Cu-Al Composite as the Negative Electrode for Long-life Al-Ion Batteries

Rechargeable Al-ion batteries have attracted great interest due to their advantages in high anode capacity, high safety, etc. However, conventionalAl foil negative electrode has critical problems in corrosion and pulverization. Here, we propose a novelCu-Al composite, which is prepared by a facile electrochemical plating approach, as the negative electrode for addressing above challenges. Remarkably, the plated Cu foil negative electrode delivers excellent stability and long cycle life compared with the Al foil negative electrode, although its thickness and areal mass density are only30% and similar to 76% of that of theAl foil negative electrode, respectively. The essential pulverization problem in bare Al negative electrode would be dramatically reduced attributing to excellent corrosion resistance of Cu foil. Besides, the plated Al is still attached to the Cu foil during repeated charge-discharge processes, resulting in a nearly 100% Coulombic efficiency even after long-term cycling. More importantly, the plated Cu foil negative electrode is convenient for the large-scale practical applications. In view of our results, this work opens an effective approach for configuring low-cost, high energy density, long cycle life and scalable negative electrode of Al-ion batteries. (C) 2019 The Electrochemical Society.