The battery shape is critical limiting factor affecting foreseeable energy storage applications. In particular, deformable metal–air battery systems could offer a low cost, low flammability, and high capacity, but the fabrication of such metal–air batteries remains challenging. Here, we show that a shape-reconfigurable materials approach, in which the deformable components composed of micro- and nanoscale composites are assembled, is suitable for constructing polymorphic metal–air batteries. We adopt an aluminum–air battery cell as an ideal platform, which involves three-electron transfer during charging reactions; as a result, it provides a specific capacity that rivals that of a single-electron lithium-ion battery. This cell is a great platform to test a shape-reconfigurable design because of easier handling, greater safety, and lower reactivity. This architecture is simple and scalable and also addresses the fundamental limitations of aluminum–air batteries by allowing the use of deformable packing designs to increase the performance output. Further, this approach is technologically unique in that it a method that enables the realization of a 3D shape change, which has never been observed for aluminum–air batteries. This significant deformability results in a specific capacity of 128 mAh/g per cell; calculated from the total mass of anode (496 mAh/g per cell; based on the mass of consumed aluminum), and a high output voltage (10.3 V) with 16 unit battery cells connected in series. The resulting battery can endure significant geometrical distortion such as three-dimensional stretching and twisting while the electrochemical performance is preserved. This work represents an advancement in deformable aluminum–air batteries using the shape-reconfigurable materials concept, thus establishing a paradigm for shape-reconfigurable batteries with exceptional mechanical functionalities.