A dynamically assembled bionic ion pump interface towards high-rate and stable-cycling zinc metal batteries

The application of a Zn metal anode in aqueous zinc metal batteries (AZMBs) is limited by an unstable interface, which induces well-known dendrite growth and corrosion. In this report, a bionic ion pump interface for a Zn metal anode is proposed and constructed by dynamically assembling acetylated protein (a-HP_ace) (Zn@BIPI/a-HP_ace). The a-HP_ace with abundant amide bonds is preferentially assembled on the fresh Zn metal surface as an interface, due to its strong recognition of Zn²⁺. It is demonstrated by TOF-SIMS that the organic –CONH– and inorganic ZnF₂/ZnS make up the uniformly dispersed section of the interface film, playing the roles of Zn²⁺ transport sites and a dense barrier layer, respectively. Thus, the bionic ion pump interface is not only beneficial for the rapid transport of Zn²⁺ but also effective in preventing aqueous electrolyte erosion. More importantly, the Zn@BIPI/a-HP_ace anode achieves uniform deposition with a predominant orientation of 91% (100) planes. The improved results show that a symmetric cell with a Zn@BIPI/a-HP_ace electrode achieves a long cycle life of over 6000 h, and a full cell with a Zn@BIPI/a-HP_ace anode and NaV₃O₈-1.5H₂O cathode exhibits a high-capacity retention of B92% after 5000 cycles at 5 A g^-1. This study, in which bionic ion-pump interface engineering is achieved, provides a novel approach to facilitate the practical application of AZMBs.