Nanostructured Nb2O5 Polymorphs by Electrospinning for Rechargeable Lithium Batteries
Nanostructured Nb2O5 Polymorphs by Electrospinning for Rechargeable Lithium Batteries
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DOI：
10.1021/jp9088589
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发表时间：
2010-01-14
影响因子：
3.7
通讯作者：
Ramakrishna, S.
中科院分区：
文献类型：
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作者：
Le Viet, A.;Reddy, M. V.;Ramakrishna, S.
采用静电纺丝法合成了五氧化二铌（Nb2O5）一维纳米结构的多晶体。通过适当的热处理，制备了Nb2O5的准六方（H-Nb2O5）、正交（O-Nb2O5）和单斜（M-Nb2O5）结构。详细研究了这些纳米纤维多晶的形态、结构和电化学性能。H相和O相保持了通常的纤维形态，而M相则采用了扭曲的核块结构。对这些相作为锂电池正极的应用进行了评价。与其他相相比，M-Nb2O5表现出最高的容量和更好的容量保留。M-Nb2O5在1.0 ~ 2.6 V的电压范围内，以50 mAg（-1）的电流循环，第二次和第25次循环时的比容量分别为242（+/- 3）和218(+/- 3)mAhg（-1）。电纺丝M-Nb2O5金块电池比其颗粒/纳米纤维电池性能更好，由于电纺丝工艺的商业可行性和由此开发的电池的特性，可以成为2v正极材料的选择。
Polymorphs of 1D nanostructures of niobium pentoxide (Nb2O5) are synthesized by electrospinning. Pseudohexagonal (H-Nb2O5), orthorhombic (O-Nb2O5), and monoclinic (M-Nb2O5) structures of Nb2O5 are developed in this study by appropriate heat treatment. Morphological, structural, and electrochemical properties of these nanofibrous polymorphs are studied in detail. The H- and O- phases maintain the usual fibrous morphology, whereas the M- phase adopted a distorted nugget structure. These phases are evaluated for their application as cathode for lithium batteries. The M-Nb2O5 exhibits the highest capacity and better capacity retention compared to the other phases. The M-Nb2O5 delivers a specific capacity of 242(+/- 3) and 218(+/- 3) mAhg(-1), cycled at a current of 50 mAg(-1) in the voltage range, 1.0-2.6 V versus Li/Li+ at the end of second and 25th cycle, respectively. The electrospun M-Nb2O5 nuggets-based battery performs better than its particle/nanofiber counterpart and could be a cathode material of choice for 2 V due to the commercial viability of the electrospinning process and characteristics of the batteries developed herewith.