Manipulating the Electronic Structure of Graphite Intercalation Compounds for Boosting the Bifunctional Oxygen Catalytic Performance.

Abstract

Developing highly efficient bifunctional catalysts for the oxygen reduction and oxygen evolution reaction (ORR/OER) can open possibilities for future zinc air batteries (ZABs). Herein, cost-effective and highly conductive few-layer ferric and nickel chloride co-intercalated graphite intercalation compounds (FeCl3 -NiCl2 -GIC) are designed as bifunctional oxygen catalysts for ZAB. The optimized few-layer FeCl3 -NiCl2 -GIC catalyst exhibits a small overpotential of 276mV at 10mA cm-2 for the OER and achieves a high onset potential of 0.89V for the ORR. The theoretical analysis demonstrates the electron-rich state on the carbon layers of FeCl3 -NiCl2 -GIC during the catalytic process favors the kinetics of electron transfer and lowers the absorption energy barriers for intermediates. Impressively, the ZAB assembled with few-layer FeCl3 -NiCl2 -GIC catalyst displays a 160 h cycling stability and a high energy efficiency of 72.6%. This work also suggests the possibility of utilizing layer electronic structure regulation on graphite intercalation compounds as effective bifunctional catalysts for ZABs.