Bamboo derived N-doped carbon as a bifunctional electrode for high-performance zinc-air batteries

Biomass-derived low-cost porous carbon electrodes are a very promising cathode material for rechargeable zinc-air batteries (ZABs). Nevertheless, the preparation of hierarchical porous carbon (HPC) electrodes with excellent oxygen reduction/evolution reaction (ORR/OER) performance on a large scale still faces great challenges as the preparation methods mostly require sacrificing the biomorph-genetic structure of biomass followed by an inefficient bottom-up synthesis process. Herein, alkali pre-treatment of bamboo with the N-doping strategy was employed to efficiently prepare biomass-derived porous carbon as bulk-phase air cathodes for ZABs. The alkali can rapidly hydrolyze part of the lignin and hemicellulose of bamboo, which not only maximizes the exposure of the bamboo's internal channels to yield rich microporous structures but also helps to dope N uniformly into the HPC during subsequent pyrolysis. The as-prepared N-doped pre-treated bamboo-based HPC (NPBC) catalysts exhibit superior ORR/OER performance (E-1/2 = 0.864 V, E-j=10 = 1.644 V vs. RHE). Furthermore, the ZABs using NPBC catalysts as an air cathode exhibit a high peak power density of 249 mW cm(-2) and long-term stability over 300 hours. This work provides guidance and ideas for designing and developing biomass-based carbon materials for electrochemical energy-related devices.