Copper nanowall array grown on bulk Fe-Co-Ni alloy substrate at room temperature as lithium-ion battery current collector

Large-scale copper nanowall array on the bulk Fe-Co-Ni alloy substrate has been prepared in aqueous solution at room temperature via an electroless deposition method. The thickness of the nanowalls is about 15 nm. A possible growth mechanism of the nanowalls was proposed. The effects of reaction temperature, reaction time and the amount of critical agent (Fe³⁺) on the morphology and crystalline phase of the nanowalls were investigated. Furthermore, the electrochemical performance of Sn film supported on the as-prepared copper nanowalls current collector is enhanced in comparison with that on the commercial copper foil when used as anode for Li-ion batteries with the operating voltage window of 0.01-2.0 V (vs. Li). After 20 cycles, the discharge capacity of Sn-Cu nanowalls anode still remained 365.9 mAh g^− 1, that is, 40% retention of the reversible capacity, while the initial charge capacity of Sn film cast on commercial Cu foil was 590 mAh g^− 1, dropping rapidly to 260 mAh g^− 1 only after 10 cycles.