Self-adaptive reconstruction of Zn (0 0 2) crystal plane for highly reversible Zn anodes

Abstract

Although Zn (002) crystal plane make it highly competitive for the design of high-performance Zn anodes, manipulating the Zn (002) crystal plane and maintaining long-term stability are significant challenges. Herein, carboxylated chitosan (CCS) is introduced as a novel bifunctional polymer electrolyte additive to protect the intrinsic Zn (002) plane from resolution and induce the highly oriented assembly of Zn atoms along (002) direction, thereby self-adaptively enhancing the Zn (002) plane over prolonged cycling. Specifically, CCS with electron-rich groups can preferentially adsorb on Zn anode, selectively etch the Zn anode with (002) texturing and appropriately affect the assembly of Zn atoms along the (002) direction. As a result, a remarkable cycling lifespan of over 300 h is achieved at 30 mA cm−2 under a deep depth of discharge of 60 %. Moreover, a highly reversible Zn anode with a high Coulombic efficiency of 99.8 % can also be achieved at 10 mA cm−2 over 1000 cycles. Furthermore, the capacity stability of NH4V4O10||Zn full cell and Zn||AC hybrid supercapacitor is significantly improved even under harsh conditions, such as high areal capacity, limited Zn resource and lean electrolyte. The CCS additive maintains a stable effect on the directional reconstruction of Zn anodes over prolonged cycling.