Highly Conductive Cu Nanoneedle-Array Supported Silicon Film for High-Performance Lithium Ion Battery Anodes

Abstract

Silicon is believed to be the most promising candidate for Lithium ion batteries anode, but its rapid capacity fading owing to huge volume change and pulverization presents a significant challenge. Three-dimensional (3D) nanostructured thin-film electrodes with Si film thinner than critical thickness have been widely considered to address the above problem because they have shown fast rates of charge and discharge maintaining high energy densities. However, the complicated and expensive synthesis process of 3D nanostructured current collectors make thin-film electrodes difficult to scale up. Herein, we fabricate an innovative Cu nanoneedle-array (NNA) structure by one-step electroless deposition without template. After silicon deposition, such engineered electrodes exhibit excellent cycling stability (1141 mAh g–1 after 1950 cycles) and high rate performance (335 mAh g−1 at rate of 12.5 C). These outstanding properties could be attributed to the void spaces and the open structure between Si nanostructures that allow free volume change and facile Li+ transport.