Long lifespan and high-rate Zn anode boosted by 3D porous structure and conducting network

Abstract

Aqueous rechargeable Zn batteries are attractive for emerging generations of large-scale energy storage due to their high safety, low cost, and high energy density. It is regrettable that the poor cycling performance limits its further commercialization due to the troublesome dendrite growth and short-circuiting issue of the traditional planar Zn anode. Herein, in this work, a three-dimensional porous Zn anode (3D ZnP/CF) composed of highly conductive carbon fiber-based network and active zinc powder fillers is designed for long lifespan aqueous Zn batteries. The new 3D ZnP/CF exhibits controlled deposition behavior and scarce short-circuiting benefiting from the fast ionic/electronic transfer and sufficient deposition space, which are enabled by the porous structure and conducting network of the anode. The symmetric cell based on 3D ZnP/CF exhibits small voltage hysteresis of 25.1 mV and extraordinarily long cycling stability of 3000 h, particularly excellent high-rate performance (8 mA cm−2, 8 mA h cm−2, 700 h), which is superior to those of the reported static Zn metal batteries. Furthermore, the assembled full cell with manganese oxide as cathode exhibits superb capacity retention of 93.2% over 7000 cycles. The structural and compositional design provides another effective approach for the commercialization of aqueous rechargeable Zn batteries.