페이지 정보작성자 최고관리자 댓글 조회 작성일 13-06-19 17:52
Catalyst-free Direct Growth of a Single to a Few Layers of Graphene on a Germanium Nanowire for the Anode Material of a Lithium Battery
-Hyungki Kim.; Yoonkook Son.; Chibeom Park.; Jaephil Cho*.; Hee Cheul Choi.*
Germanium nanowire (Ge NW) is one of the promising anode materials for high rate lithium (Li) ion battery due to its high specific capacity (1600 mAhg-1) and fast Li ion diffusivity. Similar to silicon (Si) NW, however, Ge NW shows poor cyclability due to large volume expansion accompanied during lithiation-delithiation process. Herein we demonstrate that single to few layer high quality graphene grows directly on Ge NW (Gr@Ge NW) by chemical vapor deposition process without using conventional metal catalyst, and the Gr@Ge NW exhibits significantly enhanced cycle life (200 cycles) and specific capacity (1059 mAhg-1) at high C-rate (4.0 C). The increased performance is attributed to tight encapsulation of Ge NW with high quality graphene that can suppress volume expansion and accomplish high electrical conductivity during long cycles.
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