Na2Ti7O15 Nanowires with an Oriented Tunnel Structure and High Mechanical Stability: A Potential Anode of Sodium-Ion Batteries and Gas Sensing Materials

Na2Ti7O15 (NTO) can be selected as candidate anode for high-performance sodium-ion batteries (SIBs). However, there are few reports of research on the mechanical properties of low-dimensional NTO, which is important for the stability of SIBs. In this work, by using the one-step hydrothermal method, NTO nanowires (NWs) with good orientation were prepared successfully. The transmission electron microscopy (TEM) and selected area electron diffraction (SAED)showed that the NTO NWs had a good aspect ratio and dispersion, with lengths over 20 μm. Further microstructure analysis showed that the nanowires grew along the (020) direction, and there were some "stripe" structures along the growing direction, which provides a good tunnel structure for Na ion channels. Further, the in situ mechanical analysis showed that the NTO NWs had excellent elastic deformation characteristics and mechanical structural stability. In addition, the NTO NWs also showed a good gas sensitivity to NO and NH3. Our results showed that the prepared NTO nanowires with a stripe tunnel oriented-structure and excellent mechanical properties may have a potential application in SIBs or other wearable sensor devices.