Engineering zincophilic sites on Zn surface via plant extract additives for dendrite-free Zn anode

Abstract

Aqueous Zn-ion batteries (AZIBs) are promising candidates for large-scale energy storage owing to their intrinsic safety and low cost. However, the formation of Zn dendrite caused by uneven deposition on Zn anode severely impedes the lifespan of AZIBs. Herein, we propose a green and low-cost additive, nettle extract (NE), to guide the uniform Zn deposition via in-situ engineered zincophilic sites. We show by both experiments and theoretical calculations that the zincophilic molecules contained in NE can adsorb on Zn anode surface to offer more effective sites for Zn nucleation, thus effectively suppressing the dendrite growth. Significantly, the Zn||Zn symmetric cell with NE can stably cycle over 2200 h at 5 mA cm−2 with 5 mAh cm−2 capacity. A Zn||polyaniline/carbon felt full cell also gains 84.9% capacity retention after 1500 cycles. Our strategy of engineering zincophilic sites on Zn anode via plant extracts additives ushers in new possibilities to develop dendrite-free Zn anode.