Enhanced Electrochemical Properties of Li3VO4 with Controlled Oxygen Vacancies as Li‐Ion Battery Anode. Issue 22 (27th March 2017) - Wang, Kan
Abstract: Li3 VO4, as a promising intercalation‐type anode material for lithium‐ion batteries, features a desired discharge potential (ca. 0.5–1.0 V vs. Li/Li + ) and a good theoretical storage capacity (590 mAh g −1 with three Li + inserted). However, the poor electrical conductivity of Li3 VO4 hinders its practical application. In the present work, various amounts of oxygen vacancies were introduced in Li3 VO4 through annealing in hydrogen to improve its conductivity. To elucidate the influence of oxygen vacancies on the electrochemical performances of Li3 VO4, the surface energy of the resulting material was measured with an inverse gas chromatography method. It was found that Li3 VO4 annealed in pure hydrogen at 400 °C for 15 min exhibited a much higher surface energy (60.7 mJ m −2 ) than pristine Li3 VO4 (50.6 mJ m −2 ). The increased surface energy would lower the activation energy of phase transformation during the charge–discharge process, leading to improved electrochemical properties. As a result, the oxygen‐deficient Li3 VO4 achieved a significantly improved specific capacity of 495 mAh g −1 at 0.1 Ag −1 (381 mAh g −1 for pristine Li3 VO4 ) and retains 165 mAh g −1 when the current density increases to 8 Ag −1 . Abstract : Scratch the surface : The electrochemical properties of Li3 VO4 could be improved through the introduction of oxygen vacancies after annealing in hydrogen, resulting in good performance as the anode in a lithium ion battery. Inverse gas chromatography was used to calculate the surface energies of the modified materials in order to understand the enhanced properties.