Synergy Between Metal Oxide Nanofibers and Carbon Substrates for Rechargeable Lithium-Oxygen Batteries

Rechargeable lithium-oxygen batteries have attracted increasing interests presently, according to high energy density rivaling that of current batteries.  However, one of demanding challenges has been the low practical capacity that called for improvement of the substrates and electrocatalysts in the air cathode.  In this report, we have demonstrated the use of several types of metal oxide nanofibers (e.g., ZnO, Co₃O₄, etc) as the cathode materials in single-cell measurements, which were synthesized by water-based electrospinning, tuned by various precursor loadings and diverse thermal treatments. The characterizations of metal oxide nanofibers are carried out by an array of techniques, including SEM, XPS, XRD and Raman spectrum.  In addition to charging – discharging evaluation, the correlation between the battery performance, such as capacity and cyclability, and the change of surface properties, such as surface area, pore distribution and defect state are also presented. In particular, our results reveal that when metal oxide nanofibers are incorporated into various carbon substrates (e.g. carbon black and CNT.), the resulting metal oxide/carbon hybrid catalysts exhibit great synergy, leading to the higher capacity close to 10,000 mAh/g, and better stable performance over tens of cycles.