Elastomer–alginate interface for high-power and high-energy zn metal anodes

Abstract

Spontaneous corrosion and uncontrolled dendrite accumulation of Zn rapidly degrades zinc–metal battery performance. Artificial interfaces have been widely fabricated on Zn metal anodes, yet most interfaces are detrimental to ion transfer and adapt poorly to spatial changes during Zn plating/stripping. Herein, a hybrid interface, consisting of a thermoplastic polyurethane (TPU) fiber matrix and Zn-alginate (ZA) filler, is designed, which serves as a physical barrier between anode and electrolyte to inhibit side reactions. Encouragingly, ZA regulates Zn2+ transport and endows uniform Zn deposition by inducing plating/stripping underneath the hybrid interface. At the same time, the TPU frame acts as a super-elastic constraint to further suppress rampant dendrite evolution and accommodate a large amount of deposited Zn. Consequently, the interface-protected Zn anode delivers high cycling stability (1200 h at 5 mA cm–2/5 mA h cm–2; 500 h at 10 mA cm–2/10 mA h cm–2), realizing an exceptional cumulative capacity of over 6000 mA h cm–2. This enhancement is well maintained in the full cell when coupled with a vanadium-based cathode. The unique matrix-filler architecture and mechanistic insights unraveled in this study are expected to provide a general principle in designing functional interfaces for metal anodes.