Large-scale synthesis of Ag-Si core-shell nanowall arrays as high-performance anode materials of Li-ion batteries

We demonstrate the synthesis of Ag-Si core-shell nanowall arrays via a simple displacement reaction and subsequent RF-sputtering deposition. The displacement between the Cu substrate and Ag+ leads to Ag nanowall arrays with good substrate adhesion. The Ag nanowall arrays can function as a mechanical support and an efficient electron conducting pathway for Si anode materials. These Ag-Si core-shell nanowall arrays show a discharge capacity of >1500 mA h g(-1) at a current density of 2100 mA g(-1) after 400 cycles. The capacity fade from 2nd to 400th cycles is only 0.1% per cycle. Moreover, cycling performance can be retained when the thickness of the Si layer increases, clearly demonstrating the superior cycling performance of Ag-Si core-shell nanowall arrays. Considering the simple and large-scale synthesis of Ag-Si core-shell nanowall arrays, this work may facilitate the commercial application of Si anode materials for Li-ion batteries.