Scalable Ultrathin Anodes via Energy Band-Engineered Gradient Interlayers for Ultrafast All-Climate Aluminum Battery

Aluminum batteries show promise for large-scale energy storage owing to high capacity, safety, and low cost, but are hindered by dendrite growth and corrosion in Al anodes, limiting the availability of large-area, ultra-thin electrodes for fundamental and commercial progress. Here we present a strategy integrating energy band engineering and structural optimization to achieve uniform Al electrodeposition. By spontaneously forming a porous gradient interphase with a wide-bandgap, high-ionic-conductivity component, we create mixed electron–ion conducting pathways that guide uniform Al3+ transport. Experiments and multiscale simulations reveal the composition–structure–property relationships governing ion deposition kinetics. The resulting large-area Al foil sustains stable cycling for over 5000 hours at 10 mA cm-2 and 10 mAh cm-2. An ultra-thin Al metal battery operates across −30 to 80°C with remarkable flexibility, delivering 187 Wh kg-1. This design advances high-energy, all-climate wearable energy devices.