Multifunctional fluorinated carbon dots artificial interface layer coupled with in-situ generated Zn2+ conductor interlayer enable ultra-stable Zn anode

Abstract

Stabilizing zinc anode is a systematic project for aqueous zinc ion batteries (ZIBs), which needs to solve many problems such as dendrite growth, corrosion, hydrogen evolution, and other side reactions. It is urgent to develop a protective layer for zinc anode to solve these problems at one time. Based on the results of calculation, a hydrophobic multifunctional fluorinated carbon dots (F-CDs) protective layer with three kinds of zincophilic groups (-CO, -CHO and -F) was constructed on the Zn anode surface. As expected, these zincophilic groups on the F-CDs layer functioned as zincophilic sites to achieve uniform Zn deposition. Especially, the -F group could in-situ promote the formation of ZnF2 under the F-CDs layer and the ZnF2 layer is usually considered as a solid Zn2+ conductor layer to further even Zn deposition. Additionally, the experimental results also demonstrated that the F-CDs layer coupled with in-situ generated ZnF2 interlayer can not only tackle above issues in an integrated way, but also induce the deposition of Zn on the preferred (002) plane. Therefore, the Zn@F-CDs anode exhibits an ultra-long cycling life over 3500 h at 1 mA cm–2, together with an excellent average coulombic efficiency (99.32% for over 1100 h) in half cells.