Fabrication of nanoporous germanium for the use of anode material in lithium-ion batteries

2016 Fiscal Year Final Research Report

• Project/Area Number: 26420727
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Structural/Functional materials
• Research Institution: Osaka Prefecture University
• Principal Investigator: Nakamura Ryusuke 大阪府立大学, 工学(系)研究科(研究院), 准教授 (70396513)
• Co-Investigator(Renkei-kenkyūsha): ISHIMARU Manabu 九州工業大学, 大学院工学研究科, 教授 (00264086)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: アモルファスゲルマニウム / 結晶化 / ナノポーラス構造

Outline of Final Research Achievements

An attempt to manipulate nanoporous (NP) structure of crystalline germanium films was made by using accumulation of amounts of point defects, which are intrinsically contained in amorphous Ge (a-Ge) films. When a-Ge films prepared by sputtering were annealed at a constant rate in TEM, they crystallized at 500℃. The microstructure is composed of coarse particles with the diameter of 100 nm and void network. The crystal structure is hexagonal. On the other hand, when a-Ge films were pre-annealed at 350℃ for a couple of hours and subsequently annealed at higher temperature, they crystallized at 600℃ to be the diamond cubic structure. The microstructure is composed of fine particles and isolated spherical voids, both with the diameter around 5 nm. NP structure is governed by the crystallization behavior of a-Ge, which varies from state to state of amorphous structure. The control of atomic-level structure of a-Ge is crucial to that of NP structure of crystalline germanium.

Free Research Field

材料組織学