Atsunori Ikezawa 교수

The establishment of three-electrode cells for all-solid-state lithium-ion batteries is an important issue to clarify the electrochemical behavior of the battery components and solve problems for the practical applications. Here we prepared an all-solid-state three-electrode cell with a chemically-reduced Li4Ti5O12 reference electrode and investigated electrochemical properties of a LiCoO2 composite electrode in a Li-In|Li10GeP2S12|LiCoO2 cell. Plateau potentials in charge-discharge curves were

Proton insertion–extraction mechanisms of MoO 3 were investigated using operando X-ray diffraction and density functional theory calculation. A high voltage aqueous proton battery was constructed by optimizing the operating potential of MoO 3 .

Oxygen reduction reaction (ORR) and oxygen evolution reactions (OER) on glassy-carbon-supported platinum electrodes (Pt/GCs), which are partially immersed in alkaline electrolytes, are investigated as a model of the triple phase boundary (TPB) in air electrodes for metal-air secondary batteries. ORR currents are measured with changing the vertical position of Pt/GCs, and OER currents are measured by linear sweep voltammetry. Based on the electrochemical results, it is found that thin liquid film

Alkaline secondary batteries with zinc negative electrodes are attractive power sources for large-scale energy storage systems. However, low cyclabilities of zinc electrodes prevent their wide applications. While shape change has been known as one of the predominant degradation modes, its origin has not been clarified yet. In this study, we analyze the initial charge-discharge behavior of ZnO composite electrodes using a unique “laboratory” operando observation method combining confocal optics a

NiFe-LDHs with high crystallinity and uniform composition and morphology are synthesized using soft chemistry. The highly crystalline NiFe-LDHs show superior OER activities to conventional NiFe-LDHs.

Understanding Li-ion transport at the solid | solid interface is crucial to improving the performance of all-solid-state Li-ion batteries. Electrochemical four-electrode cells have been widely used for electrochemical measurements of ion transports at liquid | liquid and solid | liquid interfaces. However, there is no report of the application to the Li-ion transport at the solid | solid interface, and the electrochemistry of Li-ion transport at the solid | solid interface has not been understoo

Abstract The high overpotential of oxygen reduction reaction (ORR) prevents the wide commercialization of fuel cells and metal‐air batteries. To accelerate the reaction rate, porous electrocatalysts draw attention to obtain a higher specific surface area. However, the effect of micropores on ORR kinetics has not been understood because of the non‐uniform pore sizes, length, and tortuosity of practical electrocatalysts. In this study, we evaluate ORR activity in a micropore using platinum model e

Impact of hydrogen peroxide on carbon corrosion is investigated by immersion tests of catalyst-deposited highly oriented pyrolytic graphite (HOPG) samples to an aqueous solution of 1.0 mol dm−3 KOH + 5 mmol dm−3 H2O2. The surfaces of the HOPG samples are observed with field-emission scanning electron microscopy and X-ray photoelectron spectroscopy. HOPG without catalyst shows almost no morphological change while the distribution of C-O and C=O functional groups increases. In contrast, Pt-loaded

• A new DEMS system incorporating microreactor and ion-exchange membrane was constructed. • The constructed DEMS system can quantitatively analyze CO 2 evolution reactions of catalyst-loaded carbon electrodes in alkaline electrolyte solutions. • The corrosion behavior of a Pt-loaded carbon is similar to that in the acidic electrolytes except for the onset of the carbon corrosion. • La 0.6 Ca 0.4 CoO 3 and Ca 2 FeCoO 5 show electrochemical carbon corrosion activity, while La 0.4 Sr 0.6 MnO 3 does

Thin electrolyte films are frequently used in electrochemical systems. We have developed a powerful tool to reveal the current distribution in such films using segmented Pt array electrodes. In this study, this electrode system was applied to a polymeric film of an anion-exchange ionomer. We found that current distributions for oxygen reduction varied widely with the thickness of the ionomer films. A combination of experimental and simulation studies revealed that the transport of ions and oxyge

Alkaline secondary batteries using zinc negative electrodes are attractive candidates for large-scale energy storage systems since they potentially satisfy low cost, high safety standard and high energy density. However, the short cycle life of the zinc electrodes hinders their practical applications. To overcome this problem, it is necessary to understand the degradation mechanism. In this work, we applied the combination of operando confocal optical system and operando x-ray diffraction (XRD)

Aqueous metal-air secondary batteries, such as zinc-air secondary batteries, are attractive power sources for large scale energy storage systems since these battery systems potentially satisfy high energy density, high safety standard and low cost. However, large overpotential in bifunctional air electrodes hinders practical applications of the systems. 1 In order to reduce the overpotential, plenty of effective reaction sites is necessary as well as highly active bifunctional electrocatalysts.