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@Fe 2 O 3 ) 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 µm) branches with well‐interconnected and entangled features, which result in highly desirable attributes such as a large specific surface area (≈6.97 m 2 g −1 ), free transfer pathway for Li + , and high electrical conductivity. The structural advantages of Cu NPF@Fe 2 O 3 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@Fe 2 O 3 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, ≈120% retention after 500 cycles), and outstanding rate capability (630 mAh g –1 at 10 C).