bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Engineering of High-Nickel NMC Cathode Materials with Fumed Al2O3 Via Dry Particle Coating for Enhanced Structure Stability and Battery Performance
Authors: He Zizhou , Xu Nengneng , Wang Yudong , Zhou Xiao-Dong
Published: December 2024

As the Li ion batteries industry moves towards high-nickel cathode materials owing to their high energy density, improved rate capability and extended working voltage, the challenges associated with these cathode materials, such as structural instability and electrochemical degradation, become increasingly prominent. Surface modification is one of the most effective ways to mitigate these problems by forming a protective layer and inhibiting transition metal dissolution. Herein, we reported a novel, highly efficient, solvent-free approach to dry coating high-nickel NMC (Lithium nickel manganese cobalt oxides) cathode materials with ultrafine fumed nano Al2O3 (10 nm). The resulting coating layer exhibits remarkable robustness via the strong van der Waals force between Al2O3 and the NMC host, which could effectively mitigate the side reaction of the high-nickel NMC cathode during cycling and thereby significantly improving the cycle performance and the rate capability of the NMC cathode materials (maintained stable at 1C over 100 cycles). We found the uniform surface coating could alleviate the mechanical fracture of NMC particles. Although the Al2O3 is electrochemically insulating, there are still some uniform porous spaces remaining on the surface of the NMC particles, serving as the fast li ion transfer pathways, which benefit the good rate capability. Moreover, the introduction of extra Al2O3 does not affect the capacity of the cathode due to the small amount (only 1%), it shows similar initial capacity at 0.1C compared with the uncoated NMC. The protection mechanism of the Al2O3 dry coated cathode surface is further revealed through electrochemical impedance spectroscopy (EIS) measurements conducted on the coated and uncoated electrode. In conclusion, the rapid dry coating process could effectively enhance the performance of the high-nickel NMC cathode materials and holds the promise to be scalable up to large-scale continuous processes which could be very desirable for industrial manufacturing.
Cation-Anion Engineering for Conductivity Enhancement in Fluorosulfide La2SrF4S2
Authors: Zhong Chengchao , Xu Tailei , Shintomi Yu , Tachibana Shintaro , Shimoda Keiji , Orikasa Yuki
Published: December 2024

The development of high-performance fluoride-ion (F−) conductors is essential for the practical application of all-solid-state F− batteries, which are expected to have a high energy density (5000 W·h/L). To date, the crystal structures of the F− conductors have been mainly limited to perovskite-, fluorite- and tyssonite-type fluorides. None of these fluorides has yet been found to have high conductivity and a wide potential window at room temperature, necessitating a paradigm shift in materials development.

We found in fluorosulfides La2SrF4S2, the triple-fluorite layer La2SrF4 allows for a two-dimensional F− conduction, which is not found in single anion fluorides[1]. The presence of a sulphur layer widens the conduction space of the F− layer and promotes the F− conduction. In this study, we attempted to improve the F− conductivity in La2SrF4S2 by cation-anion engineering. Specifically, (i) La2SrF4+xS2-xClx, in which S2− was changed to Cl− and excess F− was introduced, and (ii) La2Sr1-xPbxF4S2, in which Sr2+ was changed to Pb2+ with 6s2 lone pair electrons, were synthesized and the change in F− conductivity were explored and explained from a crystallographic point of view.

Solid-state synthesis was used for all samples. The starting materials used were La2S3, LaF3, SrF2 and LaCl3 for La2SrF4+xS2-xClx and La2S3, SrF2, PbF2 and LaF3 for La2Sr1-xPbxF4S2. The raw materials were weighed in stoichiometric ratios, formed into pellets, vacuum-sealed using a Ta container and quartz tubes, and sintered at 1000 °C for 48 h. Powder X-ray diffraction was used to identify the samples, while AC impedance method was used to measure ionic conductivity. For measurements, pellets of the synthesised powder were isostatically pressed (190 MPa), re-sintered at 1000 °C for 48 h and gold deposited on both sides.

(i) The ionic conductivity of La2SrF4.1S1.9Cl0.1 at 160 °C was 6.26 × 10−6 S cm−1, which is five times higher than that of La2SrF4S2. The increase in the conductivity might attribute to the introduction of excess F− in the lattice by replacing divalent S2− with monovalent Cl−. This suggests that the use of mixed-anion compounds allows carrier control by anions, which is different from the carrier control of by cation substitution in previous F− conductors.

(ii) The ionic conductivity of La2Sr0.6Pb0.4F4S2 at 160 °C was 2.56 × 10−4 S cm−1, which are both higher than those of La2SrF4S2 and La2SrF4.1S1.9Cl0.1. 19F MAS NMR showed that the number of F− in the hetero-cationic environment increased after the introduction of Pb2+, suggesting that the distorted cationic sublattice is partly responsible for the conductivity enhancement.

In conclusion, using the mixed-anion compound La2SrF4S2 as a model, we found new strategies to improve F− conductivity by cation-anion engineering.

[1] S. Tachibana, C. Zhong, K. Ide, H. Yamasaki, T. Tojigamori, H. Miki, T. Saito, T. Kamiyama, K. Shimoda, Y. Orikasa, Chem. Mater.
2023, 35, 4235-4242.
Intermediate-Temperature Steam Electrolysis Using Phosphate-Based Thin Film Electrolytes
Authors: Nakagami Ayuka , Tada Shohei , Kikuchi Ryuji
Published: December 2024

Hydrogen has been regarded as a key energy medium toward the realization of a carbon-neutral society. Currently, hydrogen is mostly derived from fossil fuel without capturing CO2, and does not contribute to carbon neutrality at all. Hydrogen production by water electrolysis powered by renewable electricity is attracting attention as an effective method for "green hydrogen" synthesis that does not emit CO2 in hydrogen production and utilization processes. As a water electrolysis device, we are working on solid-state electrolytic cells with a phosphate-based electrolyte operative at intermediate temperatures from ca. 100 to 300⁰C. This system offers excellent mass transfer characteristics of water (steam) in the electrode catalyst layer and superior electrode reaction kinetics due to an elevated temperature. In addition, it is applicable to electrochemical reduction of N2 and CO2 to NH3 [1] and hydrocarbons [2], respectively.

Several studies using phosphate-based electrolytic cells reported steam electrolysis in the intermediate temperature range [3, 4]. So far, thick disk-type electrolyte and composites with polymers have been employed in steam electrolysis to maintain ionic conductivity and stability under high water vapor pressures, which resulted in high applied voltage and large ohmic loss. Therefore, we aimed to develop a highly efficient steam electrolytic cell at intermediate temperature and to reduce the effective resistance of the electrolyte by developing thin film electrolyte comprising of CsH5(PO4)2/SiP2O7, which exhibits high proton conductivity in the temperature range of 100 to 300°C. Thin film of the electrolyte was synthesized on a porous substrate, and the conductivity and stability of the electrolyte have been investigated. Steam electrolysis cell was fabricated using developed thin film electrolyte, and electrochemical performance of the cell was evaluated in steam electrolysis at intermediate temperatures.

[1] Y. Yuan, S. Tada, R. Kikuchi, Mater. Adv., 2, 793 (2021).

[2] N. Fujiwara, S. Tada, R. Kikuchi, iScience, 25, 105381 (2022)

[3] N. Fujiwara, H. Nagase, S. Tada, R. Kikuchi, ChemSusChem, 14, 417 (2021)

[4] P. Bretzler, E. Christensen, R.W. Berg, N.J. Bjerrum, Ionics, 28, 3421 (2022)
Fabrication of Anode Functional Layer By Reactive Sputtering for Large Area Thin-Film Solid Oxide Cells
Authors: Ju Kyoungjae , Kim Hyong June , Shin Dong Won , Yang Byung Chan , Hong Jee Ho , Jo Sung Eun , Park Wan Woo , Son Ji-Won , An Jihwan
Published: December 2024

Solid Oxide Cells (SOCs), the electrochemical device that converts chemical to electrical energy, or electrical to chemical energy, have been highlighted for its high efficiency, fuel flexibility, and reversible operation modes between fuel cells and electrolyzers. Recent research has focused on developing intermediate-temperature SOCs (operating between 500 ~ 700°C) to address issues such as thermal durability, and cost. However, reducing the operating temperature presents challenges including decreased rates of charge and ion transport. Consequently, fabricating thin-film SOCs (TF-SOCs) constructed on porous anode supports helps maintain adequate power density even at lower temperatures.

Traditional anode supports, however, present limitations in fabricating thin electrolytes due to their rough surface topographies and large pore structures, inherent to powder-based processing methods. To overcome these challenges, vacuum deposition techniques have emerged as alternatives, offering precise control over micro to nanostructures. This precise control enables the smoother layer, referred to as anode functional layers (AFLs), characterized by finer grain sizes. The fabrication of nanostructured AFLs (n-AFLs) enhances the triple-phase boundary (TPB) length, charge transfer, and overall electrochemical kinetics of the cell.

Despite these advancements, scalability remains a critical problem that prevents the commercialization of SOCs with optimized AFLs. One of the physical vapor deposition techniques, sputtering, attracts attention due to its scalability, reproducibility, and compatibility with multilayered designs. Reactive sputtering allows the deposition of composite materials by introducing reactive gases during the deposition process.

In this study, we fabricated a large-area (12cm x 12cm) n-AFL featuring nano-sized grains via reactive sputtering. A thermal treatment at 1200°C was followed to ensure the structural integrity and stability. By optimizing sputtering power and oxygen partial pressure, we successfully suppress pore and crack formation and Ni agglomeration during the post-annealing, resulting in a durable AFL with enhanced performance characteristics.

The optimized AFL, fabricated under 3kW sputtering power and 80% oxygen partial pressure, effectively mitigates structural defects induced by the thermal process. Consequently, TF-SOCs with n-AFL exhibit impressive performance in fuel cell mode, achieving power densities of 1286mW/cm2 at 650°C and 912mW/cm2 at 600°C. In contrast, cells without the n-AFL show low open-circuit voltages (OCV) of below 0.8V. It is speculated that the gas crossover is due to the pores generated from the heat treatment.
(Invited) Input of Atomic Layer Engineering for Active and Stable Electrodes for Solid Oxide Cells
Authors: An Jihwan , Kim Hyong June , Li Haoyu , Lee Minhwan
Published: December 2024

Reversible solid oxide cells (rSOCs), which can operate both in fuel cell and electrolysis cell modes, offer an effective solution for the conversion and storage of renewable energy with hydrogen as an energy carrier. Nonetheless, the commercialization of rSOCs remains limited due to technical challenges such as yet insufficient electrochemical performance (particularly in intermediate temperature range of 500-700 °C), short lifespan caused by degradation phenomena, and high system costs associated with the high operating temperatures. rSOCs, therefore, necessitate the appropriate designing and fabrication of highly active and thermally stable bifunctional catalysts with minimal noble metal loadings.

This study demonstrates the route to incorporate highly dense metal catalyst nanoparticles onto the electrodes’ surface of SOC with plasma-enhanced atomic layer deposition (PEALD) process that is the variant of chemical vapor deposition (CVD). For hydrogen electrode, we employed Pt nanoparticles fabricated via PEALD to a nickel-yttria stabilized zirconia (Ni-YSZ) electrode as effective catalysts in fuel cell and electrolysis modes. The superior electrochemical performance of the PEALD Pt@Ni-YSZ catalytic electrode, despite the remarkably low Pt catalyst loading (0.2 µg cm-2), the notable lack of degradation of the cell voltage for 50 h operation at 700 °C. For oxygen electrode, we present a highly effective approach to enhance air electrode performance and durability by depositing an ultra-thin layer of metallic Ru, as thin as ~7.5 Å in nominal thickness, onto (La0.6Sr0.4)0.95Co0.2Fe0.8O3-δ (LSCF) using PEALD. Our study uncovers the beneficial role of a newly formed perovskite, SrRuO3, which emerges from the reaction between ALD-based Ru and surface-segregated Sr species.
Molybdenum-Catalyzed Electrochemical Ammonia Synthesis Using Zero-Gap Electrolysis Cell
Authors: Kiyota Yasuhiro , Tamura Jun , Oki Mitsuhiro , Yoshiki Masahiko , Arashiba Kazuya , Nishibayashi Yoshiaki , Sugano Yoshitsune
Published: December 2024

Ammonia, which is a valuable material not only as a fertilizer but also as a potential alternative to fossil fuels has been conventionally synthesized under high temperature and pressure conditions by the Haber-Bosch method. Recently, an innovative method for the synthesis of ammonia from water and nitrogen under ambient conditions using Mo complexes has been reported.[1] In this study, a cathode supported by the Mo complex was prepared and the electrochemical production of ammonia was demonstrated using a zero-gap electrolysis cell.

A catalyst layer consisting of porous carbon was spray coated on carbon paper. The Mo complex [MoI3(PCP)] (PCP: 1,3-bis((di-tert-butylphosphino)methyl)benzimidazol-2-ylidene) was supported on the carbon substrate by immersion. A 4-cm2 zero-gap electrolysis cell was constructed using the cathode, an ion-exchange membrane and IrOx-loaded Ti nonwoven fabric as the anode.

The nitrogen reduction reaction (NRR) was performed at constant current by supplying nitrogen gas to the cathode and K2SO4 electrolyte to the anode. Ammonia produced at the cathode was collected by a H2SO4 trap at the cathode outlet, which was changed every 5 minutes. When 50 mA/cm2 was applied, the ammonia production rate was maximized in the 10-15 minutes, with an ammonia production partial current density of 2.9 mA/cm2, a Faraday efficiency of 5.7%, and a cell voltage of 3.1 V. A high ammonia production rates (over 1000 µg mg-1 h-1) was achieved among aqueous electrochemical NRR.[2] Further improvements of the NRR electrolyzer and results of XAFS analysis of Mo complexes are also presented.

This paper is based on results obtained from a project, JPNP21020, commissioned by the New Energy and Industrial Technology Development Organization (NEDO).

[1] Y. Ashida, K. Arashiba, K. Nakajima et al., Nature
568, 536 (2019).

[2] H. Shen, C. Choi, J. Masa et al., Chem
7, 1708 (2021).

Figure 1
(Digital Presentation) Performance of a Paper-Based Microfluidic Fuel Cell Using Eco-Friendly LaFeO3 and CaFe2O4 Nanoparticles as Anode
Authors: Prado Hernandez Victor Manuel , Castellanos Bernal Cindy Vanessa , Gómez Lara Kevin Steven , Dector Andrés , Morales Jimmy
Published: December 2024

Renewable energy generation is an innovative approach that uses the electrochemical properties of substances that can be used as fuels, for example, urine and in addition to mixed metal oxides for the generation of energy from fuel cells based on synthetic urine. In this study, energy generation was carried out in a synthetic urine sample, using ferrites of the CaFe2O4 and LaFeO3 type as anode. These materials act as sensors that react with the analytes present in the urine sample, producing a detectable electrical signal. In the study, a cell with two electrodes was used, one made of platinum (cathode) and another made of synthesized material (anode). The synthesized materials were prepared using a mixture of nitrates, and the synthetic urine sample, which was deposited on a paper microfluidic fuel cell design. Six assemblies were carried out and the results were satisfactory for the study.

References

Saputra, H. A. (2023). Electrochemical sensors: basic principles, engineering, and state of the art. Monatshefte Fur Chemie, 154(10), 1083–1100

Salih, S.J.; Mahmood W.M. Review on magnetic spinel ferrite (MFe2O4) nanoparticles: From synthesis to application, Heliyon 2023, 9, e16601

Pandiyan, R., Vinothkumar, V., Chen, S. M., Sangili, A., & Kim, T. H. (2023). Integrated LaFeO3/rGO nanocomposite for the sensitive electrochemical detection of antibiotic drug metronidazole in urine and milk samples. Applied Surface Science, 635, 157672

Nemati, S. S., Salemi-Seresht, M., Abdi, Y., & Dehghan, G. (2024). Highly sensitive and label-free detection of naproxen using mixed metal oxide-based field effect transistor as a biosensor for in-vitro analysis of urine. Materials Science in Semiconductor Processing, 179, 108487
Geometrical and Electronic Structures of Red Phosphors Doped with 3d Transition Metals
Authors: Yamamoto Tomoyuki , Hirano Moe , Nematov Dilshod , Burkhonzoda Amondulloi , Umar Zafari , Brik Mikhail G.
Published: December 2024

Phosphors have become increasingly important in our lives with the spread of white LEDs in recent years. The most basic structure of a white LED is a combination of a blue LED and a yellow phosphor, but this combination results in a white color with a high color temperature that leans toward bluish-white. Therefore, red and green phosphors are demanding in order to adjust the color temperature and improve color rendering property. In addition to the demands of high efficiency and long-term stability for such phosphors, it is also important that the raw materials are low-priced. Many red phosphors achieve red fluorescence by adding a few percent or less concentration of rare earth elements. However, their supply may become unstable, since rare earth elements are unevenly distributed in certain regions of the earth. Therefore, it is requested that the phosphors without rare-earth elements. Recently we have reported stable rare-earth free res phosphors using 3d transition metals with 3d3 configuration, such as Cr3+ and Mn4+, to replace rare-earth elements [1-3]. In the current study, geometrical and electronic structures of phosphor materials doped with Cr3+ and Mn4+ are demonstrated both experimentally and theoretically. Especially, we focus upon the local environment of doped 3d transition element, which are studied in detail by X-ray absorption near edge structure (XANES) and electron spin resonance (ESR) analysis with the aid of the first-principles calculations.

References

[1] M.S. Kurboniyon et al., Phys. Status Solidi B260 (2023) 2200575.

[2] U. Zafari et al., Opt. Mater.: X 16 (2022) 100197.

[3] M. Sagayama et al., ECS J. Solid State Sci. Tech. 10 (2021) 076004.
Orthogonal Upconversion Luminescence from Core/Shell-Structured Upconversion Nanophosphors
Authors: Jang Ho Seong , Hong A-Ra , Kyhm Jihoon , Kang Gumin
Published: December 2024

Upconversion nanophosphors (UCNPs) are lanthanide ion-doped nanocrystals that exhibit anti-Stokes shift luminescence. Typically, UCNPs such as NaYF4:Yb,Er and NaYF4:Yb,Tm emit green and blue light under 980 nm near-infrared (NIR) light excitation. The emission color of lanthanide ion-doped UCNPs depends on the dopant ions in the host nanocrystals. Thus, one can adjust the dopant ions to control the upconversion (UC) luminescence color. For example, UC luminescence color can be tuned by co-doping activator ions into a single host nanocrystal and adjusting the ratio of two different activator ions. In addition, UC luminescence color can be tuned through energy migration UC process in core/shell-structured nanoparticles and by controlling the pulse of an NIR laser. Recently, orthogonal UC luminescence has been reported. In this study, UC luminescence color tuning is shown from the orthogonal UC luminescent UCNPs. To achieve orthogonal UC luminescence, core/multishell-structured UCNPs are synthesized. Depending on the excitation wavelength of NIR light, the UC luminescence color changes, and the core/multishell-structured UCNPs exhibit various UC luminescence colors by adjusting the excitation conditions. Finally, the feasibility of applying core/multishell-structured UCNPs in transparent displays is investigated.
First-Principles Analysis of the Influence of the Valence on the Optical Spectra of Uranium Ions in Oxide Crystals
Authors: Masago Toshiki , Ogasawara Kazuyoshi
Published: December 2024

Recently U6+-doped oxide green phosphors are attracting attentions for the white LED application. However, the absorption and emission mechanisms in some of these materials are still unclear. For the development of the novel uranium-doped phosphors, clarification of the origins of the peaks in the absorption and emission spectra of these materials is indispensable.

In our previous research, we investigated the origin of the peaks in the optical spectra of uranium ions in some oxide crystals by comparing the experimental spectra with the theoretical ones obtained by first-principles calculations. The results indicated that there is a U-doped phosphor whose spectrum seems to originate from 5f-6d transitions of U3+ instead of LMCT transitions of U6+. In this work, in order to investigate the influence of the valence of uranium ions, we created some hypothetical model clusters representing uranium ions in oxides and performed first-principles calculations for the LMCT transitions of U6+ and the 5f-6d transitions of U3+ using the relativistic discrete-variational multi-electron (DVME) code which is a configuration-interaction calculation program based on the four-component fully relativistic wave functions obtained by the relativistic discrete-variational Xα (DV-Xα) molecular orbital method. The effects of coordination numbers and bond distances on valence of uranium ions were also investigated in detail by performing calculations using model clusters with coordination numbers from 6 to 12.
Electrosynthesis for the Invention of New Organic Reactions
Authors: Malapit Christian
Published: December 2024

Electrosynthesis has emerged as a versatile and powerful tool in organic chemistry, facilitating the discovery and advancement of novel organic reactions. By harnessing electricity, this cutting-edge method generates reactive intermediates, driving chemical transformations to produce intricate organic compounds. This talk will present significant breakthroughs from our research group, showcasing the innovative use of electrochemistry in uncovering transformative reactions. Highlighted discoveries include (a) a site-selective arene C–H functionalization reaction, utilizing nitrogen radical intermediates generated through anodic or cathodic processes to yield aryl amines; and (b) an electrochemical strategy for generating carbon-based radicals from organoboron reagents, utilized in constructing diverse carbon–carbon and carbon–heteroatom bonds. The presentation will delve into the discovery process, development, scope, and mechanism of these reactions.
Application of Resin Adsorption Process for Mitigating Protocatechuic Acid Cytotoxicity in Corynebacterium Glutamicum Fermentation
Authors: Cho Jaehoon , Kim Hee Soo , Shin Wooshik
Published: December 2024

Recent advances in biotechnology have brought about revolutionary changes across diverse industries, with microbial fermentation technology playing a important role in the production of high-value compounds. Among these, Corynebacterium glutamicum has emerged as a key strain for efficiently producing biochemicals like amino acids. While fermentation processes using C. glutamicum are widely adopted in industries due to their high productivity and cost-effectiveness, the cytotoxicity of protocatechuic acid (PCA), a metabolic product generated during fermentation, has been a significant hindrance to productivity. PCA, known for its potent electrochemical antioxidant properties and wide application in industries such as food, pharmaceuticals, and cosmetics, poses challenges when accumulated at high concentrations during fermentation, inhibiting cell growth and reducing productivity. Therefore, this study aimed to explore the feasibility of applying adsorption processes to enhance PCA productivity in C. glutamicum. Building on previous research, we investigated an approach to effectively remove PCA from fermentation broth using specific ion exchange resins to reduce cytotoxicity and increase overall PCA production. In this study, we improved C. glutamicum strains and optimized production media to enhance PCA production capacity. Subsequently, we analyzed the impact of adsorption processes using ion exchange resins on alleviating cytotoxicity and improving productivity. Through experimentation, we optimized PCA adsorption efficiency and conditions using ion exchange resins, resulting in the production of 3.97 g/L of PCA in fermentation. This research is expected to contribute to the improvement of high-value biochemical production processes based on microbial fermentation.
An Investigation of Cell Death Induced By Electrochemical Stimulation in Ovarian Cancer
Authors: Yang Zongyu , Wang Fu-Ming
Published: December 2024

Recent research has focused on ion-permeable channels in cancer, aiming to reduce proliferation and induce apoptosis in cells. Voltage-gated calcium channel blockers [1] and ligand-gated ion/calcium channels [2,3] have been explored. By maintaining low cytoplasmic calcium concentrations at rest and mobilizing calcium in response to stimuli, calcium ions serve as second messengers, regulating diverse cellular stimulus-response reactions [4]. Disruptions in intracellular calcium homeostasis can impact cell proliferation and trigger programmed cell death.

In our study, we cultured ovarian cancer (ES-2 cells) on indium tin oxide (ITO)-coated glass as a working electrode. We optimized parameters, including membrane potential amplitude (±60 mV), pulse frequency (1 to 36 times), and duration (2 to 60 seconds). Fig. 1a shows that a single depolarization pulse increases the highest intracellular calcium levels in ES-2 cells. After 24 hours of depolarizing stimulation, the survival rate of ES-2 cells is 66.0±6.2% for single pulses and 74.7±3.7% for multiple pulses. In contrast, the survival rate following hyperpolarization electrical stimulation is 86.3±5.6% for single pulses and 76.5±2.0% for multiple pulses. Fig. 1b indicates that sequential alternating depolarizing and hyperpolarizing stimulation can further induce cell death. Within a possible consideration, the activation of voltage-dependent calcium channels during depolarization stimulation following a stimulation causes calcium influx, and each hyperpolarization stimulation increases permeability of voltage-dependent anion channels to calcium ions between cytosol and mitochondria. This reaction ultimately affects mitochondrial calcium homeostasis and causes cell death. This study of electrical stimulation may have highly possibility for clinical value on therapy method.

Reference

[1] Int J Mol Sci. 2020 Apr; 21(7): 2327.

[2] Front Physiol. 2022 Mar 8;13: 839437.

[3] Cancers (Basel). 2020 Aug; 12(8): 2232.

[4] J Pharmacol Sci. 2006;100(5):519-24.

Figure 1
Lithium Plating on Graphite Electrodes in Lithium-Ion Batteries
Authors: Yeh Che-Ning , Rose Justin , Thaman Harry , Narasimhan Swati , Huang Wei-Yi , Sun Wen , Huang William , Zhang Zewen , Chueh William C.
Published: December 2024

Fast charging of lithium-ion batteries is a critical advancement in achieving more efficient and sustainable energy storage, particularly in electric vehicles. However, fast charging often leads to lithium plating, significantly impacting battery performance and longevity. While it is essential to reduce the amount of lithium plating, characterization of lithium plating is challenging due to high sensitivity of lithium to oxygen and water, small feature sizes, and the complex morphology of the porous electrode and the deposits (dendrites with solid-electrolyte interphase, SEI). Consequently, understanding the mechanism of lithium plating and SEI's influence on it remains elusive.

In our study, we utilize operando atomic force microscopy (operando-AFM) to investigate the dynamic behaviors during lithium plating and stripping on graphite nanoplatelets. This technique allows real-time, nanoscale observation of lithium plating and stripping, providing insights into lithium nucleation, growth, and distribution on the anode surface. Notably, we observe graphite exfoliation during plating and stripping, indicating the loss of active materials and its implications for battery capacity and cycling stability. Additionally, our research explores the interaction between SEI and lithium plating. Understanding how SEI influences lithium plating dynamics is essential for developing strategies to optimize fast charging capabilities.

By gaining insights from our investigations, we aim to inform the design of electrode materials, artificial SEI materials, and electrolyte additives that promote and facilitate fast charging in lithium-ion batteries. These strategies hold promise for enhancing battery safety, reliability, and overall performance, thereby accelerating the adoption of electric vehicles and other energy-intensive applications.
High Performance Li-Ion Batteries Using Binder-Free Anodes
Authors: Brahim Sean , Maat Stefan
Published: December 2024

Li-ion batteries have polymeric binder in their electrodes resulting in high internal resistance and hence long charge times and compromised product lifetime. We previously developed Li-ion batteries utilizing binder-free NMC cathodes containing carbon nanotube (CNT). In this work, we extend the ‘binder-free’concept to two types of battery anodes - graphite and lithium titanate (LTO) anodes. Our proprietary processing of CNT into viscous organic or water-based slurry without surfactant or dispersant eliminates the need for organic binder and carbon black additives in both cathode and anode electrodes. To formulate the binder-free anodes, our processed CNT slurry was mixed with a target quantity of either battery-grade graphite or LTO in IPA solvent using a conventional planetary mixer. The IPA-based binder-free anode mixes were coated onto either Cu foil (graphite) or Al foil (LTO) using a commercial slot-die coater, resulting in uniform coatings after drying which did not exhibit any signs of flaking off or delamination from the respective current collector foils. LiB pouch cells rated at 1.5 Ah and 3 Ah were subsequently assembled containing NMC cathode paired with both types of binder-free anodes. LiB cells with binder-free graphitic anode exhibit very low impedance of 5.2 x 10-2 mΩ/cm2, or >35 % reduction in impedance compared to conventional LiB cell with binder containing graphitic anode, while LiB cells with binder-free LTO anode showed >75 % reduction in impedance compared to LiB cell with binder containing LTO anode. Moreover, the LiB cells with binder-free anodes exhibit superior high-rate capability compared to their counterpart cells containing electrodes with polymeric binder. The LiB pouch cells were tested for fast discharge rate performance at 10C. LiB cells with binder-free graphitic anode display >2x higher specific capacity compared to the cell with binder, while cells with binder-free LTO show 8x higher capacity at 10C rate than conventional LiB cell with polymeric binder after high discharge rate testing.

Figure 1
A Concentration Gradient Approach to Enhance Mechanical and Electrochemical Stability in Ni-rich Cathode Materials for Long-Lasting Lithium-Ion Batteries
Authors: Liu Qi , Huang Zhiyong
Published: December 2024

Fracturing plays a major role in the degradation of electrochemical performance of Ni-rich cathode materials during successive cycles. However, mechanical properties of the cathode materials such as hardness and fracture strength, which closely correlate with cracks formation, have not been intensively studied. Here, we introduce a concentration gradient structure with Ni-rich core and Mn-rich shell. Based on this approach, the radially aligned primary particles formed with spoke- like microstructure, which contributes to the improved hardness and fracture strength. Benefiting from the mechanical stable structure, the concentration gradient cathode can withstand the accumulated strain originated from lattice changes and fatigue destruction during repeated cycles, and thus presents less fractures, which effectively inhibiting the parasitic reaction between electrolyte and cathode through cracks. As a result, the electrochemical stability of the modified material was significantly improved. This work gives a feasible way to improve the mechanically stable Ni-rich cathode for lithium-ion batteries with high energy density.
(Invited) Diagnosis and Prognosis for Facilitating High-Performance Lithium-Ion Batteries in Electric Vehicles
Authors: Kim Duho
Published: December 2024

Recently, diagnosis and prognosis of state of health (SoH) for lithium-ion batteries (LIBs) have been acknowledged as a very critical factor for retaining their initial performances and optimizing them upon cycling in electric vehicle market because fast-charging and dynamic discharging environmental conditions give rise to a rapid decrease of battery performance even its trend is unstructured. Basically, materials used in LIB systems for EVs are a key determinant in determining their specific performances. Therefore, many researchers have tried to developing the various LIB-related materials in reaching high-energy-density and superior cyclic retention using doping in cathode and anodes, coating on their surfaces and grain boundaries, and building composites. Although these efforts led to opening the new era named as EVs, there are still unsolved degradation origins of the battery performance in chemical and physical points of view. To this end, advanced experimental analyses have been employed to provide a clear understanding of why the battery performance degrades during (dis)charging. Likewise, computational science based on density functional theory (DFT) calculations has been utilized to understand the fundamental reaction mechanism and to diagnose the veiled atomistic origins triggering the performance decrease, and coupling it with multiscale and multiphysics methodologies offered a more practical direction for diagnosing. Considering that a mechanism-agnostic data understanding of the battery materials detracts from its predictive speciality for target response values, in this talk, diagnosing and prognosing SoH based on understanding the materials via artificial intelligence technology are introduced with their feasibilities for high-performance of LIBs in EVs.
A Novel Approach to Electrode Delamination for Mechanism Analysis and Signal Detection: Fault-Simulated Li-Ion Batteries
Authors: Kim Suhwan , Choi Seungyeop , Jin Dahee , Kim Kyung-Geun , Lee Mingyu , Lee Hongkyung , Lee Yong Min
Published: December 2024

The demand for increasing energy density of lithium-ion batteries (LIBs) continues to drive research into new compositions and designs. Some prominent strategies are to reduce the content of inactive materials, such as binders and conductive materials, and to increase a thickness of electrodes. However, these approaches can lead to uneven binder distribution and delamination of electrode layers due to the continuous volumetric expansion of the active material reducing the capacity and lifespan of the LIBs. Therefore, binder content and distribution analysis plays a critical role in evaluating battery performance. However, most extensive research has focused on improving the properties and distribution of binders, and systematic analysis and non-destructive detection of defects by binders remain largely unexplored. This research also is crucial for evaluating the remaining life of the battery and determining its suitability for reuse.

In this study, we fabricated a fault-simulated electrodes which can be easily delaminated during electrochemical reactions. When the morphology and composition of the electrode were analyzed, there were no significant morphological differences compared to a normal electrode, but it was observed that the binder compositions were different. As a result of the adhesive strength measurement of the defected electrode at different thicknesses, it was demonstrated that the adhesive strength at the electrode layers and interfaces decreased compared to normal electrodes. The electrochemical signals such as capacity fading and resistance characteristics by the electrode delamination were confirmed. Through the post-mortem analysis, the composition change in the cathode-electrolyte interphase (CEI) inside the electrode was compared and analyzed in relation to the change in current density distribution based on simulation. Furthermore, in order to nondestructively detect the electrode delamination defects, a magnetic field imaging and simulation analyses were conducted, and it was confirmed that the detection of defect spots was possible through this method. By systematically analyzing the electrode delamination, the main cause of electrode degradation was elucidated.
Structural and Grain-Growth Evolution during Synthesis of Layered Li(Ni,Co,Mn)O2 Oxides through Co-Precipitation Process
Authors: Fung Kuan-Zong , Tsai Shu-Yi , Chen Yu-Hsuan , Chen Yu-Fan , Fung Kenneth
Published: December 2024

For meeting 2050 zero carbon goals, the renewable energy/electricity including solar cells and wind mills need to be stored in a good energy storage system such as Li ion batteries. Furthermore, the electrification of transportation such as electric vehicles also need Li ion batteries in a very large scale. In recent years, µm-sized layered oxides, namely single crystals, received great attention due to its enhanced cycled-electrochemical performance.

For conventional/commercial NMC layered oxides, integrated co-precipitation process is commonly used. In additions, “single-crystal” process typically requires more heat energy at higher temperatures. Therefore, the main objective of this study is to develop a cost-effective process for the synthesis of single-crystal Ni-rich layered oxides electrode. For instance, the synthesis of layered oxides may adopt the simple solid state reaction routes. The heating procedures may be optimized through the understanding of calcination and grain-growth processes. Ni-rich layered oxides, namely NCA and NMC 811 are selected and prepared. The crystal structure and microstructure of cathodes were examined using XRD and SEM. The electrochemical properties are monitored using CV, EIS and charge/discharge tests.
Minimizing the Ion/Electron Pathway through Ultra-Thin Conformal Holey Graphene Encapsulation on Li- and Mn-Rich Layered Oxide Cathode for High-Performance Lithium-Ion Batteries
Authors: Kim Sungwook , Ahn Heejoon
Published: December 2024

Lithium-ion batteries (LIBs) are increasingly favored due to their attractive features. The design of the cathode in LIBs plays a critical role in determining cell capacity, operating voltage, and overall cost. Lithium- and manganese-rich (LMR) cathode materials stand out as promising candidates for the next generation of cathode materials due to their ability to operate at high voltages and provide capacity exceeding 250 mAh g-1. However, despite these appealing characteristics, LMR faces challenges in commercialization due to factors such as poor rate capability and rapid capacity and voltage decay during cycling. These are closely associated with the fundamental structural issues arising from the two distinct phases of LMR materials, slow reaction kinetics, and structural degradation occurring through side reactions between the electrode and electrolyte. In this study, we introduce a carbon encapsulation technique that integrates polyethylenimine (PEI) and holey graphene onto the LMR surface, aiming not only to augment electrical conductivity but also to facilitate ionic conductivity. Despite its low carbon content of 0.1 wt%, the suggested PEI/holey graphene-encapsulated LMR demonstrates enhanced cycle stability and rate performance for the LMR electrode. Moreover, the thin and uniform PEI/holey graphene encapsulation layer serves a dual purpose by easing the movement of Li+/e- on the LMR surface and providing a protective barrier against physical and chemical aggressions. Throughout cycling assessments, the PEI/holey graphene-encapsulated LMR mitigates the leaching of transition metals, mitigating microcrack formation and irreversible structural alterations compared to bare LMR. Consequently, the proposed PEI/holey graphene encapsulation emerges as an attractive technology for high-performance LIB design, concurrently elevating the cycle stability and rate performance of LMR electrodes.
Carbon Based Conductive Additives for Dry Coated Cathodes
Authors: Damnali Serkan , Woehrle Thomas
Published: December 2024

In the course of climate change, electromobility is one of the biggest driving forces to reduce the CO2-emissions caused by humans. According to estimates, about 60 % of the total emissions from humans are caused by vehicles powered by internal combustion engines.[1] Thus, it is expected that the demand for lithium-ion batteries will increase from 700 GWh in 2022 to 4.7 TWh in 2030.[2] On the other hand, it must be stated that during the manufacturing of lithium-ion batteries cells, a considerable amount of energy is consumed. Estimations using publicly available data of two large-scale battery cell factories state that around 50 – 65 kWh of electricity is consumed per kWh of battery capacity.[3] Besides the operation of the dry room in battery manufacturing, the evaporation of the casting solvent in the electrode drying process consumes the most energy.[4,5,6] In a dry coating process, the casting solvent used for the conventional electrode production is eliminated.[7] Thus, this process provides a more sustainable battery manufacturing process.[8] One of the most promising approaches in this regard is the application of Polytetrafluoroethylene (PTFE) as an electrode binder which forms fibrils that anchor to active material particles and the conductive carbon additives.

The general aim of this work is to establish a fundamental understanding of processing cathodes via a dry process in a lab-scale following this route. Electrically conductive additives play a crucial role for processing, mechanical properties, and electrochemical performance of the electrode. Thus, various conductive additives (like carbon blacks, conductive graphite, and porous carbons) are characterized and their influences on process steps (like mixing and calendaring) and electrochemical performance of the cathodes is investigated to obtain structure-impact-relations for dry cathode manufacturing. Here, the focus will be on the interaction of the various carbons with the binder PTFE used in the dry coating process.

References:

[1] Golovanov, N., Marinescu, A., 8th International Conference on Modern Power System, 2019.

[2] https://www.mckinsey.com/industries/automotive-and-assembly/our-insights/battery-2030-resilient-sustainable-and-circular#/ (opened: 09.04.2024).

[3] Kurland, S.D., Environ. Res. Commun., 2020, 2.

[4] Sliz, R. et al., ACS Appl. Energy Mater., 2022, 5, 4047 – 4058.

[5] Yuan, C., Deng, Y., Li, T., Yang, F., CIRP Annals Manufacturing Technology, 2017, 66, 53 – 56.

[6] Ahmed, S. Nelson, P.A., Gallagher, K.G., Dees, D. W., Journal of Power Sources, 2016, 322, 169 – 178.

[7] Ludwig, B., Zheng, Z., Shou, W., Wang, Y., Pan, H., Scientific Reports, 2016, 6.

[8] Li, Y. et al., Materials Today, 2022, 55, 92 – 109.
High-Performance Lithium-Ion Batteries: Dispersant-Free Nanocarbon for N-Doped Si-Carbon Composite
Authors: Lee Do Geun , Cho Joon Young , Kim Jung Hoon , Ryoo Gyeongbeom , Lee Min Ho , Park Jong Hwan , Lee Dong Yun , Choi Jeong-Hee , Han Joong Tark
Published: December 2024

Nanomaterials exhibiting high conductivity have attracted immense interest for their promising applications in stabilizing electrodes for Li-ion batteries. Despite this, challenges in their dispersion and effective integration with active materials remain unresolved. In this study, we introduce an innovative strategy to augment Si-based anode materials, employing minimally defective graphene oxide (C-GO) and significantly oxidized single-walled carbon nanotubes (C-SWCNTs), synthesized via a chlorate-based oxidation process. Our technique encapsulates Si alloy (SiA) particles with C-GO and C-SWCNTs, circumventing the necessity for supplementary additives. We engineer composite structures featuring lithiophilic N-doped SWCNTs and a highly crystalline, reduced C-GO coating on SiA surfaces through spray drying, followed by chemical reduction. This synergistic integration results in impressive capacities, consistent retention performance, and exceptional initial capacities (1224 mAh g-1), alongside superior retention rates (82.3% after 100 cycles at 0.1 C). When applied in a LIB full-cell with a SiA/NC anode, the system delivers a high energy density of 350 Wh kg-1, while preserving 65% of its capacity after 200 cycles. Our results underscore the efficacy of this hybrid methodology, obviating the need for additional conducting additives and maintaining a minimal binder content (5 wt%). This research puts forth a viable solution to enhance Si-based anode materials in lithium-ion batteries, successfully addressing the persistent issues of nanomaterial dispersion and hybridization in electrode design.

Acknowledgment

This research was supported by the Primary Research Program (24A01016) of the Korea Electrotechnology Research Institute, and the National Research Council of Science & Technology (NST) grant by the Korea government (MSIT) (No. CAP21041-000).

Figure 1
Enhancing Power Density of Lithium-Ion Batteries through Controlled Reaction Mechanism of Lithium Insertion Material of LiNi0.5Mn1.5O4
Authors: Ariyoshi Kingo , Hiroshima Shinya , Masuda Shumpei , Sugawa Jun
Published: December 2024

Throughout the last two decades, numerous studies have been performed to improve the power capability of LiNi0.5Mn1.5O4 (LNMO), such as via element substitution, surface modification, and particle morphology control. The reaction mechanism is another factor affecting rate capability; single-phase homogeneous versus two-phase coexistence reactions. In this study, to improve the rate capability of LNMO by controlling the reaction mechanism, we synthesized LiNi0.5Mn1.3Ti0.2O4 (Ti-LNMO), in which a part of Mn4+ in LNMO was replaced by Ti4+ [1].

During charging, the cubic lattice constant of Ti-LNMO decreased linearly from 8.20 Å to 8.05 Å (Fig. a). This result reveals that the lithium extraction of Ti-LNMO proceeds in a single-phase reaction over the entire range, while LNMO proceeds two-phase reaction [2].

To evaluate the inherent rate capability of LNMOs, the diluted electrode method [3,4], in which replacing a part of the active material with an inactive material makes the Li-ion transport process in the solid phase rate-determining, was applied to rate-capability tests (Fig. b). The Ti-LNMO exhibited superior rate capability than the LNMO without Ti-substitution, which demonstrated that high-power capabilities could be achieved by controlling the reaction mechanism.

Furthermore, the solid-state Li-ion diffusion coefficient in the LNMOs was determined from the relationship between the discharge capacity and the current density using following equation [5],

Q = (a
2
j
W)/(15D
Li)

where a is the particle radius, and D
Li is the diffusion coefficient of Li ions in the particle. From the linear relationship between the discharge capacity and current density (Fig. c), D
Li of Ti-LNMO and LNMO was calculated to be 9.5 × 10−11 and 3.6 × 10−11 cm2 s−1, respectively. This is the reason that the rate-capability of Ti-LNMO was more than three times greater than that of the LNMO. These results reveal that the lithium insertion mechanism is important for the kinetics of lithium insertion reaction.

References

[1] K. Ariyoshi and J. Sugawa, Electrochim. Acta, 455, 142425 (2023).

[2] K. Ariyoshi et al., J. Electrochem. Soc., 151, A296–A303 (2004).

[4] K. Ariyoshi et al., J. Electrochem. Soc., 167, 140517 (2020).

[3] K. Ariyoshi et al., J. Power Sources, 509, 230349 (2021).

[5] K. Ariyoshi and J. Sugawa, Electrochemistry, 89, 157–161 (2021).

Figure 1