Electrospun hierarchical CaCo2O4 nanofibers with excellent lithium storage properties.

Hierarchical CaCo2O4 nanofibers (denoted as CCO-NFs) with a unique hierarchical structure have been prepared by a facile electrospinning method and subsequent calcination in air. The as-prepared CCO-NFs are composed of well-defined ultrathin nanoplates that arrange themselves in an oriented manner to form one-dimensional (1D) hierarchical structures. The controllable formation process and possible formation mechanism are also discussed. Moreover, as a demonstration of the functional properties of such hierarchical architecture, the 1D hierarchical CCO-NFs were investigated as materials for lithium-ion batteries (LIBs) anode; they not only delivers a high reversible capacity of 650 mAh g−1 at a current of 100 mA g−1 and with 99.6 % capacity retention over 60 cycles, but they also show excellent rate capability with respect to counterpart nanoplates-in-nanofibers and nanoplates. The high specific surface areas as well as the unique feature of hierarchical structures are probably responsible for the enhanced electrochemical performance. Considering their facile preparation and good lithium storage properties, 1D hierarchical CCO-NFs will hold promise in practical LIBs.