北海道大学 · Materials Science
요시타카 아오키 교수의 연구실은 주로 고온에서 작동하는 프로톤 전도성 세라믹 연료전지 및 전기분해 셀의 핵심 소재 개발에 중점을 두고 있습니다. 특히 프로톤, 전자, 산소 이온을 동시에 전도하는 삼중 전도성 산화물 전극과 고도로 제어된 나노구조의 산화물 필름을 설계·제조하는 데 전문성을 기르고 있으며, 표면 솔겔 공정과 같은 첨단 소재 공정 기술을 응용하여 고성능 고κ 게이트 다이일렉트릭 및 나노튜브형 투명 도전성 산화물 소재도 개발하고 있습니다. 이는 에너지 변환 및 저장 기술의 혁신을 위한 기초 소재 연구를 중심으로 하고 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
Cubic La<sub>0.7</sub>Sr<sub>0.3</sub>Mn<sub>1−x</sub>Ni<italic>y</italic>O<sub>3−δ</sub> undergoes the hydration reaction with the charge disproportionation between Mn and O atoms, and thus, can reduce the interfacial polarization of protonic solid oxide cells due to the H<sup>+</sup>/O<sup>2−</sup>/e<sup>−</sup> triple conductivity.
Solution-based fabrication of a high-quality metal oxide nano-film (∼10-nm thickness) by the surface sol−gel process and postannealing is reported. Hafnium(IV) n-butoxide in toluene−ethanol was chemisorbed onto hydroxylated Si wafer to give a uniform gel layer, of which alkoxide group was then hydrolyzed and subjected to a second cycle of chemisorption/hydrolysis. Annealing of a 10-cycle film at 500 °C produced uniform, void-free HfO2 layer of 5.7-nm thickness. Its electrical properties, dielect
The layer‐by‐layer adsorption of precursor metal alkoxides in solution and post‐annealing at 400 °C affords an alternate technique to the atomic layer chemical vapour deposition method for fabrication of next‐generation high‐κ gate dielectrics. A void‐free TiO 2 –La 2 O 3 composite film (see Figure) with 18 nm thickness is readily fabricated, and shows a dielectric constant higher than 30.
Highly efficient mixed H+/e–/O2– triple conducting air electrodes are indispensable for improving the electrochemical performance of protonic ceramic fuel cells and electrolysis cells (PCFC/ECs) operating at intermediate temperatures. This study demonstrates that single perovskite-type La0.8Sr0.2Co1-xNixO3-δ families (LSCN, x = 0–0.3) are efficient H+/e–/O2– triple conductors due to a pronounced hydration ability at elevated temperatures with a related enthalpy of −107 kJ mol–1. Thermogravimetry
Free-standing, nanotubular ITO sheet with different In/Sn ratios was fabricated by the surface sol–gel process using cellulose filter paper as template. The resulting materials have a hierarchical structure originating from the morphology of cellulosic paper, and the ITO nanotubes are composed of interconnected layers of ITO nanocrystals of a few nanometres. Semiconducting behavior was observed at temperatures above room temperature, probably because electronic migration is strongly affected by
A direct ammonia-type intermediate temperature fuel cell is examined by means of a hydrogen membrane fuel cell (HMFC) comprising 1-µm-thick BaZr<sub>0.1</sub>Ce<sub>0.7</sub>Y<sub>0.2</sub>O<sub>3-</sub> <i><sub>δ</sub></i> (BZCY) thin-film electrolyte and Pd solid anode. It generates the maximum power density of 0.58 W cm<sup>-2</sup> at 600 °C with ammonia fuels, and this value is found to be three times larger than the champion data of the recently reported direct ammonia-type proton-conducti
Abstract Protonic solid oxide electrolysis cells (P‐SOECs) operating at intermediate temperatures, which have low costs, low environmental impact, and high theoretical electrolysis efficiency, are considered promising next‐generation energy conversion devices for green hydrogen production. However, the developments and applications of P‐SOECs are restricted by numerous material‐ and interface‐related issues, including carrier mismatch between the anode and electrolyte, current leakage in the ele
Mixed proton–electron conductors (MPECs) are indispensable for the efficient operation of proton conducting ceramic fuel cells and electrolyzer cells at intermediate temperatures (below 500 °C), but robust guidelines for their material design are still missing. Here, this study for the first time reports on the massive uptake of proton carriers in cubic perovskite type La0.7Sr0.3MnO3−δ at intermediate temperatures through the hydration reaction triggered by the coupled oxygen and manganese redox
Improved electrochemical performances of protonic solid oxide steam electrolysis cells based on a BaZr<sub>0.6</sub>Ce<sub>0.2</sub>Y<sub>0.1</sub>Yb<sub>0.1</sub>O<sub>3−δ</sub> electrolyte with a La<sub>0.5</sub>Sr<sub>0.5</sub>CoO<sub>3−δ</sub> anode functional nanolayer.
Abstract Protonic ceramic fuel cells (PCFCs) have been attracting increasing attention because of their advances in high‐efficiency power generation in an intermediate‐temperature range, as compared to the high‐temperature solid oxide fuel cells (SOFCs). The greatest difference between PCFCs and SOFCs is the specific requirement of protonic (H + ) conductivity at the PCFC cathode, in addition to the electronic (e − ) and oxide‐ion (O 2− ) conductivity. The development of a triple H + /e − /O 2−
The reaction pathway of the oxygen reduction reaction (ORR) is strongly affected by the electrolytic environment. Meanwhile, the ORR mechanism on transition-metal oxide catalysts has not been studied intensely in very concentrated alkaline solutions that are used in practical metal-air batteries. Herein, we report the <i>in situ</i> activation of ORR catalysis on manganese perovskite in a concentrated alkaline solution, mediated by the spontaneous formation of oxygen vacancy sites. Electrochemic
Resistive switching gallium oxide thin films with tailored oxygen deficiency and gallium valence state were fabricated by rf cosputtering of Ga<sub>2</sub>O<sub>3</sub> and Cr.
