Orimo Shin-ichi

Tohoku University | Tohokudai · Advanced Institute for Materials Research (WPI-AIMR)

Multivalent-ion and all-solid-state batteries have emerged as potential solutions to address resource concerns and safety issues. Calcium is a promising element for multivalent-ion batteries owing to its abundance in the Earth's crust and low reduction potential. In addition, complex hydrides exhibit both high ion conductivity and reduction stabili...

All-solid-state batteries (ASSBs) are promising alternatives to conventional lithium-ion batteries. ASSBs consist of solid-fast-ion-conducting electrolytes and electrodes that offer improved energy density, battery safety, specific power, and fast-charging capability. Despite decades of intensive research, only a few have high ionic conductivity at...

Sodium superionic conductors (NASICON) are pivotal for the functionality and safety of solid-state sodium batteries. Their mechanical properties and ionic conductivity are key performance metrics, yet their correlation remains inadequately understood. Addressing this gap is vital for concurrent enhancements in both properties. This study summarizes...

Rechargeable Ca batteries offer the advantages of high energy density, low cost, and earth‐abundant constituents, presenting a viable alternative to lithium‐ion batteries. However, using polymer electrolytes in practical Ca batteries is not often reported, despite its potential to prevent leakage and preserve battery flexibility. Herein, a Ca(BH4)2...

Sodium superionic conductors (NASICON) are pivotal for the functionality and safety of solid-state sodium batteries. Their mechanical properties and ionic conductivity are key performance metrics, yet their correlation remains inadequately understood. Addressing this gap is vital for concurrent enhancements in both properties. This study summarizes...

Synthesis of novel inorganic materials involving molecular absorption is challenging owing to the control of interfacial reactions. Here, we reveal the kinetic role of applied pressure in the interfacial reaction. Specifically, we used machine-learning potential molecular dynamics simulations to investigate the initial stage of superhydride formati...

The synthesis of new superhydrides with high superconducting Tc is challenging owing to the high temperatures and pressures required. Herein, we use machine-learning potential molecular dynamics simulations to investigate the initial stages of superhydride formation in calcium hydrides. Upon contact with high-pressure H2, the surface of CaH2 melts,...

Solid‐state methods for cooling and heating promise a sustainable alternative to current compression cycles of greenhouse gases and inefficient fuel‐burning heaters. Barocaloric effects (BCE) driven by hydrostatic pressure (p) are especially encouraging in terms of large adiabatic temperature changes (|ΔT| ≈ 10 K) and isothermal entropy changes (|Δ...

Sodium superionic conductors (NASICON) are pivotal for the functionality and safety of solid-state sodium batteries. Their mechanical properties and ionic conductivity are key performance metrics, yet their interrelation remains inadequately understood. Addressing this gap is vital for concurrent enhancements in both properties. This study summariz...

Sodium superionic conductors (NASICON) are pivotal for the functionality and safety of solid-state sodium batteries. Their mechanical properties and ionic conductivity are key performance metrics, yet their interrelation remains inadequately understood. Addressing this gap is vital for concurrent enhancements in both properties. This study summariz...

Solid electrolytes are key materials in all−solid−state batteries because their ionic conductivity and stability determine battery performances, such as energy density and power density. However, most existing superionic−conducting solid electrolytes...

All-solid-state battery (ASSB) is a possible alternative to the conventional Li-ion battery (LIB). ASSB, consisting of solid-fast-ion-conducting electrolytes and electrodes, can surpass LIB in terms of energy density, battery safety, specific power, and fast-charging capability. A highly conductive solid electrolyte is a prerequisite part of ASSB....

Hierarchically porous carbon microlattices (HPCMLs) fabricated by using a composite photoresin and stereolithography (SLA) 3D printing is reported. Containing magnesium oxide nanoparticles (MgO NPs) as porogens and multilayer graphene nanosheets as UV‐scattering inhibitors, the composite photoresin is formed to simple cubic microlattices with digit...

All-solid-state batteries (ASSBs) are a class of safer and higher-energy-density materials compared to conventional devices, from which solid-state electrolytes (SSEs) are their essential components. To date, investigations to search for high ion-conducting solid-state electrolytes have attracted broad concern. However, obtaining SSEs with high ion...

As potential alternatives to Li‐ion batteries, rechargeable Ca metal batteries offer advantageous features such as high energy density, cost‐effectiveness, and natural elemental abundance. However, challenges, such as Ca metal passivation by electrolytes and a lack of cathode materials with efficient Ca²⁺ storage capabilities, impede the developmen...

Topological data analysis based on persistent homology has been applied to the molecular dynamics simulation for the fast ion-conducting phase ( α-phase) of AgI to show its effectiveness on the ion migration mechanism analysis. Time-averaged persistence diagrams of α-AgI, which quantitatively record the shape and size of the ring structures in the...

As global energy and environment problems draw increasing attention, Japan has set a target of net zero greenhouse gas emissions by 2050. It has become even more important to promote the development of technology for fully utilizing hydrogen in the future, and also to explore fundamental science.However, since the foundational science related to hy...

Complex hydrides are of great interest for being potential candidates for the solid electrolyte of all-solid-state batteries owing to their exceptionally high ionic conductivity at high temperatures. Hereafter, we study a model system (LiCB11H12) using molecular dynamics (MD) simulations based on a reported force field to investigate the role of ca...

Topological data analysis based on persistent homology has been applied to the molecular dynamics simulation for the fast ion-conducting phase ($\alpha$-phase) of AgI, to show its effectiveness on the ion-migration mechanism analysis.Time-averaged persistence diagrams of $\alpha$-AgI, which quantitatively records the shape and size of the ring stru...

Boron-based two-dimensional (2D) materials are an excellent platform for nanoelectronics applications. Rhombohedral boron monosulfide (r-BS) is attracting particular attention because of its unique layered crystal structure suitable for exploring various functional properties originating in the 2D nature. However, studies to elucidate its fundament...

Solid-state methods for cooling and heating promise a more sustainable alternative to current compression cycles of greenhouse gases and inefficient fuel-burning heaters. Barocaloric effects (BCE) driven by hydrostatic pressure ($p$) are especially encouraging in terms of large adiabatic temperature changes ($|\Delta T| \sim 10$ K) and colossal iso...

Hydrogen can be stored in the interstitial sites of the lattices of intermetallic compounds. To date, intermetallic compound LaNi5 or related LaNi5-based alloys are known to be practical hydrogen storage materials owing to their higher volumetric hydrogen densities, making them a compact hydrogen storage method and allowing stable reversible hydrog...

This work investigates the divalent conduction of Zn2+ and Mg2+ in hydrated closo-type complex hydrides MB12H12·nH2O (M = Zn, Mg) and the effects of crystal water exchange in the structure for enhancing divalent ionic conduction. MB12H12·nH2O (M = Zn, Mg), which exhibited different hydrous phases, was synthesised as a single phase and characterised...

Quasielastic neutron scattering (QENS) and neutron powder diffraction of the complex transition metal hydrides Li5MoH11 and Li6NbH11 were measured in a temperature range of 10–300 K to study their structures and dynamics, especially the dynamics of the hydrogen atoms. These hydrides contain unusual ninefold H-coordinated complex ions (MoH93− or NbH...

Due to the high cost and limited availability of lithium, Mg-based batteries are currently being investigated as a promising alternative. A critical component in these batteries is the electrolyte, with all-solid-state ones that show superior safety features but must guarantee adequate ionic conductivity to be viable for applications. In this work,...

High ionic conductivity, suitable mechanical strength and electrochemical stability are the main requirements for high-performance poly(ethylene oxide)-based electrolytes. However, the low ionic conductivity due to crystallinity of the ethylene oxide chain that limits the discharge rate and low-temperature performance has restricted the development...

Complex hydrides are of great interest for being potential candidates for the solid electrolyte of all-solid-state batteries owing to their exceptionally high ionic conductivity at a high-temperature phase. Hereafter, we study a model system (LiCB 11 H 12 ) using molecular dynamics (MD) simulations based on a reported force field to investigate the...

Hydrides based on magnesium and intermetallic compounds provide a viable solution to the challenge of energy storage from renewable sources, thanks to their ability to absorb and desorb hydrogen in a reversible way with a proper tuning of pressure and temperature conditions. Therefore, they are expected to play an important role in the clean energy...

Hydrogen is chemically flexible revealing three aspects; protium (H0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^0$$\end{document}), proton (H+\documentclass[12pt]{...

Intense literature and research efforts have focussed on the exploration of complex hydrides for energy storage applications over the past decades. A focus was dedicated to the determination of their thermodynamic and hydrogen storage properties, due to their high gravimetric and volumetric hydrogen storage capacities, but their application has bee...

The development of efficient storage systems is one of the keys to the success of the energy transition. There are many ways to store energy, but among them, electrochemical storage is particularly valuable because it can store electrons produced by renewable energies with a very good efficiency. However, the solutions currently available on the ma...

Fossil fuels and materials on Earth are a finite resource and the disposal of waste into the air, on land, and into water has an impact on our environment on a global level. Using Switzerland as an example, the energy demand and the technical challenges, and the economic feasibility of a transition to an energy economy based entirely on renewable e...

REMgNi4-based alloys, RE(2−x)MgxNi4 (RE: rare-earth metals; 0 < x < 2), with a AuBe5-type crystal structure, exhibit reversible hydrogen absorption and desorption reactions, which are known as hydrogen storage properties. These reactions involve formation of three hydride phases. The hydride formation pressures and hydrogen storage capacities are r...

Conventional hydrides obtained thus far contain at least one type of metal with high hydrogen affinity, which can form metal hydrides near ambient pressure. In contrast, we synthesized metal hydrides comprising only metals with low hydrogenation affinity which are metals that do not form metal hydrides MHx (M stands for metal element, x > 0.5) belo...

The use of hydrogen in iron and steel has the potential to improve mechanical properties via altering the phase stability and dislocation behavior. When hydrogen is introduced under several gigapascals, a stoichiometric composition of hydrogen can be introduced for steel compositions. In this study, a face-centered cubic (fcc) stainless steel was h...

Materials for safe and high density hydrogen storage 二酸化炭素排出の低減や再生可能エネルギーの活用の観点から水素を利用する社会（水素社会）の構築が切望されています． 水素社会では，水素がエネルギーを輸送・貯蔵する媒体（キャリヤ）となるため安全で効率的な水素輸送・貯蔵技術が求められ ています．そこで，本稿では，最近の水素貯蔵技術を解説するとともに，水素を原子として含有することにより，安全で高密度に 水素を貯蔵する材料（水素化物）の水素吸蔵・放出反応，種類，および特徴について解説します．

The hydrogen desorption and absorption reactions of the complex metal hydride NaAlH4 are disproportionation processes, and the kinetics can be improved by adding a few mol% of Ti compounds, although the catalytic mechanism, including the location and state of Ti, remains unknown. In this study, we aimed to reveal the generating mechanism of catalyt...

Hydrides are promising hydrogen storage materials owing to their higher gravimetric and volumetric hydrogen densities compared to compressed hydrogen gas and liquid hydrogen. Hydrogen is absorbed by different compounds (formation reaction of hydride) and thus exhibits different states—elemental hydrogen (H0), hydride ion (H−), and covalently bonded...

High-pressure hydrogenation behaviors of pure metals have not been investigated extensively, although intense research of hydrogenation reactions under high pressure has been conducted to find novel functional hydrides. The former provides us with valuable information for the high-pressure synthesis of novel functional hydrides. A pressure–temperat...

Among the various functionalities of hydrides, their use in hydrogen storage has been the most intensively studied because hydrides can store hydrogen compactly and safely. Thus, hydrides are key materials for the hydrogen economy. Here, the hydrogen storage material Al3FeH3.9 has been synthesized from cost-effective earth-abundant metals, Fe and A...

Traditional refrigeration technologies based on compression cycles of greenhouse gases pose serious threats to the environment and cannot be downscaled to electronic device dimensions. Solid-state cooling exploits the thermal response of caloric materials to changes in the applied external fields (i.e., magnetic, electric and/or mechanical stress)...

Traditional refrigeration technologies based on compression cycles of greenhouse gases pose serious threats to the environment and cannot be downscaled to electronic device dimensions. Solid-state cooling exploits the thermal response of caloric materials to external fields and represents a promising alternative to current refrigeration methods. Ho...

High-energy-density and low-cost calcium (Ca) batteries have been proposed as ‘beyond-Li-ion’ electrochemical energy storage devices. However, they have seen limited progress due to challenges associated with developing electrolytes showing reductive/oxidative stabilities and high ionic conductivities. This paper describes a calcium monocarborane c...

The bimetallic borohydride-chloride LiLa(BH 4) 3 Cl, the lithium amide-iodide Li 3 (NH 2) 2 I, and the lithium mon-ocarba-closo-decaborate Li-1-CB 9 H 10 represent complex hydrides showing superionic conductivity at room temperature or slightly above it. To study the Li-ion diffusivity that is closely related to the ionic conductivity, we have meas...

Phase transformation in hydrogenated iron during depressurization from several gigapascals was investigated through in-situ synchrotron radiation X-ray diffraction and post-mortem electron backscatter diffraction measurements. The hydrogenated iron under 8.6 GPa at 293 K showed a double hexagonal close-packed (dhcp) structure, and it gradually tran...

We report the stabilization of the high-temperature (high-T) phase of lithium carba-closo-decaborate, Li(CB9H10), via the formation of solid solutions in a Li(CB9H10)-Li2(B12H12) quasi-binary system. Li(CB9H10)-based solid solutions in which [CB9H10]− is replaced by [B12H12]2− were obtained at compositions with low x values in the (1−x)Li(CB9H10)−x...

Complex hydrides are potential candidates for the solid electrolyte of all-solid-state batteries owing to their high ionic conductivities in which icosahedral anion reorientational motion plays an essential role in high cation diffusion. Herein, we report molecular dynamics (MD) simulations based on a refined force field and first-principles calcul...

Complex hydrides are potential candidates for the solid electrolyte of all-solid-state batteries owing to their high ionic conductivities, in which icosahedral anion reorientational motion plays an essential role in high cation diffusion. Herein, we report molecular dynamics (MD) simulations based on a refined force field and first-principles calcu...

The hydrogen storage properties and crystal structures of YMgNi 4-based alloys, which were synthesized from (2 − x)YNi 2 and xMgNi 2 (0.6 ≤ x ≤ 1.2), were investigated by pressure−composition−temperature measurements and powder neutron diffraction at a deuterium gas pressure to understand the hydrogen absorption and desorption reactions viewed from...

We present a combined experimental and theoretical study of the charge transport properties of TiHx(x=1.6–2.0) epitaxial thin films. We found that the Hall coefficient of TiHx strongly depends on hydrogen content and unit-cell volume: Nearly stoichiometric TiHx(x≈2.0) films with large unit-cell volumes showed positive Hall coefficients at 4 K, wher...

Development of innovative polymer electrolytes that simultaneously possesses high mechanical stiffness as well as liquid-like ion motions is desirable for safer lithium-ion secondary batteries. Herein, bifunctional poly(ethylene glycol) diacrylate (PEGDA) based cross-linked network polymer electrolytes (PE) plasticized by tetraglyme at various lith...

Hydrogen-rich compounds show high-Tc superconductivity related to dense hydrogen under extremely high pressure (above 100 GPa). A recent investigation to search for high-Tc superconductive hydrides has advanced a synthesis technique using infrared laser heating of a hydrogen source material under conditions of extremely high pressure and temperatur...

Traditional refrigeration technologies based on compression cycles of greenhouse gases pose serious threats to the environment and cannot be downscaled to electronic device dimensions. Solid-state cooling exploits the thermal response of caloric materials to external fields and represents a promising alternative to current refrigeration methods. Ho...

To synthesize a novel titanium-containing hydride, a Co3Ti alloy with a Cu3Au-type structure was hydrogenated at 9 GPa and 900 °C. Structural changes under high pressure were monitored via in situ synchrotron radiation x-ray diffraction at BL14B1, SPring-8. The in-situ measurement reveals that novel hydride Co3TiH~4 is formed at 9 GPa and 900 °C. W...

Globally, the accelerating use of renewable energy sources, enabled by increased efficiencies and reduced costs, and driven by the need to mitigate the effects of climate change, has significantly increased research in the areas of renewable energy production, storage, distribution and end-use. Central to this discussion is the use of hydrogen, as...

Neutron powder diffraction profiles were collected for iron deuteride (FeDx) while the temperature decreased from 1023 to 300 K for a pressure range of 4–6 gigapascal (GPa). The ε′ deuteride with a double hexagonal close-packed (dhcp) structure, which coexisted with other stable or metastable deutrides at each temperature and pressure condition, fo...

The properties of the mixed system LiBH4 LiCl P2S5 are studied with respect to all-solid-state batteries. The studied material undergoes an amorphization upon heating above 601C, accompanied with increased Li+ conductivity beneficial for battery electrolyte applications. The measured ionic conductivity is 10-3 Scm-1 at room temperature with an acti...