Dendritic Nanostructured Waste Copper Wires for High-Energy Alkaline Battery

Rechargeable alkaline batteries (RABs) have received remarkable attention in the past decade for their high energy, low cost, safe operation, facile manufacture, and eco-friendly nature. To date, expensive electrode materials and current collectors were predominantly applied for RABs, which have limited their real-world efficacy. In the present work, we propose a scalable process to utilize electronic waste (e-waste) Cu wires as a cost-effective current collector for high-energy wire-type RABs. Initially, the vertically aligned CuO nanowires were prepared over the waste Cu wires via in situ alkaline corrosion. Then, both atomic-layer-deposited NiO and NiCo-hydroxide were applied to the CuO nanowires to form a uniform dendritic-structured NiCo-hydroxide/NiO/CuO/Cu electrode. When the prepared dendritic-structured electrode was applied to the RAB, it showed excellent electrochemical features, namely high-energy-density (82.42 Wh kg^-1), excellent specific capacity (219 mAh g^-1), and long-term cycling stability (94% capacity retention over 5000 cycles). The presented approach and material meet the requirements of a cost-effective, abundant, and highly efficient electrode for advanced eco-friendly RABs. More importantly, the present method provides an efficient path to recycle e-waste for value-added energy storage applications.