Fumiya Watanabe

Ni‐rich layered oxides (LiNi _x Mn _y Co _z O ₂ , x + y + z = 1) remain leading cathode candidates for transportation electrification, yet their practical deployment is constrained by lattice‐oxygen release, transition‐metal (TM) dissolution, and the emergence of unstable, resistive cathode–electrolyte interphase (CEI). Here, we report a conformal Al ₂ S ₃ coating deposited by atomic layer deposition (ALD), which fundamentally reshapes the structural and chemical evolution of LiNi _0.8 Mn _0.1 Co _0.1 O ₂ (NMC811). X‐ray photoelectron spectroscopy (XPS) and Raman spectroscopy reveal that the coating undergoes an in situ sulfide‐to‐sulfate transformation, forming a chemically adaptive interphase that scavenges lattice‐oxygen. In situ and ex situ synchrotron X‐ray diffraction (XRD) demonstrate that this sulfate‐derived layer preserves the reversible c ‐axis lattice breathing and mitigates long‐term structural deterioration. Ni K ‐edge X‐ray absorption near‐edge structure (XANES) and extended X‐ray absorption fine structure (EXAFS) show that the Al ₂ S ₃ ‐coated cathode avoids the re‐emergence of oxygen‐deficient Ni environments, while the appearance of a distinct Ni─O/S shoulder in R ‐space EXAFS and the retention of high‐ R intensity in wavelet transformed‐EXAFS (WT‐EXAFS) confirm stabilization of both local coordination and long‐range Ni–TM correlations. Collectively, these findings establish sulfide‐derived sulfate interphases as a powerful, chemically adaptive strategy for mitigating structural degradation in Ni‐rich layered cathodes and enabling durable high‐energy lithium batteries.

Fabrication of PEO–starch composite polymer electrolyte at ambient conditions, which is compatible with high voltage cathodes for high-performance solid-state Li metal batteries.

Oxygen release is a major issue associated with layer‐structured metal oxide cathodes in lithium batteries, which can further cause a series of problems, such as irreversible phase transition, microcracking, and electrolyte decomposition. Eventually, these issues jointly result in cell performance degradation and safety hazards. Thus, it is very significant to tackle oxygen release for achieving long‐term stable cyclability, but very challenging. Although intensive efforts have been invested to date, there still lacks a feasible solution. In this study, nanoscale ZrS ₂ coatings are applied on prefabricated LiNi _0.8 Mn _0.1 Co _0.1 O ₂ (NMC811) cathodes directly via atomic layer deposition (ALD). Very encouragingly, we reveal that this ALD‐deposited conformal ZrS ₂ nanocoating can serve as an exceptional oxygen scavenger and then convert into a stable sulfate (Zr(SO ₄ ) ₂ ) coating. Such an in situ conversion is very beneficial and effective for protecting the electrolyte from decomposition. In addition, the resultant Zr(SO ₄ ) ₂ coating further inhibits undesirable reactions, stabilizes the interface between NMC811 and the electrolyte, suppresses microcracking, mitigates transition metal dissolution, and maintains the structural stability of the NMC811 cathode. Consequently, the ZrS ₂ ‐coated NMC811 cathode has demonstrated extraordinary performance. Thus, this study advances the understanding of interface engineering while paving a new technical pathway for commercializing NMC811 cathodes.

Aqueous zinc ion batteries (AZIBs) have considerable potential for energy storage owing to their cost-effectiveness, safety, and environmental sustainability. However, dendrite formation, hydrogen evolution reaction (HER), and corrosion of the bare zinc (B-Zn) anode tremendously impact the performance degradation and premature failure of AZIBs. This study introduces a glancing angle deposition (GLAD) approach during the sputtering process to fabricate tellurium nanostructured (TeNS) at the zinc (Zn) anode to avoid the aforementioned issues with the B-Zn anode. Three different deposition times (5, 10, and 30 min) were used to prepare TeNS at the Zn anode. The morphology, crystallinity, composition, and wettability of the TeNSs were analyzed. The TeNSs served as hydrophilic sites and a protective layer, facilitating uniform Zn nucleation and plating while inhibiting dendrite formation and side reactions. Consequently, the symmetric cell with TeNS deposited on the Zn anode for 10 min (Te@Zn_10 min) demonstrated an enhanced cycling stability of 350 h, the lowest nucleation overpotential of 10.65 mV at a current density of 1 mA/cm², and an areal capacity of 0.5 mAh/cm². The observed enhancement in the cycling stability and reduction in the nucleation overpotential can be attributed to the optimal open area fraction of the TeNSs on the Zn surface, which promotes uniform Zn deposition while effectively suppressing side reactions.

Scalable synthesis of WO_2.76 nanostructures on W wires for low-cost catalytic device applications.

Cobalt-based catalysts are recognized as promising electrocatalysts for oxygen reduction reactions (ORRs) in fuel cells that operate within acidic electrolytes. A synthesis process involving a cobalt complex, nanocellulose, and dopamine, followed by pyrolysis at 500 °C under a nitrogen atmosphere, was used to create a cobalt and nitrogen-doped carbonaceous material. Additionally, urea was incorporated to enhance nitrogen doping in the carbonaceous material. The morphology and structure of the material were examined using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD), where SEM unveiled dispersed metal oxides within the carbonaceous framework. Energy Dispersive X-ray Spectroscopy (EDS) analysis showed an even distribution of elements across the cobalt-doped carbonaceous material. X-ray Photoelectron Spectroscopy (XPS) analysis further highlighted significant alterations in the elemental composition due to pyrolysis. The electrochemical behavior of the cobalt-doped carbonaceous material, with respect to the oxygen reduction reaction (ORR) in an acidic medium, was investigated via cyclic voltammetry (CV), revealing an ORR peak at 0.30 V against a reversible hydrogen reference electrode, accompanied by a notably high current density. The catalyst’s performance was evaluated across different pH levels and with various layers deposited, showing enhanced effectiveness in acidic conditions and a more pronounced reduction peak with uniformly applied electrode layers. Rotating disk electrode (RDE) studies corroborated the mechanism of a four-electron reduction of oxygen to water, emphasizing the catalyst’s efficiency.

Two approaches have been utilized to optimize the energy storage characteristics of doped carbon materials derived from Lignosol, a biomass product, to address the rising energy demand issues. Herein, phosphorus and nitrogen co-doped carbon (PNDC) materials with varying doping agent volumes were synthesized by utilizing microwave irradiation. Chemical activation and physical activation were employed to enhance these materials’ characteristics. Chemical activation was performed in a one-pot, single-step process, rather than a traditional multi-step protocol, using small amounts of potassium hydroxide. Furthermore, the physical activation method required multiple steps: doped carbon was prepared via microwave, exposed to water, filtered, frozen and then dried. With this, the expansion properties of water at freezing temperatures were exploited to alter the materials’ surface characteristics. All materials were characterized and compared for their physicochemical properties. All defect ratios supported the presence of doping. Additional results revealed that both chemical and physical activation approaches effectively modify the topographical features as well as the electrochemical activity (charge storage) of the doped carbon materials. The chemically activated doped carbon exhibited the highest resulting surface area of 1352 m² g⁻¹ and a specific capacitance value of 347 F g⁻¹ with excellent cycling stability as compared to other similarly synthesized materials.

Injectable hydrogels offer numerous advantages in various areas, which include tissue engineering and drug delivery because of their unique properties such as tunability, excellent carrier properties, and biocompatibility. These hydrogels can be administered with minimal invasiveness. In this study, we synthesized an injectable hydrogel by rehydrating lyophilized mixtures of guar adamantane (Guar-ADI) and poly-β-cyclodextrin (p-βCD) in a solution of phosphate-buffered saline (PBS) maintained at pH 7.4. The hydrogel was formed via host-guest interaction between modified guar (Guar-ADI), obtained by reacting guar gum with 1-adamantyl isocyanate (ADI) and p-βCD. Comprehensive characterization of all synthesized materials, including the hydrogel, was performed using nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and rheology. The in vitro drug release study demonstrated the hydrogel’s efficacy in controlled drug delivery, exemplified by the release of bovine serum albumin (BSA) and anastrozole, both of which followed first-order kinetics. Furthermore, the hydrogel displayed excellent biocompatibility and served as an ideal scaffold for promoting the growth of mouse osteoblastic MC3T3 cells as evidenced by the in vitro biocompatibility study.

Nanostructures of zinc oxide (ZnO) are considered promising photocatalysts for the degradation of organic pollutants in water. This work discusses an in situ growth and UV photocatalytic effect of ZnO nanostructures on a Zn plate immersed in methylene blue (MB) at room temperature. First, the Zn surfaces were pretreated via sandblasting to introduce a micro-scale roughness. Then, the Zn plates were immersed in MB and exposed to UV light, to observe ZnO nanostructure growth and photocatalytic degradation of MB. Scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectroscopy were used to characterize the Zn surfaces. We observed the growth of stoichiometric and crystalline ZnO with a nano-leaf morphology and an estimated bandgap of 3.08 eV. The photocatalytic degradation of MB was also observed in the presence of the ZnO nanostructures and UV light. The average percentage degradation was 76% in 4 h, and the degradation rate constant was 0.3535 h⁻¹. The experimental results suggest that room temperature growth of ZnO nanostructures (on Zn surfaces) in organic dye solutions is possible. Furthermore, the nanostructured surface can be used simultaneously for the photocatalytic degradation of the organic dye.