Synergistic Design of 3D Printed Graphene Aerogel and CoBr 2 Redox Mediator for High-Performance Li–O 2 Batteries

Non-aqueous lithium-oxygen (Li–O 2 ) batteries represent promising next-generation energy storage systems owing to their ultrahigh theoretical energy density. However, the electrically insulating discharge product of Li 2 O 2 causes severe pore clogging and high charge overpotentials, severely restricting their practical implementation. Herein, a three-dimensional (3D) printed graphene aerogel cathode is fabricated via direct ink writing (DIW). When coupled with a CoBr 2 redox mediator (RM), the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics are remarkably accelerated. Owing to the synergistic effect of 3D printed cathode and the CoBr 2 RM, the assembled battery exhibits an ultrahigh areal capacity of 21.9 mAh cm −2 and reduces the overpotential by approximately 0.8 V. It stably cycles 103 times at 0.5 mA·cm −2 with a limited capacity of 0.5 mAh cm −2 . This paper provides a synergistic design based on the combination of cathode porous structure and RM, offering a feasible pathway for advanced Li–O 2 batteries.