Engineering tunable porous carbon nanotube scaffolds for freestanding lithium-O2 battery electrodes

초록

Freestanding porous carbon electrodes are attractive for lithium-air batteries due to their lightweight architecture and the absence of binders or current collectors. However, their electrochemical performance depends on the internal pore structure. In this work, we fabricated a binder-free, single-walled carbon nanotube (SWCNT)-based cathode and investigated the effects of pore morphology on discharge product formation and cycling behavior. A series of SWCNT-based electrodes with varied pore architectures-ranging from nanoscale porous networks to dense, collapsed structures-were fabricated and evaluated. Electrodes with interconnected micro-, meso-, and macropores exhibited the highest discharge capacity (17 000 mAh g-1), along with uniform Li2O2 film formation that promoted reversible deposition and minimized pore blockage. This structure also enabled stable cycling over 70 cycles with over 80% round-trip efficiency, even without catalysts. These findings demonstrate that maintaining high surface area and pore accessibility is essential for enhancing the capacity and durability of freestanding lithium-air battery cathodes, particularly for applications where high energy density and lightweight design are critical, such as drones, aerospace systems, and next-generation portable electronics.

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