Publications by authors named "Masanobu Nakayama"

Article Synopsis
  • The study developed a data-driven battery emulator using long short-term memory deep learning models to predict lithium-ion battery (LIB) charge-discharge behavior, aiming to reduce costs and time in creating automotive prototype batteries.
  • It utilized simulation data from the Dualfoil model and experimental data from liquid-based LIBs to accurately forecast voltage profiles from various charge-discharge schedules, achieving high prediction accuracy (0.98 for simulations and 0.97 for experiments).
  • The findings suggested that using just five training datasets could yield robust model performance, highlighting that machine learning can significantly speed up battery development and lower costs for large-scale production.
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Article Synopsis
  • - Ni/Co-free positive electrode materials for Li-ion batteries are crucial for sustainable production and reducing environmental impact.
  • - A study focuses on synthesizing nanostructured LiMnO that achieves high energy density and improved cycling performance, using mechanical milling and a simpler alternative method without the need for unstable precursors.
  • - The research also demonstrates enhanced cyclability of LiMnO through a concentrated electrolyte and lithium phosphate coating, aiming for practical, low-cost rechargeable batteries made from manganese, a more sustainable resource.
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Long-term durability and safety are required to develop Li-ion batteries that can operate at high voltages. However, side reactions, including the release of O from the electrode and CO from the organic electrolyte, occur at the positive-electrode/electrolyte interface during charging at high voltages. In this study, universal neural network potential (UNNP)-driven molecular dynamics (MD) calculations are used to investigate the mechanism of the reaction between LiCoO (0 ≤ ≤ 1) or LiNiO (0 ≤ ≤ 1), as the positive-electrode material, and an ethylene-carbonate-based electrolyte, with a solid-liquid interface composed of ∼1700 atoms.

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Inexpensive and safe energy-storage batteries with high energy densities are in high demand (e.g., for electric vehicles and grid-level renewable energy storage).

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Efforts to optimize known materials and enhance their performance are ongoing, driven by the advancements resulting from the discovery of novel functional materials. Traditionally, the search for and optimization of functional materials has relied on the experience and intuition of specialized researchers. However, materials informatics (MI), which integrates materials data and machine learning, has frequently been used to realize systematic and efficient materials exploration without depending on manual tasks.

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Rechargeable batteries are essential to the global shift towards renewable energy sources and their storage. At present, improvements in their safety and sustainability are of great importance as part of global sustainable development goals. A major contender in this shift are rechargeable solid-state sodium batteries, as a low-cost, safe, and sustainable alternative to conventional lithium-ion batteries.

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Article Synopsis
  • Magnesium rechargeable batteries (MRBs) are emerging as a promising alternative to lithium-ion batteries, providing high energy storage with better safety and cost efficiency.
  • Researchers have created an ultraporous cubic spinel MgMnO (MMO) using a novel freeze-dry process, which initially has a discharge capacity of 160 mAh/g.
  • After heat treatment to remove surface hydroxy groups, the discharge capacity improved to 270 mAh/g, reaching its theoretical capacity and enhancing the battery's efficiency by stabilizing the cubic spinel phase for better magnesium ion movement.
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NASICON-type LiZr(PO) (LZP) has attracted significant attention as a solid oxide electrolyte for all-solid-state Li-ion or Li-metal batteries owing to its high Li-ion conductivity, usability in all-solid-state batteries, and electrochemical stability against Li metal. In this study, we aim to improve the Li-ion conductivity of Li-rich NASICON-type LZPs doped with CaO and SiO, , Li Ca Zr Si P O(0 ≤ ≤ 0.3, 0 ≤ ≤ 0.

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Li-metal rechargeable batteries are an attractive option for devices that require an extremely high specific energy density, high robustness, and long-term durability, such as high-altitude platform stations. However, Li dendrite growth during charge-discharge cycling causes short-circuit problems. One technical solution is to form an intermediate layer between the Li metal and electrolyte.

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Article Synopsis
  • All-solid-state Li-ion batteries are being researched as safer alternatives to traditional Li-ion batteries that use flammable electrolytes.
  • Achieving adequate charging and discharging speeds, as well as capacity at room temperature, remains a significant challenge for these batteries.
  • The study focuses on a new electrolyte material, LiZr(PO) (LZP), using advanced simulations to explore its stability and conductivity, potentially enhancing its use in mobile devices and electric vehicles.
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Dependence on lithium-ion batteries for automobile applications is rapidly increasing. The emerging use of anionic redox can boost the energy density of batteries, but the fundamental origin of anionic redox is still under debate. Moreover, to realize anionic redox, many reported electrode materials rely on manganese ions through π-type interactions with oxygen.

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Development of metal-anode rechargeable batteries is a challenging issue. Especially, magnesium rechargeable batteries are promising in that Mg metal can be free from dendrite formation upon charging. However, in case of oxide cathode materials, inserted magnesium tends to form MgO-like rocksalt clusters in a parent phase even with another structure, which causes poor cyclability.

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We report the successful synthesis, crystal structure, and electrical properties of SrReO, which contains Re with the 5d configuration. This compound is isostructural with BaReO and shows a first-order structural phase transition at ∼370 K. The low-temperature (LT) phase crystallizes in a hettotype structure of BaReO, which is different from that of the LT phase of SrWO, suggesting that the electronic state of Re plays an important role in determining the crystal structure of the LT phase.

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Solid electrolytes with high Mg-ion conductivity are required to develop solid-state Mg-ion batteries. The migration energies of the Mg ions of 5,576 Mg compounds tabulated from the inorganic crystal structure database (ICSD) were evaluated via high-throughput calculations. Among the computational results, we focused on the Mg ion diffusion in MgAl SiO, as this material showed a relatively low migration energy for Mg and was composed solely of ubiquitous elements.

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Dielectric materials that can realize downsizing and higher performance in electric devices are in demand. Perovskite-type materials of the form ABO are potential candidates. However, because of the numerous conceivable compositions of perovskite-type oxides, finding the best composition is technically difficult.

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Efficient and large-scale removal of humic acid (HA) from aqueous environments is required since HA causes human health and esthetic issues. Hydro-garnet compounds, CaAl(SiO) (OH) , have recently been suggested as HA adsorbents not only due to their superior adsorption behaviors but also because they are ubiquitous element-derived compounds. In this study, the adsorption behavior of formic acid to hydro-garnets was investigated by means of first-principles density functional theory (DFT) computations.

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Li metal electrode is the ultimate choice use in Li ion batteries as high-energy storage systems. An obstacle to its practical realization is Li dendrite formation. In this study, the desolvation resistance of the Li metal electrode, which is strongly related to the inhibition of Li dendrite formation, is investigated.

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Solid electrolyte materials exhibiting high Mg-ion conductivity are required to develop Mg-ion batteries. In this study, we focused on a Mg-ion-conducting solid phosphate based electrolyte, MgZr(PO) (MZP), and evaluated the ionic conductivity of NASICON-type and β-iron sulfate-type MgZr(PO) structures density functional theory calculations. The calculations suggest that the migration energy of Mg is 0.

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Research has recently been focused on high-performance next-generation batteries to replace secondary batteries due to capacity limitations and safety concerns. The Mg secondary battery is one candidate to realize high energy density storage batteries for practical applications. Ni and Co typically exhibit desirable electrochemical characteristics; therefore, we have attempted to synthesize new rock-salt compositions, Mg Ni Co O ( x + y + z ≤ 2.

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A polar LiNbO (LN)-type oxide LiSbO was synthesized by a high-temperature heat treatment under a pressure of 7.7 GPa and found to exhibit ferroelectricity. The crystal structural refinement using the data of synchrotron powder X-ray diffraction and neutron diffraction and the electronic structure calculation of LN-type LiSbO suggest a covalent-bonding character between Sb and O.

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Sodium ion batteries meet the demand for large-scale energy storage, such as in electric vehicles, due to the material abundance of sodium. In this report, nanotube-type NaVO is proposed as a cathode material because of its fast sodium diffusivity, an important requirement for sodium ion batteries, through the investigation of ~4300 candidates via a high-throughput computation. High-rate performance was confirmed, showing ~65% capacity retention at a current density of 10C at room temperature, despite the large particle size of >5 μm.

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Discharge of humic acid (HA) in aqueous environments is a key health and aesthetic issue. The present work investigates the use of hydrogarnet as a novel adsorbent for HA. Hydrogarnet was hydrothermally synthesized with different solvents to control the chemical composition.

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Increasing attention has been paid to materials informatics approaches that promise efficient and fast discovery and optimization of functional inorganic materials. Technical breakthrough is urgently requested to advance this field and efforts have been made in the development of materials descriptors to encode or represent characteristics of crystalline solids, such as chemical composition, crystal structure, electronic structure, etc. We propose a general representation scheme for crystalline solids that lifts restrictions on atom ordering, cell periodicity, and system cell size based on structural descriptors of directly binned Voronoi-tessellation real feature values and atomic/chemical descriptors based on the electronegativity of elements in the crystal.

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Safe and robust batteries are urgently requested today for power sources of electric vehicles. Thus, a growing interest has been noted for fabricating those with solid electrolytes. Materials search by density functional theory (DFT) methods offers great promise for finding new solid electrolytes but the evaluation is known to be computationally expensive, particularly on ion migration property.

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