1Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University, Houghton, MI 49933-1295, USA
2Department of Material Science and Engineering, Michigan Technological University, Houghton, MI 49933-1295, USA
3Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL60607-7059, USA
Using sodium as a potential charge carrier ion for rechargeable batteries has attracted attention of many researchers since Na-ion batteries are more eco-friendly and affordable due to much more abundance of sodium over lithium on earth. Another considerable issues are performance and cyclability of batteries. The anode materials usually experience large volume changes through the ion insertion and extraction. This volume change and lithium embrittlement causes cracks and loss of contact in the anode material, which ultimately causes the failure of battery. Here, we investigated and compared the structural and mechanical changes of ZnO nanowires during sodiation and lithiation by using in situ transmission electron microscopy. The cracks were created upon the first lithiation process of single crystalline ZnO nanowire. The lithiated ZnO nanowire shows multiple glassy domains, which has low strength and ductility. This results in poor cyclability of battery. On the other hand, ZnO nanowire after sodiation show dislocations on the surface of nanowire that results in more ductility of sodiated nanowire rather than lithiated one. This direct comparison demonstrates the critical role of anode material’s mechanical properties on failure mechanism and cyclability of Li/Na-ion batteries.