Trace alkynyl diol mediated interfacial engineering for ultrastable zinc metal anodes

Abstract

The uncontrolled growth of Zn dendrites remains a significant obstacle to the advancement of aqueous Zn-ion batteries (AZIBs). Here, we introduce 1,4-butynediol (BTDA) as an electrolyte additive that simultaneously reconstructs the local Zn2+/H2O environment at the Zn anode interface, directing the preferential growth of Zn deposition planes and thereby suppressing dendrite formation, to achieve uniform, compact Zn anodes. Experimental and theoretical analyses reveal that BTDA molecules preferentially adsorb onto the Zn (002) plane, inducing homogeneous and dense deposition while mitigating side reactions and hydrogen evolution, thereby enhancing interfacial stability and reaction reversibility. As a result, the ZnǁZn cell delivers ultralong lifespans exceeding 4000 and 6000 h at 30 mA cm−2/1 mAh cm−2 and 10 mA cm−2/1 mAh cm−2, respectively. The ZnǁCu cell maintains a high Coulombic efficiency of 99.5% after 3200 h at 1 mA cm−2/0.5 mAh cm−2. Moreover, full cells exhibit excellent capacity recovery under varying rates and retain 64.9% of their capacity after 2500 cycles at 1.0 A g−1. We believe our work not only offers an effective strategy for achieving a reversible Zn anode in long-lifespan AZIBs but also provides new insights into the organic molecule-engineered electrode/electrolyte interfacial physics processes.