensuring access to clean water for all, addressing the pressing need as millions of people are projected to lack access to essential services by 2030 unless progress is substantially accelerated. By employing hemp hydroponics to eliminate harmful chemicals from water sources, we present an innovative and scalable solution with the potential to improve global water sanitation and public health.
(Invited) Blended Positive Electrode Materials for Li-Ion Batteries: Electrode Dynamics and Operando XRD
Authors: Palacin M.
Published: December 2024

Transport electrification has resulted in an expansion of the Li-ion battery application from Wh to kWh storage. This has brought up additional requirements to improve performance (e.g. power, cycle life) enhance of sustainability and decrease of cost. Blending different active materials at the same cell electrode, an empirical approach commonly used for primary cells, has been readily applied to commercial EV Li-ion batteries mostly on the positive side. The global aim is to promote positive synergetic effects between the different electrode components, which have unfortunately received limited attention at the fundamental research level.

Materials with fast reaction kinetics, such as LiMn2O4 (LMO) can sustain significantly higher effective rates than the nominal rate applied to the electrode. This has motivated the widespread commercial use of NMC:LMO blends as LiNixMnyCozO2 (x+y+z=1, NMC) despite having slow kinetics, exhibits high capacity (especially for large amounts of Ni) and the addition of LMO lowers overall costs while enhancing power performance. Olivine LiMPO4 (M=Fe, Mn) based blends have a lower presence in commercial cells to date but they have also deserved attention at the laboratory scale as they can as well exhibit fast kinetics and are based on low cost abundant transition metals.

Results will be presented related to different blends, consisting of combinations of LMO, NMC, LiFePO4 (LFP) and LiFe0.35Mn0.65PO4 (LFMP). Electrochemical experiments coupled to time-resolved synchrotron operando X-ray diffraction experiments enable to capture charge transfer events between blend components which are dependent on both voltage profile and kinetics of individual blend components. The results demonstrate the significant impact of the voltage profiles of individual materials on the current distribution, with the effective C-rate of each component varying throughout the state of charge (SoC).

Finally, systematic operando synchrotron X-ray diffraction and absorption experiments will be presented for NMC and LFP with diverse experimental conditions (cell type, radiation energy etc.) to illustrate the existence of beam-induced effects which may bias interpretation of results. These range from total reaction inhibition to partial hindrance and negligible deviations from the expected mechanism, and have been consistently observed across various experimental conditions, photon energies, photon fluxes and exposure times. The total radiation dose per cycle seems to be a useful predictor of the magnitude of beam-induced electrochemical delay and could serve as a guideline to define reliable measurement protocols.
Defect and Interphase Engineering in Electrode Materials for Lithium-Ion Batteries
Authors: Xiong Claire
Published: December 2024

One of the fundamental challenges in the synthesis of solid-state materials is identifying the precise range of conditions under which a desired phase will be formed. In particular, the controlled synthesis of metastable crystalline materials is especially challenging as they are, by definition, thermodynamically unfavorable relative to other phases under typical experimental conditions. At the other extreme, amorphous materials represent a high-energy phase that can be readily formed through well-established experimental techniques such as high temperatures, ball milling, and electrochemical means. Work by Aykol et al.1 in 2018 has shown that amorphous materials represent an “upper thermodynamic limit” for the synthesis of metastable inorganic materials. In this talk, we will present electrochemically-driven amorphous-to-crystalline transformations as a controllable means to introduce composition modification in metal oxides to form high performance disordered rock salt negative electrodes.2–4 The second part of the talk includes our recent progress in operando electrochemical atomic force microscopic (EC-AFM) characterizations5,6 of the solid electrolyte interphases in carbonaceous electrode materials.

References

M. Aykol, S. S. Dwaraknath, W. Sun, and K. A. Persson, Science Advances, 4, eaaq0148 (2018) https://www.science.org/doi/10.1126/sciadv.aaq0148.

H. Xiong et al., J. Phys. Chem. C, 116, 3181–3187 (2012) https://doi.org/10.1021/jp210793u.

H. Xiong et al., Phys Rev Lett, 110 (2013) ://WOS:000314870300013.

P. Barnes et al., Nat. Mater., 21, 795–803 (2022) https://www.nature.com/articles/s41563-022-01242-0.

H. Zhu et al., Small, 17, 2105292 (2021) https://doi.org/10.1002/smll.202105292.

L. Tao et al., J. Am. Chem. Soc., 145, 16538–16547 (2023) https://doi.org/10.1021/jacs.3c03429.
(Invited) Multifunctional Polymeric Metal Phthalocyanine Hosts and Artificial Layers for Li Metal and Li-S Batteries
Authors: Park Ho Seok
Published: December 2024

Li-S batteries are considered as a strong candidate to replace existing lithium ion batteries owing to the high theoretical capacity and lowest electrode potential of Li metal anode as well as the high capacity and low cost of S cathode. However, Li metal anodes are suffered from the dendrite formation and high reactivity, while S cathodes are limited by their lithium polysulfide shuttle, large volume expansion, and low electrical conductivity. In this talk, I will introduce a rational design of multifunctional polymeric metal phthalocyanine to resolve technical issues of both electrodes for Li metal protection and S hosts of Li-S batteries.
Porous Electrode Theory-Based Rapid Simulation of Deformation of Li-Ion Batteries
Authors: Ipers Gerrit , Pathak Shakul , Jiao Junning , Berliner Marc , Fang Ruqing , Li Wei , Li Weihan , Zhu Juner
Published: December 2024

Lithium-ion batteries change their geometric dimensions during cycling as a macroscopic result of a series of microscale mechanisms, including but not limited to diffusion-induced expansion/shrinkage, gas evolution, growth of solid-electrolyte interphase, and particle cracking. Predicting the nonlinear dimensional changes with mathematical models is critical to the lifetime prediction, health management, and non-destructive assessment of batteries. In this study, we present an approach to implement an elastoplasticity model for powder materials into the porous electrode theory (PET). By decomposing the overall deformation into elastic, plastic, and diffusion-induced portions and using the powder plasticity model to describe the plastic portion, the model can capture the reversible thickness change caused by Li-ion (de-)intercalation as well as the irreversible thickness change due to the rearrangement and consolidation of particles. For real-world applications of the model to predict battery health and safety, the key lies in solving the mathematical equations rapidly. Here, we implemented the coupled model into the open-source software PETLION for millisecond-scale simulation. The computational model is parameterized using values gathered from literature, tested under varying conditions, briefly compared to real-world observations, and qualitatively analyzed to find parameter-output relations.
Multivalent Cation Additives for Building Dendrite-Free and Stable Electrode-Electrolyte Interface on Lithium-Metal Anodes
Authors: Li Hongyi , Ichitsubo Tetsu
Published: December 2024

Li-metal anodes are ideal anode materials for Li-based batteries owing to high theoretical capacity and low redox potential. However, the practical application of Li-metal anodes face challenges, such as uneven deposition morphology and progressive electrolyte decomposition during repeated Li deposition and dissolution. To improve the reversibility, high-concentration electrolytes (HCEs), such as 4 M Li[FSI] in DME,[1] have been reported to effectively flatten the deposition morphology and improve the Coulombic efficiency. Nevertheless, HCEs have several limitations, including poor oxidation stability, high viscosity, and high production costs.[2] Therefore, technologies for creating the HCEs’ features in lower concentration ranges are expected to be developed.

In this presentation, we introduce an effective approach to utilize multivalent cations (e.g. Ca2+, Ba2+) as electrolyte additives to construct dual-cation electrolytes (DCEs) for Li-metal anodes. Because multivalent cations have much stronger coordination with anions and solvent molecules than Li+, it is usually difficult to reduce multivalent cations to metal state in organic electrolytes. When multivalent cations are mixed with Li+ in electrolytes, the Coulomb interaction among different cations would modify the solvation structure. Anions are promoted to directly coordinate with cations increasing the ratio of the contact-ion pairs (CIPs) to diminish the free energy of the electrolyte system.[3] This phenomenon creates the solvation environment similar to HCEs, which contributes to maintaining a dendritic-free deposition morphology. Furthermore, as a unique feature of DCEs, multivalent cations are prone to be involved in the formation of solid-electrolyte interphase (SEI) in addition to Li+. The chemical bonds between multivalent cations and the other SEI compositions (e.g., F, O, S, C and N) can enhance the structural stability and functionality of SEI, as an effective controlling factor for the reaction behavior of Li-metal anodes.[4]

[1] J. Qian, J-G. Zhang et al, Nat. Commun.
6, 6362 (2015)

[2] Y. Yamada, A. Yamada et al, Nat. Energy
4, 269 (2019)

[3] H. Li, T. Ichitsubo et al, Cell Rep. Phys. Sci.
3, 100907 (2022)

[4] H. Li, T. Ichitsubo et al, submitted.
Stable Solid Electrolyte Interphase Formation with Optimal Charging Protocol
Authors: Lee Donggyun , Kim Minsu , Kim Minji , Kim Minjae , Kim Junghwan , Kim Yeonghyun , Kim Youngkeun
Published: December 2024

Stable solid electrolyte interphase (SEI) layers are key to the high performance of lithium-ion batteries, impacting metrics such as coulombic efficiency and cycle life. The instability of the SEI on the surface has severely impeded its practical applications due to poor cycling stability and safety concerns. A non-uniform SEI layer can cause delamination or promote dendrite growth on the surface of the material. Dendrite growth is accompanied by parasitic responses and high electrolyte consumption. Dendritic structures can penetrate the separator and eventually reach the electrode side, compromising battery safety. Therefore, it is important to prevent local concentration of lithium and form a uniform SEI. The SEI varies as a function of electrode material, electrolyte and additives, temperature, potential, and formation protocol. In this study, the charging method and conditions for stable SEI formation are identified using design of experiment method. To achieve high coulombic efficiency, variables such as charging and discharging time, charging and discharging current, and rest time were optimized. Because experiments are time-consuming and expensive, formal experimental design methods optimize measurements of the design space to obtain the best model with the fewest observations. In classical experimental design, the processes of modeling and optimization are distinct; however, contemporary approaches that are based on models have the capability to modify the response surface for more effective sampling and incorporate optimization directly within the modeling process. In this study, charging conditions are identified using machine learning based design of experiments. As a result, optimal charging protocol conditions with high coulombic efficiency are found with fewer experiments compared to classical experimental design methods.
Simulation of the Solid Electrolyte Interphase Layer in Lithium Metal Batteries – a Systematic Study
Authors: Morey Madison , Lobel Maya , Ryan Emily
Published: December 2024

Instability of the anode-electrolyte interface and uncontrolled lithium (Li) dendrite growth pose serious safety concerns hindering the commercialization of high energy density Li metal batteries (LMBs). In particular, the Solid Electrolyte Interphase (SEI) layer is a key factor causing instability at the interface. The SEI layer is formed due to side reactions between Li, electrons, and electrolyte. When stable, this layer acts as a passivation layer that allows for transport of Li ions (Li+) to the anode while keeping the electrolyte and anode separated reducing the side reactions along the anode surface. However, following the initial growth of the SEI layer, the diffusion and reaction kinetics initiate dendrite growth, leading to the rupture of the SEI layer and exposure of fresh metallic Li. The high reactivity of Li metal results in continuous and rapid growth due to high reaction rates and fast kinetics. Finally, the SEI layer will reform over the exposed Li leading to excess electrolyte consumption causing permanent capacity loss and reduced coulombic efficiency.

We present a systematic computational study of the various methods that are used to simulate the impact of the SEI layer, with varying level of complexity. Methods that were studied include varying reaction rates based on thinning and fracture of the SEI layer, a fixed SEI layer that possesses effective transport properties based on the porosity and tortuosity of the compact layer, the consideration of surface energy, and a competing current system that accounts for the ions consumed due to the parasitic SEI formation reaction.
Cycling Performance Research on Disordered Rock Salt Cathode Material in Lithium Ion Batteries
Authors: Fu Yanbao , Battaglia Vincent
Published: December 2024

A worldwide effort is presently underway to develop electric vehicles (EVs) or hybrid electric vehicles (HEVs) to reduce fossil fuel consumption in the transportation area. Lithium-ion batteries are the first choice to be used in EVs and HEVs due to their high energy and power density in the existing commercial battery eco-system. With the ever growing EV market, lithium ion battery manufacturers and researchers are facing many challenges, one of which, is how to cut down the metals in the cathode which are rare, expensive, and unbenign to the environment. Over past few years, cobalt-free is a popular topic in the cathode materials research and development effort. Under this topic, disordered rock salt (DRX) cathode materials, that were invented in recent years, have been attracting interest due to their potential high capacity and high energy-density compared with current commercial cathode materials. In the DRX materials, a disordered arrangement of cation species is established, which imparts the DRX materials with its unique lithium transport properties and small volume changes during charge–discharge cycling [1]. Disordered arrangement of cation species also leads to the sloping voltage profile which makes the capacity of the DRX materials dependent on the cut-off voltage. In this research the effect of cut-off voltage on the electrochemical performance of Li1.2Mn0.6Ti0.2O1.8F0.2 DRX was investigated along with the long-term cycling performance.

Figure 1. The cycling performance of Li1.2Mn0.6Ti0.2O1.8F0.2/Li half cells with different test protocols.

Reference

[1] R. J. Clement, Z. Lun and G. Ceder. Cation-disordered rocksalt transition metal oxides

and oxyfluorides for high energy lithium-ion cathodes, Energy Environ. Sci., 2020,13, 345-373.

Figure 1
Electrochemical Analysis of the Cathode/Electrolyte Interface in Li-Ion Batteries by Scanning Electrochemical Microscopy (SECM)
Authors: He Rong , Zhou Meng , Luo Hongmei , Tenent Robert
Published: December 2024

Lithium ion battery (LIB) performance degradation is a complex process involving multiple overlapping, but still poorly understood mechanisms. Processes occurring at the anode-electrolyte interphase, commonly known as the “solid-electrolyte interphase” (SEI) in LIBs are known to stabilize cell performance and have been extensively studied. Similar processes occurring at the cathode-electrolyte interphase (CEI) are less well studied, however, CEI processes are known to form products which drive cell degradation. How these products form, and hence, how they can be controlled remains an active area of research. Multiple processes are known to occur at the CEI including oxidation of the electrolyte, dissolution of transition metals and gas evolution both from electrolyte decomposition as well as decomposition of the cathode material itself. Recent work has shown that electrolyte oxidation processes in the presence of metal oxide cathode materials may occur through multiple mechanisms including direct electron transfer from the electrolyte to the electrode as well as the potential chemical oxidation of the electrolyte by reactive species leaving the cathode at high voltage.

Scanning electrochemical microscopy (SECM) is a powerful scanning probe technique that can be used to characterize near surface electrochemical processes under steady state conditions. The technique is particularly well suited to study short-lived reactive species as well as the presence of chemical reactions coupled to electron transfer processes. Our work uses these capabilities to help unravel some of the complex processes occurring as part of the electrolyte oxidation process at the CEI. We use SECM to explore electrolyte oxidation processes occurring at non-intercalating electrodes (Pt and glassy carbon) and compare to companion studies using model metal oxide cathode materials. This allows isolated study of direct electron transfer between the electrode and electrolyte and potential chemical oxidation processes that may occur at the metal oxide surface. Studies of these two processes appear to show both similarities and differences between apparent chemical and electrochemical oxidation routes for the LIB and results will be shared in this presentation.
Solvent-Free Molten Salts for Next Generation Lithium Metal Batteries
Authors: Amanchukwu Chibueze
Published: December 2024

Lithium metal batteries (LMBs) promise high energy densities for electrified transport. Liquid electrolytes are currently state-of-the-art, but they are highly volatile and flammable and exacerbate safety concerns. In addition, the desolvation barrier for metal electrodeposition can be high. Solid state batteries promise to address the safety concerns plaguing liquids but suffer from highly resistive electrode/electrolyte interfaces. In our work, we explore the use of low melting inorganic molten salts as electrolytes for LMBs. These electrolytes do not contain organic moieties and are not susceptible to the reactions that plague organic moieties in conventional ionic liquids and small molecule electrolytes. Furthermore, they are non-volatile and nonflammable, retaining the promise of solid-state systems. We show these electrolytes have high ionic conductivities at ~80°C, enable smooth lithium deposits, support high Coulombic efficiencies, and can support battery cycling. These inorganic molten salts with accessible melting temperatures open a new class of electrolyte media for both conventional and next generation battery chemistries.
Pyrochlore Structure Enables Stable Cycling Performance of Iron Fluoride Cathodes
Authors: Baumgartner Julian F. , Stoian Dragos C. , Marshall Kenneth P. , Jafarpour Mohammad , Klimpel Matthias , van Beek Wouter , Abdolhosseinzadeh Sina , Kravchyk Kostiantyn V. , Kovalenko Maksym V.
Published: December 2024

Iron (III) fluorides are appealing low-cost cathode materials for next-generation lithium-ion batteries due to the virtually unlimited supply of the constituting elements and high energy densities.[1] However, the lack of sufficiently large Li-ion diffusing channels in the thermodynamically stable rhombohedral iron fluoride modification impede fast Li-ion conduction, while also inducing phase transformations of the active material during lithiation, ultimately causing contact loss with the conductive network, and resulting in rapid capacity fade. Meanwhile, the pyrochlore modification of iron fluoride may enable fast Li-ion diffusion due to its 3D interconnected channels, as well as significantly improved cycling stability.[2] Inspired by the synthesis of porous materials, such as metal organic frameworks, zeolithes and Prussian blue analogues, which often employ dissolved precursor building blocks that condense into the desired porous structure in the presence of a suitable templating agent, we recently reported on the synthesis of pyrochlore iron hydroxy fluoride (Pyr-IHF) from soluble iron (III) fluoride precursors at ambient conditions.[3] This facile dissolution-precipitation synthesis allows the production of Pyr-IHF particles with narrow particle size distribution at low costs (10-20 $ kg-1), competitive with Lithium iron phosphate. Moreover, we demonstrated excellent rate capability up to 1 A g-1 (4 C) with a capacity retention of > 80% after 600 cycles, and provided the first experimental evidence for Li-ion diffusion occurring through the 3D channels of Pyr-IHF, by studying the electrochemical performance of Pyr-IHF samples with varying contents of zeolithic water within the 3D channels.

Herein, we extend our work on the lithiation mechanism of Pyr-IHF. We demonstrate its outstanding structural stability during cycling with almost no volume change or morphological changes to the particles, challenging the notion of iron fluorides as conversion-type materials. Using operando spectroscopy, and X-ray total scattering, we study the lithiation mechanism of Pyr-IHF on an atomic level. Without the need for elaborate cathode designs, we demonstrate outstanding cycling stability for 500 cycles at 100 mA g-1 (0.4 C), with a high cumulative discharge capacity close to 60.000 mA h g-1.

[1] F. Wu, G. Yushin, Energy Environ. Sci.
2017, 10, 435.

[2] C. Li, C. Yin, L. Gu, R. E. Dinnebier, X. Mu, P. A. van Aken, J. Maier, J. Am. Chem. Soc.
2013, 135, 11425.

[3] J. F. Baumgärtner, M. Wörle, C. P. Guntlin, F. Krumeich, S. Siegrist, V. Vogt, D. C. Stoian, D. Chernyshov, W. van Beek, K. V. Kravchyk, M. V. Kovalenko, Adv. Mater.
2023, 35, 2304158.

Figure 1
Electrochemical Behavior Variation of Graphite/LiNi0.6Co0.2Mn0.2O2 Cells during Overdischarge
Authors: Kim Bong Jin , Yoon Geon Woo , Ryu Ji Heon
Published: December 2024

As the demand for secondary batteries surges with the growth of the electric vehicle market, challenges related to the disposal and recycling of used batteries are escalating. Proper recycling of lithium-ion batteries (LIBs) necessitates the implementation of an efficient discharge process to deplete their stored energy. Successful disposal and disassembly hinge on conducting a thorough discharge, including deep overdischarge, to effectively eliminate stored energy.

This study aims to provide a thorough comparative analysis of the electrochemical behavior of lithium-ion batteries during overdischarge. Coin-type full cells were fabricated using the commonly employed graphite negative electrode and LiNi0.6Co0.2Mn0.2O2 (NCM622) positive electrode, and their electrochemical behavior during overdischarge and forced discharge was evaluated by constant current, constant current/voltage discharge, and galvanostatic intermittent titration technique (GITT).

Cells were manufactured with varying electrode compositions, N/P ratios, degrees of deterioration, etc., and their electrochemical behavior during overdischarge was compared. Additionally, the evaluation was conducted using various current magnitudes, application methods, and temperature conditions. While minor discrepancies in electrochemical characteristics emerged during spontaneous discharge up to 0 V, variations in cell configuration and evaluation conditions induced differing behaviors during forced discharge below 0 V. These findings contribute to a better understanding of battery overdischarge behavior and offer fundamental insights for developing an efficient overdischarge process in battery recycling.