Enhancing Li-O2 battery performance with conductive hierarchical metal-organic framework composite cathodes

Abstract

Li-O2 batteries are recognized for their high theoretical capacity and energy density, positioning them as excellent candidates for next-generation energy storage. This study explores the use of Metal-Organic Frameworks (MOFs) with high specific surface areas and open metal sites as cathode materials to address existing challenges. We developed conductive “cactus-like” composites by employing hydroxylated graphene (G-OH) as a substrate to grow columnar M3(HHTP)2 and MxM3-x(HHTP)2 (M = Cu, Ni) in a one-pot synthesis, enhancing the structure's conductivity and order. The cathode, especially the [Cu1.5Ni1.5(HHTP)2]1-(G-OH)1 composition, demonstrated a specific capacity of up to 12542 mAh g-1 at a current density of 50 mA g-1 and maintained stability over more than 40 cycles at a limited capacity of 500 mAh g-1 in an O2 atmosphere. This performance surpasses that of M3(HHTP)2, MxM3-x(HHTP)2, or G-OH alone, highlighting the potential of MOF-based composites in improving the efficiency and durability of Li-O2 batteries and opening new avenues for cathode material design.