Template-free synthesis of LiV3O8 hollow microspheres as positive electrode for Li-ion batteries

摘要

The development of hierarchical micro-/nanostructures has received great attention in the field of electrochemical energy storage and conversion. In this report, we demonstrate a template-free synthesis of LiV3O8 hollow microspheres from vanadium ethylene glycolate intermediate, which in turn was obtained by a facile solvothermal route. Evaluation of morphological features with FE-SEM and HR-TEM shows hollow spheres of size 1.8 +/- 0.1 mu m diameters with wall thickness and void size of 200 +/- 20 nm and 1.5 +/- 0.1 mu m, respectively. Powder X-ray diffraction confirms that both the intermediate and LiV3O8 hollow spheres are highly crystalline without any impurity phase. Tested as a positive electrode in lithium-ion batteries, the LiV3O8 hollow spheres constructed electrode shows a discharge capacity of 304 mAh g(-1) at 0.1 C rate and 246 mAh g(-1) at 1 C rate during the first discharge. More importantly, LiV3O8 electrode delivers stable cycle-life performance with a specific capacity of 156 mAh g(-1) after 300 (dis)charges at 1 C rate. The present hollow LiV3O8 structures would be expected to offer additional active sites, void space to counter volume expansion, and thin-shell structures to provide shortest path for Li+ ion/electron transport, thereby enhancing the cycling stability and rate performance.