| 초록 |
Sodium ion batteries have been spotlighted recently due to lower material costs, the abundance of sodium resources, and analogous electrochemical components with existing Li-ion battery systems. White anatase TiO2 nanomaterials have been developed for suitable anode materials enabling facile insertion/extraction of Na ions. However, low electronic conductivity originated from large electronic band gap (~3.2eV) and narrow interstitial sites to accommodate large Na ions often limit the battery performance. In this regard, new class of TiO2 material called 'black TiO2' is more attractive owing to its flexible structural feature and narrower band gap of approximately 2.2eV and consequent high electrical conductivity. In this work, we report highly conductive black TiO2 nanofiber electrode for high performance Na-ion batteries. The introduction of black TiO2 offer benefits; (1) formation of oxygen vacancy as numerous defective sites leads to fast electron transfer in the structure (2) the glassy structure provides efficient intercalation of Na-ions in the structure. We also elucidate thermal effects on the structural and chemical feature of the samples. |
