Bifunctional Interface Stabilizer of Promoting Preferential Crystal Face Adsorption and Inducing Planar Zn Growth

Abstract

Aqueous Zn-ion batteries (AZBs) with the 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 molecules with two zincophilic sites (O-containing and amino groups) has been used as bifunctional interface stabilizer (BIS) for modifying common electrolyte of AZBs. Interestingly, O-containing groups in BIS prefer to tightly adsorbing on the (100) and (101) planes of Zn metal, selectively exposing (002) plane that can guide planarized Zn growth. On the other hand, amino groups play the significant roles in attracting Zn ions and promoting the homogenous distribution. According to the theoretical calculation and in/ex situ experimental observations, dendrite-free plating and reduced by-products performances can be determined. Therefore, 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 delivered. The BIS exploration can provide a beneficial progress for constructing the stable and long-life AZBs.