| 초록 |
Powder X-ray diffraction (PXRD) is the most popular and powerful tool to nondestructively characterize the phase of polycrystalline materials under operational conditions. In particular, synchrotron radiation provides high energy and high photon flux, which make it possible to conduct detailed structural analysis of complex materials such as battery electrode materials. I will briefly introduce the 9B HRPD (high resolution powder diffraction) beamline of PLS(Pohang Light Source)-II, and related researches using the HRPD beamline in the first part of the presentation. Among various scientific opportunities using synchrotron XRD, this talk will be focused on structural studies of Na-based electrode materials by synchrotron XRD. Research on Na-based cathode materials has been renewed because of natural abundance and low cost of Na resources in recent years. However, structural stability and transition behaviors of Na-based cathode materials exhibit different trends as compared to the conventional Li-based cathode materials. Therefore, both the crystalline structure of an electrode material and its structure changes during electrochemical cycling are considered to be critical factors to understand reaction mechanism of Na-electrode materials. Furthermore, structural information plays a pivotal role to design electrode materials for high performance Na-ion batteries. In this regard, I will present the case study about phase transitions of two Na-layered oxides during electrochemical desodiaion/sodiation by in situ synchrotron XRD. Lastly, current works about crystal structure changes of mixed-anion phosphates as cathode materials for Na-ion batteries will be shortly discussed in the last part of the talk. |
