Ultrafine Copper Nanopalm Tree-Like Framework Decorated with Iron Oxide for Li-Ion Battery Anodes with Exceptional Rate Capability and Cycling Stability

Abstract

Ultrafine copper nanopalm tree-like frameworks conformally decorated with iron oxide (Cu NPF@Fe2O3) are prepared by a facile electrodeposition method utilizing bromine ions as unique anisotropic growth catalysts. The formation mechanism and control over Cu growth are comprehensively investigated under various conditions to provide a guideline for fabricating a Cu nanoarchitecture via electrochemical methods. The optimized Cu NPFs exhibit ultrathin (<90 nm) and elongated (2-50 mu m) branches with well-interconnected and entangled features, which result in highly desirable attributes such as a large specific surface area (approximate to 6.97 m(2) g(-1)), free transfer pathway for Li+, and high electrical conductivity. The structural advantages of Cu NPF@Fe2O3 enhance the electrochemical kinetics, providing large reactivity, fast Li+/electron transfer, and structural stability during cycling, that lead to superior electrochemical Li storage performance. The resulting Cu NPF@Fe2O3 demonstrates a high specific capacity (919.5 mAh g(-1) at 0.1 C), long-term stability (801.1 mAh g(-1) at 2 C, approximate to 120% retention after 500 cycles), and outstanding rate capability (630 mAh g(-1) at 10 C).