Elastomer-Alginate Interface for High-Power and High-Energy Zn Metal Anodes

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.

Automated summary

In this study, a hybrid interface was designed for zinc-metal batteries, consisting of thermoplastic polyurethane (TPU) fiber matrix and zinc-alginate (ZA) filler. This interface effectively inhibited side reactions, regulated Zn2+ transport, and enabled uniform Zn deposition. The TPU frame acted as a super-elastic constraint to suppress dendrite evolution and accommodate a large amount of deposited Zn. The interface-protected Zn anode exhibited high cycling stability and exceptional cumulative capacity.