Kenichi Oyaizu

Redox polymer layers with 2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl (TEMPO) groups showed nernstian adsorbate-like electrochemical behaviors up to submicrometer thicknesses, based on a fast charge propagation within the bulk layer and persistency in electrolyte solutions.

In search of polymer backbones to bind organic radical pendant groups as redox centers for high-density charge storage application, polyether was employed as a flexible chain with a low glass transition temperature and affinity to electrolyte solutions. Cyclic ethers bearing nitroxide radicals were synthesized and polymerized via ring-opening polymerization utilizing various initiators. Polyethers bearing robust radical substituents such as 2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl and 2,2,5,5-te

To maximize the theoretical redox capacity of polymers containing cyclic nitroxides as redox-active pendant groups for high-density charge storage application, a compact five-membered ring with the smallest equivalent weight among the robust cyclic nitroxides was directly bound to a poly(ethylene oxide) chain. 2,2,5,5-Tetramethyl-3-oxiranyl-3-pyrrolin-1-oxyl was synthesized and polymerized via anionic coordinated ring-opening polymerization utilizing diethyl zinc/H2O as an initiator. The unpaire

It has long remained challenging to predict the properties of complex chemical systems, such as polymer-based materials and their composites. We have constructed the largest database of lithium-conducting solid polymer electrolytes (10⁴ entries) and employed a transfer-learned graph neural network to accurately predict their conductivity (mean absolute error of less than 1 on a logarithmic scale). The bias-free prediction by the network helped us to find superionic conductors composed

A novel carbon−sulfur (C2S) analogue of polyacene has been synthesized and characterized. The polymer is composed of a nondegenerate trans−cisoid polyacetylene backbone in which all hydrogen atoms are replaced with sulfur atoms to form thiophene rings that are fused into a linear cross-conjugated ladder-type structure. The newly developed synthetic route of the ladder-type polymer is based on an intramolecular condensation of a prepolymer consisting of 3-(alkane-1-sulfinyl)thiophen-2,5-diyl unit

Persistent radicals can hold their unpaired electrons even under conditions where they accumulate, leading to the unique characteristics of radical ensembles with open-shell structures and their molecular properties, such as magneticity, radical trapping, catalysis, charge storage, and electrical conductivity. The molecules also display fast, reversible redox reactions, which have attracted particular attention for energy conversion and storage devices. This paper reviews the electrochemical asp

Condensation of anthraquinone‐2‐carboxylic acid with poly(4‐chloromethylstyrene) afforded a high‐density redox polymer containing the anthraquinone pendants with reversible charge storage capability at negative potentials near −1 V versus Ag/AgCl. Electrochemically reversible redox response of the polymer, which was ascribed to the reduction of the pendant group to the anion radical and the dianion, suggested that the polymer was sufficiently robust in these redox states for charge storage appli

A fast and reversible charge storage capability was established for the radical polyether/SWCNT composite layer with a large layer thickness of several tens of micrometres despite the low SWCNT content of 10%.

Hydrophilic redox-active polymer nanoparticles with different redox potentials and radii were synthesized via the dispersion polymerization to yield their stable dispersion in aqueous electrolyte media as promising catholytes and anolytes in redox flow batteries. Despite the small physical diffusion coefficient (10–9 cm2/s) of the nanosized particles, the sufficiently large coefficient for charge transfer within the polymer particle dispersion (10–7 cm2/s) was observed as a result of the fast el

Electroreduction of a vanadium dinuclear complex [(salen)VIVOVIV(salen)]2+ in the presence of O2 resulted in the stoichiometric formation of a [(salen)VIVOVV(salen)O]+ complex. The process provided not only evidence for the interconversion of vanadium(III)/oxovanadium(V) in the action of vanadium complexes operating as redox catalysts, but also possibilities for the use of the vanadium complex as electrocatalysts for the 4-electron reduction of O2.