Aluminophilic Layer-Modified 3D Electrodes toward Stable Anode-Free Aluminum Secondary Batteries

The pursuit of the next-generation electrochemical energy storage device has aroused noticeable research interest in aluminum (Al) secondary batteries, owing to the unique merits of the Al metal anode such as good availability, high safety, and considerable theoretical capacities. However, the practical application of Al secondary batteries is mainly impeded by poor cyclic performance. Despite the successive development of cathode materials, further exploration for a desirable anode is of great importance, due to severe corrosion and dendrite issues, which impair the long-term stability of the conventional Al metal anode. Although the design of an Al-free electrode for anode-free Al batteries without an Al metal anode provides an opportunity to suppress Al metal corrosion caused by Lewis acidic ionic liquid electrolytes, it still remains challenging to develop the ideal Al-free electrode with high capability through a facile process. Herein, a simple method is utilized to prepare the novel Al-free electrode (A-CC electrode), where the freestanding carbon cloth is modified with an aluminophilic Au layer. The 3-dimensional structure tends to reduce local current density while the modified interface regulates the interaction between the deposited Al and the A-CC electrode, which induces a reversible and uniform Al deposition and ensures the stable cycling of the Al-free electrode. The half-cell with the A-CC electrode offers a long lifespan over 2,800 h, and the full cell coupled with carbon cathode delivers high stability up to 2,000 cycles. Theoretical analyses and experimental measurements further reveal the working mechanism and superior behavior of the unique A-CC electrode, which sheds light on the profound understanding of anode-free Al batteries.