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

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 µm diameters with wall thickness and void size of 200 ± 20 nm and 1.5 ± 0.1 µm, 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.