Laser-electric-driven biomimetic assembly for super-foldable aqueous battery

The shortage of substrate materials that simultaneously possess super-foldability and high electrical conductivity restricts the development of foldable electronics. To tackle that challenge, this work establishes a dual-physical-field fabrication technology, denoted as Laser-Electric-field Coupled Biomimetic Spinning Technique (LECBST), and fabricates carbon fiber metamaterials encapsulating axially aligned carbon nanotubes with a high conductivity of 1.075×10 3 S·m –1 , which can endure 2,000,000 cycles of real folding. On this basis, NiCo layered double hydroxides are designed and assembled to mimic the topological structure of bovine reticulum, yielding super-foldable electrodes with a conductivity of 3.21×10 2 S·m –1 and stable foldability over those 2,000,000 cycles. It also delivers a high specific capacitance of 2680 F∙g –1 at a current density of 1 A∙g –1 . We then fabricate the first aqueous super-foldable battery via multi-stage biomimetic synergistic assembly. The as-assembled battery can stably withstand 500,000 consecutive real folding cycles with nearly unchanged structural integrity and electrochemical performance. Combined with macro and micro mechanical tests, in situ dynamic SEM observation during folding, and finite element mechanical simulations, the stress dissipation mechanism of the aqueous battery under folding is revealed. This research lays a solid foundation for the investigation and practical application of other super-foldable energy storage materials and devices.