Stable anode enabled by an embossed and punched structure for a high-rate performance Zn-ion hybrid capacitor

Abstract

Zinc (Zn)-ion hybrid capacitors (ZICs) have been considered as the next-generation energy storage technology due to their high energy density and excellent safety. However, ZICs still have serious challenges in overcoming the poor rate performance and low long-term stability at high current density related to the inefficient use of the interface between the Zn anode and electrolyte, along with the poor wettability of the electrode, which lead to the growth of uniform Zn dendrites on the anode surface. To address these drawbacks, an advanced surface-engineering approach is presented herein, involving a uniform, embossed, and punched anode structure. The as-fabricated ZIC exhibits a superb energy storage performance and reversibility, with improved energy densities of 108 and 69 W h kg(-1) at 450 and 9000 W kg(-1), and an excellent fast long-term stability, with a capacity retention of 90% during 10 000 cycles at 10.0 A g(-1). These findings suggest that advanced surface engineering is an influential tool for the next-generation ZICs.