Tokyo Institute of Technology · 공학
Hajime Arai 교수의 연구실은 리튬이온 배터리의 핵심 소재인 고전압 정산재 및 음극재의 전기화학적 거동과 구조적 안정성을 고해상도 분석 기법을 통해 규명하고 있습니다. 주로 X선 흡수 분광법(XANES, EXAFS)과 X선 회절(XRD)을 활용한 실시간 상전이 분석을 통해 리튬 이온의 이동 메커니즘과 열적 안정성 향상을 연구하고 있으며, 특히 니켈· manganese 기반 산화물 정산재와 TiO₂-B 음극재의 리튬 삽입 거동을 중심으로 기초 및 응용 연구를 수행하고 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
We report the synthesis and electrochemical properties of highly stoichiometric samples. With the excess lithium method, samples with a well‐defined layered structure can be prepared in air. A large rechargeable capacity of about 200 mAh g−1 is obtained for 10% substitutives. Structural changes during charging and lithium ordering phenomena are discussed. We describe the thermal behavior of the substitutives and report the enhanced thermal stability and large rechargeable capacity of the mangane
Lithium nickelate is a promising electrode material for lithium-ion batteries, however, its low thermal stability is a problem that should be solved. We studied the thermal stability of delithiated lithium nickelate compounds in the presence of electrolyte solvents/solutions. We measured the exothermal heat generation of the reaction system using differential scanning calorimetry. We examined simple systems such as ethylene carbonate with using hermetically sealed pans that allowed us to perform
The activity and stability of bifunctional air electrodes for electrically rechargeable metal air batteries were investigated using ac impedance spectroscopy. The poly(tetrafluroethylene) bonded electrodes consisted of a perovskite-type catalyst (La<sub>0.6</sub>Ca<sub>0.4</sub>CoO<sub>3</sub>) dispersed on high surface area carbon (Ketjen black) or on graphitized carbon (Vulcan XC 72). The impedance spectra were analyzed using an equivalent circuit containing two finite diffusion terms. The dif
In situ time-resolved X-ray absorption near-edge structure (XANES) and X-ray diffraction (XRD) measurements are applied to track the phase transition processes of LixNi0.5Mn1.5O4, which is one of the most promising positive electrode materials for lithium ion batteries with its high redox potential of 4.7 V vs. Li/Li+ and good rate capability. Thanks to the high time resolution brought by a strong synchrotron X-ray beam, the XANES and XRD measurements separately capture the three phases involved
X-Ray absorption fine structure (XAFS) spectroscopy was carried out on submicron sized TiO2-B, which is one of the promising candidates for negative electrode materials, in order to clarify the electronic and local structural changes during its lithium-ion insertion process. From the extended X-ray absorption fine structure (EXAFS) results of lithiated LixTiO2-B, we propose the changes in lithium-ion insertion sites during electrochemical discharging. The lithium ions are inserted into the five-
