Liquid Metal Composites Enabled High‐Safety Flexible Solid‐State Aluminum Batteries

ABSTRACT Rechargeable aluminum batteries (RABs) are promising for stationary energy storage due to their intrinsic safety, low cost, abundance, and use of non‐flammable chloroaluminate ionic liquid electrolytes. However, aluminum anode instability from dendrite growth and corrosion limits cycle life. This study presents a facilely fabricated Al 20 ‐LM‐Ti composite anode, featuring a structure where aluminum microparticles are semi‐embedded in EGaIn. This design not only resists electrolyte corrosion but also utilizes the fluidic nature of the EGaIn to suppress the outward growth of aluminum dendrites. Furthermore, by providing a crystallographic orientation similar to that of the subsequently deposited layer and offering higher adsorption energy for reactive ions, this anode enables uniform aluminum deposition while enhancing interfacial ion transport and diffusion. Consequently, the assembled Al 20 ‐LM‐Ti//Al 20 ‐LM‐Ti symmetric cell achieves stable cycling for over 2200, 3000, and 1600 h at high current densities of 1, 2, and 3 mA cm −2 , respectively. Leveraging this structurally robust anode, a full Al 20 ‐LM‐Ti//graphite cell operates stably for over 39 000 cycles at 1.5 A g −1 . Extreme tests under heavy striking, mechanical cutting, and burning reveal its outstanding reliability. This work holds significant implications for realizing high‐performance RABs and offers a promising strategy for anode development in other battery systems.