Bifunctional interface stabilizer for promoting preferential crystal face adsorption and inducing planar Zn growth

Abstract

Aqueous Zn-ion batteries (AZBs) with high safety and low cost have been considered as one of the most promising energy storage devices, but the related application is always impeded by the uneven Zn deposition and uncontrollable dendrite formation. Herein, a unique kind of organic small molecule with two zincophilic sites (O-containing and amino groups), 2-aminoethanesulfonic acid, has been used as a bifunctional interface stabilizer (BIS) for modifying the common electrolyte of AZBs. Interestingly, O-containing groups in BIS prefer to tightly adsorb on the (100) and (101) planes of Zn metal, selectively exposing the (002) plane that can guide planarized Zn growth. Meanwhile, amino groups play significant roles in attracting Zn ions and promoting homogenous distribution. According to the theoretical calculation and in/ex situ experimental observations, dendrite-free plating and reduced by-product performances can be determined. AZBs adopting functional electrolytes with BIS display improved electrochemical results. An extremely high CE value over 99.5% for 2000 cycles, stable and ultralong lifespan of 4000 h and high capacity retention of 73.8% after 700 cycles for the full cell loading MnO₂ can be obtained. The exploration of BIS can provide beneficial progress for constructing stable and long-life AZBs.