Hierarchical Cr2O3@OPC composites with octahedral shape for rechargeable nonaqueous lithium-oxygen batteries

Abstract

The development of catalyst materials is the most significant issue that hinders the practical applications of Li-O2 batteries. Herein we show the design and synthesis of the hierarchical chromic oxide-octahedral porous carbon (Cr2O3@OPC) composites catalyst with octahedral shape that derived from Cr-based metal-organic frameworks (MIL-101(Cr)) precursor. When applied as cathode catalysts in rechargeable Li-O2 batteries, the electrode with Cr2O3@OPC composites catalyst exhibits a low charge and discharge over-potential, high discharge capacity and excellent cycling stability. What's more, the electrode with Cr2O3@OPC composite shows a discharge capacity up to ∼4800 mAh g(catalyst + carbon)−1 at a current density of 0.1 mA cm−2, and exhibits a very stable discharge voltage plateau of 2.7 V and a charge voltage plateau of ∼3.9 V. With the addition of Cr2O3@OPC composite, the Li-O2 batteries can obtain good cycle performance over 50 cycles at a fixed capacity of 800 mAh g(catalyst + carbon)−1. These results indicating that the Cr2O3@OPC composite derived from MIL-101(Cr) would be a promising catalyst for Li-O2 batteries.