High-Performance Aqueous Na-Zn Hybrid Ion Battery Boosted by Water-In-Gel Electrolyte

Aqueous hybrid Na-Zn ion batteries (ASZIBs) are promising for large-scale energy storage due to their low cost and potential for high output voltage. However, most ASZIBs show limited discharge voltage (<2.0 V) and capacity (<100 mAh g(-1)) due to inefficient usage of the dual ions. In this study, a novel large-electrochemical-window water-in-gel electrolyte based CuHCF-CNT/Zn Na-Zn hybrid battery is proposed, which achieves a high extraction voltage of Na ion (2.1 V vs Zn/Zn2+), together with a large discharge specific capacity (260 mAh g(-1)) thanks to the Zn-ion insertion, delivering a superior energy density of 440 Wh kg(-1). The hybrid battery also shows a high capacity retention of 96.8% after 450 cycles. Moreover, an ultrahigh discharge capacity of 1250 mAh g(-1) is achieved when further coupled with the Zn-O-2 reaction, delivering the promising application of ion intercalation and metal-air hybrid battery.

Automated summary

The study introduces a novel water-in-gel electrolyte based CuHCF-CNT/Zn Na-Zn hybrid battery, which achieves high discharge voltage and large capacity, delivering superior energy density and cycling stability. When further coupled with the Zn-O-2 reaction, an ultrahigh discharge capacity can be achieved.