Tokyo Institute of Technology · Engineering
Professor Masaaki Hirayama's research lab specializes in the development and characterization of advanced functional oxide thin films for solid-state batteries and energy storage applications. The lab focuses on epitaxial thin films of cathode and solid electrolyte materials—such as LiMn₂O₄, Li₄Ti₅O₁₂, Li₇La₃Zr₂O₁₂ (LLZO), and LiFePO₄—using pulsed laser deposition to achieve precise control over crystal orientation and interfacial structure. By combining in situ and ex situ X-ray and neutron reflectivity, surface X-ray diffraction, and electrochemical measurements, the lab investigates atomic-scale structural and ionic changes at electrode/electrolyte interfaces during battery operation. Their work provides fundamental insights into interfacial stability, lithium diffusion, and ion conduction mechanisms critical for designing high-performance, all-solid-state batteries.
Figures are computed from collected data and may differ slightly.
Gaining a thorough understanding of the reactions on the electrode surfaces of lithium batteries is critical for designing new electrode materials suitable for high-power, long-life operation. A technique for directly observing surface structural changes has been developed that employs an epitaxial LiMn(2)O(4) thin-film model electrode and surface X-ray diffraction (SXRD). Epitaxial LiMn(2)O(4) thin films with restricted lattice planes (111) and (110) are grown on SrTiO(3) substrates by pulsed l
Epitaxial thin films of Al-doped Li7La3Zr2O12 (LLZO) with a cubic garnet-type structure were successfully synthesized using pulsed laser deposition to investigate the lithium ion conduction in grains. Two orientations of the films were obtained depending on the Gd3Ga5O12 (GGG) substrate orientation, LLZO(001)/GGG(001) and LLZO(111)/GGG(111). The ionic conductivities in the grains of the (001) and (111) films were 2.5 × 10(-6) and 1.0 × 10(-5) S cm(-1) at 298 K, respectively, which were lower tha
Structural changes at electrode/electrolyte interface of a lithium cell were studied by X-ray reflectometry and two-dimensional model electrodes with a restricted lattice plane of . The electrodes were constructed with an epitaxial film synthesized by the pulsed laser deposition method. The orientation of the film depends on the substrate plane; the (111), (110), and (100) planes of grew on the (111), (110), and (100) planes of the substrates, respectively. The ex situ reflectometry indicated th
Epitaxial Li(4)Ti(5)O(12) thin-films were successfully synthesized on SrTiO(3) single-crystal substrates with (111), (110), and (100) lattice plane orientations using pulsed laser deposition (PLD). Thin-film X-ray diffraction (XRD) revealed that the Li(4)Ti(5)O(12) films had the same orientation as the SrTiO(3) substrates: Li(4)Ti(5)O(12) (111) on SrTiO(3) (111), Li(4)Ti(5)O(12) (110) on SrTiO(3) (110), and Li(4)Ti(5)O(12) (100) on SrTiO(3) (100). These epitaxial films contained island structure
The electrode surface of a lithium battery was characterized using in situ reflectivity techniques and epitaxial thin films. Epitaxial LiFePO4 thin films were fabricated by pulsed laser deposition. Changes in interfacial structures on the surface are determined by X-ray and neutron reflectivity (NR) measurements using an X-ray-transmission electrochemical cell. The LiFePO4 surface is stable during the first charge/discharge process. NR analysis indicates a reversible change in the concentration
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