Germanium coated vertically-aligned multiwall carbon nanotubes as lithium-ion battery anodes

• Main Authors: Susantyoko, Rahmat Agung, Wang, Xinghui, Sun, Leimeng, Pey, Kin Leong, Fitzgerald, Eugene, Zhang, Qing
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Materials::Energy materials; DRNTU::Engineering::Materials::Microelectronics and semiconductor materials::Thin films; DRNTU::Science::Chemistry::Physical chemistry::Electrochemistry; DRNTU::Engineering::Nanotechnology
• Online Access: https://hdl.handle.net/10356/100589; http://hdl.handle.net/10220/24125
• Institution: Nanyang Technological University

The performance of polycrystalline and amorphous germanium (Ge) as anode active materials for lithium-ion batteries was studied systematically. Polycrystalline Ge on vertically-aligned multiwall carbon nanotube (MWCNT) arrays (MWCNT/c-Ge) and amorphous Ge on the arrays (MWCNT/a-Ge) were fabricated using a low pressure chemical vapor deposition system and a radio frequency sputtering system, respectively. The vertically-aligned MWCNT arrays were used as a platform to minimize pulverization problem. The MWCNT/a-Ge had a specific capacity of 1096.1 mAhg−1 at the rate of 162.4 mAg−1 at the 100th cycle. In comparison, the MWCNT/c-Ge only showed a specific capacity of 730.2 mAhg−1 at the rate of 162.4 mAg−1 at the 100th cycle. The MWCNT/a-Ge sample showed better performances as the MWCNT/a-Ge skipped the electrochemically-driven solid-state amorphization of crystalline Ge during the first lithiation.