An Efficient and Stable Lithium‐Oxygen Battery Based on Metal‐Organic Framework Separator Operating at 160 °C

Abstract

AbstractA lithium oxygen battery (LOB) with molten salt electrolyte operating at elevated temperature has aroused great interest because it enables fast reaction kinetics. However, there is still a lack of open literature on the separator (membrane) of this kind of LOB. Metal‐organic framework (MOF) materials are widely used as components of separators in many kinds of energy storage devices, due to their regular crystalline and well‐defined pore structures. In this work, a MOF material, zirconium (II) 1,4‐benzenedicarboxylate after lithiation (UiO‐66‐SO3Li) with a narrow pore size (6 Å), is used as a key component of the separator for LOB operating at elevated temperature. A “rolling dough” method is adopted to prepare the separator, which achieves 100% material utilization. The LOB with this membrane operates at 160 °C and delivers a specific capacity of 5.1 mAh cm−2 with an overpotential as low as 40 mV at 0.1 mA cm−2 and a prolonged cycle life, 180 cycles with a high coulombic efficiency of 99.9% at 0.5 mA cm−2. This MOF‐based membrane provides efficient Li+ transfer and restricts discharge product migration during battery operation, which is promising for the development of LOB in large‐scale practical applications.