材料科学
石墨烯
纳米晶
储能
介孔材料
纳米技术
离子
法拉第效率
纳米颗粒
电极
化学工程
电解质
催化作用
工程类
物理
物理化学
功率(物理)
量子力学
生物化学
化学
作者
Gyu Heon Lee,Jung Woo Lee,Ji Il Choi,Sangjun Kim,Yong‐Hoon Kim,Jeung Ku Kang
标识
DOI:10.1002/adfm.201601355
摘要
A hierarchical architecture fabricated by integrating ultrafine titanium dioxide (TiO 2 ) nanocrystals with the binder‐free macroporous graphene (PG) network foam for high‐performance energy storage is demonstrated, where mesoporous open channels connected to the PG facilitate rapid ionic transfer during the Li‐ion insertion/extraction process. Moreover, the binder‐free conductive PG network in direct contact with a current collector provides ultrafast electronic transfer. This structure leads to unprecedented cycle stability, with the capacity preserved with nearly 100% Coulombic efficiency over 10 000 Li‐ion insertion/extraction cycles. Moreover, it is proven to be very stable while cycling 10 to 100‐fold longer compared to typical electrode structures for batteries. This facilitates ultrafast charge/discharge rate capability even at a high current rate giving a very short charge/discharge time of 40 s. Density functional theory calculations also clarify that Li ions migrate into the TiO 2 –PG interface then stabilizing its binder‐free interface and that the Li ion diffusion occurs via a concerted mechanism, thus resulting in the ultrafast discharge/charge rate capability of the Li ions into ultrafine nanocrystals.
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