Interconnected Hierarchically Porous Graphene‐Based Membrane Electrode for High‐Power and Long‐Cycle Lithium–Oxygen Battery

Abstract The energy–power trade‐off in lithium–oxygen batteries (LOBs) arises from sluggish oxygen (O 2 ) transport in the porous positive electrode and pore clogging by lithium peroxide (Li 2 O 2 ). While increasing porosity enhances electrolyte accessibility and Li 2 O 2 storage, it also increases electrolyte demand, compromising the overall energy density of the cell and necessitating alternative strategies to boost power capabilities without sacrificing energy density. In this study, theoretical simulations of O 2 transport reveal that reducing tortuosity by improving pore interconnectivity has a more significant impact on O 2 transport than porosity itself. Based on this insight, a freestanding graphene‐based electrode with a highly interconnected macroporous network is fabricated via a non‐solvent‐induced phase separation approach using polyacrylonitrile (PAN) as a carbon scaffold and polyethylene oxide (PEO) as a sacrificial porogen. The selective decomposition of PEO creates spatially interconnected macropores, effectively reducing tortuosity. The resulting electrode enables LOB cells to achieve >2500 mAh g −1 at 1.0 mA cm −2 under lean‐electrolyte conditions. Stable cycling at 4 mAh cm −2 is maintained with only 3.25 g Ah −1 electrolyte, and high‐rate performance persists over 90 cycles at 1.5 mA cm −2 . This work demonstrates a robust strategy to simultaneously improve energy and power performance in practical LOBs through rational electrode architecture.