Electrical-Conductive/Insulating Bi-Functional Layers for Stable Zn Metal Anode.

ABSTRACT

Zinc-ion batteries are regarded as an extremely promising candidate for large-scale energy storage equipment due to the inexpensive ingredients and high safety. However, dendrite growth and side reactions occur in the Zn anode, which lead to exceedingly low coulombic efficiency (CE) and poor cycling stability. In this work, we propose a strategy of a conductive/insulating bi-functional coating layer (CIBL) for stable Zn metal anodes. Porous Ag nanowires (NWs) coating as a conductive layer effectively reduces the nuclear barrier and contains Zn2+ deposition in a certain space. Polyimide (PI) coatings as insulating layer implement a shunting effect on Zn2+ , which could reduce the differential concentration on the Zn surface and induce uniform deposition of Zn2+ . Therefore, the CIBL-Zn//CIBL-Zn battery achieves stable plating/stripping of over 1300 h at 1 mA cm-2 . The CE of CIBL-Zn//CIBL-Zn battery maintains at 99.2 % even after 1000 cycles. Moreover, the CIBL-Zn//V2 O5 battery exhibits a capacity of nearly 289.2 mA h g-1 at 5 A g-1 after 3000 cycles and no sign of capacity degradation is found, which further demonstrate the feasibility of this strategy in practical application.