Rechargeable multivalent metal (e.g., zinc (Zn) and aluminum (Al)) batteries are ideal choices for large-scale energy storage owing to their intrinsic low cost and safety. However, the poor compatibility between metallic anodes and electrolytes strongly hampers their practical applications. Herein, it is demonstrated that confining multivalent metals in a biomimetic scaffold (Bio-scaffold) can achieve highly efficient multivalent metal plating/stripping. This Bio-scaffold is well-tailored through the synergy of a parallel-aligned array of fractal copper branches and a CaTiO3 (CTO)-based coating layer. By virtue of this design strategy, the as-developed Bio-scaffold-based Zn- and Al-metal anodes exhibited dendrite-free morphologies with high reversibility and long lifespan, as well as excellent performance for Zn and Al full batteries. Theoretical modeling and experimental investigations reveal that the fractal copper array not only facilitates multivalent ion diffusion and electrolyte wetting but also effectively reduces the local current densities during cycling; Meanwhile, the CTO-based coating layer effectively blocks interfacial side reactions and enables a homogeneous ionic flux. This work opens a new avenue for developing multivalent metal batteries.
Keywords: biomimetic scaffolds; dendrite growth; fractal structures; interfacial side reactions; multivalent metal batteries.
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