To achieve high performance in all-solid-state batteries, it is necessary to improve lithium-ion transport in the solid electrolyte (SE) and lithium diffusion in the active material (AM) by understanding the internal reaction mechanisms. However, the lithium diffusion behavior of various AMs in all-solid-state batteries and its effects on battery performance have not been fully clarified. Herein, we performed 3D simulations that reproduce the actual cathode structures visualized by X-ray CT images, using LiCoO2 (LCO), LiNi0.8Co0.1Mn0.1O2 (NCM811), and LiNi0.5Co0.2Mn0.3O2 (NCM523) as AMs. The 3D simulations were validated by comparing the predictions of capacity with experimental results for various C-rates. Subsequently, 3D simulations were employed to elucidate the lithium diffusion behavior within the AM structures. Results indicate that LCO can maintain a higher lithium concentration in the center of its structure (i.e., inside the particles, away from the surface) owing to its high lithium diffusivity, achieving a higher capacity under high C-rates than the other AMs. However, for NCM811 and NCM523, lithium is only present near the AM-SE interface, thereby constraining the battery performance. These findings suggest that lithium diffusivity in AMs plays a crucial role in battery performance during fast charging and discharging, highlighting LCO as a promising AM candidate. Active materials were analyzed by 3D simulation based on X-ray CT and experiments.3D simulations based on the actual material structure have high accuracy.LiCoO2 exhibits a higher discharge capacity than NCM811 and NCM523 at high C-rates.LiCoO2 accumulates Li throughout its structure, owing to its high Li diffusivity.LiCoO2with high Li diffusivity may be promising for enabling fast charge/discharge.
This study investigates the influence of lubricant additives, surface roughness, and material hardness on gear damage behavior under boundary lubrication conditions. We conducted both the Short-term Test and the Standard Test using an FZG gear test machine to evaluate how lubricant additives and gear surface roughness influence damage progression when the surface roughness exceeds the oil-film thickness. Acid phosphate ester effectively suppressed micropitting through surface smoothing but led to severe damage such as pitting and scuffing during prolonged use. In contrast, sulfurized fatty oil promoted mild wear, delaying catastrophic failures and extending gear life. Higher surface roughness accelerated wear, while increased hardness reduced deformation but it expanded damage areas. The study found that initial surface roughness and its progress during load stages strongly correlate with gear durability. Measurement of arithmetic mean roughness after sufficient running-in under actual load conditions proved useful for predicting long-term performance. These findings highlight the importance of selecting lubricant formulations tailored to specific gear operating environments and damage modes. Understanding the interplay between lubrication chemistry and material properties enables the design of more durable gear systems.
As nations pursue carbon neutrality targets, tribological innovations represent a significant yet under-recognized pathway for emissions reduction. While renewable energy deployment and electrification dominate climate mitigation discourse, friction-related energy losses persist across transport, industry, and energy conversion sectors. This study quantifies tribology's potential contribution to Japan's 2050 carbon neutrality goal through systematic literature review and sector-specific modeling.A comprehensive review of 77 peer-reviewed studies established tribological intervention potentials across six key sectors: transportation (road and aviation), renewable energy, energy production and electrification, hydrogen technologies, industrial operations, and manufacturing. These interventions encompass friction reduction through advanced lubricants and coatings, wear mitigation via surface engineering, and lifecycle extension of mechanical components. Sector-specific reduction potentials are modeled using Japan's 2022 emissions baseline (964 Mt CO₂) and projected energy transition pathways according to national policy documents, with sensitivity analysis across conservative, central, and ambitious deployment scenarios.Results indicate that tribological optimization could reduce Japan's annual emissions by between 42 and 167 Mt CO₂ by 2050, representing 4.4 to 17.4% of baseline emissions. Transportation systems show the highest absolute potential (30–38% of tribological reductions), while renewable energy demonstrates strong proportional contributions in conservative scenarios. Industrial operations and electrification exhibit increasing importance under ambitious technological advancement scenarios.This study demonstrates that tribology functions as a cross-sectoral enabling technology rather than a standalone solution, amplifying the effectiveness of renewable energy, electrification, and hydrogen systems. Policy integration, targeted R&D investment, and lifecycle-based standards are recommended to mobilize this pragmatic, engineering-grounded pathway toward carbon neutrality.
Since 1985, Idemitsu Kosan Co., Ltd. (Idemitsu) has continuously developed OLED materials with a primary focus on fluorescent blue emitters. Along with material development, performance enhancement through device structure optimization has also been actively explored. This paper reviews our progress in fluorescent blue technology and introduces recent advancements, including the Dual EML (a stacked emitting layer consisting of high‐T₁ and low T₁ blue hosts), the Dual HTL (a stacked hole transport layer combining high n and low n HTLs).
Ammonia (NH3) synthesis is central to the chemical industry, but its production still depends on the energy-intensive Haber–Bosch process. Electrochemical reduction of dinitrogen (N2) offers a possible route to green ammonia synthesis under ambient conditions; however, most reported systems are limited to half-reactions coupled to sacrificial anodic processes. Here we report an electrocatalytic system based on a flow battery architecture that couples molybdenum complexes promoted catalytic NH3 synthesis from N2 at the cathode with anodic oxidation. This architecture enables the separate design of cathodic and anodic processes within a full electrochemical cell. Using alcohol oxidation at the anode, the system avoids the need for stoichiometric reductants and proton sources and enables catalytic NH3 formation in a stable full-reaction operation under ambient conditions. Under optimized conditions, the system produces more than 100 equiv. of NH3 per Mo atom of catalyst with a maximum Faradaic efficiency of 63%. NH3 synthesis is also achieved when water (H2O) is used as an electron and proton sources, with oxygen (O2) evolution confirmed at the anode. These results establish a molecular catalyst–based full-reaction system for green ammonia synthesis and represent a step forward towards the ideal direct conversion of N2 and H2O into NH3.
