摘要
介晶是一种可能同时具有高比表面积和良好结晶度的新型材料,因而,介晶材料被认为在储能材料中具有很好的应用前景~[1,2]。本文采用溶剂热法合成了高度有序的Nb_3O_7F纳米线簇介晶,其由大量的超细纳米线聚集成簇而形成的一种类似于阵列的结构,纳米线的直径约为5 nm,长度约为200 nm,BET表面积可达111.4 m~2 g~(-1)。本文对Nb_3O_7F介晶的影响因素以及生长机制进行了详细探讨。研究发现,Nb_3O_7F介晶的定向吸附型的生长机制是氢氟酸的刻蚀过程与纳米线聚集过程二者的交互作用。同时,本文也对Nb_3O_7F介晶的储锂性质进行了研究。Nb-3O_7F介晶表现出高的比容量(在100 mA g~(-1)的电流密度下具有356.7 mAhg),优秀的倍率性能以及长循环寿命(0.8 Ag~(-1)电流密度下循环3000次后仍有~234.3 mAhg~(-1),容量保持率为~91%)。
The highly-ordered Nb_3O_7F nanowire-clusters mesocrystals were prepared by a template-free solvothermal route. The Nb_3O_7F mesocrystals are composed of a large amount of ultra-fine nanowires with a diameter of ~5 nm and a length of ~200 nm. And the BET surface area is as high as 111.425 m~2 g~(-1). The effects of reaction conditions and formation mechanism of Nb_3O_7F mesocrystals were discussed in detail. It was found that oriented attachment formation mechanism of Nb_3O_7F mesocrystals was combined etching effect of HF with aggregation process of nanowires. Also, the electrochemical properties of Nb_3O_7F mesocrystals were tested and the Nb_3O_7F mesocrystals exhibited an initial high capacity of ~356.7 mAhg~(-1), excellent rate performance and ultra-long cycling life.
引文
[1]Colfen,H.;Mann,S.Angew.Chem.Int.Ed.2003,42:2350.
[2]Betzler,S.;Wisnet,A.;Breitbach,B.J.Mater.Chem.A 2014,2:12005.
